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THE NATURAL HISTORY OF OUR CONDUCT
THe NATURAL HISTORY OF OUR CONDUCT 4y Pete CAM: Ee RITTER
President of Science Service; Professor Emeritus of Zoélogy & Director Emeritus Scripps Institution of Oceanography, University of California
WITH THE COLLABORATION OF EDNA WATSON BAILEY
Lecturer in Education & Associate Director of Practice Teaching, University of California
als
NEW YORK HARCOURT, BRACE & COMPANY
COPYRIGHT, 1927, BY HARCOURT, BRACE AND COMPANY, INC.
PRINTED IN THE U.S.A. BY THE QUINN & BODEN COMPANY, RAHWAY, N. J.
PREFACE
Tuts book and one to come are intimately connected with my long and close association with that remarkable man, E. W. Scripps. Realist, student, philosopher, successful journalist and business man, and above all humanist, Scripps was quick to see important implications in the biological idea of “the organism as a whole” for humankind, once that idea had gained secure foothold in his mind. As a consequence, even before he had read any comprehensive biological exposition of the idea, he began to wonder what a thorough-going study of human beings from this stand- point would bring to light; for the enigma of man with his infinite capacity for noble thoughts and deeds and his equal capacity for ignoble thoughts and deeds harassed Scripps beyond measure.
By the time my mind and hands had worked themselves free from enthrallment with The Unity of the Organism, his demands to know what this “damned human animal is, any- way,” became so insistent that I could hardly escape taking them seriously, even though they were not usually leveled at me personally.
These demands, superimposed upon rather strong human- istic and philosophic tendencies of my own, must be put down as the “effective environmental factor” in the produc- tion of this book and a companion soon to follow.
The other book will have as title The Natural Philosophy of Our Conduct. Despite the circumstance that the product of my task is wrapped up in two packages, the task itself ' was a unit and not twofold. This follows from the unitary point of view implied by the organismal conception.
Adequate acknowledgment of all to whom I am indebted, Vv
oly ae
vi PREFACE
more or less personally, for help in carrying forward the undertaking, it would be impossible to give in the narrow bounds of a foreword. It seems, consequently, that my only course is to attempt nothing whatever of the kind. I must trust that my unmentioned helpers will be-.satisfied with having taken the chance in this case that all of us must and do take constantly, of getting reward for some of our help- ful deeds from the vast stores of general but undefinable good which constitutes so large a part of human culture.
I must presume that some at least of the readers of the books would be made uneasy by an entire absence of in- formation concerning the role of the collaborator in the enterprise. To Dr. Bailey’s own contention that she has not contributed a single fact or idea or argument, at least wholly, I can assent only with much reservation. But whatever dubiousness I may have about what she has not done, I have none about what she has done. Any merits the books may have as to organization, readableness, and cogent presentation of the relevancy to human welfare of the subjects treated, are due far less to me than to her.
Wir11am E. RITTER.
TABLE OF CONTENTS
CHAPTER PAGE
I. INTRODUCTION 3
2. THE ABILITY OF LIVING BEINGS TO EXIST AND DEVELOP DESPITE ADVERSE CONDITIONS: THE PHENOMENON OF ADAPTATION It
3. THE PROBLEM OF MAN’S ORIGIN AND KIN- SHIP: FACTUAL EVIDENCE AND ITS PROPER TREATMENT 17
HOW WE THINK ABOUT EVOLUTION, 17. COM- MON SENSE AND THE EVOLUTION THEORY, 18. THE PRINCIPLE OF IDENTITY AND THE EVOLU- TION THEORY, 20. THE PROBLEM OF NAMING A DEVELOPING THING, 24. ACTUALITY AND POTENTIALITY IN EVOLUTION, 28. THE PRIN- CIPLE OF RESEMBLANCE AND THE EVOLUTION THEORY, 32.
4. THE PROBLEM OF MAN’S ORIGIN AND KIN- SHIP (con.) : CERTAINTY AND PROBABILITY AS TO MAN’S EVOLUTION 25 THE WORTH AND THE LIMITATIONS OF PALE- ONTOLOGICAL EVIDENCE, 44. MAN’S MOST PROBABLE DIRECT ANCESTOR, 52. MAN AND THE SOLIDARITY OF THE ANIMAL KINGDOM, 57. THE INFLUENCE OF MAN’S BELIEF IN HIS OWN EVOLUTIONARY ORIGIN ON HIS SELF-RESPECT AND CONDUCT, 62.
§. SUCCESS AND FAILURE IN ANIMAL ACTIVITY 64. SOURCES, TRUSTWORTHINESS, AND ORGANIZA- TION OF DATA, 64. THE CRITERION OF SUCCESS IN ANIMAL ACTIVITY, 70. ACTIVITIES CLASSI- FIED AS LIFE-OR-DEATH AND LIFE-FULFILLING, 73. CLASSES OF MALADAPTVE ACTIVITY, 75.
6. SUCCESSFUL ANIMAL ACTIVITY a7 AT THE LEVEL OF REFLEX ACTION, 78. AT THE LEVEL OF INSTINCTIVE ACTION, 79. AT THE vii
viii
CONTENTS
CHAPTER
Io.
ir.
12.
13.
14.
LEVEL OF INTELLIGENT ACTION, 88. OF LOW TYPE, 88. OF HIGH TYPE, 90. SYSTEMATIC STUDY OF SUCCESSFUL ACTIVITY IN SUB- HUMAN ANIMALS, 94. PERSONALITY AS AN ELEMENT IN GROUP SUCCESS, I12.
MALADAPTIVE ACTIVITY RESULTING IN WASTE OF TIME AND ENERGY
MALADAPTIVE ACTIVITY RESULTING IN WASTE OF USEFUL MATERIALS AMONG INSECTS, 125. AMONG BIRDS, 128.
WASTE OF USEFUL MATERIALS (con.): AMONG MAMMALS
MALADAPTIVE ACTIVITY RESULTING IN IN- JURY TO KIND
AMONG ARTHROPODS, 159. AMONG LOWER VER- TEBRATES, 165. AMONG BIRDS, 169. AMONG MAMMALS, 174.
MALADAPTIVE ACTIVITY RESULTING IN SELF- INJURY AMONG INVERTEBRATES, 184.
SELF-INJURY (con.) : AMONG BIRDS EXTINCTION OF SPECIES PROMOTED BY MAL- ADAPTIVE ACTIVITY, 200. SELF-INJURY DUE TO DEFECTIVE FEAR, 2I1I.
SELF-INJURY (con.) : AMONG MAMMALS UNDER-ACTIVITY IN THE PRESENCE OF DAN- GER, 221. OVER-ACTIVITY IN THE PRESENCE OF DANGER, 232. DUE TO RAGE, 237.
MALADAPTIVE ACTIVITY IN MONKEYS AND APES
EXTENT OF ACTIVITY RESULTING IN EXCESSIVE- NESS: IN FOOD-TAKING, 242; IN MATERNAL SOLICITUDE, 245. MISDIRECTION OF ACTIVITIES RESULTING IN SELF-INJURY, 246; IN INJURY TO KIND, 248. SELF-INJURY FROM NORMAL TYPES OF ACTION, 251.
PAGE
117
125
159
182
214
241
CONTENTS ix
CHAPTER 4 PAGE I§. MALADAPTIVE ACTIVITY AMONG LOW-CUL- TURED HUMAN BEINGS 254
FOOD-TAKING AMONG SAVAGES, 255. SAVAGE FESTIVALS, 258. MISDIRECTED ACTIVITIES, 264; FOR SECURING FOOD, 265; COMPARED WITH BRUTE ACTIVITY, 270.
16. MALADAPTIVE ACTIVITY AMONG HIGH-CUL- TURED HUMAN BEINGS 272
OUR VERDICT ON OUR OWN ACTIVITIES; COM- MON KNOWLEDGE OF MALADAPTATION, 272. MALADAPTIVE ACTIVITY AS CORRECTED BY SCI- ENCE, 284. MALADAPTIVE REPRODUCTIVE AND SEXUAL ACTIVITIES IN THE HUMAN SPECIES, 288. REPRODUCTIVE MALADAPTIVE ACTIVITY: OVER-POPULATION, 296. DANGERS TO THE MOTHER IN CHILD-BEARING, 296. DANGERS ARISING FROM RELATION OF OFFSPRING TO PAR- ENTS, 297. MALADAPTIVE SEXUAL ACTIVITY,
297.
I7. THE ELEMENTS OF MAN’S PHYSICAL STRUC- TURE WHICH ENABLE HIM TO BE THE MOST ACTIVELY ADAPTIVE OF ALL LIVING BEINGS 30I
STRUCTURAL AND FUNCTIONAL ASPECT, 301. EVOLUTIONAL ASPECT, 315.
BIBLIOGRAPHY 225
INDEX 329
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THE NATURAL HISTORY OF OUR CONDUCT
t o ,
CHAPTER 1 INTRODUCTION
Tue best part of my life has been devoted to the study of nature. Nature, for me, has always encompassed man in the fullness of his heing. This largeness and inclusiveness of nature as it has stood in my conception are largely due, I think, to my having been unwilling to suppress the emotional aspect of my response to nature to any such extent as many scientists seem to do. The emotional part of man has seemed to me no less natural than the coldly rational part. To suppose that in order to deal adequately with nature all emotion must be suppressed appears to presuppose the superior validity of a partial response to nature, as com- pared with the fullest response of which human beings are capable. This fallacious view concerning the influence of emotion on reason in the study of nature probably has arisen through failure to distinguish between the suppression of emotion and the guidance of it.
I have never been able to find proof that man is apart from nature, is over against and above nature in such a sense as is held by much of philosophy and especially of theology. Never have I had the feeling that there exists an implacable and irreconcilable hostility between man and nature such as sorely harasses many persons and has strongly influenced many religious doctrines. Neither the terrible calamities which befall man occasionally, nor the lesser injuries which he frequently receives at the hands of nature, nor yet the misfortunes, disasters, and miseries which he brings upon himself, have seemed to me to re-
3
4 INTRODUCTION
quire such doctrines or to be explained by them. The ab- sence of such sentiments from my general consciousness is justified by my maturer, more critical thoughts about the whole scheme of the world and man’s place therein. I find no way of conceiving a true Universe, a state of things that is unified through and through, if the human spirit is not inseparably and essentially identified with it all.
The theory according to which man is divine in a sense that nothing else in the world is divine seems to have arisen because many men in many ages have sensed the unique- ness of the powers accruing to them through their posses- sion of conscious rational minds, but have failed to perceive the way in which these powers are connected with the scheme of things by which we live from day to day. There are two aspects of man’s relation to nature revealed by scien- tific study that go far toward explaining the origin of these separatist doctrines. One of these aspects pertains to man’s physical make-up; the other to his mind. In these two aspects man must be recognized as the most surprising and marvelous of all natural productions. The most surprising product is he, because of certain of the combinations of his bodily parts; the most marvelous, because of his being conscious, rational, and, at his best, highly intelligent.
The bodily parts to which reference is particularly made are his brain and his hands. That forelimbs terminating in structures called hands should occur in man is not sur- prising since these structures are almost universally present in land vertebrates. That both hands and brain in so high a State of perfection should be man’s possession is cause for genuine surprise.
Head and hands, which represent in a sense the develop- mental and functional climaxes of the nervous system and the muscular system, can be shown to hold such a reciprocal relation to each other that neither could have come into being, nor continue to be, without the other. The powers
INTRODUCTION 5
of knowing which characterize man could never have been acquired, nor could they continue to exist wholly apart from the powers of doing with which his hands endow him. It is the uniqueness of the anatomical combination here pre- sented that is surprising.
While this physical combination of brain and hands is a surprising phenomenon, the consciously knowing and thinking mind is a marvelous phenomenon. The fact that a natural object should be able not only to enter into such relations with other natural objects as that called by us knowing, but should be able also to establish a similar rela- tion with itself, is so distinct from all other natural facts with which we are acquainted and is so far beyond our present powers of analytic description as to entitle it to be characterized as marvelous. Man’s supreme glory is not only that he can know the world, but that he can know himself as a knower of the world.
During recent years discoveries and speculation concern- ing the structure of the stellar universe have been attracting much attention. The facts, certain and highly probable, are justly characterized as wonderful, marvelous. Surely the numbers and sizes of the celestial bodies are wonderful. Wonderful too are the radiations from them, especially in the form of light, by which knowledge is gained. But this wonder comes solely from the augmentation of what is very familiar to us. Sizes, distances, and radiations are around us on every side. No absolutely new kinds of phenomena enter nature by these newly discovered sizes and distances and vast journeys of light. The knowledge obtained by the investigations leading to these discoveries constitutes a kind of relation between man and the celestial objects con- cerned. A purely physical relation existed before as well as after the knowledge was gained. Stellar gravitation and light act on the child and on the savage just as certainly as on the astronomer. But the moment the physical facts
6 INTRODUCTION
become part of man’s knowledge, another sort of relation between him and the objects is established. It is the nature of this new relation and of man’s ability to establish it that seems to me to constitute not merely the central won- der of human nature, but the central wonder of all nature.
The doctrines of man’s apartness from nature have en- couraged an easy-going manner of knowledge-getting which has largely destroyed the sense of the wonderfulness of the ability of an organism to think and reason. By con- ceiving mind as belonging to a wholly different realm from that to which the other phenomena of nature belong, the realm of the supernatural, we cut ourselves off from any basis of comparison, any standards by which to appraise the powers and capacities of the human mind.
The recognition of man as a part of nature makes it necessary to adopt a different attitude toward his knowl- edge-getting processes. By such recognition these processes are brought down from the realm of the supernatural into the everyday world of phenomena-which-can-be-known. Like other activities of living things, mental processes must be scrutinized as to their stimuli, their courses, and their fruitfulness. That is to say, they become proper subject- matter for the naturalist. Certain highly respectable thinkers have recognized the possibility and the desirability of a “natural history mode of philosophizing,” contrasting such a way of thinking about the universe with the pro- fessedly subjective mode on the one hand, and the quanti- tatively exact or mathematical mode, on the other.
The naturalist’s way of working is a different way from that of the theologian, or the metaphysician, or the pure mathematician. It is even a different way from that of many modern biologists who restrict the term biology to knowledge gained from experimentation, and who seek only to explain all organic phenomena in terms of physics and chemistry. In other words the naturalist whose realm
INTRODUCTION 7
of study is living nature, as contrasted with the biologist in the modern, restricted sense of biology, seeks all the knowl- edge and understanding he can possibly get of organisms, regardless of whether he can express or explain all he ob- serves in terms used in other realms of nature or not.
The naturalist begins his career when he begins his life, and hence has no presuppositions, postulates, and axioms at the outset. These come later. They grow out of his experiences and are not basic for them. His work and his interest date from a time when he has very little else, men- tally speaking, than ability to respond to stimuli.
If he should decide to make a professional career of studying some segment of the universe for the purpose of understanding it and helping himself and others to live in it more successfully than they otherwise could, he might find that career taking on two sharply different phases. On the one hand he might be occupied with the job of gathering and interpreting facts about the universe external to him- self, and with making them useful to himself and other people. This would make him a thoroughly objective nat- uralist. His single-minded devotion to his career might be greatly productive of good. Because of its sincerity and simplicity of devotion to ideas and ideals this phase of his career could well be characterized as naive. While work- ing in this way he might be spoken of as a naive naturalist, and the phase itself might be called naive naturalism. Then, should he further determine to study minds and what they accomplish as seriously as he studies the phenomena of the Universe external to himself, he would find himself launched into a quite different undertaking. But since he would find nothing to make him doubt that his newly as- sumed tasks were any less natural than all he had been doing as a naive naturalist, he would consider himself as passing into a different phase of his career as a naturalist. This new phase he might well characterize as philosophical,
8 INTRODUCTION
or critical. He would become a critical naturalist as well as a naive naturalist.’
My starting-point, my motive, and my procedure in this book have been strictly that of the naturalist in the two- fold sense just defined. Neither as psychologist nor phi- losopher in the specialized sense of these terms, do I make any claim for myself. Recognizing that searching and potent understanding of mind is impossible apart from such understanding of body, I have attempted to describe the working of mind-and-body in human beings and in other living things; to examine critically the mental technique in- volved in such descriptions; and to reason broadly as to the bearings of the facts and processes on human life.
A disparaging remark frequently made about certain persons is that they “do not know their own minds.” The assumption seems to be that all really normal and capable people do “know their own minds.” As a matter of fact very few people know their own minds even moderately well in a technical sense, and none know their minds fully. Neither do people know their own bodies, so far as that goes. Most of our bodily processes run on quite independently of our knowledge of them. The organs of digestion do their work quite as well in the new-born babe as they do in that same person after he has become a full-fledged physiologist with digestion as his specialty. It is demonstrable that many of the processes involved in acquiring knowledge and in knowing, which are certainly dependent upon the nervous system, run on as independently of our knowledge of those processes and their organs, as is the case with the digestive
1The terms naturalist and naturalism as here used have only a re- mote connection with those terms as used in traditional philosophy. The naive naturalist never seriously doubts either the reality of the objects with which he is occupied or the trustworthiness of his knowledge of those objects, once this has been fully verified. Every astronomer, chemist, botanist, psychologist, or sociologist whose observational knowl- edge does not permit him to be diverted by dogmatism in one direction or skepticism in the other, is a naturalist in this sense.
INTRODUCTION 9
processes and their organs. The mere fact that we have minds and can use them is no evidence that we understand them. If we would know our own minds we must acquire knowledge of them in much the same ways that have made us know our own digestive or circulatory systems.
No one who has considerable acquaintance with any of the biological sciences can have failed to note the constancy with which the comparative method is resorted to. In any good modern treatise on the digestive or circulatory or nervous system of man, the discussions are based upon observations on animals of very diverse rank in the zo- ological scale, with as little question about the trustworthi- ness of the facts for elucidating the human problem under treatment as those based on observations on man himself. Within limits which the investigator should know well, the structures and functions of the lower creatures are so sim- ilar to the corresponding human structures and functions that the conclusions drawn from them can be applied with- out hesitation to man also.
This similarity between man and inferior animals in so many physical particulars makes it possible for man to know many things about himself and to do to himself many ad- vantageous things that he could never know and do but for his knowledge concerning these less complex creatures. Such a measure of knowledge of the human circulatory and nervous systems as we now possess could not have been reached but for the opportunity of studying them in their varied and much simpler expressions in the lower orders and particularly in the embryos of these orders. Our en- terprise aims to utilize the activities of the lower animals as effectually for enabling us to know our own activities and to control our own conscious acts, as we now utilize the bodies of such animals for enabling us to know our own bodies and to control our purely vegetative functions.
It has long been recognized on the basis of their activities
Toss INTRODUCTION
that many animals possess minds, and that these are similar in a considerable number of respects to human minds. Great progress has recently been made in the comparative study of these two orders of minds, each order having been made to contribute much to an interpretation of the other; but no such pronounced success has attended these studies in the direction of closing the gap between the minds of brute animals and the minds of men, as has attended the comparative morphological and physiological studies. In consequence of this, although men are well aware of their supremacy over all other living creatures, we do not yet possess a thoroughly critical presentation of exactly in what this supremacy consists. Such presentation this book will, I trust, go far toward furnishing.
CHAPTER:2
THE ABILITY OF LIVING BEINGS TO EXIST AND DEVELOP DESPITE ADVERSE CONDITI9NS: THE PHENOMENON OF ADAPTATION
AmoNnG the myriads of bodies in the world there is one great class whose individuals are able to perform a con- siderable number of acts upon which their continued exist- ence depends. Atl such bodies we call living, or organic. There is another great class, the individuals of which we call non-living, or inorganic, whose continued existence does not depend on any such actions of their own. One great subclass of living bodies has greater ability for acting than another subclass. The more active subdivision we call animal, the less active vegetable. This way of classifying the world of bodies is rough-and-ready but unquestionably true as far as it goes, and useful for our present purposes. One of the surest tests we can apply toward deciding whether a strange body is an animal is to touch it and see whether it moves after the manner familiar to us as animal movement: movement due to contraction induced by stimu- lation. So characteristic of animals is action of this kind that for most ordinary purposes positive results of such an experiment satisfy us. We conclude it is an animal because of our wide knowledge that no other bodies than animals move in that fashion and under such circumstances. ‘This presents in terms of common experience the familiar gen- eralization as to what essentially characterizes an animal organism. What animal organisms essentially are, that plant organisms are also in some of their deepest attributes. Living beings are fundamentally set apart from non-living beings by their activities and by what these activities ac- complish. Man’s way of doing things, especially his ra- II
12 ABILITY OF LIVING BEINGS
tionally conscious activities, distinguishes him within living nature as a distinct kind of living body, and the very thing that separates man most decisively from nature in general identifies him most closely with living nature.
The undertaking upon which we are entering is grounded in the conviction of the essential correctness of the evolu- tionary view of man’s origin, and his kinship with the whole living world. The soundness of this point of view is ex- amined in Chapters 3 and 4, “The Problem of Man’s Origin and Kinship.” Accepting it for the present without ques- tion, such acceptance implies that any study of man must proceed as a two-fold task: first, to point out those of his characteristics which ally him with the living world gen- erally; and second, to establish with equal clearness those characteristics peculiar or specific to man. This involves special emphasis on the comparative method of Louis Agassiz and the older naturalists; but since it is in man’s activities, rather than in his bodily structure that we find his most sharply distinguishing characteristics, our task also resembles that of the student of animal behavior.
The point of view maintained here differs from that of many comparative psychologists in requiring us to consider, not only wherein man’s activities resemble those of other animals, but wherein these activities are different. The net result of comparative psychology has tended to dehumanize our conception of man, to throw us back on his possessions held in common with the brutes. The treatment in this book starts with the common heritage of man and brutes, but carries the comparison throughout the range of his endow- ments and activities, to examine closely wherein he differs from the brutes. The base line for our comparison is found in the unique ability of living things as compared with all other things to fit themselves into different environments. This ability is known as adaptation and is widely recognized in the treatment of man and all other organisms.
TO DEVELOP DESPITE ADVERSITY 13
There appears to be no human activity whatever that does not have to submit to the question: How well is it done? It is in the very nature of mankind’s knowledge of its own activities to recognize that these are of different degrees of excellence. Some carpenters, some lawyers, some base-ball players, are better than others. The good, better, best criterion is applied down to the smallest ele- ments that enter into the various activities. Some generally good carpenters are specially good at inside finishing or perhaps at shingling. Some lawyers are excellent counselors . but indifferent advocates. A star out-fielder may be rather poor as a base runner; and so on without end. This per- ception of difference in excellence of our own acts seems to be as deep seated as our knowledge of the acts.
May the activities of creatures below man be judged in the same way? As to all domestic animals, we surely do judge them thus. With horses, mules and oxen, the good, better, best criterion is applied to their human-service ac- tivities. Concerning such activities as egg-laying by hens, milk-giving by cows, and meat-production by hogs, the regular “performance” records kept by farmers tell the story.
But what about wild animals? Any one who has lived by the seaside where he could watch pelicans, cormorants, and other fish-eaters at their fishing, will not hesitate to pronounce these all successful, and hence good fishers. No- body’s observations in this connection would warrant him in supposing the excellence of their fishing to be entirely faultless. Whether the members of any one of the species differ from one another as individual humans differ in fishing ability is by no means easy to decide, so difficult is it to observe in detail, and thus to compare the perform- ances of a large number of individuals. But as to wild animals generally, we now have a sufficient mass of trust- worthy observations to make it clear that diversities in
14 ABILITY OF LIVING BEINGS
quality of performance occur here also. This evidence we hold to be fundamental to our undertaking. It has never been brought together and systematically studied to get at its meaning in relation to human activities.
How effective are those activities of animals by which they solve their problems of getting food, securing mates, protecting themselves from injurious things in their sur- roundings and securing their welfare generally? This ques- tion is the essence of the problem of adaptation as applied to the activities of animals. The larger part of all that has been written about adaptation has referred to the structure of organisms only. When one speaks of birds as being adapted for locomotion in the air, what he thinks of is the structure of the forelimbs, of the feathers, of the shape of the body, and so on. The acts involved in flying are not often thought of as adaptive. Birds are more apt to be spoken of as adapted for than as adapted in flight. As a matter of actual observation, organic activity is far and away more adaptive than is organic structure. Many or- ganic parts, particularly of the higher animals, can act in a variety of ways with little effect on the structures con- cerned. No one would suppose that the magpie’s acquired habit of getting its food from the flesh of live sheep would have any perceptible effect on the bird’s beak during an individual life time, and perhaps never for the species as a whole. Yet the change of activity might be very important for the welfare of the individuals concerned. The fact that a mule can use his hind limbs to good effect for kick- ing does not prove at all that this particular form of action has had any part in determining the form of the hind limbs. So far as we can judge, the mule’s hind legs have been de- veloped for one kind of action and he has found he can use them for an additional kind. The variety of acts that every normal human hand performs may be taken as rep- resenting the highest exemplification of the general principle
TO DEVELOP DESPITE ADVERSITY 15
that one and the same structure may be used by its possessor in more than one way.
The ordinary knowledge of life contains the idea of adap- tation in both structure and activity as essential to life. The idea is inherent in the facts of death and injury as opposed to life and health. Latterly a considerable number of biologists have expressed the view that ordinary knowl- edge is wrong in holding this idea. It ought either to be applied to both non-living and living bodies or to neither. Living bodies are constituted, just as non-living ones are, of “matter” and “energy” and nothing else. If the idea of adaptation is not needed for lifeless beings (composed of energy-yielding matter) no more is it needed for living ones (also composed of energy-yielding matter), according to these biologists.
We are fundamentally cpposed to this view that adapta- tion is a useless conception for the description and interpre- tation of vital activity. It is impossible to describe living beings with anything approaching fullness, without constant reference to attributes of them the very existence of which is inseparable from this idea of adaptation. All living be- ings must have constant supplies of substances called foods; otherwise they die. All such beings must reproduce their kind, or they become extinct as a kind. There is always the possibility of their failing to get food or to propagate. To a very great extent successes and failures in these and vari- ous other ways depend on particular structural features of the organisms, and upon what they do or fail to do. This being constructed in such-and-such ways, and acting so-and- so relative to success or failure is what common knowledge calls adaptation. The proposal to eliminate the idea from the biological sciences is tantamount to proposing the elim- ination from these sciences of the ideas of food-taking, of propagating, of dying, and of all the other ideas best es- tablished in all knowledge of organisms. If organisms come
16 ABILITY OF LIVING BEINGS TO DEVELOP
into living existence at all and continue to live, doing these things is prima facie proof that they are at least partially adapted to do them. The alternatives would be that they would never become living, or would.not continue to live. The final meaning of adaptation is the continuance of in- dividual life to its wonted end. The final meaning of maladaptation is the discontinuance of individual life before its wonted end. Life-or-death for the individual is the final criterion of adaptation.
While adaptation and adaptability in the human species will be the central interest in this book, we shall be obliged to devote much time to adaptation in animals generally. Their successes and failures in solving their life problems will occupy us in Chapters 5 to 14. The significance of this mass of material for the interpretation of human con- duct depends on the assumption that human animals and brute animals belong to one great family by common de- scent, and that brute activity lends as much assistance to the understanding of human activity as does brute structure to the understanding of human structure. While the kin- ship of humans and brutes in bodily structure is generally recognized, their equally significant kinship in mentality as manifest in their activities is not. To many honest and reverent men, such kinship is open to serious question.
If established, there is no doubt whatever that our con- ception of Man, and of Nature conceived as including Man, will be changed. Therefore our next undertaking, in Chap- ters 3 and 4, will be a careful examination of the evidence available as to the origin and kinships of human beings, giv- ing attention both to the factual evidence and to our mental technique in dealing with it.
CHAPTER 3
THE PROBLEM OF MAN’S ORIGIN AND KINSHIP: FACTUAL EVIDENCE AND ITS PROPER TREATMENT
Our primary interest throughout this book lies in the study of the way in which man’s adaptive activities are superior to those of other animals. The value of such a study for human affairs lies in indicating the most effective lines of development, of conscious improvement, of conduct.
Man is, in general, more than a match for the beasts. In the words of the Hebrew Scriptures, the Lord has given him dominion over the earth, beasts and all. In just what raanner is this “dominion” made secure? The answer to this question is not to be found in his structure alone. — Slow of foot, naked, shivering, short-sighted, dull of ear, on the basis of structure alone man possesses no primacy. When the use of his bodily parts is considered, we find that in the realm of reflexive and instinctive activities, he is still far from establishing superiority. It is only when we come to deal with that group of activities consciously directed toward securing his own well-being, which we call intelligent, that we find man the unquestioned superior of all other living things. Our study therefore becomes psycho- biological; and concerned primarily with the development of psychical activities as adaptive agencies.
HOW WE THINK ABOUT EVOLUTION
Our mode of treatment, which may be characterized as that of comparative psychobiology, involves an assumption of the kinship of man with the rest of the living world, and of an especially close kinship with the upper levels of the
17
18 PROBLEM OF MAN’S ORIGIN
animal world. ‘Kinship” as used here is not figurative but literal, carrying the idea of “blood-kin,” of common descent, or genetic relationship.
This is too large an assumption, on a matter vital to human welfare, to be taken for granted. It therefore be- comes necessary to examine the basis of the assumption in facts and in logic. The degree of probable truth revealed by this examination is a measure of the usefulness of the comparative method for the psychobiological study of man and of the trustworthiness of the generalizations which may be made from the descriptive material to be presented later.
COMMON SENSE AND THE EVOLUTION THEORY
Rational human beings living as part and parcel of animate nature have always known a great deal about and have accepted evolution quite independently of any formal theory of evolution. If any one doubts this let him turn to The Origin of Species. ‘Variation under Domestica- tion” is the title of the first chapter. ‘Under domestica- tion”! what a body of ordinary experience this connotes; and how skillfully Darwin made use of it!
The main classes of facts and principles upon which rests the evolution theory are well-known and unquestioningly accepted. Such knowledge while positive enough and im- plicitly trusted does not reach much beyond the bounds of immediate observation and experience. With reference to every one of the basic principles considered, the question arises as to whether or not they do hold good beyond the scope of common experience and knowledge. A serious at- tempt to answer the question would, if the answer were affirmative, result in a general hypothesis and theory, or doctrine of evolution.
As is well known, such an hypothesis and theory were
FACTUAL EVIDENCE 19
ushered into the modern world by the publication about sixty-five years ago of The Origin of Species by Means of Natural Selection. This epochal book dealt, not with the all-embracing problem of organic development, but with one specific though crucial aspect of it, namely that of how new species originate; and it proposed and defended with great ability a casual explanation of such origin. This is the point at which man’s understanding of the phenomena of development in living nature may be considered to have passed from the realm of common knowledge to that of technical knowledge, and marks the beginning, in modern times at least, of study by the methods and for the purposes of science of the origin of those species or kinds which compose the vast world of living things.
From the broad outlook to which we have been led by the progress of knowledge since Darwin’s great book was writ- ten, we see that instead of defining the evolution theory as being a theory of the “origin of species” merely, it should be defined as the theory that the well-known principles gov- erning the origin of the comparatively few organisms with which the common life of man has made him familiar, govern also the origin of the whole living world. Common knowledge now accepts evolution as the mode of the origin of individual men and all other organisms, animal and plant. There is no longer any question that men and animals and plants originate from parent organisms. The idea of “spon- taneous generation,” the origin of organisms without parents, widely prevalent up to seventy-five years ago, is now wholly discarded in common teaching and experience no less than in technical teaching and experience.
Nor does the common acceptance of evolution stop with its application to the growth of individuals, and the causa- tion of individuals by other individuals. Such acceptance has now gone far into the more obscure realm of the origin of kinds of individuals. In agriculture, in horticulture, in
20 PROBLEM OF MAN’S ORIGIN
floriculture, in animal husbandry, and in pet-animal cul- ture, new kinds are so numerously produced that they are much more commonly seen than are the original or parent kinds. The principles upon which such producing depend are widely known and applied, even more so by non-technical persons than by professional biologists. New varieties of potatoes, tomatoes, corn, and wheat; of roses, dahlias, daisies and irises; of chickens, sheep, pigs, cats, dogs, and rabbits, are so commonplace as to attract little attention except for their usefulness or beauty. So far as the evolu- tion or development of a great variety of kinds of organisms is concerned, common sense not only accepts it in knowledge and faith but goes much further than that. It actually lives by it, thus applying to it the supreme test of all knowl- edge and faith in conduct.
THE PRINCIPLE OF IDENTITY IN THE EVOLUTION THEORY
One of the things which makes the problem of origin of new kinds or species peculiarly difficult, no matter from what angle it be approached, is the fact that it inevitably involves the problem of the origin of man himself. As was fully recognized by Darwin and practically every other nat- uralist or philosopher or theologian who has tried seriously to understand the nature of man, his resemblance to other living beings, especially the higher animals, has been obvious enough to arouse the strong conjecture that the ultimate origin of man was involved with the ultimate origin of all the rest of the animate world. The tremendous hold on men’s minds and the influence upon their lives exerted by The Origin of Species was only secondarily due to the purely scientific problem of how new kinds of plants and inferior animals originate. The power of the book lay and still lies in its emotional impingement upon man’s own life as dependent upon how he came into being. This vital truth
FACTUAL EVIDENCE 21
it is necessary to take full cognizance of in such an under- taking as we are engaged upon.
Why is it that men have so generally desired a mode of racial origin wholly different from and presumably superior to the well-known mode of individual origin? Why have men felt that a supernatural or divine mode of racial origin would be better for them than any natural mode would be, even though they were obliged to be satisfied with a natural mode of individual origin?
Broad information about man in different stages of his culture shows him io be more solicitous about the character of his origin in advanced than in lowly states of his develop- ment. Many savage peoples are apparently well satisfied with the idea that they originated from animal or from even more lowly subhuman ancestors. On the other hand, most of the highly cultivated peoples, as those of Christian na- tions, have been and still are sorely disturbed by any ques- tioning of their supposed supernatural origin. Why is this? An element in the explanation is the fact that men are strongly given to believing their own present natures depend upon the source from which they came in a sense close examination finds not to be correct.
No one now doubts that in general “like produces like” in organic propagation, that the nature of organisms is determined in some sense by the nature of their parents and other ancestors. From the standpoint of the knowledge- processes involved in our knowing anything about the nature and origin of natural bodies, we recognize that in another sense the nature of the organism is quite independent of its origin. Neither the reality of any object nor the certainty of our knowledge about it depend upon what we know or do not know about the origin of that object. The sugar with which you sweeten your breakfast coffee is sugar and not salt or anything else, regardless of whether it originated from sugar-cane or sugar-beets. It makes not the slightest
22 PROBLEM OF MAN’S ORIGIN
difference in your certainty that you have put sugar and not salt into your coffee, whether you have any information about where the sugar came from and how it originated. Knowledge of form, structure, activities of any object, and knowledge of the origin of that object are wholly distinct so far as actual knowledge in itself is concerned.
According to the principle of identity, a man is a man regardless not merely of any hypothesis or doctrine which may be held concerning his origin, but regardless of his actual origin. If I meet A, a person whom I have never before seen or heard of, and if upon becoming more or less personally acquainted with him, I decide to call him “a man,” it would be a violation of this principle for me to deny later that he is a man, merely on the strength of something I might have learned in the meanwhile about his origin.
The history of man is filled with violations of this prin- ciple. Every prophet, taking the word in its usual meaning of a person held to be something more than human, illus- trates such violation. A famous instance from “profane” history is that of Alexander the Great and his episode with the Egyptian god Zeus Ammon. We take in substance the story as told by Grote. During the three years just pre- ceding the entrance of the Conqueror into Egypt, his achievements “had transcended the expectations of every one, himself included—the gods had given to him such in- cessant good fortune, and so paralyzed or put down his enemies—that the hypothesis of a superhuman personality seemed the natural explanation of such a superhuman ca- reer. This caused him to recur to the heroic legends which connected his own ancestral line with Perseus and Herakles. He resolved to ascertain the fact about his own real nature by questioning “the infallible oracle of Zeus Ammon” at a temple to the god on a remote oasis in the desert. After a hard journey the temple was reached and Alexander was
FACTUAL EVIDENCE 23
addressed by the priest “as being the son of the god” (probably quite to Alexander’s surprise! ). Grote bases his acceptance of the genuineness of Alexander’s faith in his own supernatural origin and nature partly on “that exor- bitant vanity which from the beginning reigned so largely in his bosom.” Today, with wider knowledge of the de- velopment of the human mind, we can accept it as not so much a display of excessive vanity as a fairly typical mani- festation of human nature in a particular developmental stage.
Of the numerous examples which could easily be cited in which men and women of our own day have made them- selves and others believe they possessed supernatural powers of one sort or another, we mention only Joseph Smith, the founder of Mormonism. In The Book of Mormon Smith “was declared to be God’s ‘prophet’ with all power and en- titled to all obedience.”’ According to the system of the doc- trine of the Mormon church, not only Joseph Smith but also Brigham Young are listed with Christ and Mahomet as “partaking of divinity.”* The history and present state of Mormonism are very illuminating as to what is possible today, in a modern civilization, in the super-naturalization of human beings.
Critical attention to the history of man’s understanding of himself shows conclusively that in the systems of positive knowledge and theory which he has built up on the subject, he has tried in various ways to make himself something different from what he actually is by conceiving a mode of origin for himself specially favorable to what he desired to be.
The effort in all such cases is to gain some advantage for or through the person held to be specially endowed by attributing to him powers over and above any thing he could be supposed to possess as “mere man.” Such en-
1“Mormonism,” Encyclopedia Britannica.
24 PROBLEM OF MAN’S ORIGIN
dowment must be supposed to have originated somehow, sometime. A common way of conceiving this origination has been to impute it to the birth of the person. The case of Alexander illustrates this. Another way of conceiving the origin of the unique endowments has been that of sup- posing the persons to have been the recipients, sometime after birth in the ordinary manner, of special Gifts or Visi- tations from on High. The Joseph Smith case is an example of this.
THE PROBLEM OF NAMING A DEVELOPING THING
Our decision to attempt to answer the question of whether evolution is universally as well as narrowly true by expand- ing into technical knowledge our already-possessed common knowledge of organic origin and development gives this effort a peculiar character. If the attempt should lead us to an affirmative answer we should find ourselves in the wholly unique position of an organism trying to discover, by its own processes of getting knowledge, how the organism itself came into existence. We should be involved in the curious undertaking of directing our own knowledge proc- esses, which can be such only while they are going on, to finding out when and how they went on sometime in the past. Does the effort decided upon involve such absurdity? Undoubtedly many philosophers have thought so. Cer- tainly the great rank and file of ordinary mortals have felt so, though they have not raised the feeling into expressible thought. That is the reason why so much of mankind has believed itself in need of, and to have received, Divine Rev- elation touching matters which concerned it most vitally. Man has not been willing to trust his own ordinary knowl- edge-getting ability to furnish him with all he has desired to know about himself: his ultimate origin, highest earthly welfare, and final end. If we make up our minds to trust
FACTUAL EVIDENCE | 25
our own knowledge-getting powers in our effort to answer the question of our own origin, we ought to give careful at- tention to the character of those powers and the processes by which they work. Many a professed evolutionist has launched boldly upon the sea of evolutional theory as applied to man, whose fitness for the task so far as concerns knowl- edge of the working of his own mind was distinctly ques- tionable.
Our enterprise of applying technical knowledge to the evolution theory must therefore begin by learning something about the nature of that knowledge itself. We must attend to the knowledge processes involved in acquiring, arranging and connecting facts, as well as to the facts themselves. Every objective fact like every other fact is just itself and nothing else, and cannot change into any other fact. The moiety of an objective fact that inheres in the object or body observed can disappear and be replaced by the cor- responding part of some other fact, as when the green of summer foliage is replaced by the brown or red of autumn foliage. Each fact has another moiety belonging to the mind, and the permanence of this latter does not depend on the single objective fact. If we are to understand and trust facts, we must consider their subjective as well as their objective moities.
Let us notice, therefore, how we think about or reason about some of the simplest, most common cases of “organic evolution.” Take the case of the evolution of the adult man or woman from the new-born babe. That the development up to adulthood consists not merely in increase in size but in many pronounced changes, structural and functional, is obvious. Reflect on how we think and talk about such evolutions. To be very specific take a boy baby a month old. Let us “name” him Robert. When he is a year old he is still Robert, is he not? And when he is ten, or fifteen, or one-and-twenty, Robert he still is, despite all that he was not
26 PROBLEM OF MAN’S ORIGIN
on the christening day. Is the Robert of Tam O’Shanter really the same as the month-old Robert of the rude Scot- tish home? And the Robert of victory at Chancellorsville, is he truly the same as the just-christened Virginian Robert?
One is tempted to answer these questions negatively by trying to think out too fully how it can possibly be that such frail and inconsiderable bits of flesh and blood as were these two infant Roberts should become the great forces in the world they did become. In reality, the name Robert E. Lee was never intended by those who gave it to the infant Virginian to fit the infant merely. It was given with the full intention that it would be as applicable to the mature man and all the stages intervening between infancy and maturity as to the infant stage. Names, as proper names of individual humans, are in their very nature expansive © enough to cover not only potentiality and actuality but also different stages and kinds of actuality. The infant, the lad, the youth, are all actually what they are as well as poten- tially what they are to become.
Notice what we do in thinking and talking about such cases, for the purpose of conforming ourselves to what actually occurs in nature and in history, even though we are greatly perplexed as to just how and just why it occurs. At the outset we designate one indubitably observed natural object with the label “Robert Burns” and another with “Robert E. Lee.” In doing this we commit ourselves to applying these designations to the respective objects just as long as we can observe them and identify them as con- tinuations of what we have observed before, no matter how little or how much they may change from the one time of observation to another. Robert Burns is Robert Burns and Robert E. Lee is Robert E. Lee exactly as sugar is sugar.
How can this be so in view of the fact that we have ac- cepted the famous Robert as an observational reality, just as unquestioningly as we have accepted the infant? It
FACTUAL EVIDENCE 27
“can be” so by our making it so.’ We make it so by a kind of mental sleight of hand always practiced in connection with our naming such objects. That sleight of hand con- sists in stretching somewhat the mark whenever we need to in order to make it cover or include the whole of the object marked. While the object bearing the mark, Robert Burns, is unquestionably quite different in the Tam O’Shanter period of its life from what it was in the month-old-infant period, the mark itself remains the same. Consequently the capacity, or as we ordinarily say the definition of the mark must be enlarged. It will be useful to compare the names applied to persons with the names applied to clothes worn by them. While we do not enlarge a man’s name? with his advancing years so definitely and consciously as we do his clothes, that we do it as certainly there is not the least doubt.
In common practice nobody ever thinks of the name Robert E. Lee as having exactly the same scope and content when applied to the great commander as when applied to the infant; just as nobody ever questions that Robert E. Lee is Robert E. Lee whether in the infant, school-boy, West Point Cadet, or Commanding-General stage of his life. Common sense never goes wrong among highly civilized peoples in these matters. Proper names of individuals as ordinarily used are really general names the scope of which is over the series of developmental stages in time as con- trasted with general names the scope of which is over groups of individuals; that is in space.’ So far as any name
2 The whole matter of naming objects presents great complexity among all peoples, especially among those of primitive culture. “No more strange and fascinating study of the vagaries of the human mind is supplied,” writes Edward Clodd, “than is furnished by this phenomenon of the written and spoken name; and in the early stages of society it played no small part in the identification of the human with the non- human” (“Primitive Man on His Own Origin,” Quarterly Review, July, IQII, p. 117).
31f this is correct, Mill’s statement, “Proper names are attached to the objects themselves, and are not dependent upon the continuance of
28 PROBLEM OF MAN’S ORIGIN
can be applied to an individual organism, especially to a developing organism, it must be general or “it would be useless as a guide to action.” *
ACTUALITY AND POTENTIALITY IN EVOLUTION
Another aspect of the evolution problem which adds to its complication both in its phenomenal phase, and in its psychological-logical phase is the difficulty of including in our conception of an organism the potentiality or latent ca- pacity which every organism has in any one of its develop- mental stages to pass into the next stage. The evolution of the oak from the acorn, of the hen from the egg, and of every other organism from its germ, are illustrations. Here again common knowledge, because of the commonness of the phenomenon and the absolute dependence of human existence upon it, always goes right so long as it is contented to operate within its own proper sphere, but is in constant danger of getting into rational difficulties when it tries to go beyond that sphere.
In behalf of thinking correctly as well as merely noticing correctly let us consider a particular instance. Take the development of the silkworm moth. Recall the sharply set- off stages into which the individual life history of this insect divides itself—egg, larva, pupa, imago. These stages are so different from one another that were each studied only by itself it could hardly be suspected that each comes from the other in the order mentioned. Since, however, a great many persons have raised silkworms, there is not the least question that the various stages originate thus, and that each individual moth lives for a time in these distinct forms.
any attribute of the object” (A System of Logic), would not be true. By what means could the parents of Robert E. Lee recognize their son upon his return after months of absence if there were no “continuance of any attribute’ of the son?
* Carveth Read, The Origin of Man and His Superstitions, p. 99.
FACTUAL EVIDENCE 29
No silkworm raiser has any more doubt about the sameness of an individual from egg to winged adult than has the human mother about the sameness of her child from infancy to middle life.
What do we do in our ordinary thinking and talking about such evolutionary phenomena as that of the ability of the egg to transform into the larva, of the larva into the en- cased pupa, and of the pupa into the imago? There are two things in particular which we take on faith every time we say or do anything involving such cases. We recognize the latent capacity of each stage to undergo just the trans- formation it actually does undergo. We take it for granted it will do so, and our faith is of such kind and degree as to cause us to base on it common and very important actions. Every seed-planting by the farmer, every egg-hatching by the poultry man, every moth-imago production by the silk raiser is an act of faith. Farmer, poultry-man, and silk- raiser base their actions to only a slight extent on what they can observe in the particular kernels of wheat, hen- eggs, and cocoons from which they expect to get wheat- plants, chickens, and moth-imagoes. Nor yet do they base them upon certain knowledge of the outcome. They rely on hundreds of thousands of instances in their own and other people’s past experiences that such kernels, such eggs, and such pupz actually do give rise to plants, chickens, and moths of the desired kind.
When the farmer or poultryman examines his seed grain and breed eggs he does this merely to discover whether they are “good,” i.e., are the kind, as grain and as eggs, that he wants. The farmer has no expectation of discovering any- thing in the kernel of wheat that will of itself reveal to him what kind of plant it will produce or indeed if it will pro- duce a plant at all. Had no one ever before. seen kernels of wheat and wheat plants, no amount of examination of such a kernel could yield the slightest hint as to what it
30 PROBLEM OF MAN’S ORIGIN
would transform into. It is a striking limitation on man’s knowledge-acquiring ability that he has no sensory equip- ment for apprehending directly what is only potential in natural bodies. Observation on a piece of ice gives us no direct information about water as fluid and steam.
The second thing taken on faith is our belief that any full- grown plant or animal with which we have to do was pro- duced from a germ and passed through developmental or evolutional stages of some sort whether any one has ever actually seen these germs and stages or not. The experi- ences of other persons and of ourselves that plants and animals do arise in this way, and the complete absence of experience that they arise in any other way, is the sole basis of this faith. ‘The literalness and force of the truth that faith is the evidence of things not seen, are rarely recog- nized. How often and how closely do any of us examine the grounds of our belief that every person we see was born of a woman? As a matter of fact, with the great majority of us the belief rests on no direct experience at all. Only a small portion of us have actually observed a single birth. How much direct evidence is there that you and I and most other people came into existence in this way? It is not sur- prising that despite the overwhelming probability that all human beings are “born of woman,” great and varied con- fusion should have arisen on the subject in early ages among lowly people. In dealing with any organic development we always, consciously or subconsciously, recognize poten- tialities of some familiar pattern; and we similarly recognize that whatever structures or activities are observable have sometime been merely potential, i.e., present though not in the form or activity in which we now observe them. The
5 Although the doubts and confusions to which the human mind has been subject in connection with the origin of individual humans have been largely removed for modern men, they are not wholly things of the past by considerable. That cases like those of Alexander the Great and Joseph Smith (p. 23) are remnants of the same old confusion there seems to be no question.
FACTUAL EVIDENCE 31
young infant’s teeth we know to be present in germ long before they are cut and brought into active service.
The reasoning involved in our common knowledge of the evolutional origin of the individual man leads us to believe in the evolutional origin of the species man. As an individ- ual, he probably originated from some other individual; as a species he probably originated from some other species. Even in the case of individuals concerning the origin of whom we are without direct, positive knowledge, our con- clusions that these were born of mothers can be only prob- ably true even though the probability be so great as to leave no room for serious question. The factual and logical conditions involved in the problem of the origin of the species man are such as to make the probable truth of the evolutional origin as much as we shall ever be able to attain. We are able to conclude that the evolutional origin of the species is more probably true than is its origin by any other mode that has been suggested.
We saw the indubitability of stages in individual evolu- tion, every one of which presents a certain amount of ac- tuality and a certain amount of potentiality. Every stage is being something and doing something now, and also is capable of becoming something somewhat different, and do- ing something else later. Metamorphosis, or change of form and of ability to act despite a certain degree of continuous- ness and sameness, constitutes the very fabric of our lives. Not the obscurity but the familiarity of all this blinds us.
Finally, we dwelt upon the naturalness with which our every-day thought and speech adapt themselves to the situa- tion so far as our own practical lives are concerned. The word Man, as it is used in all ordinary experience, includes the whole developmental series from babyhood to full man- hood, not only of some one or a few human beings but of all human beings. With equal legitimacy, it is applied to all the innumerable kinds and stages and ages of men revealed
32 PROBLEM OF MAN’S ORIGIN
by history and anthropology. The term “Man” is one of our most common and useful generic terms, “generic” having its logical meaning, a term applied to many things sufficiently alike to warrant combining them into.one group but at the same time enough unlike to warrant dividing the groups into subgroups, these subgroups again having individuals of still other likenesses.
THE PRINCIPLE OF RESEMBLANCE AND THE EVOLUTION THEORY
“The evolution problem” conceived as applying to the origin of species is only part of the whole problem. For surely individuals orginate and develop as well as do species. The knowledge processes involved in the two parts of the problem must have much in common. Applying the same reasoning to the part of the problem dealing with the origin of the human species as to the part dealing with the origin of the individual led us to conclude that the species must have originated from some other species. But this conclu- sion suggested no more as to what the parent species may have been than that it most probably resembled rather closely the offspring species.
Nothing is more crucial for sound reasoning on the prob- lem of origins in living nature, including the origin of species, than the use we make of, and the reliance we place on, resemblance. If I see in a zodlogical garden an adult gorilla recently captured in an African forest, how do I affirm with so much confidence that it was born of gorilla parents? Many elements enter into the how; absolutely basic and indispensable is the resemblance of the creature before me to other creatures which in common practice have been called gorillas. No amount of knowledge of the laws of animal reproduction and heredity would of itself enable
FACTUAL EVIDENCE 33
me to make this assertion or would increase my confidence in its truth,
The first man who cultivated regularly any crop, as rice or maize, was in as little doubt about what he would have to do at every seed time in order to get a crop as any scientific farmer or geneticist can be. His recognition of resemblance between crop after crop at the harvest time was the most fundamental element in his confidence. Resemblance plays an indispensable part in knowledge of any developmental series. If I have before me a developing animal embryo concerning the identification of which I am doubtful, I watch the changes it undergoes from day to day. As soon as I become satisfied that the upper and lower jaw regions of its head are being drawn out and encased in peculiar hard epidermal sheaths, one large block of my doubt in- stantly vanishes. Bird! What is it that thus drives away my doubts? It is my recognition of the resemblance of the newly arrived part to what, from an abundance of past ob- servation by myself and others, I know as “bird’s beak.”
That the principle of resemblance plays a much more im- portant part in all biological reasoning, especially in all reasoning about development, than is ordinarily appreciated, has been disclosing itself to me little by little from the years when I taught embryology and comparative anatomy. With this gradual disclosure has come increasing surprise at the inadequacy of treatment the subject receives in such text- books and treatises on logic as I have been able to consult. Being a naturalist, I have been occupied primarily with problems of the living world and only secondarily with the problems of mind as the chief means through which I and my fellow naturalists are thus occupied. Such excursions as I have made into the field of theory of knowledge and of logic have been mainly in search of aid to my efforts at knowing the world. These excursions brought very slight
34 PROBLEM OF MAN’S ORIGIN
success until A Treatise on Probability by J. M. Keynes came into my hands and I had read the portion dealing with analogy (which the author seems to regard as essentially the same thing as resemblance). I had supposed that the kind of aid I needed was available somewhere, and that my failure to secure it had been due to an unfortunate choice of authorities. In this book we read: “Inductive processes have formed of course at all times a vital, habitual part of the mind’s machinery. Whenever we learn by experience, we are using them. But in the logic of the schools they have taken their proper place slowly. No clear or satis- factory account of them is to be found anywhere. Within and yet beyond the scope of formal logic, on the line, ap- parently, between mental and natural philosophy, Induction has been admitted into the organon of scientific proof, with- out much help from the logicians, no one quite knows when.” ® No one is quite so well able as the thoughtful student of biological development to appreciate the truth and the force of this paragraph. It is surprising and sig- nificant, both for the attitude of logicians toward science and for the attitude of scientists toward their own mental proc- esses, that nothing adequate for the present state of advance- ment of natural knowledge has been done, especially in the domain of induction and analogy, the very domain in which the principle of resemblance chiefly operates.
Sop ary.
CHAPTER 4
THE PROBLEM OF MAN’S ORIGIN AND KINSHIP (con.): CERTAINTY AND PROBABILITY AS TO MAN’S EVOLUTION
WE have previously recognized that there is not the least prospect of our ever knowing absolutely from what ancestral species we descended. The best we can do is to increase as much as possible tke probabilities in the case. We have also found that resemblance plays a great and indispensable part in establishing such probabilities. Let us now turn to this specific task: Where in the whole subhuman animal series do we find the most numerous and closest resem- blances to man?
If resemblance has played as large a part in man’s spec- ulations about his own kinship and origin as we have as- sumed we should expect modern science to seek with special eagerness among the primates for human likenesses. We should also expect that those primitive peoples who have inhabited portions of the earth likewise inhabited by pri- mates would fix upon some of their primate neighbors as being their own closest kindred. There are numerous legends involving the confusion of monkeys and men in all lands occupied by both. The illustrations selected are taken from E. B. Tylor. ‘One of the most perfect identifications of the savage with the monkey in Hindustan,” we read, “is the following description of the bunmanus, or ‘Man of the woods’ (Sanskr. vana=wood, and manusha=man). ‘The bunmanus is an animal of the monkey kind. His face has a near resemblance to the human; he has no tail and walks erect. The skin of his body is black and slightly covered with hair.’ That this description really applies not to apes,
but to the dark-skinned non-Aryan aborigines of the land, 35
36 PROBLEM OF MAN’S ORIGIN
appears further in the enumeration of the local dialects of Hindustan, to which it is said ‘may be added the jargon of the bunmanus or wild man of the woods.’ ” *
And further: “In the islands of the Indian Archipelago, whose tropical forests swarm both with high apes and low savages, the confusion between the two in the minds of the half-civilized inhabitants becomes almost inextricable.” ? So much for the recognition of resemblance between apes and men in Asia.
For Africa and South America we have: ‘‘To people who at once believe monkeys a kind of savages, and savages a kind of monkeys, men with tails are creatures coming under both definitions. Thus the Homo caudatus, or satyr, often appears in popular belief as a half-human creature, while even in old-fashioned works on natural history he may be found depicted on the evident model of an anthropoid ape. In East Africa, the imagined tribe of long-tailed men are also monkey-faced, while in South America the coata tapuya, or ‘monkey-men,’ are as naturally described as men with tails.” °
Would any present-day anthropologist who interprets Pithecanthropus as a connecting link between man and ape contend that he has at his command some principle of inter- pretation other than that of resemblance, which gives his conclusions a probability of truth entirely different from that which has been producing imaginary connecting links through the ages of man’s observations upon himself and his anthropoid contemporaries? Who is so bold as to deny that the connecting links reconstructed today on the basis of the fragmentary paleontological information we possess may at some future time be characterized as “old-fashioned works on natural history”? This reflection is not designed to
1 Primitive Culture, Vol. I, p. 380. 2Tbid., p. 381. 3 [bid., p. 383.
CERTAINTY AS TO EVOLUTION 37
imply that these modern efforts at closing up evolutionary gaps are unjustifiable and useless, but to emphasize their hypothetical and tentative nature; to focus attention on the fact that resemblance (structural resemblance alone at that) is basic in them; and finally to remind ourselves that logically similar efforts have been made for thousands of years and by numberless observers.
In the combined light of our present-day factual knowl- edge of organic beings and our insight into the operations of our minds in getting and using this knowledge, what are we justified in believing as to the ancestry of the human species? Our examination has revealed that neither do we know absolutely, nor is there any likelihood that we ever shall know exactly, from what other species we originated. It is in the highest degree more probable that we originated in such a way than that we originated in any other way that has ever been suggested. The probability of our hav- ing originated from some other species is very much greater than the probability that we originated from any particular species which we can specify.
There are only two kinds of evidence upon which we rely for proof of the origin of anything whatever. Most funda- mental is the evidence of knowledge through direct experi- ence. Beyond this is probability dependent at bottom on resemblance. Our task is that of sifting from the vast body of factual knowledge we now possess, those portions which will enable us to decide what subhuman species the human species most closely resembles.
Part of this task has already been performed, not by sci- ence in the strict sense of today, but by the common knowl- edge of innumerable peoples and ages. That man’s resem- blance to the animal creatures below him, especially to the “beasts of the field” is closer than to any other natural ob- jects has been recognized always and everywhere in human history. Many people have gone much further in the task
38 PROBLEM OF MAN’S ORIGIN
than the mere recognition of these resemblances. ‘They have designated particular animal kinds as being originative of man, if not his actual ancestors. Many of the myths and legends of primitive peoples which implicate animals in the origin of man are, from the standpoint of the theory of knowledge, in the nature of hypotheses involving the genetic kindred of many of the animals concerned. Stories of direct origin of man from animals are extremely common. Stu- dents of California Indians dwell on the part which the coyote plays in the origin and lives of these people. We read: “The present mode of life is determined by the results of the activities of the beneficent Creator and the tricky Coyote.” A point deserving special notice here is the con- ception of codperation between Creator and coyote in doing the job. Many such instances might be cited from the mythology of human origination.
No single group of superstitions is more striking than is totemism. Certain facts suggest the warrantableness of looking upon this institution as a sort of prescientific stage of the evolution theory. The word totemism “was first applied at the end of the last century . . . to the Red In- dian custom which acknowledges human kinship with an- imals.”* One of the highest developments of totemism, certainly its highest expression in art forms, is among the Indians of Northwest America, familiar in the totem poles of many museums. Apparently all authorities agree that the idea of kindred between the totemites and their totems is common, if not universal, and that the most common totems are animals. From Clodd’s endorsement of Lang’s theory of the origin of totemism we read: ‘We feel bound to say that . . . if there be any approach to a solution of the origin of totemism, Mr. Lang’s theory most commends itself as having valid ground in certain world-wide savage conceptions which supply sufficient material for tracing the
4 Andrew Lang, Myth, Ritual and Religion, Vol. I, p. 59.
CERTAINTY AS TO EVOLUTION 39
development of that institution. These are, belief in kinship between man and brute, and in the names of things as in- tegral parts of things.” ®
it is impossible to contend that all the varieties of totem- ism known to exist now depend directly upon resemblance and kinship between the totemists and their totems, but a general survey of totemism shows clearly that animals, especially mammals and birds, are the predominant totems. Out of a total of 202 such objects enumerated by these authors, 164 are animals, 22 are plants, and 16 are inanimate things. “Animals,” Read says, “lend the greatest plausi- bility to any notion of blood-relationship....” “To hunters animals must have been of all things the most in- teresting.” * Why should animals be the most interesting of all things to hunters? The reply which comes to one’s mind first, that it is because they are the objects of the hunter’s pursuit and largely his sustenance, does not tell the whole story. The evidences are innumerable that an- imals have been among the most interesting things to most people whether hunters or not. This interest has been due largely to the recognition of resemblance of the animals to men.
Man at all levels of his culture tends to respond emo- tionally to animals somewhat differently in both quality and intensity from what he does to any other natural objects. Even our modern interest in animals is by no means cir- cumscribed by the economic use we can put them to or the fears we have of them. Our way of companioning with them and making pets of them in certain cases, and of standing in mortal fear of them and making them symbols of the worst of evils in other cases, is quite without parallel outside the animal kingdom. The zodlogy of toydom is an unmistak-
5 “Primitive Man on His Own Origin,” by Edward Clodd, Quarterly
Review, July, 1911. ; 6 Appendix B, Spencer and Gillen. Bs 7 The Origin of Man and His Superstitions, p. 296.
40 PROBLEM OF MAN’S ORIGIN
able witness to mankind’s fundamental relation to animal life. The great vogue in modern times of effort against cruelty to animals, manifesting itself at times in the highly commendable societies having this designation, and at other times in the highly condemnable crusades against experimen- tation on animals for the furtherance of scientific knowl- edge, may be interpreted in the same way.
It is not difficult to recognize something of the psycho- biology of this peculiar interest of man in animals. The fact that so many of the most common of them have two eyes much like our own and a face that can be “looked into,” tells a large part of the story. Man’s association with the dog is especially significant. Full of meaning are such familiar remarks about this animal as “he looked up into my face with an almost human expression.” But the dog is by no means the only creature the face and eyes of which make a peculiar appeal to man. Indelibly stamped upon my own mind are the faces, with their strange eyes, of the first sheep I as a very small child ever saw at close range.
Writing on totemism, A. A. Goldenweisser § has the fol- lowing on the point before us. ‘While plants and inanimate things have long since been relegated to the realm of the matter-of-fact, animals still inhabit a region where fact and fancy are peacefully wedded together. As between the animal and its human master, verbal usage reveals a com- mon range of physical and psychic qualities. One thinks of the eagle eye, the leonine heart, the dogged perseverance, the bull-neck. Current metaphor, half earnest half jest, has introduced the fox and the beaver, the bear and the rabbit, the cat and the cow, the ape and the shark, as char- acters of the human scene.” Surely this is not due to pure fancy. It rests on a basis of some resemblance. The effect of these unescapably recognizable likenesses between hu- mans and inferior animals upon the minds of people very low
8 Early Civilization, 1922, p. 2809.
CERTAINTY AS TO EVOLUTION 41
in the cultural scale must be especially intense and difficult for us of higher culture to appreciate.
The kinship recognized in totemism is of at least three quite distinct kinds. The most important of these from the evolutionary standpoint is that which assumes descent in the strict meaning of the word. This is found in many parts of the world. A typical example is furnished by the creation story of some of the natives of Australia. “The origin of the first-formed human beings is ascribed to two individuals named ungambikula who lived in the western sky, and, seeing far away to the east a mob of inapertwa, creatures who were the incomplete transformations of animals and plants, came down to earth, and with their knives released their half-formed arms and legs, cut open their mouths, bored holes for nostrils, slit the eyelids apart, and thus out of the inapertwa made men and women... . The totemic ancestors who originated in this way marched in groups across the country, every one of them carrying with him, or her, not only a personal Churinga, but often many others also.” ®
A second variety of kindred recognized in totemism is what may be called kindred by adoption. Persons of one totem may upon occasion be adopted into another totem otherwise than through the regular avenue of marriage from one totem into another. This involves a change of name, the name borne by a totemic group being usually a vital matter. A process of adoption, of bestowing a group name (in logic a generic name) with an appropriate ceremony, establishes a kind of heredity and kindred which may be superior in power to actual genetic heredity. Nor is it essential that this kindred by adoption shall be based on any known blood kin- dred. There are many cases in which adopted children of no blood relation whatever enjoy all the bonds in affection,
2 The Northern Tribes of Central Australia, by Baldwin Spencer and F. J. Gillen, 1904, p. 150.
42 PROBLEM OF MAN’S ORIGIN
social and family advantages and legal benefits enjoyed by blood kindred. There is not the slighest question that resemblance contributes greatly to the possibility of forming these relations. White people might adopt negro or Indian children and become very fond of them. I doubt if any one would contend that parental feeling could ever go out quite as strongly and inclusively to such children as to adoptions within the same race.
A third form of kindred resulting from the custom of totemism might be called animistic kindred. In our modern English terminology, this is an affair of spirits or ghosts. The kindred assumed in totemism may sometimes be through the mediumship of spirits, and have little or no reference to lineage in the sense of modern genetics. Ac- cording to the meaning of animism which rests upon the most indubitable observation, any object whatever may have something in it (a spirit) which is not the thing itself but is the real cause or explanation of the thing, or at least of some of its attributes. A stream, a mountain, a stone, may have each its appropriate spirit. There is always some sort of correspondence or resemblance between the object and its spirit. The closer the resemblance between man himself and any particular object the closer would be the resemblance between the human spirit and that of the object. As to animals, especially the higher animals, the resemblance of which to man is so striking in many respects, the resemblance between these spirits and man’s spirit would naturally be correspondingly close.
A main attribute of spirits is their ability to separate themselves upon occasion from the objects they inhabit and enter into other objects; thus, the stage is well set for all manner of mix-ups among the spirits of animals and men. Hardly anything plays a larger part in the lives of primitive peoples than this very matter of their own commingling, largely via their spirits, with their animal neighbors. One
CERTAINTY AS TO EVOLUTION 43
of the most learned of all writers in this field tells us: “The sense of an absolute psychical distinction between man and beast, so prevalent in the civilized world, is hardly to be found among the lower races. Men to whom the cries of beasts and birds seem like human language, and their actions guided as it were by human thought, logically enough allow the existence of souls to beasts, birds and reptiles, as to men. The lower psychology cannot but recognize in beasts the very characteristics which it attributes to the human soul, namely, the phenomena of life and death, will and judgment, and the phantom seen in vision or in dream. As for be- lievers, savage or civilized, in the great doctrine of metem- psychosis, these not only consider that an animal may have a soul, but that this soul may have inhabited a human being and thus the creature may be in fact their own ancestor or once familiar friend.” *°
We have, I hope, now gone far enough in our study of man’s world-wide and eons-old efforts to satisfy his curi- osity about his own origin to recognize three basic things about these efforts: The great majority of them have linked man in some organic, vital way with the rest of living nature, especially with the animals assigned by zoological science to a place in the system of classification not far below man: what we moderns call the logical principle of analogy (posi- tive and negative) or of resemblance and difference, has played a very great part in these efforts; that the conception of immaterial entities (shadows, ghosts, spirits, souls) sim- ilar to but independent of and often separable from man, other animals and plants and natural objects generally, have been very widely invoked, always to the detriment of clear understanding and effective treatment of the objects con- cerned.
Our modern problem of the origin of man is the same old problem by which man has been confronted in all his history.
10 Primitive Culture, by Edward B. Tylor, sixth ed., Vol. I, p. 469.
44 PROBLEM OF MAN’S ORIGIN
All peoples have had some sort of explanation of their own origin, embodied for the most part in religious tradition and cherished as a precious part of the racial heritage. It seems a question we cannot let sleep, this matter of whence and how we have come. We moderns are able to state it more exactly than any of our predecessors, and have vastly more information upon which to base our conclusions than they have had.
THE WORTH AND THE LIMITATIONS OF PALEONTOLOGICAL EVIDENCE
Our task of sifting factual evidence which will enable us to decide what subhuman species the human species most closely resembles has now completed a very inadequate survey of the contribution made by the common knowledge of common folk of many lands and times. Our next task is to look at the facts which science presents as evidence for the truth of evolution, and examine the way in which that evidence is used. To many evolutionists the paleontological evidence is most convincing. It furnishes an order or kind of evidence not found in any other direction. So numerous and well worked-out are the evolutionary series and lines of descent in many animal groups possessing fossilizable parts, that there can be little doubt in the mind of any per- son who uses his observational and logical powers correctly, that the completest of these are phylogenetic and not merely pieced-together resemblance series. Our concern is more with the observed facts as evidence than with them as facts. We are taking for granted a vast mass of facts. What do they prove?
The famous horse series will serve well as a basis for our examination. There are few educated persons to-day who are not informed as to the evolutionary history of this one
CERTAINTY AS TO EVOLUTION 45
of man’s closest, most useful subhuman companions. De- spite the fact that the fossils which constitute the observa- tional evidence in the case have been well known for a full half century, and have been accepted as conclusive evidence in favor of evolution by a long line of distinguished scien- tists, there have been from the outset and still are many educated, rational persons to whom the admitted facts do not prove evolution at all. How are such differences of con- clusion possible? Is it really true that the minds of highly cultured men are so fundamentally different that from the same body of unquestioned objective evidence irreconcilably opposed conclusions can be drawn? Until a satisfactory answer to this question is found there can be no prospect of agreement either as to the origin and nature of man or as to what his conduct should be.
Let us apply to the fossils so widely held to be the remains of horses the common principles of interpretation which, in the earlier portions of this discussion, we found to lead to universally accepted conclusions relative to the most familiar cases of evolution.
Everybody knows that these fossils are found in great variety and in many parts of the earth, the western portion of North America abounding in them especially. It is well known, too, that they are found at very different geological levels. The earliest animals of which they are the remains are estimated on the basis of evidence giving considerable probability of truth, to have lived from eight hundred thou- sand to one million years ago.’ From this far-away time and deep geological level (the eocene or beginning period of the tertiary era) the fossils are scattered in America through the intervening geological levels up to near the present time (the pleistocene); above which, however, none have been found. Whereas America appears to have been extensively
11 The Horse Past and Present, by H. F. Osborn.
46 PROBLEM OF MAN’S ORIGIN
populated with horses in earlier geological times, no living ones existed on the continent when it was discovered by Europeans.
What put into anybody’s head the idea that all these fos- sils are racially related to one another and all in turn are ancestral to the familiar animal known to us as the horse? The only answer is that the fossils look like certain of the parts, the bones, of the horse. We undoubtedly violate a fundamental principle of inductive knowledge if we sup- pose ourselves absolutely certain that any fossil bones what- ever are the remains of a horse or any other animal our original knowledge of which comes from observations on living representatives of the species in question. That the fossils upon which the supposed evolutionary history of the horse is based were once parts of horses or any other living animals is only inferential knowledge and hence can never emerge from the class of probable truth into that of certain truth. If any one questions this let him ask himself if he can possibly be as certain that a skull or other bones he may chance upon in some pasture, or even a complete mounted skeleton he may see in a museum, were once part of a horse, as he would be were he to dissect a dead horse and find in in it the corresponding skeletal parts.
I doubt if any paleontologist will contend that he is quite as certain of the derivation of fossil horse remains from horses or any other living animals as he is of the derivation of a given skeleton he has himself prepared from some ani- mal body; or that he is quite as certain of the derivation of any one of the fossil species from some other species of the series as he is of the derivation of some adult frog from a tadpole he has kept under constant observation.
If this be granted, the whole conception of an evolutional horse series as based on the evidence available falls inevi- tably into the category of probable truth, the degree of prob- ability being determined by the valuation placed upon the
CERTAINTY AS TO EVOLUTION 47
similarities and differences brought to light by the critical comparison of bone with bone of the entire mass of the fossil material; and of all these*with the corresponding bones of the horse actually known to us. Concerning a particularly complete skeleton of Eguus scotti found in a pleistocene deposit of Texas, we read: “It is of an animal about 15 hands in height, having somewhat the proportions of a western broncho, but with a very large head and with teeth greater than those of a modern dray horse, although very similar in pattern.” ** The mounted skeleton and the resto- ration of this species show the animal to have been so much like the modern horse that the skill of the expert is more needed for recognizing differences than similarities. From Equus to Eohippus and Hyracotherium this basic principle of comparison in search of resemblances and differences can be recognized, the limbs, feet and teeth receiving most atten- tion. The paleontologist, Richard Owen, who named Hyra- cotherium did not recognize anything horse-like about it but considered it to have been a coney-like beast (as the name implies). Its (Hyracotherium) relation to the horse was not at that time suspected by Professor Owen, and was recognized by scientific men only when several of the in- termediate stages between it and its modern descendant had been discovered.” Another quotation from Lull illustrates the point as it applies at the bottom of the series; where likeness is rela- tively slight and unlikeness is relatively great. This has reference to the comparison between Hyracotherium, a European fossil, and Eohippus from North America. “These two genera are much alike, but the premolar teeth of Hyra- cotherium, especially the second one of the upper jaw, are more simple than in Eohippus, thus stamping the Old World
12 Organic Evolution, by R. S. Lull, p. 610. 13 Re aioe of the Horse, by W. D. Matthews, Amer. Mus. of Nat.
History Guide, Leaflet Series, No. 36, Sept., 1913.
48 PROBLEM OF MAN’S ORIGIN
type as the most primitive horse-like form known.” ** The kernel of the argument here is that the two genera are “much alike.” Hyracotherium is adjudged to be the most “primi- tive” “horse-like” form, on the ground of being “more sim- ple” in various respects, particularly in the fact that the second premolar tooth of the upper jaw bears the “stamp” of relative simplicity. By turning to a fuller description of the teeth we are informed wherein consists the greater sim- plicity of the Hyracotherium in contrast with the Eohippian teeth. The molars of Eohippus “foreshadow” the “future complication” of the true horse, while the hinder premolar is becoming ‘“molariform.”
All these fossils can be ranged in a series chiefly on the basis of a succession of complications in the molar and pre- molar teeth (their degree of “molariformity” after the type of the modern horse); of a succession of changes in foot and limb structure (reduction in the number of toes, and so forth); and of a succession of sizes of the animals from about that of a fox terrier (Eohippus) to that of the full-sized horse. The making of this series does not necessarily imply any conclusion concerning any derivational relation between the members of the series. This is quite generally admitted by believers as well as by disbelievers in the evolutionary theory. The disagreement over such cases is due to the very inadequate criteria heretofore applied in assessing the facts as evidence favorable to the hypothesis that the members of the series are derivationally connected. Writers on the subject have expressed themselves in such a way as to con- fuse their readers as to the rational difference between the series as thoroughly legitimate and good classificatory ar- rangements, and the inference of derivative connection be- tween the members of the series.
A wording from Lull may be used to illustrate the point. An illustration from this author should be especially instruc-
14Lull, p. 610.
CERTAINTY AS TO EVOLUTION 49
tive because his language is much freer from unwarranted implications than is that of many another writer. “In Merychip pus,” we read, “the milk teeth are short-crowned and have little or no cement and are thus reminiscent of its ancestry.” *° Obviously, the short-crowned, slightly-ce- mented milk teeth of Merychippus are “reminiscent of its ancestry” if its ancestry had teeth thus characterized. But whether or not the ancestors had such teeth is exactly what we do not know, but which the facts in the case justify us in regarding as exceedingly probable. The short-crowned ce- mentless milk teeth of Merychippus are suggestive rather than reminiscent of the creature’s ancestry. They are not reminiscent in the sense of calling up memories of the an- cestry, for what the ancestry was is the very thing we do not know but are trying to imagine on the basis of facts observed in this and other cases.
No matter how complete this or any other fossil series is as evidence on which to found a classification and arrange- ment, resemblance and difference between the members are the most basic facts we possess. Consequently, whatever conclusions may be drawn as to the origin and relation of these members must fall short of full demonstration. How far we are from tracing “every step in the evolution of the horse” (or of any other animal by the paleontological evi- dence) becomes obvious the moment we examine this word- ing critically. No naturalist contends that we are as certain of “every step in the evolution” of the teeth and feet of ex- tinct horses as we are of the evolution of these structures in the individual life of horses now living. For many peo- ple, and among them no small number of scientists, the case is then closed; people, that is, for whom the origin and development of species must be demonstrated with the same certainty that the origin and development of individuals is demonstrated, if the hypothesis of evolutional origin is to
15 Ibid., p. 616.
50 PROBLEM OF MAN’S ORIGIN
have any standing. Undoubtedly a number of different ele- ments go to the making of this attitude. From the stand- point of reason and logic the main elements are the failure to inquire seriously what the observed facts do signify if they do not signify evolution; and, growing immediately out of such inquiry, failure to appreciate the vast importance to the whole intellectual life of man of weighing observational evidence for determining the probable as contrasted with the certain truth which can be found therein.
We are now prepared to state in the briefest language possible the conclusions as to relationship and origination, justified by such facts as those of the horse-like fossils we have been considering: That the fossils once belonged to animals which resembled horses known to us by actual ob- servation is probable, the degree of probability being very different for the different fossil species. As to the geolog- ically more recent species, in which the resemblance to known horses is very close, the probability of these being actual horse remains is so great as to render negligible such uncer- tainty as necessarily inheres in the nature of the evidence. In the light of the evidence furnished by the fossils them- selves and from many collateral sources, and in the further light of the knowledge processes involved in innumerable cases where the reasoning is similar, it is extremely probable that the animals represented by the fossils were related to one another by actual genesis. In other words, it is ex- tremely probable that as species no less than as individuals they originated by evolution.
I hasten to make a few remarks forestalling two kinds of response to this statement. On the one hand I anticipate vigorous objection from paleontological experts. They are likely to say that such an outcome is so filled with qualifica- tion and skepticism as to rob it of intellectual satisfaction. Such scientists are likely to feel that if this sort of thing is the best that can be done, if nothing more certain can ever
CERTAINTY AS TO EVOLUTION 51
be attained from paleontological research, then such re- search has little allurement. My reply to this is that the question is not one of our likes and dislikes, but of what the truth is. What are the realities of nature and the realities of our minds as interpreters thereof? Such, as I see it, are the problems with which we have to deal. I do not believe it possible for any scientist or for that matter any other in- telligent, educated person to examine for himself the facts, principles and conclusions we have been occupied with and come to a result as to the paleontological evidence of evolu- tion essentially aifferent from that contained in our state- ment.
The second kind of response to our statement which I would forestall, is that of those persons, by no means few in number nor devoid of influence, who rejoice at the least sign of discomfiture of evolutionists. To such persons I would earnestly commend attention to the first part of my remark to the other group: Not primarily our likes and dis- likes but the realities of nature and man are what confront us. In this, the scientific expert and the most ordinary per- son are on common ground. It is the great problem of life which we are all compelled to do something toward solving for our individual selves. The measure of our success in this depends very largely upon whether we conceive the prob- lem as it actually is in contrast with conceiving it as we would wish it to be or may erroneously believe it to be.
This whole discussion of evolution is an effort to resolve the contradictory theories of the origin of man and other liv- ing beings by examining the unquestioned facts bearing on the case with a view to finding which of the various theories have the greatest probability of truth. If opponents of the evolution theory would be faithful to the principles of their own mental life they cannot avoid explaining what the mean- ing is of the many close resemblances between the fossil remains which have been woven together to make the ad-
52 PROBLEM OF MAN’S ORIGIN
mittedly hypothetical horse series, if they do not mean that the members of the series are genetically related. Our re- sults have led us to see the necessity of concluding that the members of the series are somehow derivatively related to one another if we conclude that the individual members of a given living species or genus, concerning the parentage and birth of which we are ignorant, are yet somehow derivatively related.
MAN’S MOST PROBABLE DIRECT ANCESTOR
Our critical general examination, now completed, of the nature of evidence for evolution furnished by the structure of animals living and extinct, has brought us to the place where we can examine the facts as evidence which have given such wide currency to the hypothesis that the human species originated from ancestors whose nearest living kindred are the anthropoid apes.
We must first reiterate what has been said several times, making the point more specific than heretofore: There is not the least likelihood that we shall ever know certainly from what particular species or even genus of prehuman animals man descended, or more truly, ascended. Vague- ness on this point is constantly having unfortunate results, with the esoteric as well as with the exoteric. Such common expressions as those about some new discovery of “the missing link” between man and ape, and such undertakings as those of expeditions in search of “the ancestor of man,” arouse interests and hopes, the unwarrantableness of which can only disappoint the credulous and encourage the in- credulity and hostility of the skeptical. We have not the least chance of learning by direct observation from what source, when, or how, man originated, simply because the thing happened ages and ages ago. Common sense readily enough accepts the limitations on knowledge of many past
CERTAINTY AS TO EVOLUTION 53
events. It is well aware that it cannot know to-day any event which happened last year or ten years ago with the same directness and certainty that it could have known them . by direct experience at the time they happened. Only when we become sicklied o’er with the pale cast of thought do we make ourselves believe we are as certain of things sen- sorily unexperienceable as we are of things which are thus experienceable. Nor have we any appreciable chance of learning second-hand, on the testimony of witnesses who did observe man’s origin. Such witnesses left no record of what they saw even if ihey knew what they were seeing.
So long as it is admittedly impossible for any one, no matter how learned, to discover with certainty the parents of a given human individual by knowing his structure alone, just so long will it be impossible to discover with certainty the parent of the human species. Discovery of the prob- able ancestral species will be more difficult than would be discovery of an individual’s parents on the sole basis of knowledge of its structure, in proportion as the origin of a species is more complex than the origin of an individual.
Despite this excessively skeptical attitude (as it is likely to appear at first sight to many evolutionists) we feel that the evidence justifies conclusions of the utmost importance, practical as well as theoretical, even though there is con- siderable disagreement among those most highly informed on the subject. After examination of what is written, and of my own first-hand information (very limited as to technicali- ties, though considerable as to generalities) the conclusion which seems to me most satisfactory on the whole is that reached by William K. Gregory. As to the evidence derived from the resemblances between existing man and existing anthropoids, we have: “‘(1) Comparative anatomical (in- cluding embryological) evidence alone has shown that man and the anthropoids have been derived from a primitive anthropoid stock and that man’s nearest existing relatives
54 PROBLEM OF MAN’S ORIGIN
are the chimpanzee and gorilla. (2) The chimpanzee and gorilla have retained, with only minor changes, the ancestral habits and habitus in brain, dentition, skull and limbs, while the forerunners of the Hominidae, through a profound change in function, lost the primitive anthropoid habitus, gave up arboreal frugivorous adaptations and early became terrestrial, bipedal and predatory, using crude flints to cut up and smash the varied food.” *°
Rewording the first of these paragraphs in conformity with the results of our study of the logical processes involved in reaching the conclusions, we have the following: Exami- nation of the comparative anatomical (including embryo- logical) evidence alone shows that the hypotheses that man and the anthropoids were derived from a primitive anthro- poid stock and that man’s nearest existing relatives are the chimpanzee and gorilla, are far more probably true than are any other hypotheses that have been proposed on the matters at issue. I have little doubt that this reworded sentence expresses more exactly what was really in the au- thor’s mind than does his own language. Nobody knows better than Gregory himself that the evidence referred to does not show for a certainty (as the wording implies) that man and the anthropoids have been derived from a primitive anthropoid stock.”
While it is highly probable that the chimpanzee-gorilla group is genuinely blood kindred to man, the evidence makes probable in almost equal degree that neither chimpanzee nor gorilla are in man’s direct ancestral line. The anthropoids have reached their culmination in the gibbon, orang, chim- panzee and the gorilla. Discussing this topic, John M.
16 “Studies on the Evolution of the Primates,” by William K. Gregory, Bull. Amer. Mus. of Nat. Hist., 1910, Vol. XXV, pp. 239-255.
17 Jt appears to me that there are two practical advantages in guarding statements of this sort more carefully than most authors are wont to do. One of these is the avoidance of the charge of being dogmatic so often
made against men of science by those who are not very sympathetic with science. The second is that such carefulness promotes attention to the
CERTAINTY AS TO EVOLUTION 55
Tyler ** says: “Every one of them approaches or resembles man in some respect more closely than does any other of them, and every one differs from him in certain important characteristics.”
The practical question then becomes that of what con- clusion the evidence warrants as to man’s general as con- trasted with his specific ancestry. This is in conformity with the logic of the situation which does not permit us to anticipate that we shall ever know from what particular anthropoid species man sprang. Turning to the actual evi- dence, we come back to our familiar realization of depend- ence on resemblance. Undoubtedly paleontology is giving us distinct help here. Southern Asia has yielded fossils de- rived from several species of primates including some an- thropoids. These have been discovered particularly by the Geological Survey of India and have been studied with great care and skill, according to Gregory, by Dr. Guy E. Pilgrim.
Teeth are the most important objects among these fossils and certain resemblances of some of these to human teeth are striking indeed. Thus Gregory gives, on Pilgrim’s de- terminations, a comparison between the breadth indices of all the lower cheek teeth of man and those of one of these creatures (Sivapithecus) as follows:
Sivapithecus Man MOAR eo We nonin 0% iid a is | 037 91.6 PAE TANAT: S055 ga bias 0 ataie 94.6 04.4
differences between different hypotheses touching the same matter, which in turn promotes appreciation of the common ground there is almost sure to be for such hypotheses. Scientific men not infrequently dwell upon their differences of opinion to an extent and with a vehemence that is entirely out of proportion to the importance of their differences as compared with the importance of their agreements. This is detrimental from the standpoint of science’s rdle as a torchbearer for general public enlightenment. Perhaps at no time and on no question has there been greater need that all there is of solidarity in science shall be openly manifest than just now and on this very question of man’s nature and origin. 18 The Coming of Man, p. 38.
56 PROBLEM OF MAN’S ORIGIN Sivapithecus Man
ICSU MMOUAL cb 54 cin cs eee eee 92.1 92. Fourth. premolar ©. s:.0). 7. arene 116.5 112.7 Lbird premolar: y..2:. ion. eyeaes IIO.1 111.6
No competent anatomist or paleontologist would make too much of such a resemblance as this, especially since it is merely quantitative. He would suspect that it is too close to be allowed face value as indicating general resemblance and real kindred. As a matter of fact the tooth and jaw characters do not on the whole bear out what is suggested by these measurements, though the premolars are said to approach the human type in fundamental pattern. The canines, however, are sharply apelike instead of manlike. Only after the comparison has been extended to all the parts and features available for examination can the best possible valuation of the resemblances and differences be reached.
Gregory’s summing up from the studies by both Pilgrim and himself of these Indian fossils, may be taken as what is justifiable on the basis of the few parts of the creatures thus far discovered. He writes: “The ancestral chimpanzee- gorilla-man stock appears to be represented by the Upper Miocene genera Sivapithecus and Dryopithecus the former more closely allied to, or directly ancestral to, the Homini- dz, the latter to the chimpanzee and gorilla.” Then fol- lows a statement whose justification and significance come far more from the evidence as a whole than from that fur- nished by these Indian fossils alone. ‘Many of the differ- ences that separate man from anthropoids of the Sivapithecus type are regressive changes, following the profound change in food habits above noted. Here belong the retraction of the face and dental arch, the reduction in size of the canines, the reduction of the jaw muscles, the loss of the prehensile character of the hallux. Many other differences are sec-
CERTAINTY AS TO EVOLUTION 57
ondary adjustments in relative proportions connected with the change from the semi-gression to fully terrestrial bipedal progression.”
Concerning the relative structural resemblances between man, chimpanzee, gorilla and other primates, the labors of Arthur Keith have furnished important evidence. He tells us ** that between 1890 and 1900 he made complete dissec- tions of more than eighty animals extending the comparison to more than a thousand characters. This comparison brought out the fact that the number of points in common (resemblances) are greatest of all between man, gorilla, chimpanzee, and orang, and that there is a distinct falling off of resemblance on passing to the old world and still more to the new-world monkeys, especially when the Lemurs are reached. Could the comparison have been carried to any mammalian genera below the Lemurs, the falling off would be still more striking, bringing out the genus resem- blance between Homo and the anthropoid genera still more sharply.”
MAN AND THE SOLIDARITY OF THE ANIMAL KINGDOM
As a purely observational matter we are bound to recog- nize that in structure man’s resemblances to the higher primates, and especially to the chimpanzee-gorilla group, are closer than to any other living beings. Hence the conclusion, on the basis of resemblances as indicative of common origin among living beings, that man’s genetic kinship to the chim- panzee-gorilla group is closer than to any other group.
19 “Klaatch’s Theory of the Descent of Man,” Nature, Vol. 85, Feb. 16, I9II, p. 508. oie
20 For the benefit of readers not versed in the practices and principles of zoological classification it should be said that the “common” char- acters entering into this discussion do not by any means include all the resemblances between the several organisms compared, but only such as are common in characterizing the different genera to which the organisms belong. The four-chambered heart is common to many other genera of mammals as well as to those here compared.
58 PROBLEM OF MAN’S ORIGIN
Does the fact that the definitive resemblances (hence, supposedly the genetic relation) between man and other creatures diminish as we go down the scale, mean that they disappear entirely if we go down far enough? Not at all. The resemblances diminish only with respect to those at- tributes made use of in the comparison. When we draw other attributes into the comparison we find the scope of the resemblances broadening. The hordes of multicellular animals have nervous and muscular systems of some sort, as man has; the cellular constituents of both these systems are much alike everywhere. Even unicellular animals are by no means devoid of resemblance to man, many features in the structure of their cells resembling the cell structure of man. Finally all plants as well as all animals have certain likenesses to man, being composed of cells which have many things in common with the cells of the human organism.
The different emotional effects on us of recognizing re- semblances between ourselves and all other living beings, and discovering scientifically that these resemblances are probably due to actual physical kinships, is great and im- portant. The recognition of these resemblances is easier than is the discovery of their meaning, and hence, the former makes a more general appeal than the latter. For instance it would hardly be stretching the truth to say that poetry is rooted in such recognition. Would it be untrue to dis- tinguish poetry from science by saying the first concerns itself chiefly with the likenesses of external objects and that the second concerns itself chiefly with their differences?
The distinguished surgeon, W. W. Keen, has presented his personal experiences on recognizing certain resemblances between man and brutes. “Not from the controversial side or from general arguments,” we read, “but from a plain statement of a series of facts, many of them drawn from my personal experience as a surgeon and anatomist,” would he exhibit evidence which ‘‘to my mind absolutely demonstrates
CERTAINTY AS TO EVOLUTION 59
the solidarity of animal life, more especially in the verte- brates, such as fish, birds, other mammals and man, the highest mammal.” *?
The specific instance relates to brain structure and in- volves the phenomenon of localization of motor centers in the cerebral hemispheres. The incident goes back to a time when knowledge in this field was meager as compared with what it is now. He says: “In 1888, I reported my first three cases of modern surgery of the brain. Attending the meeting of the American Surgical Association in Washing- ton, when I read this paper, was Sir David Ferrier of Lon- don. He had contributed very largely to this then wholly new mapping of the brain centers which control motion. In one case, I described how I had stimulated a certain small, definite motor area in the brain of my patient by a battery, and described the resulting movements of the arm at the shoulder. Ferrier afterwards said to me, ‘I could hardly restrain myself from leaping to my feet, for this was the very first demonstration on the human brain of the exact identity of my own localization of this very center in an- imals.’” After giving a few other instances of his own experience in this same field Keen writes: “Do not such exact localizations of the brain centers in animals, as directly applied to man, in hundreds, if not thousands of operations by now, most closely ally man to animals?”
The other instance we will take from Keen hinges upon the fact that if the vagus nerve be divided in a cat, several results follow, among them being: (1) The pupil of the eye on the same side diminishes from the normal large sized pupil of the cat to the narrowness of a thread. (2) The corresponding ear becomes very red from increased flow of blood. The blood vessels become greatly dilated. (3) On that side there is an increased sweating due to increased
21“Surgical and Anatomical Evidence of Evolution,” by W. W. Keen, Science, June 9, 1922, p. 603.
60 PROBLEM OF MAN’S ORIGIN
activity of the sweat glands which in turn results, partly at least, from the increased blood flow. (4) The temperature of the affected area is increased. Keen’s incident reached back to the impression made upon him by a picture of a cat’s face and eyes which he had first seen as a medical student in Dalton’s textbook of physiology. In this picture one of the pupils was much smaller than the other conse- quent upon division of the vagus nerve on the side of the reduced pupil.
The narrative follows: “In 1863, during the Civil War, when I was assistant executive officer of a military hospital, one day a new patient approached my desk just as I was about to sign a letter. The moment I looked up at him I was struck with his appearance and instantly said to my- self, ‘Surely you are Dalton’s cat.’ ‘Where were you wounded?’ I quickly said. He pointed to his neck and I said to myself, ‘His sympathetic nerve must have been cut.’ Further observation showed the reddened ear, the increased temperature, the sweating and the greater flow of saliva, thus confirming in every particular the results of Brown-Se- quard’s experiments on animals. It is interesting to know that this was the very first case in surgical history in which division of the sympathetic nerve had ever been observed in man.’ Usually such an accident means severing the ca- rotid artery and immediate death. Further experiments on this nerve in animals have “revealed a wholly new world of most important phenomena,” all of these being just as true for man as for the other animals.
Keen is a convinced evolutionist, and his convictions rest largely on just such evidence as he gives here. Is his rational acceptance of the theory as potent with him as his emotional attitude, engendered by his recognizing the resemblances de- scribed? While he uses the term evolution in the title of his paper when he summarizes the meaning of his illustra- tions he does not use the word in a single instance. “Do
CERTAINTY AS TO EVOLUTION 61
not such exact localizations of the brain centers in animals as directly applied to man . . . most closely ally man to animals?” Further: Here, again, you perceive the solidarity of the animal kingdom in such identity of function that the thyroid gland of animals . . . performs precisely the same function as the human thyroid.” (Italics are the present author’s.)
Keen is apparently more convinced of the solidarity of the whole animal kingdom than he is of the relation of all animals by actual genesis. This feeling for “solidarity,” is more to him than is his logical conviction of the truth of the evolution theory. ‘Do not so many such exact parallels be- tween the human and the animal body strongly suggest a close interrelation of the two?” Undoubtedly they very strongly suggest such relation. But do they prove it? It would seem from Keen’s language so far examined that he is dubious on this point. However, in the following we have his own answer: “Man’s ascent from an animal of low in- telligence seems to me to be absolutely proved by the many phenomena which reveal identical organs and physiological processes in the animal and the human body.”
Keen’s deductions from the evidence would be entirely acceptable to most present-day evolutionists. They would accept, as we do, his conclusion about the solidarity of the whole animal kingdom, man with the rest, but they would also accept his conclusion that man’s ascent from a lower animal is “absolutely proved” by the evidence. Yet our discussion has shown conclusively that the evidence does not “prove absolutely” man’s origin in this way. It proves only that his origin thus is vastly more probable than is his origin in any other way that has ever been suggested.
62 PROBLEM OF MAN’S ORIGIN
THE INFLUENCE OF MAN’S BELIEF IN HIS OWN EVOLUTIONARY ORIGIN ON HIS SELF-RESPECT AND CONDUCT
This discussion of the evolution theory in its application to man must end in a brief examination of the effect the theory tends to have on man’s view of himself. How does it influence him rationally and emotionally? Does it enable him to understand his own life more, or less, truly, and to order it more, or less, wisely than do the other theories which it would supplant? If man should become entirely con- vinced that he is blood-kin to the whole living world, is part and parcel of nature, will this make him think better or worse of himself than if he should become convinced, as he has so long believed more or less positively that he orig- inated in a different way, and stands in a different relation to the natural order? Would the final establishment of the hypothesis that he originated from ancestors which were not man but something much his inferior, make his self- respect more genuine and potent? Or would it commit him for all time to the spiritual slough of cynicism and pessi- mism relative to mankind generally, which has been such a blight on the neo-Darwinian view of human life?
In the present stage of our enterprise our answer to this query can be only an expression of personal conviction. An adequate presentation of the grounds of the conviction must be reserved for future presentation. This conviction may be summed up as follows: From the doctrine of or- ganic evolution comes to us the fullest revelation attain- able of man’s moral nature, no less than of his physical nature. Faith in kindred by descent, that is, by evolution, of all mankind, known directly through sense-experience and indirectly through emotional response plus rational infer- ence, is the substance out of which has been woven the entire fabric of civilized life. The conception of the brotherhood of the human species will become potent for human conduct
CERTAINTY AS TO EVOLUTION 63
only through recognizing that such unity is rooted just as truly in the physical as in the spiritual nature of man, and is validated by his reason no less certainly than by his affec- tion. The culminating human usefulness of the doctrine of organic evolution lies in its revelation that the totality of relations among all the members of the human species which conditions the highest good of them all, called the moral law, is natural law, and must be so understood and practiced to accomplish the greatest benefits of which that law is capabie.
From the doctrine of universal evolution comes the full- est revelation of man’s religious nature. The narrower, intenser unity of man is but a segment in the all-embracing unity which is the matrix and source of all our under- standing. From such gradually verified conceptions as the web of life, solidarity of the animal kingdom, and the limitlessness of natural bodies dynamically related into a true universe, arise all our strength and faith as well as our understanding, regardless of whether our reason con- ceives and our language names that unity as infinite nature, or as the living God.
From these combined sources come the perception that science is not religion, and religion not science, but that each is the complement and fulfillment of the other. Re- ligion is the common magma of all emotional life as science is of all rational life. Religion is the individual’s mighty reservoir of spiritual impulse and energy upon which all wisdom for personal and social life must freely draw in order that it may attain its greatest scope and efficacy and richness.
The supreme desideratum for man in this era is that he should understand the evolution theory to the end not merely of believing it but of living it. For man to live evolution means that so long as he is truly living he must be in some measure truly developing.
CHAPTER 5. SUCCESS AND FAILURE IN ANIMAL ACTIVITY
SOURCES, TRUSTWORTHINESS, AND ORGANIZATION OF DATA
THE task of getting before us enough data on activities in the animal world to serve as a basis for broad conclusions relative to the meaning of these activities for human life is basic for the standpoint of this book. It is therefore important that the source of the data and the methods of securing them should be placed before the reader at the outset.
The material appertains largely to animals living their lives in their own way under natural conditions. Students of animal psychology have for the most part regarded data of this kind with little favor. Recognizing the impossibility of getting evidence for analyzing such aspects of the animal mind as they were interested in without themselves control- ling the activities of the animals, these investigators have largely restricted their efforts to laboratory experimenta- tion. Furthermore, so fragmentary and lacking in critical spirit is much of what is told by out-of-door naturalists as to the doings of animals that it has appeared little of value could come from field studies.
Nevertheless, if one is more interested in the way an- imals solve their own problems than in the way he may solve his problems of their psychology, his only recourse is to do the best he can toward learning what the creatures do in the state of nature. This calls for study of them in nature by any means possible, whether by watching them with no interference whatever on the watcher’s part; by such interference to a limited extent; or by carefully ex-
64
ANIMAL ACTIVITY 65
amining their “works” when they are not around. The life- problems of animals must be solved, with insignificant ex- ceptions, as nature imposes them; otherwise the conclusions drawn by the investigator as to their problem-solving abili- ties and methods are deductively rather than inductively arrived at, and subject to all the dangers of the deductive procedure.
The question of the trustworthiness of the factual data is crucial. Here as in connection with the raw material of all scientific research two questions must be satisfactorily answered: Were the observations themselves accurate and adequate? Are the facts used as bases for generalizations thoroughly typical? With these touch-stones of the trust- worthiness of data in mind the reader must judge for himself whether the factual underpinning we are about to lay is strong enough to carry the superstructure to be erected upon it.
The question of who made and reported the original observations is particularly important. A respectable frac- tion of the matters of fact presented is of my own gathering. Rather extensive personal observations have been made through many years on the doings in nature of a number of widely separated animal groups. Beavers, one species of woodpecker, and a few species of ants, have received especial attention.
But such a wide range of data is needed that great de- pendence must be placed on the work of other observers. The most careful discrimination as to what is and what is not trustworthy is essential. The interpretation placed upon animal activities is liable to be influenced by what the reporter knows or believes concerning human ac- tivities. Observers who are genuinely fond of animals, who are strongly sympathetic with them, tend to overhu- manize the activities, to put them in too favorable a light. Observers who are emotionally negative or positively hostile
66 ANIMAL ACTIVITY
to animals tend to underestimate such man-likeness as their activities have. Observers who are emotionally neutral to- ward animals but look upon them from an extreme mechanis- tic standpoint tend to unduly mechanize their activities, thus making too little of the organism’s share in its own behavior.
The reported material in this field is fragmentary and chaotic. It has never been critically gathered nor critically studied, because there has been no organizing principle to direct observation and reflection. Such an organizing prin- ciple is operative when we study the activities of any or- ganism with regard to the contribution made by those ac- tivities to the welfare of the organism. When we ask, not only how does the organism respond to a given stimulus or set of stimuli, but how does this response affect the welfare of the organism, we are making more adequate and fruitful application of the experimental method than when its use is directed wholly to the discovery and not at all to the interpretation of facts.
Much laboratory research has been devoted to animal behavior by professional psychologists. The purpose of this research has been primarily the interpretation of “the animal mind.” Such research might be expected to produce the very kind of knowledge we are deficient in. But however much researches of this kind have enlarged our information and enriched our understanding of certain aspects of animal mentality they are able to do but little toward such a testing of activity as we are calling for.
The crucial thing about such activity is out of reach of direct laboratory research. Animal activities are so inti- mately tied up with innumerable other processes presented by the general system of nature that it is impossible to isolate any animal from its natural setting (as in its very essence the laboratory method aims to do) without breaking in upon the original system to such an extent that the ac-
ANIMAL ACTIVITY 67
tivities under the new and simplified conditions cannot possibly be an exact duplication of what they would be under the original conditions. Think of the question of what the individual sparrows or mice or bears of any given area might do during a season so excessively dry as to seriously reduce their normal food supply. Any set experiment which dupli- cated such a situation would lose its character and value as an experiment, becoming as complicated and difficult to cope with in detail as the original.
To have any value for interpreting a given animal activity formal experimentation must be planned and executed with reference to questions defined on the basis of knowledge as broad and accurate as the natural conditions under which it occurs will admit. Experimentation can have no other legitimate aim, so far as concerns the general problem here before us, than to get more light on special details than studies in nature can obtain.
In so far as the acts of animals fall short of perfection, and are therefore judged to be maladapted, this judgment of maladaptation must be made with reference to animal lives under natural conditions. The struggle which we be- lieve to have contributed so largely to making the animal world what it now is has already occurred, and in nature, not in laboratories. Animals under domestication, or in confinement in zodlogical parks and experimental labora- tories, cannot exhibit much of the perfection or the imper- fection of their abilities to act, nor can they teach us much about how they came by these abilities. It makes a crucial difference to an animal whether it is running wild in nature depending on itself alone for water, food, mates, and avoid- ance of enemies, or is shut up in a safe cage with no respon- sibility whatever for its necessities, these being furnished it by a bountiful Providence. Students whose experiences with animals are limited to those which live under these man- made conditions are incapable of treating either their mal-
68 ANIMAL ACTIVITY
adaptive or their well-adaptive actions with full adequacy.
We have drawn as extensively from the zodlogical realm as has seemed necessary to provide a background for an adequate description of human conduct. This man-cen- tered enterprise is approached in a way that appears strange and hostile to man as contrasted with the approaches of generally accredited students of human life. The human anatomist and embryologist draws freely upon any portion of the animal kingdom that will facilitate his description and understanding of such an infinitely complex part of adult man as his brain. Without this freedom of range as to material for research, and the confident acceptance of the evolutional idea of true homology between the human brain and the brains of all other vertebrates, no such fullness of knowledge of man’s brain as we now have could ever have been reached. The comparative method possesses even wider applicability and importance for gaining knowledge of man’s activities. Whereas no human neurologist would pretend to see a strict homology between the parts of the human brain and the parts of the brain of ants or wasps, no human psychologist would hesitate to regard the reflexive and instinctive activities of man and these invertebrate animals as strictly comparable in their basic natures. An- imals are more broadly and in a sense more closely akin in their activities than in the chief structural bases of these activities. The food and mate-getting instinctive activities of insects and humans are more alike than are the mech- anisms of the two groups by which the activities are per- formed. We are no less dependent on comparative psycho- biological studies on brute and human animals in nature for sound conclusions relative to the origin and nature of these activities, than on comparative morphological studies for sound conclusions relative to the origin and nature of structure.
ANIMAL ACTIVITY 69
The fact that on the activity side of animal life we have no “record of the rocks” coming to us from the past is a sore deprivation to students of comparative activity. This makes it all the more imperative that such data as are available should be assiduously collected and critically treated. The extensive deductive studies relative to the prob- able size of the brains of various classes of extinct verte- brates, based on actual studies of the cranial capacities of the fossil skulls, are genuinely instructive. But they can give no satisfactorily detailed pictures of the lives of the individual creatures. How defective must necessarily be any imaged picture we can make of the performances of a Diplodocus as compared with what the real performances must have been! This is one of the animals in which much of the total work done was neurally presided over by an enlarged lumbar section of the spinal cord instead of by the brain, to judge from the size of the neural canal in this region as compared with the size of the portion of that canal represented by the brain case. Researches into the life activities of such reptiles as those modern Australian lizards which depend largely on the hind limbs for locomotion would help toward picturing the activities of Diplodocus. Manifestly we are forever precluded from knowledge of what the daily lives of these creatures of a long by-gone age must have been.
These reflections bring forcefully home to us the impor- tance of any trustworthy bits of knowledge that can be se- cured relative to the activities of extinct animals from obser- vations on objective results of their activities. “Fossil tracks” are perhaps the most common sources of knowledge of this kind, and considerable has been learned from this source about the modes of life of some animals. Another source of raw material for deductive knowledge of the activi- ties of extinct animals is the remains of food either from the
70 ANIMAL ACTIVITY
digestive canals of the animals or from their excrements. These enable investigators to infer something as to the nutritional activities involved.
Material remains of extinct activities, as they might be called, which contribute most directly to psychobiological knowledge, are those that show any sort of constructional ability on the part of the animals concerned. Every bit of man’s handiwork that has been gathered into the great art and science collections of civilized countries which is unac- companied by written records made at the time the objects themselves were made, must be recognized as evidence of this sort. The crude stone implements, and the prehistoric wall-paintings assigned to times thousands of years in the past, are as strictly evidence of extinct activity as is a fossil-worm tube or wasp’s nest.
THE CRITERION OF SUCCESS IN ANIMAL ACTIVITY
Since Darwin’s time all students of living nature have recognized the enormous mortality that occurs over and above what death from old age entails. So general is this phenomenon that some zodlogists and botanists have doubted whether there is any such death. It rarely happens that an organism dies from an inherent lack of ability to live longer. It does not die; it is killed. Vast numbers of in- dividuals of nearly all species fall victim to external destroy- ing agencies before, often long before, old age comes upon them. Countless millions of seeds and eggs and also of the very young of both plants and animals, are destroyed every year by inimical forces of inorganic nature and by parasites and other kinds of organic depredators, in ways against which the victims have not the slightest recourse.
This great victimized world is immobile and helpless; it is a static world so far as its fate is concerned. Thus do we become accustomed to look upon it. A large part of the
ANIMAL ACTIVITY via:
directly observable evidence of destruction among adult higher animals, and of our information about defects that contribute to the destructicn, is morphological. This aspect of life, no matter how complicated and perfect it may be, is inert, passive, static. From all this we have been habitu- ated to associate the great mortality in living nature chiefly with the static aspects of organisms. An unexpressed, semi- conscious contra-theory appears to have grown up to the effect that if an organism is highly active there is no room for question about the quality of the action. The old notion of a sort of divine inerrancy of “instinct” and the tendency in animal biology to think of animal adaptation in morpho- logical terms have conspired to shield all those activities of animal organisms commonly classed as instinctive, from rigorously scientific study as to their significance and effec- tiveness for the organisms performing them. Recent physi- ology has done much to correct the staticism of morphology and to do away with what might be called the theological conception of instinct. The next step in the study of animal activities is to subject to scientific examination the question of how far the activities attain the ends at which they are unmistakably aimed.
Every naturalist whose attitude toward the realm he studies is permeated with feeling as well as guided by reason must of necessity find it more pleasant to dwell on the suc- cesses than on the failures among living beings, especially among those belonging to the higher orders. We are better satisfied with the sleek, well-shaped, vigorous dog or horse, than with rough-haired, scrawny, or mutilated individuals. Nobody really likes down-and-outers. When we speak of the beauties, the wonders, the harmonies, of animate nature we mean that those aspects of the great scheme of things which impress us in these emotional ways are the successes of nature.
It cannot escape the notice of anybody who observes
72 ANIMAL ACTIVITY
animals that some individuals of any species or variety are much finer, much more pleasing to look at and to be in- terested in, than others. It does not require very extensive zoological knowledge to discover that, much of this kind of difference among individuals is connected with different de- grees of success in the activities characteristic of the organ- isms. The “lean and lank” or “scrawny” condition of cer- tain individuals is seen to be due to the failure of the creatures’ food-procuring or food-using activities. We are apt to attribute conditions of the sort indicated to shortage of food and let the case go at that. We are apt to charge the whole responsibility to the environmental side of life. Buta moment’s reflection will convince us that this way of dis- posing of the matter is inadequate. The fact that an or- ganism has the ability at all to seek for food means some ability to meet special conditions. In a special case of food scarcity what happens to a creature is essentially a matter of how far he can go by virtue of his seeking ability. In this very matter of the extension of the food-procuring and food-using activities is found one of the most important factors in the development of the higher animals from the lower, and in making man the most successful of all crea- tures.
The term “maladaptation” is convenient as a name for all kinds and degrees of falling short of completeness in any type of structure and of success in any kind of action. The nature of our undertaking will require us to examine the maladaptive side of activity somewhat more extensively and closely than the well-adaptive side. Works on the natural history of animals are very inadequate in dealing with this general subject, and especially with unsuccessful activities.
ANIMAL ACTIVITY "3
ACTIVITIES CLASSIFIED AS LIFE-OR-DEATH AND LIFE-FULFILLING
After all is made that possibly can be made of the lives of creatures long since dead and gone, our main reliance for the task in hand must be the actually observed performances of living creatures. The task before us is to examine as critically as possible typical activities of animals, from the smallest, simplest creatures known to us up to and including man at his best, with a view to learning all we can about the effectiveness of stich activities for conserving and promoting the lives of the creatures.
When the whole round of animal activities is viewed with reference to the welfare of the animals performing them, three groups, or categories stand out with boldness. No animal ever fails to reveal his awareness of the absolute necessity for food, using the term to include every class of materials which must be taken from external nature in order that the organism may continue to live in health and strength. The unqualified self-centeredness of this category of needs and activities is almost as striking as are the needs and activities themselves. That no living thing can meet an animal’s food needs as long as it is living, is an impres- sively ego-centric fact. Nothing alive is useful for this pur- pose to any of us until it is dead.
How different in kind is another group of needs with its corresponding activities! The mate, no less imperatively needed than food by all highly developed animal organisms, must be as fully alive as the needy individual itself. The activities the réle of which is to satisfy these needs cannot possibly be ego-centric in the sense in which the food-secur- ing activities must be. In mating the aim is as positively other-conserving as it is other-destroying in food-getting.
The third group of needs and corresponding activities is less sharply delimited than are the other two, but no less
"4 ANIMAL ACTIVITY
real and imperative. The fact that health, and life itself, are subject to countless inimical external agencies escapes the attention of nobody, even members of the most assid- uously “safety first” communities. When it comes to those ages of human life and those places of its habitation wherein not much has yet been done by man to secure himself against these agencies, dangers beset him so thickly on every side that the need for activities in behalf of safety, and so the activities themselves, are as much in evidence as are those of the other two groups.
It is not contended that all the needs and activities of brute, much less of human, animals are included in these three groups. Since successful life at any level is condi- tioned on the fulfillment of these three groups of needs, the degree of success of activities relative to these groups will be a true measure, so far, of the efficiency of all organic activity. These three groups of activities are, from the standpoints of the species and of the individual, life-sustain- ing activities. Unless they are successfully performed, na- ture puts a check, abrupt and unmistakable, upon the life- adventure of individual and species.
There is another large group of activities which may be designated as life-fulfilling. As responses to stimulatory agencies these are as inevitable, as normal, as natural as are responses to agencies which answer to the organism’s life- or-death needs, but they do not contribute anything to such needs. Light reaching my eyes from a wayside stone is as stimulatory as is light coming from a loaf of bread; and the light from neither source tells me anything about the nature of either object. In order, therefore, to fulfill my responsive nature I am as much bound to respond to the useless as to the useful agency.
From this universal but undiscriminating character of responsiveness it comes about that the life-fulfilling activities
ANIMAL ACTIVITY 75
have great importance in organisms in which they are as numerous and varied as they are in man. They engage us in detail in the companion volume of this general enterprise; so far as this book is concerned we shall consider human activities chosen from the same life-sustaining groups of activities as have furnished the material for the examination of brute activities, and shall classify them under the same general kinds of successful and unsuccessful activities.
CLASSES OF MALADAPTIVE ACTIVITY
The character of the maladaptive activities found by us in this study only confirms and extends results previously reached by other investigators.. Thoughtful students of animal activities sum up their conclusions in some such phrase as, “All instinctive activity is wasteful.” Although this is too terse to be unqualifiedly true, it contains unescap- able truth. The wastefulness and otherwise maladaptiveness of instinctive activities result in part from the ever-present liability of organisms to overdo, i.e., to perform a useful, or at least a harmless, act more times than are necessary to yield the best results for the organism itself. This may be desig- nated as the tendency to excessiveness. This excessiveness may be wasteful of the animal’s energy and time, and may even work positive harm. The woodpecker, equipped to store
1 The maladaptivity of animals in what they do has received relatively little special attention by experimentalists. We are acquainted with the work of no one who has approached the subject from the side of the experimental control of animal activity who seems to have come so near conceiving the problem as it is conceived by us as does the psycho- pathologist, G. V. Hamilton. His important book, An Introduction to Objective Psychopathology (1925), to which R. M. Yerkes contributes a significant foreword, escaped us until our book was nearly through the press. It would otherwise have received more attention. This author’s thought appears to run parallel with ours in several particulars, most notably, perhaps, in recognizing the large part played by imperfect adaptation in the doings of animals, brute and human, and in perceiving the transcendent importance of reason, especially human reason, as a corrective of the imperfection.
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nuts in holes which he has pecked in trees, pecks far more holes than he ever fills, and fills far more than he or his fellows ever empty. If a woodpecker’s time and his acorns are worth anything to him (and they certainly are if his life is worth anything to him) this excessiveness of activity is wasteful and may be positively harmful.
The organism tends not only to excessiveness but also to misdirection of otherwise advantageous activities. The woodpecker who stores pebbles instead of acorns has plainly chosen the wrong objects for his activity; judged as a food- storing enterprise this undertaking is a failure, however neatly the pebbles are fitted into the holes.
So vast in quantity is the material available for such an undertaking that the use of more than a small fraction of it is out of the question. Practically the problem is one of making such selections from the data as will be most widely illustrative of the basic phenomena and most cogent and con- vincing as to the general conclusions reached. As should be expected the two great zodlogical subdivisions of arthropods and vertebrates have furnished a large majority of the in- stances used. Even from these subdivisions selection has had to be restricted. Entire major divisions, as for instance that of fishes among vertebrates, have been requisitioned but little, though innumerable data are here available.
CHAPTER 6
SUCCESSFUL ANIMAL ACTIVITY
Ovr central requirement in the criterion of success will be attainment of welfare—welfare of the individual creature performing the act, and welfare of the group of which the individual is a member. The mere bringing to a successful conclusion of a specific set of activities, as those involved in a piece of construction or in the accomplishment of a journey, does not constitute success as we shall use the term. The final test of successful animal action is not found in any material product or immediate accomplishment but in the administration of that action to the life of the animal, individual and group. Were a food-storing rat or squirrel to lay up enough grain or nuts to make an ample food supply for a long winter, this of itself could not be accounted full success. Such could only be ascribed to the accomplish- ment when the stores had actually done their part in pre- serving the animal the whole winter through. Should hard rains or some marauding’ enemy destroy the stores before they had been eaten by their owner, the storage work would fall short of real success. It would have to be regarded as defective in not providing adequately against such destroy- ing agencies. No matter what else may be included in wel- fare, the continuance of existence in the individual and in the species, and the continuance of some measure of func- tional efficiency, is basal. When life terminates in an or- ganism, or comes so near it as to render the organism utterly helpless, the term welfare can hardly be said to have any meaning as applied to that organism.
There are many activities which, though typically pro- motive of welfare, become positively subversive under some conditions, as when carried beyond a certain quantitative
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optimum. Eating, no matter how good the food or how much needed, may be carried to excess by any organism.
Many kinds of activity other than those indispensable to the mere continuance of physical existence in health, effi- ciency and comfort are highly promotive of welfare in man and in many animals below man. We have:to recognize spiritual welfare, welfare that is psychical in the broadest sense, as well as physical welfare. The idea of welfare can be extended without ambiguity to a great range of activities, covering some of life that is physical and some that is spiritual or psychical, by defining welfare as being nearly synonymous with the common expression: “fullness of life.”
In examining the activities of animals for the purpose of ascertaining their successfulness it will be convenient and sufficiently accurate to recognize these activities as occurring at three levels of complexity.
AT THE LEVEL OF REFLEX ACTION
At this level the action is an immediate and often direct response to a stimulus. It is relatively much more impor- tant in the lowly animal orders, as in the ccelenterates and molluscs. The direct though slow contraction of the ten- tacles of sea-anemones and hydroids has been seen by most persons who have had experience at the seaside. The prompt closure of the open shells of the living clam when the mantle edge is touched is also familiar. The closure of the clam’s shell is a less direct response than is the con- traction of the anemone’s tentacles, for the stimulus must be transmitted from the mantle to the muscle of the shell hinge. The stimulus is applied to one organ and the response is in another some distance away, whereas in the case of contraction of the tentacle, response and stimulation per- tain to the same organ. The lightning speed with which the tube-dwelling annelid worms disappear into their tubes
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upon the slightest contact of their tentacles with foreign bodies, is well known to frequenters of the seashore. In these animals the action, always regarded as reflex, is executed by the body muscles as well as by the tentacles, though the stimulus is applied to the tentacles rnly.
Tn ali these cases there is no ground for doubting the general usefulness of the actions to the creatures, nor can there be any doubt about the successfulness of each specific act in most instances. If the mussel’s shell and the annelid’s tube are real protections of the creatures against enemies, or against desiccation when the animals are left high and dry every day by the outgoing tide; and if the closures are perfect, as they usually are, there seems nothing to be said against the completeness of the success of the actions which accomplish them. On the whole it is beyond question that a great range of reflex activities in animals are successful even as judged by our rather exacting test of success. The importance of such success is particularly striking in those animals in which this type of action constitutes the whole repertoire of activities upon which their lives depend.
While it is true that in all higher creatures other types of action play a far more dominating part, the reflexes are still indispensable. Except for the constantly successful performance of a great number of reflex actions there could be no successful life; in the entire absence of such reflexes there could be no life in us at all. The major portion of the digestive, respiratory, circulatory and reproductive func- tions, upon which continuance of life in the individual and the species is absolutely dependent, is accomplished by ac- tivities of this sort.
AT THE LEVEL OF INSTINCTIVE ACTION
The second type of activity which our examination will recognize we shall call instinctive. For the purpose of this
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discussion, we need not be concerned with the question de- bated by modern psychologists as to what instinct is, or whether there is any such thing. We are in need of a de- scriptive term for a kind of activity of animal organisms which is unmistakable throughout a great part of its range. Those actions which are common to all the individual or- ganisms of the same natural kind or sex of that kind, the performance of which implicates many parts or the whole of the individual, and which do not have to be learned, we shall characterize as instinctive.
In no other classes of animals does instinctive action come to quite as clear expression as in the insects and spiders. As a first illustration we will describe the nest-building operations of the trap-door spider. Since I have watched ‘this operation being performed by very young individuals it is worth while to describe it somewhat fully. These spiders, representative of several species inhabiting a large area of southwestern United States and adjacent Mexico, make their nest by digging a cylindrical hole in the ground, lining it with a thin layer of web-material, and closing the entrance with a lid attached by a hinge to the edge of the orifice. The nicety of fit and ease and efficiency of action of this “‘trap-door” elicit the admiration of all who examine the structure. The lid, which is composed chiefly of hard sun- dried dirt reénforced by web-material and especially by an inside covering of this material, is beveled at its margin all around, and fits so perfectly a corresponding bevel inside the rim of the hole as to make the closure almost water- tight. At least, the closure excludes absolutely any wasps or other small creatures that might try to enter the nest through the doorway. The bore of the full-sized nest of the California species with which I am familiar is an inch or more in diameter, and the depth is four to seven inches.
The young spiders, though essentially the same in struc- ture as the adults, are very small, not more than two or
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three millimeters in length. Yet these young, relatively mi- nute spiders construct a miniature nest exactly on the pat- tern of, and almost as perfect as, the adults’ nest, though they have never seen the adults perform the task nor had an opportunity to examine a completed nest.
Enough details will be given to enable the reader to ap- preciate something of the elaborateness, orderliness, and exactness of the activities involved. The baby spider begins by making a hole in the moist clayey ground, the mouth of which is sharp edged and almost a perfect circle. The diameter is just exough to permit the animal to go freely in and out, about three millimeters. The depth of the hole at this stage is sufficient to permit the animal to enter and hide himself completely in it. So far the hole seems to be made more by pushing the body into the ground than by excavating. Lid-making soon begins and is prosecuted in the following way: A minute projection is made at some point on the edge of the hole’s mouth, by the combined use of the two front pairs of the spider’s appendages. To this projection additions are made by particles or pellets brought from within the hole, probably from the bottom, deepening of the hole being thus combined with constructing the lid. Following every deposition and fixation of a load of earth by the anterior appendages, which implies that the animal comes to the place of deposit head-end up, a descent into the tunnel and a reversal of ends are made. Then follows a backing-up to the mouth of the tunnel, a placing of the tip of the abdomen against the edge of the lid-to-be, and a moving of the tip over the surface. This performance is undoubtedly accompanied by a discharge of web-material from the web-secreting gland which is located in this part of the body.
The two acts of bringing earth from the depths, the animal being head-end uppermost, and depositing it on the expand-
| ing lid; and of discharging web-material on the earth, al-
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ternate with perfect regularity until the lid mass has become broad enough to completely close the orifice of the tunnel. But a mere cumulation of materials, clay and web-substance, would not make the lid. Obviously there must be some gen- uine fashioning of materials. This modeling of raw materials into the nicely fitting, freely working trap-door is the really astonishing part of the whole operation. Each deposition of clay is immediately followed by a shaping operation, this being done chiefly by the same body members by which the earth was brought to the lid and put in place. By this means the lid is given its proper circular outline and thick- ness. After the lid has become broad enough to reach nearly across the orifice it is pulled down from time to time with sufficient force to do considerable toward beveling its own and the mouth’s edges for producing that nice fit which is so conspicuous a feature of the completed product. Fol- lowing each trial closure the lid is pushed open again for further construction work.
Two of my most vivid memory pictures of the operation, the whole of which I watched with such thrills of expectancy and surprise as to make me almost dubious at times about the trustworthiness of my eyes, must be specially mentioned. One of these pictures is of the little animal’s abdominal tip being rubbed back and forth around the circumference of the nearly completed lid. A house-painter’s brush or a plasterer’s trowel could hardly work with more efficacy. The other special performance, even more startling than the first because less regularly done, consisted in pulling down the nearly finished lid, finding where the closure crack was widest, and then promptly pushing up the lid and refashion- ing it at the defective spot. It seems almost incredible that this last-mentioned act could be instinctive, yet such it must have been if judged by the characteristics of such actions as given above. It is certain that these spiders had no chance to learn the process they went through or even to do it by
\ >
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sheer imitation, for immediately upon hatching they had been taken from the parental nest into the laboratory and placed by themselves in a large dish containing moist earth.
This illustration of instinctive action presents evidence that the process was not learned but that the ability for it must have been obtained by inheritance from the creatures’ ancestors, and that the ability is probably a common pos- session of all normal individuals of this species of spider. This particular observation was limited to members of only one brood. But since there were some dozens of these; since most of them were at work in the same way; and since observations on activities of other species have shown this commonness of ability, we are safe in presuming that all normal trap-door spiders, whether young or old, can con- struct the same kind of nests about equally well, and with- out having to be taught to do it. That nest construction by these spiders is a success in a majority of cases is certain. Were this nct so the species would presumably have become extinct long ago.
There are innumerable other activities in the insect world and in many other animal classes, which are as unmistakably instinctive as is the nest-building by the trap-door spider, and as unmistakably successful. One other very striking form of such activity among bees and wasps is found in the wide range of cases in which the mother makes a nest solely for the young, deposits in it not only her egg or eggs but also food for the young, then leaves the whole accomplish- ment to its fate, either completely abandoning it or, in some cases, dying. In such a scheme there can be no possibility of the young mother’s acquiring the building art from her parent either by direct imitation or by formal learning, since she never sees her mother; just as, in turn, her offspring will never see her.
It is difficult if not impossible to find such elaborate and clear-cut instances of purely instinctive activity among any
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of the vertebrate classes as these noticed among the higher arthropods. Especially among the higher vertebrates, the activities are modified from the hard-and-fast hereditary and mechanical type, in the direction of what we call intelligent action. That the ancient type of action still predominates even among the highest vertebrates below man there can be no doubt. Among the lower vertebrates, fishes, amphibians and reptiles, activity is almost wholly instinctive, but it rarely attains to such elaboration and nicety of detail as it does among the best of the arthropods. The lower verte- brates, notably the great piscine tribe, must be looked upon as less well off from the standpoint of mentality than the higher arthropods, being the inferiors of their arthropodian kindred in perfection of instinctive activity but not yet hav- ing attained more than the earliest stages of modification in the direction of intelligent activity. The real significance of the lower vertebrates, more particularly the amphibians, may be said to lie in the developmental possibilities, both physical and mental, which their type of organization gives them.
Two unmistakable examples of instinctive activity among vertebrates which are almost as “pure” as any to be found among arthropods are furnished, one by fishes and one by birds.
The fish example is furnished by the Grunion (Leuresthes tenuis) from the coast of California. It has been long known that at its breeding time in March and April this species comes in vast numbers onto sandy shores at high tide. Only recently has the full meaning of this performance been worked out. Thanks to the investigations of Mr. Will F. Thompson we now have a fairly complete picture of what happens during the exciting night runs of these fishes.1. Fer-
1 The Spawning of the Grunion (Leuresthes tenuis), California Fish and Game Commission, Fish Bull. No. 5, 1919, pp. 1-29.
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tilization of the eggs is accomplished as the commingled females and males are thrown upon the beach by the waves. The females become partly buried, tail downward in the sand, where the eggs are “planted” with a shallow cover of sand over them. The planting ground being near the upper limit of wave action at the full-moon high tide of a given month, remains undisturbed by further wave action until the next run of high tides, approximately two weeks later. During this period the embryos develop to the hatching stage within the tough egg membranes. When the next high tide comes the encased embryos are washed out of the sand, and the wetted membranes so softened that the little fishes are enabled to escape into the water and be carried by the retreating waves into the sea.
Certain points of similarity between this and such re- productive procedure among bees and wasps as was re- ferred to above are obvious. Perhaps the most notable of these is that the mother fish, like the mother wasp, goes through a definite and rather complex set of activities in depositing her eggs, the chief significance of which has ref- erence to the welfare of the young yet to be, she herself taking no further part in the business, even to the extent of being present to see what goes on. As a consequence, with the fish as with the wasps, there is no chance for the young to learn from their mothers what to do when they in turn are to become mothers. In the one species as in the other the ability to perform the acts essential to the next generation is inborn, instinctive. With the fish as with the insects there is no evidence that any of the new-born fe- males are devoid of this peculiar ability. All alike inherit it, thus furnishing another evidence that it is instinctive within the limits of our definition of that term.
The single illustration of what appears to be purely in- stinctive activity among birds is taken from an observation
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of my own on the crowing of roosters. Having moved several years ago to a home isolated by some two miles from the nearest human habitation, it was decided to raise a few chickens for the family larder. To this end a dozen or more recently hatched incubator chicks were secured from a dealer some ten miles away. As these youngsters developed, healthy and strong, to the stage in which the sex differences gradually came to view, I was on the lookout to learn what would happen as to the crowing ability of the young cocks, the assumption being that they had not, since the first few days of their lives outside the eggshells, had a chance to hear, much less to see, a rooster crow. One day while I happened to be near the cage in which the flock were con- fined, I saw one of the most developmentally advanced roosters stretch himself up in true rooster fashion and deliver a clarion blast as typical and well rounded as ever issued from the most learned and best experienced of his kind.” While it is impossible to assert that this rooster’s crow- ing mechanism had not been influenced to some extent through eyes and ears during the few days of its extra-ovate life while it was still in its original chicken-yard environ- ment, this much seems certain: Immature as that mechanism certainly was at that early period it is impossible to con- ceive that the series of acts constituting a completed crow was learned and remembered in any such meaning as we ordinarily attach to those words. The mechanism must have been potentially and not actually capable of perform-
2Tt is certain that young roosters do not all begin their crowing with any such perfection of the act as that here described. In the ordinary chicken-yard conditions, the youngsters often begin with quite remark- able noises and only become real crowers by a course of practicing. The discrepancy between this and the performance in the instance de- scribed may be due to the fact that when a young rooster is constantly surrounded by crowing adults his crowing ability is stimulated into action earlier, by imitation, and so begins before the mechanism is ma- ture enough to enable the first effort to be as perfect as it might be if it were brought into action only at a later time, as might have been the case in the instance described. It is barely possible that my individual practiced a few times before I heard him; but I do not think so, as I was near, and on the look-out, pretty constantly.
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ing the acts. The tiny cock-chick was no more able to im- itate his grown-up companions or to act on the basis of learning from them in the matter of crowing than in the matter of doing or being anything else that makes the full- grown rooster different from the rooster just out of the shell. Even granting all that might possibly be attributed to external crow-inducing influence upon the just-hatched rooster, by far the major part of the performance actually witnessed must be attributed to heredity, that is, specifically, to instinct.
The act of cro-ving involves much more than uttering a particular form of vocal sound. There is the characteristic up-stretching of legs and body and the characteristic for- ward movement of the head and crooking of the neck, to say nothing of the movements of the beak and other parts more directly concerned in producing and emitting the sound. The activity viewed as a unitary whole belongs so unmis- takably to the physical organization of the creature that at best there is little room in the small mental part of it for anything else than what is instinctive. How far the notes and modulations of the crow were exact reproductions of those of his ancestors, it is impossible to say. Quite likely they were different in these respects, for it is known con- cerning various birds that whereas they possess large in- stinctive ability to produce vocal sounds, the particular form which these sounds take on, the particular notes and songs they actually produce, is dependent on what sounds, as songs of other birds, they hear. The song of the noisy mocking bird for example is made very largely of imitations of noises occurring around him.
There is no room for doubt that much of the ac- tivity of the higher vertebrates is instinctive even though considerable modification occurs in the direction of activity which we call intelligent. Nor is there any doubt that to a considerable extent these modifications are due to imitation
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of the old by the young, and to the actual teaching of the young by the parents and other grown-ups of the species.
AT THE LEVEL OF INTELLIGENT ACTION
The third level or type of action we shall call intelligent action. Here, as in the discussion of instinctive action, we are much more concerned with a particular type of action performed by some but not all organisms, than with a defi- nition of an abstract principle called intelligence or intellect which some organisms are supposed to possess. Whenever an organism receives a stimulus and has an impulse to act, but withholds the act pending a decision as to whether the act would be likely to procure the welfare of the organism, and finally acts according to the decision reached, we shall call such an act intelligent.
OF LOW TYPE
A familiar illustration is seen in the method by which the house cat catches its prey. This can be observed to par- ticular advantage when a cat is laying for a ground-burrow- ing rodent which ventures to emerge from its burrow. In order to succeed the cat must select a position not so near the hole as to scare the occupant when it comes to the hole’s mouth, but also not so far away as to be beyond the cat’s ability for an effective spring. A rather nice measuring of distance is here required. The cat holds a crouching posi- tion during the period of ‘‘watchful waiting.” The tension under which a number of muscles are held while the belly side of the body is lowered nearly to the ground, and the position taken by all four limbs in maintaining this body posture while preparing for the impending jump, involve a series of significant psychobiological adjustments. The cat usually has to execute repeated starts and stops, according
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to the behavior of the victim. The instant eyes or ears of the watcher detect the slightest evidence that the prey is about to emerge, the readiness to spring is redoubled; but despite this renewed preparation to spring, the actual spring is withheld long enough to enable the cat to make sure whether or not the prey has emerged far enough to give the greatest chance for a successful trial. Stimulus and impulsion to action and organismal readiness therefor, but also a withholding of the full act till the greatest prob- ability of its success is assured, are all well exemplified; as is both success and failure of action. Any one who has observed hunting cats must have seen them triumphantly running away with the dead victim dangling from their mouths. The observer must also have seen the well-calcu- lated spring miss its goal, and the cat go more leisurely away with a certain manner that may easily be imagined to have in it something of disappointment or disgust.
The question of when a particular act can be counted a success arises here. If the would-be victim of the cat is actually captured and killed, is the operation entitled to be declared successful? Not necessarily, according to our cri- terion of success. Suppose that some hostile dog chances along just in time to be attracted by the cat’s spring or the victim’s cry, and plunges for the cat with as deadly intent as the cat sprang for the gopher, with the result that neither the cat herself nor her kittens benefit in the least degree by her “kill.” Or suppose that serious injury or even death comes to the cat from this canine raid. The cat’s charac- teristic hunting activity has no other meaning than the se- curing of food for herself or her young. That activity is composed of a whole series of acts in a sense distinct, yet all so related to the whole as to admit of being accounted successful only if the whole series succeeds.
Although the type of activity presented by the cat’s hunt- ing operations meets our test of intelligence, the level of the
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type is too low to serve as a basis for such examination of successful activity as we wish to make. The intelligence il- lustrated is of a decidedly simple order. The welfare sought, satisfaction of the need for food, is positive and imperative. The kind of food (fresh meat) is stri¢tly accordant with all of cat experience. The benefit sought is for the immediate future, the consumption of the prey to be at once and com- plete. No recognizable question of psychical welfare ob- trudes itself into the case. The only point in the whole activity at which appears guidance of action involving inhi- bition of impulse anticipatory of a more favorable chance of attaining the ends sought is in the delay of the leap until the prospective victim is sufficiently advanced in com- ing out of its hole.
OF HIGH TYPE
Just as it is impossible to understand the animal brain without including in the study of it examples from the whole range of the type, the human brain at its highest development not excluded, so is it impossible to understand animal intelligence without including in the study of it examples from the whole range of the type, human intelli- gence not excluded. Where shall we go among mankind for such illustrations except to such as not only bear all the marks we have indicated of such activity, but which were performed sufficiently long ago to enable us to see unmistakably that they contributed to human welfare in exceptional measure? High-level intelligent activity is illus- trated by the discovery of America by Christopher Colum- bus, Copernicus’ achievement in astronomy, Galileo’s in physics, Harvey’s in physiology, and Lavoisier’s in chem- istry. But on the whole some one of the achievements of Louis Pasteur will perhaps serve us best as an illustration
SUCCESSFUL ANIMAL ACTIVITY QI
to be closely examined. Let us take his work on the diseases of silkworms.
The life and labors of this great Frenchman are now so fully told that a general knowledge of what he did for the silk industry can be assumed. During the first half of the nineteenth century sericulture was one of the most important industries of southern France. By the middle of the century a disease of the silkworm had grown to such an extent, despite efforts to check it by some of the ablest statesmen and scientists of the time, as to almost ruin the industry not only in France but in other parts of the world. This caused great loss and suffering among those dependent on sericul- ture for a livelihood. Finally in 1865 when Pasteur was bringing to a triumphant conclusion his researches on spon- taneous generation, on the diseases of wine, and on vinegar, an appeal was made to him to undertake an exhaustive re- search for the cause and a cure of the blight on the silk industry. To this appeal Pasteur yielded after much hesi- tation, due to the fact that he knew very little about insects or any other branch of zodlogy and had, as he said, “never touched a silkworm.” The researches occupied much of his time and those of several assistants for about six years. The whole story is told by Pasteur himself in his Etudes sur les maladies des vers @ soie.
We will restrict our examination to so much of the case as illustrates intelligent activity, centering the examination around the elements which constitute the chief marks of such activity. These marks are: the fact that the activities are in an essential part muscular; that activities of the par- ticular class are known to promote welfare; and that de- cision as to performance of the specific acts is made on the basis of their probable welfare-production. In this case the welfare sought was the relief from distress of the people suffering from loss of the silk industry, by learning enough
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about the disease to make its control possible. That this rather than a desire to carry out a purely scientific research was the ruling motive with Pasteur we may definitely learn from his own words. In the preface to his Studies on Silk- worm Diseases he wrote, “Nothing is more agreeable to a man who has made science his career than to increase the number of discoveries, but his cup of joy is full when the result of his observations is put to immediate practical use.” * Many other statements of like purport might be quoted from his writings.
The mark of intelligence which we have listed as second, that of muscular activities of certain kinds inseparably con- nected with brain activities, is obvious in this case. All research in natural science is a sort of sublimated manual labor. No scientist ever advanced real knowledge of nature without using his hands or other body members along with his brain and sense organs. The most cursory glance at the descriptions of these silkworm studies shows that the truth of this general statement is exemplified in the special case before us. Sorting over grubs and chrysalids and adults as part of the work of observing which were diseased and which were not; dissecting many individuals preparatory to searching with the microscope for the “corpuscles” which were the particular telltales of the disease; grinding an- imals in a mortar with a bit of water to get pulp for exami- nation; arranging eggs to protect them from contagion—the “intense work” during this period frequently mentioned in biographies of Pasteur was by no means a figure of speech, even from the purely physical standpoint.
The third attribute of intelligence, the making of decisions and choices as to what particular actions shall be performed under particular conditions, is clearly displayed in this illus- tration. The whole matter is involved in the most distinctive thing about the methods of natural science, namely, experi-
3 Vallery-Radot, The Life of Pasteur, p. 150.
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mentation. In a letter which Dumas wrote to Pasteur in connection with the work of Lavoisier, we read:“The art of experimentation leads from the first to the last link of the chain, without hesitation and without a blank, making suc- cessive use of Reason which suggests an alternative, and of Experience, which decides on it, until, starting from a faint glimmer, the full blaze of light is reached.” * Choosing be- tween two or more alternative possibilities, then acting in accordance with the choice—these two things lie very close to the heart, not only of scientific research, but of all intelli- gent living. The making of decisions as to how and when to act is cardinal in all scientific research. Consider as a typical instance of such decision-making the observation made early in the studies that eggs from healthy worms and moths might develop into diseased worms, while on the other hand, eggs from diseased worms and moths might pro- duce healthy worms. “Ts it,” we find Pasteur asking, “that among the eggs of a very much diseased male and female there may be some sound ones? or are some eggs less in- fected and able to produce grubs which will return to health during culture?” “I do not know,” is his answer at the outset, “which of these two explanations is the better, and there may be reason in both.” Three alternatives, you see, necessarily indicating as many variations in the course of action to be pursued for ascertaining in which direction the truth lay. When it was finally discovered that a second disease, named by Pasteur “flacherie,” was involved, as well as pebrine, the researches had revealed enough of the truth to make control of the disease possible.
Concerning the welfare attained by this six-year period of activity we will let Stephen Paget tell.* In his brief enumeration of the achievements of Pasteur we read with reference to this one: “He had been the very saving of the
4Ibid., p. 122. 5 Pasteur and after Pasteur, p. 54.
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silk trade. It is only a few weeks ago, at Le Nuy, near St. Raphael, that I went over a silkworm nursery, and found his methods in use, as in 1870, s0 in 1914. Flacherie, I was told, has disappeared: pebrine is detected in good time. Of late years, in the south of France, horticulture has become a far more important industry than sericulture. : . . But the exportation of seed (silkworm eggs) goes on: and that seed is tested by Pasteur’s methods.”
Although it would be impossible to locate the welfare ele- ment in every scientific discovery as positively as it is located in this particular case of Pasteur’s, we are of opinion that any genuine discovery in natural science examined closely enough and after the lapse of sufficient time will be found to be definitely promotive of human welfare in some of its forms and hence can be shown to possess this as well as the other marks of intelligent activity. Unless a reputed dis- covery can be shown sooner or later to have this mark it does not properly belong to the category of intelligent activ- ity. Final judgments concerning the lives of nations are pretty sure to rest upon their kind and grade of culture and this is found upon analysis to depend more upon the achieve- ments in literature, art, science, philosophy and religion than on purely physical developments and the accumulation of material wealth.
SYSTEMATIC STUDY OF SUCCESSFUL ACTIVITY IN SUBHUMAN ANIMALS
Having presented illustrations of intelligent action at low and high levels we shall now bring forward evidence that the success of the lives of various animals below man re- sults to some extent from activities of the grade we are characterizing as intelligent. The ability to act with some degree of intelligence is very wide-spread in the animal world. There are numberless instances reported by hun-
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dreds of observers wherein it is contended that creatures of diverse rank in the zodlogical scale have shown intelligence. Although these descriptions of intelligence are rarely based on so clear-cut a criterion of what constitutes intelligence as we have adopted, close examination of specific instances finds recognizable actions of the kind we are regarding as intelligent among lower animals. The widely reputed in- telligent action of certain species of ants affords instances of true intelligence and also of overestimating the degree of intelligence manifested in them.
Even naturalists of excellent reputation have interpreted so erroneously and written in such humanized language concerning what they have seen some of these animals do as to give wide currency to the notion that ants in general are far more intelligent than they really are. Here is an example: “Observe the little ants of our fields and paths, and see how they work. Watch how they dig their tunnels and cover them in, like so many railway engineers. . . . See how they stop every now and then to study out their plans; how they consider all obstacles and avoid them; how they use every leaf and stick and straw to make a wall or a roof for their galleries. ... Then they watch the state of the weather very carefully. If the sun is warm, and it will do the eggs good to be in the upper galleries, every little ant begins tugging them along to put them in a warm place.”
Something of the way human sentiment is imported into such narration as this is illustrated by a passage in Thoreau’s account of the battle he witnessed between two races of ants. Concerning the effect upon him of what he saw, he says: “I was myself excited somewhat as if they had been men. The more you think of it, the less the difference. . . . I felt for the rest of the day as if I had had my feelings excited and harrowed by witnessing the struggle, the ferocity, and carnage of a human battle before my door.”
We now know for a certainty that such interpretations of
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the doings of ants is largely erroneous. So little similarity is there between the fighting of ants and the “ferocity and carnage of a human battle” that there is no occasion for being thrown into such a state of mind as Thoreau exper- ienced from being an eye-witness of fighting of this sort. It may be true that the “more you think about it” in Tho- reau’s sense of thinking, “the less the difference” between ants and men; but it certainly is not true that the more you know about it the less the difference. No critical present-day student of animal behavior believes for a moment that any species of ants “stop every now and then to study their plans.” Nor do they ‘‘watch the state of the weather” very carefully, or even very carelessly in any human sense.
That a residuum of true intelligent activity among ants is left after the dross of humanization is completely driven off seems almost certain in some cases. We will take a case reported by Thomas Belt in his Naturalist in Nicaragua. The species concerned was one of the leaf-cutting ants, genus Occodoma, though Atta is, I believe, the name now used. The observation was on colonies which raided Belt’s own garden so it had a double reason for being thorough: it was made by an able naturalist bent on getting scientific knowledge and saving his own property.
Having discovered the nest a short distance outside the garden, and having tried unsuccessfully several methods of heading off the raiders, he finally routed them by pouring carbolic acid mixed with water down their burrows. “The effect was all that I could have wished, the marauding parties were at once all drawn off my garden to meet the new danger at home. .. . Next day I found them busily employed bringing up the ant-food from the old burrows, and carry- ing it to a new one a few yards distant.” It was in connec- tion with their moving that Belt says: “I first noticed a wonderful instance of their reasoning powers.” Between the old burrows and the new one was a steep slope. Instead
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of descending this with their burdens, they cast them down on the top of the slope, whence they rolled down to the bottom, where another relay of laborers picked them up and carried them to the new burrow. It was amusing to watch the ants hurrying out with bundles of food, dropping them over the slope, and rushing back immediately for more. They also brought out great numbers of dead ants which the fumes of carbolic acid had killed.” Even this much of the operation justified, I should say, Belt’s conclusion that the ants acted rationally: they met an unusual situation promptly and in a genuinely advantageous manner. It seems as though they must have decided between the al- ternative possibilities of action, and then carried out the decision effectively. The rest of the story confirms this view.
“A few days afterward,” the narrative continues, “when I visited the locality again, I found both the old burrows and the new one entirely deserted, and I thought they had died off; but subsequent events convinced me that the sur- vivors had only moved to a greater distance. It was fully twelve months before my garden was again invaded... . I followed them to their nest, and found it about two hun- dred yards from the one of the year before. I poured down the burrows, as before, several buckets of water and car- bolic acid. . . . The ants, as before, were at once with- drawn from my garden; and two days afterwards, on visit- ing the place, I found all the survivors at work on one track that led directly to the old nest of the year before, where they were busily employed making fresh excavations. .. . It was a wholesale and entire migration.” Then, after a few sentences giving further details, comes the concluding statement: “I do not doubt that some of the leading minds in this formicarium recollected the nest of the year before, and directed the migration to it.” °
8 The Naturalist in Nicaragua, 2nd ed., pp. 75-78.
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Despite many gaps in this, we do not believe any interpre- tation of the case can be given that will accord as well with the facts presented as the one taken for granted by the author himself, that it was a “display of reasoning powers.” Expressed in closer conformity with our conception, it was a manifestation of genuine intelligence even though of low order and mingled with much purely reflex and instinc- tive activity.
This view is made the more justifiable by other observa- tions on ants of this same species and of different species. One other observation on the same species made by the same observer is worth noticing. A certain nest was so situated that the ants had to cross a tramway to reach the trees which they particularly liked. For a while they trailed over the rails and many were crushed to death by the wheels of the passing trams. Finally they set to work and tun- neled under the rails, thus making the crossing safe. One day when the trams were not running, Belt stopped up the tunnels with rocks. “But although great numbers carrying leaves were thus cut off from the nest, they would not cross the rails, but set to work making tunnels underneath them.”
We might go on indefinitely winnowing chaff from writ- ings which attribute all sorts of mental excellence to many kinds of animals, finding considerable wheat in the form of evidence of genuine intelligence. We will take time for a few other studies in order to secure to the higher animals the proportionally greater attention to which their suprem- acy in this matter undoubtedly entitles them. The first of these will pertain to bears, the second to beavers. These two animals are chosen not because they are entirely unique in the amount of “fact and fancy” woven about them in the literature of animal life, but because they stand near the top of the list in this respect and each presents in a rather striking way certain traits of mentality that are especially important for us.
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It is the opinion of some naturalists of wide experience with wild mammals that bears are among the most intelli- gent of all animals. Of all bears the North American Griz- zly appears to be allowed first place in this regard; accord- ing to Hornaday’s intelligence tests, this species is “the most keen-minded species of all bears.”* The single bear case chosen as our illustration is one described by Wright.° Wright and his hunter companions tried to capture this bear in the Bitter Root mountains. The specimen being a par- ticularly large one, they first tried to take it alive by means of a log pen and a steel trap so devised as to hold the animal without seriously injuring it. The bear eluded these efforts. The next plan was to kill him with two spring guns. The hunters were particularly confident of success by this means in that the cache of elk-meat which the grizzly was nightly visiting was so situated as to restrict his possible approaches to the meat. “The next morning when we went out to ex- amine our trap we found written in footprints on the dirt as wonderful a record of animal sagacity as i have ever seen. The bear had come as usual for his evening meal. He had come down from his covert, circled the two cedars where our steel trap still waited for him, crossed the creek, and climbed to where the lower string (of the spring gun) was stretched across his path. But though he had come up to it he had not touched it. On the contrary his track showed that he had turned to his left, followed the string to the barrier of fallen trees, had found himself unable to get around it there, had turned and followed it to the rocks, had found himself blocked there also, and retraced his steps to the creek. He had then circled the rocky point, had climbed to the flat above, and had tried to reach the cache from the other side. But here he had again encountered the sus- picious string. Once more he followed it down to the timber,
7 The Minds and Manners of Wild Animals, p. 128. 8 The Grizzly Bear, by H. M. Wright, 1909.
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turned and made his way along the rocks, and then the wily old fellow had climbed out on the rock point, and making his way from ledge to ledge, had arrived safely between the two strings, eaten his meal in comfort, and gone out the way he came. We never got that bear.” *
We see no reason for questioning the essential accuracy of the narrative here given. Nor do we see that any causal explanation fits the facts as well as the one assigned by the author, that of intelligence; and, we may add, intelligence in the sense in which we are using the term. There were surely two phases of the welfare of the bear himself in view. He needed food and he needed to avoid danger to himself while in pursuit of it. He went through a rather extensive set of actions to accomplish his twofold needs, and he several times found himself in situations where he chose between alternative possibilities of action.
Of all the lower animals there is no other species known to us whose industrial activities so much resemble those of the human species as do those of the beaver. The kinds of work done by beavers may be treated under four heads, namely, the construction of dwellings, the building of dams, the felling and disposing of timber, and the digging of canals.
Our immediate aim is to ascertain how well the operations actually serve the ends to which they appertain. The work done possesses a very high degree of general usefulness, of adaptiveness. Due attention to the most highly elaborated beaver creation taken each by itself and in its completed form, finds these to be truly wonderful in their exhibition of what, were they the handiwork of man, we should not hesi- tate to ascribe to conscious foresight in planning, and manual skill in executing. Subhuman animal accomplishment seems here to reach its climax. Consider first the general useful- ness of each of the four categories of accomplishment in- dicated above.
9P. 141.
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The house proper of the beaver is the family residence almost exactly as the human house is the family residence. It is where the children are born and reared and where parents and youngsters sleep, eat, and pass much of their time. In the typical beaver habitat the winter season is long and severe. As a result the dwelling is very important as a protection against snow and ice. This aspect of the protectiveness of the beaver house we humans can appreci- ate quite readily. Its protection against enemies we modern men can not so readily appreciate, since it is not ourselves but our remote ancestors whose experiences corresponded to those of the beaver in this respect. Bears, wolves, mountain lions, and coyotes are mortal enemies of beavers. The house proper and other structures often associated with it play as large a part in saving the family from destruction by these enemies as from killing temperatures.
The dams are used for impounding the waters of streams, to secure a depth of water into which the beavers can dive beyond the reach of their chief enemies, and in which they can move about freely. Of these aquatic activities the most characteristic is that of towing portions of trees and shrubs, for food and for the construction of dams and houses. By storing green timber with the bark on at the bottom of the reservoirs in autumn, a winter supply of food is assured, which is security against the two deadliest natural foes of the beaver, frost and marauding carnivores. The value of the artificially produced ponds as water supplies in times of drought is undoubtedly considerable. The similarity to man’s water supplies in arid and semiarid countries is obvious.
The canals are transportation waterways, and as such are of high usefulness in the general economic and social life of the animals. They enable the animals to swim from one place to another where this mode of travel would be otherwise impossible. Usually they lead from the body of
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' water where the dwelling is located toward the trees and shrubs which are the beavers’ source of raw material for food and timber. In other words, the canals greatly facili- tate the transportation of these materials from the place where they grow to that where they are used. Some good observers have regarded these structures as the highest ex- pression of beaver engineering.
Lumbering is the chief source of food supplies and of material for houses and dams. Although beavers feed on grass and other succulent vegetation, and on roots, still the great staple is bark, the bark of trees and shrubs, fresh and green or as nearly so as possible. This being the case there is no way of getting a sufficient quantity except by felling the timber. The bark of a tree of moderate size once prostrate on the ground or in a pond is available for beaver use. But actually to consume all the bark by gnawing it off where the tree fell would be greatly to expose the animals, old and young, to their deadly carnivorous enemies. The places of greatest safety for the beaver are the depths of its home body of water, its dwelling house, or the burrow or passage- way leading to it. The creature is a submarine under condi- tions of perpetual war so far as safety is concerned. The material must be transported as soon as possible to some safe base, the bark there to be gnawed off from the sticks, the sticks later to be used in construction and repair. Even trees of small size are too large and awkward to be trans- ported and dealt with whole. They must be cut up into manageable pieces. The branches must be trimmed and the body and all limbs of considerable length must be re- duced to pieces that can be readily dragged along the ground or floated in the water and, frequently, carried into the houses.
Given beavers living under present conditions, lumbering of such character as we actually see among them is indis- pensable to their existence. The activity as a whole is use-
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ful, is adaptive, in a vital sense. To assess the value of this adaptiveness accurately we must examine some of the opera- tions and their fruits. For this we will take the dwelling and the dam, and the relation between the two.
It is probable that the primordial element in this com- bination of things was the burrow in the bank of a stream or pond of considerable depth of water. The animal was a bank burrower before it was a house builder; various facts indicate that both burrowing and house building are more ancient habits than dam building. The habit of damming up streams probatly came into being for the purpose of producing depth of water sufficient to make the house proper, plus the underground, underwater passageway by which it is reached, practicable and safe. House, passageway and dam are normally intimately and remarkably related. The house is typically so placed at the water’s edge on an island or on a mainland bank that its floor is only a few inches above the water level. One end of the passageway is in the pond at considerable depth; the other end is in the floor of the house. As a consequence the passage must slope up to the house, and the water level of the pond cannot change much without seriously interfering with the household life of the beaver family. An important element in the beaver’s problem of dam construction and maintenance is therefore that of keeping the water level of the pond as nearly con- stant as possible. On this point Morgan writes: “From the uniform relation found to subsist between the level of the floor and of the pond, it is evident that the beavers regulate the discharge of the surplus water through their dams with a view to the maintenance, as near as possible, of a uniform level of the pond. Any great variation in this respect would either flood their habitations or expose their entrances; and therefore the maintenance of their dam becomes a matter of constant supervision and perpetual labor.” *® This constant
10L, H. Morgan, The American Beaver and His Work, p. 146.
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supervision and labor consist in repairing leaks in the dams to keep the water up to the proper level, and making open- ings in the dam at times of high water to keep the water down to the proper level.
The remarkable adaptiveness displayed in connection with dwellings does not end with this production and maintenance of a proper relation between house and dam. The construc- tion of the entrance passages themselves, is, according to Morgan’s account, quite as notable. He writes: “‘The en- trances to a beaver lodge, of which there are usually two, and sometimes more, are the most remarkable parts of the structure. They are made with great skill, and in the most artistic manner.” ** After stating that the difference between the two passages is such as to indicate that one is a mere > entrance for the animals while the other is the “‘wood en- trance,” by which the wood cuttings used for food are brought into the house, Morgan gives a detailed description of the passageway. “Both entrances were rudely arched over with a roof of interlocked sticks filled in with mud intermixed with vegetable fiber, and were extended to the bottom of the pond and trench. . . . At the places where they were constructed through the floor they were finished with neatness and precision; the upper parts and sides form- ing an arch more or less regular, while the bottom and floor edges were formed with firm and compact earth, in which small sticks were embedded. It is difficult to realize the artistic appearance of some of these entrances without actual inspection.” *°
This account should be coupled with the statements by Morgan and others that the earthen floor of a well-made house is so hard and resistant to water that it remains dry and solid although it stands typically only a few inches above the water level. Obviously a prime object, if object they
11 Pp 144. 12 [bid.
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consciously have, in the construction of floor and passage- ways is to make the walls and surfaces both strong and as nearly as possible impervious to water.
The wall of the house presents some features of special interest in connection with the problem of adaptation. Sticks and poles of wood are the main materials entering into the composition of full-sized beaver houses. Mud containing great quantities of vegetable fiber plays a large part in many houses. Morgan and other observers affirm that in some localities the exterior surface of the walls is given a coat of mud by the beavers at the approach of winter. This in- creases not only the warmth of the dwelling but, through the freezing of the mud, the strength of the walls against the depredations of carnivorous animals which, under the hunger stress of winter, often try to reach the beaver families by house-breaking.
Although a few authors deny that the animals avail them- selves of this means of protection, the earlier affirmations of it were verified by so many recent observers that there no longer seems any doubt about it. Thus both Enos A. Mills * and A. R. Dugmore ** give accounts of such procedure with so much particularity in both description and illustration, that the statements of Morgan and others must be accepted.
Because of the remarkable resemblance of the construc- tions by beavers to some of those by men all sorts of ex- travagant estimates of the intelligence of the creatures have been made. Thus we have from Samuel Hearne, writing in 1785: “There cannot be a greater imposition, or indeed a grosser insult on common understanding, than the wish to make us believe the stories of some of the works ascribed to the beaver.” But: “To deny that the beaver is possessed of a very considerable degree of sagacity would be as ab- surd in me as it is in these authors who think they cannot
13 [y Beaver World, 1923. 14 The Romance of the Beaver, 1914.
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allow them too much. I shall willingly grant them their full share.”” As an example of the sort of thing Hearne was aiming his irony at, he mentions the yarn that beavers “drive stakes as thick as a man’s leg into the ground three or four feet deep” and then “wattle these stakes with twigs.” Such stories are not necessarily, indeed not usually, deliberate falsifications, nor are they pure fiction; they usually result from bad observation coupled with bad general information and bad use of the imagination. They do not appertain to any particular people or cultural state, though unquestion- ably they become less general and less glaring with the ad- vance of culture.
My own observations on the work of beavers lead me to conclude, as numerous other observers have concluded, that as a matter of fact the creature’s activities are no more in- telligent than are those of numerous other mammalian species. Various members of the wolf and bear families, for instance, are probably somewhat superior to beavers in this respect; and beyond question any of the monkeys, to say nothing of the anthropoids, are greatly their superiors.
The most significant thing about beaver work is the illus- tration it affords of the extent to which instinctive activity can come to resemble rational and even intelligent activity.
It is now beyond question that the creatures which come nearest to man in ability to act intelligently are the an- thropoid apes, the same creatures which, as everybody knows, most resemble man in structure. Any doubt con- cerning the degree of intelligence of these creatures is due to the meagerness of our knowledge of them in the most crucial situations of their wonted careers in their native wilds. Such situations are the final test of intelligent action. So difficultly accessible to civilized man are the regions in- habited by the anthropoids that the observations on their habits in nature are very few and fragmentary as compared with those on many other groups of animals. We are de-
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pendent for what is known about the activities of man’s closest of kin among the lower orders on studies of indi- viduals taken by force from their natural environments and held in captivity.
But thanks to the efforts of several people who have lately interested themselves in the activities of these creatures considerable has already been done to improve our knowl- edge of them. The investigations of Kéhler and Yerkes are outstanding for the chimpanzees and orangs; as are the amateur, but none the less important, experiences of Miss Cunningham with the gorillas.
Se abundant, varied, and convincing is the evidence of manlike psychical attributes of chimpanzees presented in The Mentality of Apes, by Wolfgang Kohler, and so simply and entertainingly is the story told, that we will assume all readers particularly interested in this aspect of our general subject will acquaint themselves with this book. We will restrict our presentation to one of the most telling instances of human-like activity. We take the widely quoted instance of stick-splicing for a purpose by the chimpanzee, Sultan.” The ape had acquired facility in using a stick to get food which was beyond the reach of his hand thrust through the bars of his cage. The situation created for Sultan by the experimenter was this: Food (a banana) was placed outside the ape’s cage, too far away to be reached with one stick but not too far to be reached with two sticks spliced together. Two separate pieces of bamboo, which thus spliced would be long enough to reach the fruit, were placed in his cage. Such pieces, one sufficiently smaller than the next to let its end be slipped a little way into the bore of the other, were placed within easy reach of the ape. Question: Would Sultan’s intelligence be sufficient to enable him so to com- bine the several detached elements in the situation as to secure the coveted food?
15 Op. cit., pp. 130 ff.
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The situation and the problem stated in this way seem to have been too much for the ape. He made no real prog- ress toward getting the food. But a little later two other elements came into the situation through which the problem was solved. These elements were the animal’s playfulness after experimenter and animal had wearied of the formal experiment, and mere fortunate accident. From this point the story can best be told in the words of the keeper and the experimenter: “Sultan first of all squats indifferently on the box, which has been left a little back from the railings; then he gets up, picks up the two sticks, sits down again on the box and plays carelessly with them. While doing this, it happens that he finds himself holding one rod in either hand in such a way that they lie in a straight line; he pushes the thinner one a little way into the opening of the thicker, jumps up and is already on the run towards the railings, to which he has up to now half turned his back, and begins to draw a banana toward him with the double stick. I call the master: meanwhile, one of the animal’s rods has fallen out of the other, as he has pushed one of them only a little way into the other; whereupon he connects them again.”
The key to the problem once in Sultan’s hands, by these partly playful, partly accidental and partly intelligent activ- ities, was used regularly and varied in several advantageous ways. A noteworthy thing about the ape’s success in solv- ing this problem was the evidence of satisfaction shown by him, not merely in getting the food but in the achievement itself: “The proceeding seems to please him immensely; he is very lively, pulls all the fruit, one after the other, towards the railings without taking time to eat it, and when I dis- connect the double stick, he puts it together again at once and draws any distant objects whatever to the bars.” <A modification of this experiment in which intelligence shows distinctly, consisted in putting three instead of two sticks at
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the ape’s disposal, two of them being nearly the same size, and larger than the third. Kohler emphasizes the statement that Sultan never tried to join the two larger sticks. Good observation coupled with judgment seem unmistakable here.
Concerning the manipulative difficulties encountered in using the double-length stick, we are told: “The long tool sometimes gets into his way .. . by its farther end getting caught between the railings, when being moved obliquely, so the animal quickly separates it into its parts, and finishes the task with one tube only.”
When the fruit was placed beyond the reach of the double- length stick, but not beyond a triple-length one, and the three pieces were at hand, the solution of the problem pro- ceeded as follows: “He puts them (the two larger pieces) opposite to each other for a moment, not touching, and looks at the two openings, but puts one aside directly (without trying it) and picks up the third thinner one; the two wide tubes having openings of the same size. The solution fol- lows suddenly: Sultan fishes with a double-stick, consisting of the thinner one and one of the bigger ones, holding, as usual, the end of the smaller one in his hand. All of a sudden he pulls the double-stick in, turns it round, so that the thin end is before his eyes and the other towering up in the air behind him, seizes the third tube with his left hand, and introduces the tip