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Rene Dubos

The conjunction of the two words "humanistic" and "biology" will probably seem artificial because very few scientists, and even fewer humanists, really believe that biological knowledge has relevance to the traits which account for the humaneness of man. Admittedly, biological determinants do not seem at first sight to play a significant role in the manifestations of life which are most characteristically human, for example, ecstasy, logic, or simply the experience of happiness and despair. Religious and ethical doctrines, philosophy, linguistics, literature, the arts, are part of the humanities because their problems obviously relate to the social and cultural history of man, but their connections with the biological attributes of Homo Sapiens are not so readily apparent. "Man has no nature, what he has is history," wrote Ortega y Gasset.

While it is obvious that man is the product of his social and cultural history, it is equally certain, on the other hand, that everything he does is conditioned by his biological attributes. The performance of each human being , and of each human group, reflects biological necessities and propensities inherited from the evolutionary and experiential past. Human decisions create social and cultural history, but the raw materials of this edifice are derived from man's biological history.

It is always dangerous, of course, to use biological terminology and concepts in discussing human affairs. Half a century ago, for example, the illustrious biologist Elie Metchnikoff published under the title "Etudes sur la Nature Humaine" a book in which he attempted to explain the properties of the human flesh and the manifestations of the human spirit in the light of the biological knowledge of his time. His English translator, the zoologist P. Chalmers Mitchell, found it difficult to convey the full meaning of the expression Nature Humaine in Metchnikoff's title. As he wrote in the preface to his translation, " Human nature is not an exact equivalent of la nature humaine , for the latter phrase has a more complete significance, and definitely implies, not only the mental qualities of man, but his bodily framework, with its inherited and acquired anatomical structure and body functions." Mitchell thought that "The Nature of Man" was a more accurate rendering of Metchnikoff's title than "Human Nature." In 1930, the American biologist H.S. Jennings also recognized implicitly the limitations of the phrase "human nature" when he qualified it as "The Biological Basis of Human Nature" in the title of a book which he devoted to "those aspects of experimental biology that are of most interest in considering the problems of human personality and society."

Throughout the present essay, I shall use the phrase "man's nature" instead of "human nature" to emphasize my conviction that the somewhat limited meaning implied in the English usage of human nature does not convey the depth and richness of the knowledge which biological sciences could bring to bear on cultural and social history. I shall attempt to show that the psychological and ethical attributes of man, and the preoccupations which constitute his humaneness, are inseparable from the physiological needs and urges which biological experience has inscribed in his flesh and bones. My theme is that better knowledge of man's nature would enlarge and deepen the understanding of man's history.

The doctrine of evolution has made it obvious that living organisms cannot be understood except in the light of their past. Surprisingly enough, however, the science of human biology has been little influenced by the historical outlook. The knowledge of man has progressed far, of course, since Descartes and his followers tried to base it on the study of the mechanical models with which they were familiar, but its most spectacular advances have been along the road first opened in the 17th century. There is an almost universal tendency to identify the "science" of man's nature with the physicochemical description of the body's structures and mechanisms, and with the laws which govern the transmission of its hereditary characteristics. Yet, human life clearly constitutes an experience far more complex than the phenomena which are encompassed by this limited approach; its dynamic processes constantly alter the physical and mental structure of man as he responds to the challenges of the natural environment and of the ways of life that he himself creates. The almost complete irrelevance of present day biology to the humanities comes largely from the fact that it emphasizes the mechanical aspects of man's nature rather than his experiences; it is concerned more with his being than with his responding and becoming.

Increasingly during recent decades, the exact biological sciences have been focused on the phenomena which are common to all mammalian species and indeed to all living forms. This trend away from the special attributes which particularize human beings makes scientific biology appear even further remote from humanistic preoccupations. The kind of knowledge to which it leads throws very little light on the problems which are the primary concern of humanists, namely the experiences of the throbbing human person in a particular culture. Yet, while they appear at first sight so coldly detached from living man, the findings of orthodox biological sciences have nevertheless profoundly influenced some of the largest philosophical expressions of modern humanism.

Man in the great chain of being
The doctrine of evolution has influenced all aspects of modern culture by providing biological evidence for the social concept of historical change. Surprising as it may seem to us, it is only during modern times that the myth of eternal return has been displaced in the Western mind by the concept of progress, namely the belief that the universe, and especially the world of men, are constantly moving toward states differing not only from those of the present, but also from anything in the past. Whatever its origins, the doctrine of progress idd not become part of collective consciousness until the theory of biological evolution provided a scientific model for it.

Most enlightened persons now accept as a fact that everything in the cosmos- from heavenly bodies to human beings- has developed and continues to develop through evolutionary processes. The great religions of the West have come to accept a historical view of creation. Evolutionary concepts are applied also to social institutions and to the arts. Indeed, most political parties, as well as schools of theology, sociology, history, or arts, teach these concepts and make them the basis of their doctrines. Thus, theoretical biology now pervades all of Western culture indirectly through the concept of progressive historical change.

One of the most practical contributions of biological science to sociology has been to provide a scientific basis for the ancient ethical and religious doctrines of the brotherhood of man, by demonstrating that all human beings belong to the same species. Comparative biology has revealed, furthermore, that man is linked to all living organisms through a common line of descent, and shares with them many characteristics of physicochemical constitution and of biological organization; the philosophical concept of the "great chain of being" can thus be restated now in the form of a scientific generalization. Even St. Francis's love of his brothers the beasts and the Hindoo reverence for life can be regarded as the poetical, ethical, and philosophical expressions of the biological law that all living forms exhibit a deep underlying unity even though they are so strikingly diverse.

Paradoxically, the very success of comparative biology and evolutionary doctrines in relating man to the rest of creation may have retarded the growth of knowledge concerning man himself. Since all living forms have so many characteristics in common, biologists and even medical scientists naturally tend to focus their investigative efforts on organisms which are simpler than man, and therefore easier to manipulate in the laboratory. This tendency is based on the widespread, though unproven assumption, that understanding of man will eventually emerge from detailed knowledge of the elementary structures and functions which occur in all living things. One of the deplorable consequences of this attitude is the common belief that the only fields of biology which deserve to be called "fundamental" are those which deal with the simplest manifestations of life, and preferably with lifeless reactions and structures derived from living things! Yet it is certain that such a limited approach is not sufficient to create a science of life, let alone of man.

Vague though they are, words such as "mind" and "emotion" nevertheless symbolize essential aspects of human life which cannot be related to isolated morphological structures, or formulated in physicochemical terms. Thus, some of the most interesting aspects of human life, and certainly the most influential, do not come within the purview of what is presently called "fundamental" biology. I hasten to emphasize that this statement does not imply surrender to hoary vitalistic theories. The failure to account at present for many cognitive and emotional aspects of human life does not come from inadequacy of knowledge concerning the universal aspects of life; it has its origin in the fact that the words "mind" and "emotion," as commonly used, cannot possibly refer to attributes located in fragments isolated from the body or associated with special chemical reactions. They denote activities of the integrated organism responding as a whole to external or internal stimuli. In consequence, the aspects of biological science which are most relevant to the interests of the humanist are probably those which deal with the response of individual human beings to their total environment. But information on this score becomes much more meaningful if seen in the light of man's evolutionary past.

Anthropological studies and evolutionary doctrines have suggested useful hypotheses concerning the progressive emergence of the physiological and behavioral characteristics which define each animal species and particularly Homo sapiens . Man, it now appears, was not yet fully evolved, either physically or mentally, at the time when he began creating the crude elements from which most of his culture derives. Recent evidence indicates that, one million years ago, very primitive hominids with brains hardly larger than those of anthropoids had reached the stage of tool making. The further growth of the human brain apparently coincided with a progressive change in the hominid way of living. For example, when primitive man shifted from hunting small animals to big game hunting, this change required new skills in planning, in leadership, and in communication- and this created selection pressure for the development of these capacities. Contrary to the old belief that men anatomically like ourselves slowly invented culture, it is probably, in other words, that the increase in the size of the human brain occurred simultaneously with the first phases in the unfolding of human culture. Man and his culture evolved, simultaneously, as it were, through a complex series of feedback processes.

It seems a reasonable kind of science fiction to imagine that the first subhuman creature who used a tool thereby opened an evolutionary channel in which greater ability to use tools provided a selective advantage. Through analogous evolutionary mechanisms, somatic changes and organization of reaction patterns followed upon the development of family structure and of practices for hunting in groups. Soon after, perhaps, the primitive forms of art, of religion, and even of "science" also played their part in affecting the development of neural processes and their integration. New reaction patterns thus became progressively molded on the ways of life, as the brain enlarged. And reciprocally, the ways of life evolved as the brain and its functions became better fitted to them and more complex.

The "higher" functions of the human brain probably result therefore from progressive structural-functional transformations giving rise to a system which permits the physiological and behavioral adaptation of man to his own culture. By necessity, of course, this adaptation cannot be perfect, since culture is continuously evolving. What is almost certain, however, is that the various components of human culture are now required not only for the survival of man, but also for his existential realization. Man created himself even as he created his culture and thereby he became dependent on it.

Another fact which relates biological studies to humanistic problems is that the higher the position of an animal on the phylogenetic ladder, the more unpredictable is its behavior with regard to environmental stimuli. Up to the lower mammals, the emergence of relative independence from external influences can be correlated with the appearance of novel neural mechanisms, but no such anatomical substratum is yet known to account for the high degree of freedom exhibited by the higher mammals. Irrespective of explanation, however, it can hardly be doubted that man is the most evolved organism with regard to the degree of his independence from the direct effects of the physicochemical environment. One of the most profitable approaches to the definition of Homo sapiens might therefore be to describe the mechanisms through which his evolutionary ancestors have progressively increased their experiential independence, thus creating his biological identity. But I shall limit myself here to a few remarks concerning man as he exists today, or rather concerning his reactions with, and his responses to, the forces which impinge on him.

I have purposefully differentiated reaction from response because these two words symbolize in my view the two extreme ends of the wide spectrum of interplay between man and his environment. From one end of the spectrum, man appears as an ordinary physicochemical machine, complex of course but nevertheless reacting with environmental forces according to the same laws which govern inanimate matter. From the other end, man is seen as a creature which is rarely a passive component in the reacting system; the most characteristic aspect of his behavior is the fact that he responds actively and often creatively. Man is able to shut out some of the stimuli to which he is exposed; he modifies others through symbolic and sociocultural mechanisms; most importantly, he can use the effects of stimuli to his own selected ends. All degrees of variation exist between the passive reactions with the environment and the creative responses through which the personality asserts itself. Man is the more human the better he is able to convert passive reactions into creative responses.

The divine madness
The performance of any living organism in any given situation is conditioned of course by environmental forces. But its characteristics are determined by the potentialities and the limitations which the organism has acquired and retained from its evolutionary and experiential past. Admittedly, man often behaves as if he were completely independent of his biological history. However, while his outward behavior reveals such a large degree of freedom, physiological reactions elicited in him by environmental and sociocultural forces appear to be very similar to those manifested by his paleolithic ancestors. His ancient needs and urges persist even when their overt manifestations are so masked or distorted that he himself is not aware of their existence. The survival of the paleolithic past in modern man accounts for many puzzling aspects of his responses to the total environment-for the pathological as well as the expressive and creative aspects of his behavior.

The extraordinary degree to which the physiological processes of human life are still linked to cosmic rhythms provides a striking illustration of the persistence of traits having their origin in man's evolutionary past. Modern man is wont to boast that he can control his external environment; he can indeed illuminate his rooms at night, heat them during the winter, and cool them during the summer; he can secure an ample and varied supply of food throughout the year. But even when he elects to follow unchangeable ways of life in an environment which appears uniform, all the functions of his body continue to fluctuate according to certain rhythms linked to the movements of the earth and of the moon with respect to each other and to the sun. His hormonal activities, in particular, exhibit marked diurnal and seasonal rhythms and probably other rhythms also linked to those of the cosmos.

All aspects of behavior are affected by physiological processes. Man's responses to any situation are different in the morning from what they are at night, and different in the spring from what they are in the autumn. The writers of Western stories are on a sound biological basis when they recount that the Indians always attacked at dawn, because the spirits of the white man were then at a low ebb. The wild imaginings of the night, and the fears which they engender, are indirectly the effects of the earth movements because the human organism readily escapes from the control of reason under the influence of the physiological changes associated with darkness. The lunar cycles are also reflected in the physiology and behavior of animals and probably therefore of man. It would not be surprising if the moon worshippers as well as the "lunatics" were really affected-as the words suggest-by lunar forces to which all of us are also sensitive.

Seasonal changes, in any case, certainly affect most living things, including man, even when the temperature and illumination are artificially maintained at a constant level. In the most mechanized, treeless, and birdless city, just as in the hills of Arcadia long ago, men and women perceive in their senses and reveal by their behavior that the exuberance of springtime and the despondency of late fall have origins more subtle than the mere change in temperature. It is for good biological reasons that carnival and Mardi Gras are celebrated when the sap starts running up the trees, and that men commemorate their dead in late fall when nature is dying. Thus, modern man in his sheltered environment continues to be under the influence of cosmic forces much as he was when he lived naked in direct contact with nature. Similarly, he continues to react physiologically to the presence of strange living things, and especially of human competitors, as if he were in danger of being physically attacked by them. The fight and flight response, with all its deep physiological accompaniments, is a biological carry-over from the time when the survival of primitive man encountering a wild animal or a human stranger depended upon his ability to mobilize the body mechanisms which enabled him to engage in physical struggle or to flee.

Man, on the other hand, evolved as a social animal, and he can neither fully develop, nor function normally, except in association with other human beings. All social stimuli express themselves in the forms of phenomena which in their turn condition the response to the life situations which had evoked them. Thus, crowding, isolation, challenge of any sort have effects which have their origin in the evolutionary past, and tend to imitate the kind of response which was then favorable for biological success-even when such a responses no longer suitable to the conditions of the modern world. Many aspects of human behavior which appear incomprehensible, or even irrational, become meaningful when interpreted as survivals of attributes which were useful when they first appeared during evolutionary development and which have persisted because the physical evolution of man came to a relative halt about 150,000 years ago. Phenomena ranging all the way from the aberrations of mob psychology to the useless disturbances of metabolism and circulation which occur during verbal conflicts at the office or at a cocktail party are as much the indirect expressions of the distant biological past as they are the direct consequences of the stimuli which were their immediate causes.

The urge to control property and to dominate one's peers are also ancient biological traits which can be recognized in the different forms of territoriality and dominance among most if not all animal societies. Animal behavior provides prototypes of the lust for political power, independently of any desire for financial or other material rewards, which is so common among men. Even the play instinct and certain kinds of esthetic expression correspond to derivative but nevertheless important biological needs which exist in one form or another in animal species and which have probably always been part of man's nature.

These biological characteristics and many others which cannot be mentioned here are woven in the very fabric of the human race, and they condition all aspects of human behavior. Unfortunately, they have been grossly neglected by biologists. This neglect is the result of the historical accident that scientific biology has been identified from its very beginning with the concept that the body is a complex but otherwise ordinary machine, and that detailed analysis of its elementary structures and energy mechanisms is the only valid approach to the understanding of the living organism. Such an attitude had discouraged the scientific study of the biological problems which do not lend themselves to the reductionist analytic methods now in vogue among experimental scientists. In particular, it has inhibited the study of the biological phenomena which are the consequence of the organism's evolutionary history-for example, the manifestations of the ancient urges which do not come readily to the surface under the conditions of civilized life, or the effect of the season and the hour of the day on the reactions elicited by physicochemical stimuli and various life situations.

Yet, numerous observations have now established that the organism, in physiological and mental processes affect all activities of the organism, and even the efficacy of therapeutic procedures. The orthodox reductionist approach is not suitable for the study of these phenomena because biological clocks, like the mind, disappear when the organism is dissected into its lifeless component parts. In fact, the most important problems of life can be recognized only when the organism responds actively to its environment as an integrated unit. Interestingly enough, space research is at present creating a wave of interest in topics as earthy as the effects on man of the tides, the seasons, and the diurnal cycles. Just as rockets and satellites are giving new importance to celestial mechanics, so does the prospect of space travel call attention to the potentialities and constraints which are the consequences of biological rhythms.

Philosophers, writers, and artists have always been acutely aware of the immense role played by occult biological processes in human life. In phaedrus, Socrates speaks with passion of the creative forces released in man by the "divine madness." The text of the dialogue makes it clear that the word "madness" as used by Plate refers not to pathological mental states, but rather to those deep biological attributes of man's nature which are almost beyond the control of reason and transcend its reach. These attributes remain concealed under the usual circumstances of ordinary life, but they constitute the most powerful sources of inspiration for the scientist as well as the artist. Creativity depends in part on the ability to hear "the voice of the deep" and to tap resources from regions of man's nature which have not yet been explored.

Nietzsche was referring to innate forces analogous to Socrates' divine madness when he wrote in "The Birth of Tragedy" that the Dionysian inspiration is a necessary complement of the Apollinian order. In fact, as shown by Dodds in "The Greeks and the Irrational," ancient civilizations were aware of the existence of these powerful biological needs of man's nature which are not clearly perceived and thus appear irrational. They symbolized the occult passions-the divine madness-by a ferocious bull struggling against reason.

Empirically all over the world, social practices have been developed to let these occult forces manifest themselves under somewhat controlled conditions. The Dionysian celebrations, the Eleusinian mysteries, and many other myths and rituals served as release mechanisms for biological urges which could not find an otherwise acceptable expression in the rational aspects of Greek life; even Socrates participated in the Corybantic rites. Needless to say, such ancient traditions still persist even in the most advanced countries of the Western world, though often in a distorted form. Even when man has become an urbane city dweller, the paleolithic bull which survives in his inner self still paws the earth whenever a threatening gesture is made on the social scene. The passions depicted by classical tragedies have their roots deep in the paleolithic past.


Experiential innocence
All human beings have fundamentally the same anatomical structure, function through the same chemical activities, exhibit the same physiological manifestations, and even possess the same occult biological needs; yet no two human beings are alike. Clearly knowledge of the attributes which are common to mankind as a whole is not sufficient to account for the manner in which each individual person behaves as he does, develops his own peculiarities, in brief becomes different from all other human beings. Since man's sense of discreteness is among his most cherished and most pronounced characteristics, the failure of theoretical biology to emphasize the uniqueness of individual human beings contributes to its lack of influence on thehumanities.

Individual persons differ, of course, by reason of the fact that they do not have the same genetic makeup; only identical twins are alike genetically. But at least equally important is the fact that the individual characteristics of human beings are constantly being shaped and modified by environmental factors which endlessly vary with time, differ from one place to the other, and therefore are never the same for two different persons. Recent studies have confirmed the ancient knowledge that many characteristics of the adult result from the effects of so called "early influences," namely of those environmental factors which impinge on the organism during early life, while he is still developing. Such formative effects can take place even in utero . For example, even though the Dionne quintuplets were genetically identical, they could be differentiated shortly after birth, probably because their different positions during intrauterine life had differentially affected their development. Prenatal and early postnatal influences can affect almost every trait-from nutritional needs and rates of growth, to learning ability and emotional attitudes. Moreover, the effects of early influences are so deeply rooted in the biological structure of the person involved that they often and perhaps always persist throughout his whole life span.

Environmental influences shape personality through two different groups of mechanisms. On the one hand, they determine certain patterns of response which can affect al manifestations of behavior. Physiologists, psychologists, psychiatrists, and novelists have described, each in his own way, a seemingly endless variety of conditioned responses ranging from the imprinting of ducks by early association with a foreign object or the salivation of dogs at the sound of a bell, to the pathological effects of the Freudian complexes or the remembrance of things past evoked by a madeleine dipped into a cup of tea. The widespread belief in the existence of an all embracing and lasting biological memory is symbolized by Tennyson's statement in Ulysses, "I am a part of all that I have met."

On the other hand, environmental influences contribute also to the shaping of the personality by interfering with the acquisition of new experiences. Ideally, man should remain receptive to new stimuli, new events, and new situations in order to continue developing mentally. But in fact, the aptitude to apprehend the external world with freshness of perception commonly becomes saturated as the mind and senses become conditioned by repeated experiences.

The environmental influences which are ubiquitous in a given geographical, national, or social group naturally tend to bring out many characteristics which are common to all members of the group. For this reason, there is much truth in Emerson's statement that "We resemble our contemporaries more than our progenitors." But environmental influences also affect each person in an individual manner, even when the ways of life appear uniform in a standardized environment. Genetic uniqueness makes for differences in response and consequently in mental and physical development; furthermore, each one of us lives as it were in a private world of his own.

Human beings thus perceive the world, and respond to it, not through the whole spectrum of their potentialities, but only through the areas of this spectrum which have been made functional by environmental influences, especially the early ones, and which are not blocked by inhibitory mechanisms. I have intentionally formulated this problem in very general and consequently vague terms, because the word potentiality is meant here to denote the whole range of the organism's genetic endowment, in both its physical and mental expressions. The life experiences determine what parts of this endowment emerge in the form of functional attributes.

In obscure ways, the kind of creation associated with the word genius must be related to the developmental processes which determine the manner in which the mind responds to external stimuli. Whether it manifests itself by revealing heretofore unrecognized aspects of reality, or by making new patterns out of facts already known, creativity often involves the ability to contemplate the world with a holistic and unconditioned attitude. Complete receptivity, however, is the prerogative of childhood, and of the few privileged adults who have retained or recaptured the directness of perception and experiential innocence which enable them to perceive "things as they are." Hence, the deep biological truth of Baudelaire's arresting and visionary image "Le genie, c'est l'enfance retrouvee." Genius is childhood recaptured.

Unfortunately, it appears that the knowledge acquired through the practice of daily life or by systematic learning must often be paid by loss of ability for truly original creation. Brancusi's statement that "when we are no longer young, we are already dead" expresses the cruel but inescapable truth that the mature stages of life are often encumbered with traditional and conventional attitudes which interfere with the receptivity for new experiences. The fact that the human personality tends to "set" with age suggests some functional "rigidification" of the potential ability for continual progressive changes in the engrams stored in the brain-as if there were sharp limitations to the experiential life span. Thus, one of the great problems of biology is to determine whether the effects of early influences are truly irreversible, as ordinary experience seems to show, or whether they can be erased partially at least, as a few animal experiments suggest.

Electrophysiological studies have revealed that the activity of neural processes in the brain is continuous, and that the effect of stimuli is to give form to the activity going on, rather than to arouse inactive tissue. These findings, as well as the knowledge that sensory deprivation commonly results in a transient disintegration of the personality, seem to suggest that ways may be found to prevent or retard the "setting" of personality so that man's body does not outlive the better of his mental faculties. In practice, however, the only evidence suggesting that the mind can be reshaped has come, tragically, from brain washing or confessions of political guilt, and, more hopefully, from certain forms of religious conversions.

The loss of experiential innocence during childhood is of course inevitable and is indeed a sine qua non of mental and emotional growth. But what matters is the kind of experience through which innocence is lost because this determines in large measure the shaping of the personality. The ancient dream of the Fountain of Youth might acquire a new and richer meaning if an acceptable technique could be developed to reestablish a state of receptivity in the fully developed and conditioned organism. Recapturing childhood, in Baudelaire's sense, implies reacquiring the ability for direct apprehension of the external world. It would be the surest approach to a true enlargement of human life.

Man creates himself
The fundamental biological nature of man has not changed since late paleolithic times. The same arrangement of 20,000 pairs of genes still controls his physical development and his physiological reactions; the implements he made during the Stone Age still fit his hands; the ancient drives which shaped his cultural evolution are still operative; the rituals and symbolic representations which he performed in the paleolithic caves are still meaningful to him. But while Homo sapiens has remained essentially the same, the manifestations of his life, and the structure of his societies, are endlessly changing, never repeating themselves identically. The permanency comes from the nature of the raw materials out of which human beings are made, the change from the creative responses which man makes to the challenges of his total environment. To live is to function, which means to respond.

Biological science has been immensely successful in describing the structures and mechanisms which constitute living things , and through which they operate. But it has contributed much less to the knowledge of man as a functioning organism. Yet the human condition cannot be dealt with scientifically unless a systematic effort is made to describe and analyze the pattern of responses which man makes to all the stimuli which impinge on him. For it is precisely this pattern which defines the human condition. In my judgment, such knowledge could be acquired if biologists elected to devote to the study of the living experience as much skill and energy as they have devoted to the description of the body machine. Fortunately, they can undertake this task with the confidence that they will find in the animal kingdom experimental models for many of the most interesting problems of human life.

The paradox is that while man unquestionably occupies a unique place in creation, his responses to environmental stimuli have their counterparts in the life of one or another animal species. Man's physiological urges, including the need to play, are common aspects of animal life in nature; most of his social activities and organizations are also represented in the different types of animal communities; even the ability to express attitudes and desires through symbolic sounds, postures, objects, and other representations is widespread among animals. Furthermore, it has been clear ever since Kropotkin published his book on "Mutual Aid, A Factor in Evolution," that social attitudes arising from biological necessities can evolve into ethical principles. In brief, it will probably be possible to find somewhere in the living world experimental models suitable for the study of many aspects of human life.

While models are useful and indeed essential for the scientific analysis of particular problems, they cannot, however, provide a complete knowledge of man. Models never truly represent nature. This limitation is not peculiar to the knowledge of man, or of other living organisms; it applies also to inanimate nature as well. On this score, I shall content myself with quoting statements made by Eugene P. Wigner in Stockholm when he accepted the Nobel Prize for physics in 1963:

"Physics does not endeavor to explain nature. In fact, the great success of physics is due to a restriction of its objectives: it endeavors to explain the regularities in the behavior of objects. This renunciation of the broader aim, and the specification of the domain for which an explanation can be sought, now appears to us an obvious necessity. In fact, the specification of the explainable may have been the greatest discovery of physics so far.

"The regularities in the phenomena which physical science endeavors to uncover are called the laws of nature. The name is actually very appropriate. Just as legal laws regulate actions and behavior under certain conditions but do not try to regulate all actions and behavior, the laws of physics also determine the behavior of its objects of interest only under certain well-defined conditions but leave much freedom otherwise."

The word freedom as used by the physicist has a meaning which is very different, of course, from the one it has when applied to human affairs. Nevertheless, even though the analogy is only formal, I shall use it in an attempt to state my faith concerning the kind of contribution that scientific biology can make to the humanities. First, however, I must emphasize that the biological information discussed in the preceding pages was not intended to give an account of the living throbbing man whom the humanist tries to apprehend and the artist to express. Its role was only to describe the raw materials out of which man creates himself, through a continuous series of personal decisions. A few remarks concerning the plastic arts will serve to illustrate my view of the manner in which man's ability to choose and decide determines and limits the relevance of biological knowledge to the humanities.

The paintings, statues, engravings, and other artefacts found in paleolithic sites leave no doubt that the faculty for artistic expression is very ancient; indeed, it does not seem to have improved with regard either to acuity of perception or to skill in representation over the past 20,000 years. There is consequently every reason to believe that the ability to perceive and to represent corresponds to deeply seated physiological attributes of man's nature. This esthetic faculty is probably analogous to that which makes animals perform movements or build nests which have an intrinsic harmony. Certain colors clash or certain elements in a drawing appear to be out of proportion, when the experience of them conflicts with some built-in set of relationships in our own organs. In contrast, we would not be pleased with the way certain things look unless our organs and senses were so constituted as to be in harmony with the proportions and rhythms associated with these things. Whether the manner in which the senses or organs respond has a purely genetic basis, or is the product of conditioning influences, irrelevant here. The point I want to convey is that esthetic consciousness depends on innate faculties which are biological in essence and which do not seem to have progressed since paleolithic times.

However, the ability to perceive and to represent is not sufficient by itself to create works of art; other factors are involved which fall outside the realm of the biological sciences. While human beings respond to their environment through their biological attributes, they do not react passively as if they were but mechanical intermediaries in stimulus-response couplets. The artist's response is not mechanical, nor even simply motivated by the need to cope with the environment. It constitutes rather an expressive behavior in which the artist uses the environment for the purpose of self actualization.

The act of artistic creation thus provides a convenient example to illustrate the role of human choices in willing a certain course of action among the possibilities of dealing with external nature through the needs, drives, and urges which are inherent in man's nature. Similarly, all other aspects of human life present opportunities for active intervention on the part of man-the creature who can choose, eliminate, assemble, decide, and thereby create.

As is well known, man has now the technical means to transform his life and himself by manipulating his environment, as well as his physiological and mental processes; soon he may even be able to alter somewhat his genetic makeup. The powers of action generated by scientific advances are so great that the classical discussions on the ideals of the good life now take on very practical meaning. Mankind-that is to say we-shall find ourselves drifting aimlessly toward a state incompatible with the maintenance of the humanistic values from which we derive our uniqueness, unless we formulate goals worthy of they human condition, and are willing to take a stand at the critical time. This kind of freedom is the final criterium of humaneness. In the words of Paul Tillich, "Man becomes truly human only at the moment of decision."

Values and goals naturally involve choices and decisions. But the more deeply human life is influenced by technology, the more essential it becomes that these choices and decisions be made in the light of the proper kind of biological knowledge. Man's nature constitutes such a highly integrated system that it cannot be altered safely except within rather narrow limits. Unconsciously, the writers of science fiction acknowledge this fact when they make the human beings who function in an automated world or who travel in spacecraft continue to behave as if they were in a boy scouts' camp or in lovers' lane.

Since radical changes in human life are excluded by biological limitations, imaginings based on limited concepts of the body machine, or on the hope of technological breakthroughs, are of little use in defining what the ideal man should be. The glory of the coming age must be conceived within the framework of man's nature-of his biological limitations as well as his potentialities.


In the very process of responding to environmental stimuli, each individual human being creates his physical and mental personality from the biological attributes which are shared by all men. Human societies and cultures emerged from the progressive integration of these responses.

While the outward manifestations of behavior are governed by the values and rules of each social group, inwardly man continues to react to his environment in much the same way that he did in the distant past, through the very same way physiological mechanisms which he has retained from his evolutionary development. These ancient biological attributes express themselves in the form of reactions which are often unsuited to the modern world and are therefore the cause of difficulties; but, on the other hand, they also constitute a source of inspiration for creative endeavors.

Individual human beings differ not only in their genetic endowment, but also by reason of the stimuli to which they have been exposed in early life, both prenatal and postnatal-which give them an experiential uniqueness. These early influences shape the physical and mental characteristics by stimulating into activity certain parts of the genetic endowment, and also by inhibiting the expression of others. The extent to which a person has retained the ability to apprehend the external world in an unconditioned manner, and to respond to it in his own way, probably plays a large part in his creativeness.

The role of the biologist is to study the raw materials of man's nature and the mechanisms through which each person uses them to create his own experiential individuality. This role is becoming of increasing importance as human life becomes more deeply influenced by technology and therefore more remote from man's evolutionary experience.

By adding to the knowledge of man's biological nature, science helps the humanist better to understand the human condition, and to define the good life. Unfortunately, while biological sciences have been immensely successful in describing the elementary structures and processes of the body machine, they have tended to neglect the study of living as experience. Indeed, it is commonly stated that biology has lost contact with the humanities because it has become too "scientific" and as a consequence no longer deals with the problems peculiar to the humaneness of man. There is no doubt, of course, about the loss of contact, but the explanation of the difficulty, in my judgment, is that biology is not scientific enough.

By neglecting the study of a large variety of man's responses, biology is betraying one of the responsibilities of science-namely, the development of objective methods for describing all aspects of reality. Today, as in the past, the most compelling and interesting problems of human life come from the manner in which man reacts passively, and responds creatively, to the challenges of his total environment. Biology will once more become a complementary aspect of the humanities if it accepts the urgent social task to provide knowledge of the raw materials of experience out of which man creates himself.

(This paper has been presented as it appeared in American Scientist , Vol. 53, 1965, pp. 4 - 19.)

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