Essays of a Biologist

by Julian Huxley

But in his mode of life and type of social organization he is unique. All detailed comparisons between the communities of man and those of bees and ants are as unprofitable in the working-out as they are easy in the making. It is futile to direct the sluggard or any other human being to the ant, since the whole physical and psychical construction of ants is different from that of man, the whole organization of their communities from that of his.

His mode of life is unique because his psycho-neural mechanism is built on a new plan, new modes of connection between parts of the brain being associated with new possibilities of mind. Let us briefly run over the biologically most important points in which he differs from the lower organisms.

In the first place, he is capable of speech, and possesses a true language—not a mere repertory of sounds or signs associated with different states of mind, as in some higher organisms, but a language comprising special symbols for particular external objects, and thus making it possible to have a much more detailed knowledge and classification of the outer world. In the second place, he can frame abstract ideas or concepts, and is thus enabled to extract the general kernel from the husk of innumerable separate and different particulars. As a result of these two faculties, he possesses what we may call a new, accessory form of inheritance. True biological inheritance takes place by means of the reproductive cells. In some birds and mammals, the behaviour of the young is modified by what they learn from their parents, so that they profit by the experience of their elders; however, this profiting by experience is not cumulative, but must be repeated afresh in each generation. In man, on the other hand, speech and writing make it possible to construct a continuous tradition, by means of which experience may be actually accumulated from generation to generation. There are thus two forms of inheritance in man, two hereditary streams—biological inheritance, by means of germ-cells or detached portions of the organism, in which favourable mutations may be accumulated by selection, and “experience-inheritance,” by means of tradition, in which useful experience may be accumulated by the activity of mind. By means of tradition-inheritance, man is virtually enabled to “inherit acquired characters”; thus the environment in which the latter stages of his development are passed through, and consequently his adult self, the end-product of that development, can be altered far more rapidly than in any other organism. Finally, it is possible, as is being increasingly realized, thus to accumulate experience relating to the alteration of biological inheritance, and so eventually to substitute conscious purpose for blind natural selection in man’s future evolution.

Next point: by means of speech, tradition, and invention, man has been enabled to extend his biological environment—in other words, that part of the cosmos with which he stands in relation—till it has reached an enormously greater size than that of any other organism. He is learning ever more facts about the celestial bodies, studying stars that are at an inconceivable distance from him. He is able to travel at will to all parts of the globe. He can penetrate by means of tradition to remote periods of the past: as Mr. Wells has forcibly put it, a modern Englishman can know more of the world in the Classical Epoch than could the most learned Greek or Roman. And even when he can no more get into contact with ideas, he can still unravel facts: flint implements help him to the history of man, fossils to that of life, rocks to that of the globe, stars to that of the solar system. In time, as well as in space, his environment enlarges to a size that is for practical purposes infinite, whereas no other organism can penetrate beyond its own memories, or, at most, do more than profit by those of the generation immediately before it. Professor Keyser,[20] in a suggestive article, has characterized this unique attribute of man by calling him “the time-binder.”

Speech and reasoning, with all their consequences, have only been rendered possible through another important qualitative change in the human brain, which in its turn has led to other new potentialities of life being realized in man and in man alone—its flexibility.

In some of the lowest forms of life, such as Paramecium, there are but one or two possible modes of reaction—reactions which it attempts in response to any one of the myriad changes that may occur in the outer world. As we ascend the scale, we find two chief types of alterations: in the first place an increase in the number of hereditarily-given modes of reaction, and in the second an increased power of “learning,” of altering behaviour in adjustment to experience. In the insects, the first is chiefly in evidence. Although many insects undoubtedly can profit by experience to a limited degree, yet most of their behaviour is instinctive, in the sense that it unrolls itself automatically and efficiently in the absence of previous experience or of any possible instruction. In the vertebrates, on the other hand, we see as we pass from the lower to the higher groups a definite, steady increase in the power of learning by experience, from the fish that takes weeks to associate a given colour with a given event such as feeding-time, to the dog or monkey capable of learning elaborate tricks after a couple of trials. But even in the most “intelligent” of birds or mammals, the power of image-formation is very probably absent,[21] and the power of concept-formation, of generalizing, certainly so. This fact (quite apart from the absence of tradition, although this too operates in the same direction) means that the associations of animals can only be arbitrary and individual: a rook in one country (to choose a somewhat far-fetched example) may happen to associate danger with fire-arms, one in another with bows and arrows. Life, for the animals, is a cinema, different for each individual, in which one event may be associated with another in the most diverse and haphazard ways. With the advent of the human type of brain, however, experience can be sorted out and properly docketed; the mere cinematographic record is converted into a drama full of significance, the diary into a card-index. By this means, and by tradition, it is possible for man to obtain a much more accurate and more complete grasp of the relationships of the objects that compose the outer world than is possible for any other animal. Through knowledge, as ever, comes power: and as a result, man has been enabled to invent tools and machinery, and so to enlarge enormously his control over his environment. Just as his “range,” in the zoogeographical sense, is extended to an unprecedented degree both in space and time, so tools represent, biologically speaking, an extension of himself as an operator. While man is using a tool, he and the tool together constitute but a single unit in the struggle for existence. As various writers have put it, tools and machines are temporary organs of man, which have the additional merit of being replaceable if lost or damaged.

But this is not all: the great power of association possessed by man, together with his faculty of generalization and of speech, makes it possible for him to learn his rôle in the community, instead of being born with it as are the bee and the ant. Great educability instead of differentiated instinct, infinite possibility, at the expense of the pains of learning, instead of an effortless but limited stock of inborn modes of behaviour—in this again man represents a qualitatively new organic type.

By this means he can escape what has always been a necessity with lower forms: by means of education and machinery he can play a specialized part in the community life, and so build up a community with a high degree of division of labour, without being born specialized. He could not thus learn his rôle if he were not educable, nor if he could not manufacture tools. An ant or a duck or a dog possesses admirable tools for its particular job: but they are living parts of the organism’s own body. A worker ant cannot lay down its serviceable carpentering mandibles and become a soldier by picking up a large and warlike pair:—once a worker, always a worker; once a soldier, always a soldier—that is the rule for ants, but not for men.

The efficiency and biological success of communities depends on the degree and accuracy of the division of labour and co-ordination between the units of which they are built up. This is true of cell-communities and the second-grade individuals or metazoa or multicellular animals and plants to which they give rise,[22] and also of the communities of metazoa and the third-grade individuals to which they give rise, whether the members of such communities of higher grade are physically bound together, as in a Hydroid or a Portuguese Man-o’-War, or united only by mental bonds, as are the communities of ants and bees and termites. As we have seen, the individuals are differentiated structurally for the different functions which they have to perform.

This is not so in human species: a man is not born cross-legged to be a tailor, or broad-thumbed to be a miller, or big-armed to be a blacksmith. Even in the hereditary castes of India, the trade or profession is determined by tradition, and not by inborn structural adaptations.