Essays of a Biologist

by Julian Huxley

Man differs biologically from other organisms in the following main ways. First, he has the power of thinking in concepts; in other words, his power of learning by experience is not always conditioned directly by the accidents of his own life, as is the case with animals endowed only with associative memory, but he can, by reaching the general from the special, attain to the possibility of dealing with many more, and more complicated, eventualities. Next, by means of speech, writing, and printing, he has developed a new mode of inheritance.[10] Each community, and indeed humanity as a whole, transmits its peculiarities to later ages by means of tradition, using that word in its largest sense. Physical inheritance of the same type as in all higher animals and plants is the necessary basis, but the distinctive characters of any civilization are based on this new tradition-inheritance. Thirdly, the type of mind which has been evolved in man is much more plastic—a much more elastic and flexible mechanism than any tool previously evolved by life for handling the problems of existence. As a consequence of this we have the substitution of general educability for specific instincts. For the power of performing comparatively few actions smoothly and without trouble, there is exchanged the possibility of a vastly increased range of action, but one which has to be learnt. As another consequence, man has come by the power—impossible to any other organism—of leading what is to all intents and purposes a multiple existence. It is for this very reason difficult to fit man into many of the ordinary biological categories. The physical and mental structure and the mode of life of even the highest of the animals are for all practical purposes a fixed quantity. An ant, for all its delicacy of adjustment, is little less than a sentient cog shaped to fit in just one way into the machinery of the community; a dog, for all his power of learning, is tied down and imprisoned within a rigidity and narrowness of bodily and mental organization difficult for us to imagine.

Man passes freely from one aggregation to another. He can change his nation or his city; he can belong to a dozen organizations—biologically speaking, can be aggregated in a dozen different ways—and play a different part as unit in each. He can follow one profession in the morning, another at night, and be a hobby-horse rider in between.

This plastic mind has endowed him with a new biological possibility. He can do what no other organism can—he can be both specialized and generalized at one and the same time.

In biology, the aggregation of units to form units of higher grade has been always followed by division of labour among the units; and this division of labour has, in all infrahuman history, been made possible only by an irreversible specialization.[11] A soldier-ant is a soldier, and there its possibilities end. It cannot do what the worker or the queen can do. A muscle-cell, because it has gained the power to contract, is cut off from other possibilities; it cannot secrete, or digest, or carry messages. The aggregate of nerve-cells which makes the physical basis of mind is held fixed to its post, incapable of turning to other functions.

It follows that the units of all such aggregates are subordinate to the whole—they have lost their independence, and can often no longer be considered as individuals at all, except historically. But in man, none of these things hold. A man can for half his day be the merest cog, subordinate in every detail of his action to the needs of the community, but for the other half be himself, a full and complete individuality, making the community serve his own ends and needs. For him, aggregation does not mean complete and irreversible subordination; his specialization is reversible, and indeed his potentialities as an individual actually increase with the increased individuality of the aggregate to which he belongs.

Bearing these differences in mind, we may turn to consider how our doctrine of progress helps us in studying humanity.

At the outset we must guard ourselves against the idea that human society has reached any high level of biological individuation. I may perhaps quote from what I have written elsewhere: “If we were to draw a parallel between primitive types of society and some primitive mammal such as a duck-billed platypus, and to compare the course which we hope society will in time accomplish with what has been accomplished in the progress of the mammalian type from a creature resembling the platypus up to man, with what creature should we have to compare the existing state of human communities? I venture to say that we should be flattering ourselves if we were to fix upon the dog.”

Then we must remember that Natural Selection in man has fallen chiefly upon groups, not upon individuals, and differences in the nature and organization of human groups are determined chiefly by what we can best sum up as differences of tradition in the widest sense of the term. The later history of mankind, from a period long antedating written records, has been one of the rapid rise and equally rapid extinction, not only of one group-unit after another, but of one type of group-unit after another. It is further obvious at first glance that the group-units, the types of society which are at present dominant, are far from perfect and far from stable, and indeed that they are evolving, with speed of change hitherto unsurpassed, towards new and unknown forms.

When the mammalian type first became dominant on the globe—at the transition between the Secondary and Tertiary periods—a somewhat similar history was passed through. The new type of organization gave its possessors marked advantages over other animal types: but the full potentialities of the mammal (excluding man) were not realized until well over half of the Tertiary period had elapsed, and man was being prepared in the womb of circumstance. The Pliocene sees the triumph of the perfected types of mammal: the preceding Miocene, broadly speaking, sees the first rise of these new types, while the Eocene and Oligocene show us a rapid rise and as rapid extinction of variation upon variation on the original theme.[12] With man, however, only the beginnings of a similar process have as yet come to pass.

Further, we must distinguish clearly between the different ways in which progress may be operative in man. In the first place it can appear, as we have just pointed out, in the organization of the communities to which he belongs and on which natural selection seems mainly to act. Secondly, it can appear as a raising of the average of certain qualities among the individuals composing those communities. And thirdly, it can appear as a raising of the upper level of attainment in those qualities, in the appearance of individuals biologically higher than any that have previously existed.