Essays of a Biologist

by Julian Huxley

There thus comes a time when it is impossible or extremely difficult to give an organism advantage in the struggle by improving its sense-organs or its locomotor system, or indeed any of its general physical construction, whereas it is still possible to confer the most important advantages upon it by means of improvements in the adjustor mechanism, improvements which involve and imply improvements of mind.

This stage was reached by mammals and birds quite early in the Tertiary period; and one of the most striking spectacles of biology, revealed in the fossils of successive strata, is to see Mind coming into its own after this epoch. Over and over again a group of animals is seen to appear and spread, only to be extinguished and replaced by another type which to all outward appearance is similar, no better adapted to the conditions of life. But the two types differ in one point: the later possessed a larger brain, and so, from all analogy, a better mind. Or, to take another example, man differs from the lower animals in no notable physical specialization except the upright posture.

After this critical point in the evolution of organisms was reached, further development has consisted chiefly in the development of mind: and this has meant, from the objective, purely biological standpoint, the possibility of summing-up ever more and more power and fine adjustment of response in the present, in the single act.[6]

The first main function of the improved adjustor mechanism was to make ever more complicated actions possible; but this again tended speedily to a limit. The next step was to make it possible for the past to act in the present. Through associative memory, present behaviour is modified by past experience. What this has meant to organisms can be realized if we reflect that certain terms which can justly be applied to a mammal or a bird have no real meaning if applied to lower forms. If we speak of a cunning wolf or a wary crow, we imply that their life has taught them new qualities; but it is nonsense to talk of a cunning crab, and, though we might properly ascribe wariness to a trout, I would not like to speak of a wary Amoeba. In the same way we can justifiably say that one dog is affectionate, another intelligent: but to speak of an affectionate earthworm or an intelligent snail has no more proper significance than it would be to say that a dog was intellectual or religious.

Quickness of learning then became of importance; but so long as the faculty of generalizing is absent, associative memory, although liberating organisms from the prison of a fixed and inherited mental constitution, still pins them down to the accidental and the particular; an organism can only learn to react to those particular experiences which chance has decreed that it should have had.

The next and last salient step in evolution was a double one. Which of its two parts came first is hard to say; probably they acted reciprocally throughout. This step was, on the one hand, the attainment of the power of generalization—of reason, concept-formation, or what you will—and on the other the origin of tradition, which in its turn was made possible by the acquisition of speech and of a gregarious mode of life. By these means, the human species and its evolving ancestors were gradually enabled, first, to free experience ever more and more from the accidental and to store what was essential; and, secondly, to bring gradually more and more of the experience of the whole race to bear upon the present problem, and to plan further and further ahead, and on a larger and larger scale.

This has meant, among other things, that for the first time in biological history there has been an aggregation (in the technical biological sense) of minds. Over and over again in evolution does the process of aggregation appear.[7] It is an advantage, for at one jump it lands life on a new level of size, with new possibilities of division of labour and specialization. It appears in the aggregation of Protozoa to form the colonial ancestor of all higher, many-celled forms. It appears again on this new level in the aggregation of hydroid polyps, of polyzoa, of ascidians, and especially in the beautiful floating Siphonophora, in which the polyp-like units (themselves historically aggregates of cells) have become so subordinate in relation to the whole that they can often scarcely be recognized as individuals, and the individuality of the aggregate is much more marked than that of its components. It appears in a new way in the Termites and in the social Hymenoptera—ants, bees, and wasps. Here the bonds uniting the members of the aggregate are not physical but mental, their sense-impressions and instincts; but the principle is identical throughout. Finally in man we have not merely aggregation of physical individuals held together by mental bonds, but aggregation of minds as well as of physical individuals.

In many mammals and birds, each generation can extend its influence on to the next, and the experience of the parents is in part made available to the offspring. But never until the origin of speech was it possible for a whole series of generations to be linked together by experience, never could experience be cumulative, never could one mind know what another mind, remote in time, had been thinking or feeling. Biologically, evolution since the time of origin of this new process has consisted essentially in the enlargement and specialization of aggregations of minds, and the improvement of the tradition which constitutes the mode of inheritance for these aggregations—that tradition which, like Hugo’s “Nef magique et suprême” of human destiny, will eventually have “fait entrer dans l’homme tant d’azur qu’elle a supprimé les patries.”

It will, I hope, have been clear, even from the few examples which I have given, that there has been a main direction in evolution. At the close of the paper I shall try to point out that since motion in this direction has led to the production of an increasing intensity of qualities which we are unanimous in calling valuable, since in other words the application of our scale of values tends in the same direction as has the march of evolutionary history, that therefore we are justified in calling this direction progressive, and indeed logically compelled to give to motion in this direction a name which, like progress, implies the idea of value.

I shall therefore, from now on, use the term biological progress to denote movement in the direction which we have sketched in outline, and shall shortly proceed to define more accurately. In so doing, I perhaps beg the question, to be proved I hope later, as to whether the observed direction is progressive: but I no longer beg the question of whether evolution is a directional process. However we may argue on the facts, the facts remain: and the facts are that there has been an increase in certain qualities of organisms, both physical and mental, during geological time.