It is a commonplace of evolutionary doctrine that, other things being equal, those races will survive, in the constituent members of which intelligent behaviour enables them to deal most effectually with an environment of increasing complexity. And it is a matter of familiar observation that such behaviour is closely connected with delicacy and refinement of development in those senses which take the lead in cognitional process, and with rapidity and precision in the motor co-ordination through which prompt and skilful advantage is taken of the situation which has, through experience, acquired meaning.

But though the importance of intelligent adjustment to the circumstances of life is widely admitted as a general principle, it is perhaps through a study of animal behaviour that we are best able to realize its full range and extent. Biologists are so largely, and quite wisely, occupied in the study of morphological and physiological problems, which admit of a treatment more exact than the most ardent advocate of the investigation of behaviour, under natural or even under experimental conditions, can claim; they devote, again quite rightly, so large a share of attention to the variation and natural selection of adaptive structure in its adult condition and embryonic stages; the pendulum of opinion has, under the teaching of Professor Weismann, swung so far in the direction of the non-acceptance of the hereditary transmission of characters individually acquired through intelligent adjustment or otherwise; that the part played by consciousness in the evolution of the higher and more active animals is apt to pass unnoticed or unrecorded. It is well, therefore, to put in a reminder that a great number of animals would never reach the adult state in which they pass into the hands of the comparative anatomist save for the acquisition of experience, and the effective use of the consciousness to which they are heirs; that their survival is due, not only to their possession of certain structures and organs, but, every whit as much, to the practical use to which these possessions are put in the give and take of active life; and that many interesting problems which are keenly discussed by evolutionists in the light of natural selection presuppose conscious situations which are more or less tacitly taken for granted.

Let us cast a rapid glance over some of these topics of biological discussion. The fascinating subject of mimicry, involving as it necessarily does the discussion of the value of warning colours and behaviour, a subject opening up an extensive group of problems so brilliantly studied by Professor Poulton, is meaningless save in so far as there is implied a conscious reaction to colour and form on the part of animals which can learn from experience. The warning colours reinstate a conscious situation, so that, misled by appearances, a bird mistakes the mimicking insect for its nauseous “model.”

The whole range of behaviour, included under play, experimentation, and practice, on the importance of which, following the lead so ably given by Professor Groos, we have insisted, is equally meaningless, save as a means to the acquisition of serviceable experience for use in the more serious business of after-life; and experience is the establishment, through association and coalescence, of conscious situations which possess guiding value. And if, as we shall hereafter see, they may also be regarded as a means of securing pleasure, as a psychological end of behaviour, it is not less obvious that it is only through the development of consciousness that such a psychological end can have any existence.

It matters not if the particular form assumed by play and experimentation be largely dependent on instinctive tendencies. For all the phenomena of instinct, profoundly organic as are the modes of behaviour comprised under this head, definite as are the inherited co-ordinations in the most typical examples of its occurrence, have also, except in some doubtful cases, a conscious aspect. At any rate this is the case in so far as instinctive response forms the hereditary basis on which is reared a more nicely adjusted intelligent edifice, in so far as instinctive procedure is subsequently modified and guided by acquired experience, in so far as there creeps in that “little dose of judgment” which Huber found in bees, Lord Avebury attributes to ants, Dr. Peckham sees in spiders and solitary wasps, and all observers find in birds and mammals. For if in these cases instinctive behaviour were unconscious, it would, as such, remain outside experience; and if outside experience, there could be no data on which consciousness could base any modification of inherited behaviour, no opportunity of taking up the ready-formed responses into the mental synthesis and utilizing them for the wider ends of intelligent purpose.

In social behaviour there is a reciprocity of suggestion between the members of the community. And such suggestion is operative through an appeal to consciousness. However instinctive the forms of procedure may be in social insects, there remains much beyond which is hard to explain on the hypothesis that there is, in them, nothing analogous to a conscious situation; while in such vertebrates as birds and mammals we cannot but believe that consciousness is the main determinant of much behaviour which seems to imply the germs, or more than the germs, of sympathy. The little monkey I saw in Hamburg cuddling up caressingly to a wounded companion, must surely have experienced a conscious situation analogous to that which prompts a child to nestle alongside her companion in distress. And he who has seen no signs of sympathy in dogs, has either watched their behaviour in vain, or is himself lacking in sympathy.

In sexual selection by preferential mating, even if we follow Professor Groos in believing that it is a special mode of natural selection, the conscious situation is essential. If we accept the theory in any form, we must regard the adornments, antics, and display of the male as an appeal in some way to the consciousness of the female, whatever particular form the effects in that consciousness may take, whether the appeal evoke a sense of beauty, or simply be a means of exciting to the consummation of the natural end of courtship. Even if we follow Mr. Wallace in regarding plume and song as “recognition marks,” it is only by their appeal to consciousness in this way, if in no other, that they are of any biological value. And this, of course, applies equally to the whole range of his theory of recognition marks—their sole utility lies in their being a stimulus to consciousness through which the end of recognition is secured. So, too, not only the specialized behaviour which we dignify by the name of “courtship,” but every case in which mate is drawn to mate through sight, smell, hearing—any of the leading senses—testifies to the importance of consciousness in furthering an end of supreme biological importance.

And if, as Darwin urged, the “law of battle” among the males co-operates with preferential mating, as we can hardly deny, in securing strong, vigorous, and healthy fathers of the generation they beget, here, too, consciousness is an important factor. Can we conceive a “law of battle” among unconscious beings? If success in the combat were a mere matter of brute strength, it would imply some consciousness in its dull exercise. But it is more. It is also a trial of skill. Were it not so our forefathers would not have spent hours in watching a cock-fight, or laid heavy odds on their particular “fancy.”