physical symbols of their consciousness, it would be the height of folly to consider this information complete, for it leaves out the most important thing about men. This greatest asset of all so transcends in value to us the knowledge of its physical basis, that even if every feeling and thought we have comes only with such changes in our brains as a skilful chemist and physicist might detect, measure and tabulate, it still remains true that we have used and are using our minds advantageously in the almost complete absence of such records. Had Shakespeare been dependent on a knowledge of the chemical changes in his nervous tissues as he wrote Hamlet, it is needless to insist that the play would not yet be written. To know a thing, to perceive and appreciate beauty, to recognize natural law and truth, all these are experiences in consciousness whose value and importance in human life no man can deny, nor can any man give a satisfactory explanation of the actions of his fellow-men without considering their feelings, emotions, and thoughts.
Since consciousness must be reckoned with in a scientific explanation of men, the question arises whether something analogous is not also true of living things in general. Does not the fitness of living things, the fact that they perform acts useful to themselves in an environment which is constantly shifting, and often very harsh; the fact that in general everything during development, during digestion, during any one of the complicated chains of processes which we find happens at the right time, in the right place, and to the proper extent, does not all this force us to believe that there is involved something more than mere chemistry and physics? Does not all this show that there must be present something, not consciousness necessarily, but yet its analogue — a vital X?
If we begin with what each one knows best of all, we may say that we can not doubt the existence of consciousness in ourselves. By intimate association with our fellow-men, and by comparing their acts with our own, we infer that they too are conscious, though we do not know this with the same certainty with which we know it of ourselves. If we descend in the scale of life, we know that it is practical to deal with many animals as though we knew for certain what in all probability is true, namely, that they also are conscious, but when we descend still farther, and reach forms built on a different plan, forms devoid of sense organs, and of brains, forms leading totally different lives, and with responses often simple and direct, what shall we say of them? Are they conscious? Is the amœba, the germinal disc of a hen's egg, or the sapling oak conscious? Nothing short of a method of communication as complete, delicate and trustworthy as the language of men, could ever enlighten us on this question, unless indeed we could transform ourselves at will into amœbæ, hen's eggs or oak trees. Even then we