203. The discussion of these disintegrations of personality needs, I think, some little clearing of the ground beforehand, if it is to avoid confusion. It will be needful to speak of concurrent and alternating streams of consciousness, - of subliminal and supraliminal strata of personality and the like; - phrases which save much trouble when used with care, but which need some words of preliminary explanation. It is not easy to realise that anything which deserves the name of consciousness can be going on within us, apart from that central stream of thought and feeling with which we identify ourselves in common life. Something of definition is needed; - not indeed of any formal or dogmatic kind; - but enough to make clear the sense given to such words as consciousness, memory, personality, in the ensuing pages.

I begin, then, with the obvious remark that when we conceive any act other than our own as a conscious act, we do so either because we regard it as complex, and therefore purposive, or because we perceive that it has been remembered. Thus we call the fencer or the chess-player fully conscious; or, again, we say, "The man who seemed stunned after that blow on the head must really have been conscious all the time; for he afterwards recalled every incident." The memorability of an act is, in fact, a better proof of consciousness than its complexity. Thus consciousness has been denied both to hypnotised subjects and to dogs; but it is easier to prove that the hypnotised subject is conscious than that the dog is conscious. For the hypnotised subject, though he may forget the incidents of the trance when he awakes, will remember them in the next trance; or he may be trained to remember them in the waking state also; while with regard to the dog we cannot decide from the mere complexity of his actions how far he is conscious of their performance. With him, too, the best line of proof lies in his obvious memory of past acts. And yet, although all agree that our own memory, broadly speaking, proves our past consciousness, some persons would not admit that a dog's memory does so too.

The dog's organism, they would say, responds, no doubt, in a new manner to a second repetition of a previous stimulus; but this is more or less true of all living organisms, or parts of organisms, even far below what we generally regard as a conscious level.

Reflections of this kind naturally lead to a wider conception of consciousness. It is gradually seen that the earlier inquiries which men have made about consciousness have been of a merely ethical or legal character; - have simply aimed at deciding whether at a given moment a man was responsible for his acts, either to a human or to a divine tribunal. Common sense has seemed to encourage this method of definite demarcation; we judge practically either that a man is conscious or that he is not; in the experience of life intermediate states are of little importance.

As soon, however, as the problem is regarded as a psychological one, to be decided by observation and experiment, these hard and fast lines grow fainter and fainter. We come to regard consciousness as an attribute which may possibly be present in all kinds of varying degrees in connection with the animal and vegetable worlds; as the psychical counterpart of life; as conceivably the psychical counterpart of all phenomenal existence. Or, rather, we may say this of mind, to which, in its more elementary forms, consciousness bears somewhat the same relation as self-consciousness bears to consciousness, or some higher evolution may bear to self-consciousness.

This being so, I cannot see how we can phrase our definition more simply than by saying that any act or condition must be regarded as conscious if it is potentially memorable; - if it can be recollected, under any circumstances, by the subject concerned. It does not seem needful that the circumstances under which such recollection may occur should arise while the subject is still incarnated on this planet. We shall never on this planet remember the great majority of our dreams; but those dreams were presumably no less conscious than the dreams which a sudden awakening allowed us to keep in memory. Certain hypnotic subjects, indeed, who can be made to remember their dreams by suggestion, apparently remember dreams previously latent just as easily as dreams previously remembered. And we shall have various other examples of the unexpected recollection of experiences supposed to have been entirely devoid of consciousness.

We are bound, I think, to draw at least this negative conclusion: that we must not take for granted that our apparently central consciousness is something wholly different in kind from the minor consciousnesses out of which it is in some sense elaborated. I do indeed believe it to be in an important sense different; but this difference must not be assumed on the basis of our subjective sensations alone. We must approach the whole subject of split or duplicated personalities with no prepossession against the possibility of any given arrangement or division of the total mass of consciousness which exists within us.