If there be no science of the common man, still less is there a science of the different man, since the manifestation of this difference makes him solitary and unique, that is to say, incomparable. Yet, just as there is a general physiology, so there is a general psychology, also. Whatever their nature, all the beasts of the earth breathe the same air, and the brain of the genius, like that of the ordinary mortal, derives its primordial form from sensation. We have only a rough idea by what mechanism sensation is transformed into action. All we know is that the intervention of consciousness is not needed to bring about this transformation. We know also that this intervention may prove harmful through its power to modify the predetermined logic, to break the series of associations in order to create in the mind the first link of a new volitional chain.

Consciousness, which is the principle of liberty, is not the principle of art. It is possible to express quite clearly what has been conceived in the unconscious shades. Intellectual activity, far from being intimately allied with the functioning of consciousness, is more often disconcerted by it. We listen badly to a symphony, when we know we are listening. We think badly, when we know we are thinking. Consciousness of thinking is not thought.

The subconscious state is the state of automatic cerebration in full freedom, while intellectual activity pursues its course at the extreme limit of consciousness, a little below it and beyond its reach. Subconscious thought may remain for ever unknown. It may, on the other hand, come to light, either at the precise moment when the automatic activity ceases, or later—even after several years. These facts of cogitation do not, then, belong to the domain of the unconscious, properly speaking, since they can become conscious. Besides, it will doubtless be preferable to reserve to this rather vast word the meaning given it by a particular philosophy. The subconscious state differs also from the state of dreams, though dreams may be one of its manifestations. The dream is almost always absurd, with a special sort of absurdity, and is incoherent or orderly, according to its associations which are entirely passive,[2] and whose procession differs even from that of ordinary passive associations, conscious or unconscious.[3]

Imaginative intellectual creation is inseparable from the frequency of the subconscious state, and in this category of creations must be included the discovery of the scientist and the ideological construction of the philosopher. All who have invented or discovered something new in any field whatsoever, are imaginatives as well as observers. The most deliberate, the most thoughtful, the most painstaking writer is constantly, and in spite of himself, enriched by the effort of the subconscious. No work is so completely a product of the will that it does not owe some beauty or novelty to the subconscious. No sentence, perhaps, however worked over, was ever spoken or written in absolute accord with the will. The search for the right word in the vast, deep reservoir of verbal memory is itself an act which escapes so completely from the control of the will, that very often the word on its way flees at the very moment when consciousness is about to perceive and to grasp it. Everyone knows how hard it is to find, by sheer force of will, the word wanted, and also with what ease and rapidity certain writers summon up, in the heat of composition, the rarest or the most appropriate words.

It is, however, imprudent to say: "Memory is always unconscious."[4] Memory is a secret pool where, unknown to us, the subconscious casts its net. But consciousness fishes there quite as readily. This pond, full of chance fish previously caught by sensation, is particularly well known to the subconscious. Consciousness is less skilful in provisioning itself from this source, though it has at its service several useful tricks, such as the logical association of ideas and the localization of images. Man acquires a different personality, according as the brain works in the darkness or by the lantern-light of consciousness; but, save in pathological cases, the second of these states is not so well defined that the first cannot intervene without interrupting the effort. It is under these conditions, and in accordance with this concert, that most works conceived, in the first instance either by the will or by the dream faculty, are completed.

In Newton's case (as a result of constant attention) the work of the subconscious is continuous, but connects itself periodically with voluntary activity. Now conscious, now unconscious, his thought explores all the possibilities. With Goethe, the sub-conscious is almost always active and ready to deliver to the will the multiple works which it elaborates without its aid and far from it. Goethe himself has explained this in a marvellously lucid and instructive page:[5] "Every faculty of action, and consequently every talent, implies an instinctive force at work unconsciously and in ignorance of the rules whose principle is, however, implicit. The sooner a man becomes educated, the sooner he learns that there is a technique, an art, which will furnish him the means of attaining the regular development of his natural faculties. It would be impossible for what he acquires to injure in any way his original individuality. The supreme genius is he who assimilates and appropriates everything without prejudice to his innate character. Here we are confronted with the divers relations between consciousness and unconsciousness. Through an effort of exercise, of apprenticeship, of persistent and continuous reflection, through results obtained, whether good or bad, through the movements of resistance and attraction, the human organs amalgamate, combine unconsciously the instinctive and the acquired, and from this amalgam—from this chemistry at once conscious and unconscious—there issues at last a harmonious whole which fills the world with words. It is nearly sixty years since, in the full flush of my youth, the conception of Faust came to me perfectly clear and distinct, all its scenes unfolding before my eyes in the order of their succession. From that day the plan never left me, and living with it in view, I took it up in detail and composed, one after the other, those bits which, at the moment, interested me most, with the result that, when this interest has failed me, there have occurred gaps, as in the second part. The difficulty, at such points, was to obtain, by sheer force of will, what, in reality, is obtainable only by a spontaneous act of nature." It also happens conversely that a work conceived in advance and deferred in execution, comes at last to impose itself upon the will. The subconscious then seems to overflow and submerge the conscious, dictating things that are written only with repugnance. This is the obsession which nothing discourages, and which triumphs over even the most lackadaisical laziness, the most violent aversion. Later, once the work is completed, there is often experienced a sort of satisfaction. The idea of duty, which, ill understood, causes so many ravages in timid consciences, is no doubt an elaboration of the subconscious. Obsession is perhaps the force which impels to sacrifice, just as it is that which incites to suicide.

Schopenhauer used to compare the obscure and continuous effort of the unconscious, in the midst of impressions imprisoned in the memory, to rumination. This rumination, which is purely physiological, may suffice to modify convictions or beliefs. Hartmann discovered that a hostile idea, at first brushed aside, succeeded, after a certain time, in supplanting in his mind the idea which he was accustomed to entertain of man or of a fact: "If you wish or have the occasion to express your opinion upon the same subject, after days, weeks, or even months, you discover, to your great surprise, that you have undergone a veritable mental revolution—that you have completely abandoned opinions which, up to that time, you had firmly believed to be yours, and that new ideas have completely taken their place. I have often noted this unconscious processus of digestion and mental assimilation in my own case, and have always instinctively refrained from disturbing the process by premature reflection, whenever it involved important questions affecting my conceptions of the world and of the mind."[6] This observation might be extended to the exceedingly interesting problem of conversion. There is no doubt that people have suddenly felt themselves brought, or brought back, to religious ideas, when they had neither wish nor fear nor hope for this change. In conversion the will can act only after a long effort on the part of the subconscious, and when all the elements of the new conviction have been secretly assembled and combined. This new force, which supports the convert, and whose origin is unknown to him, is what theology calls grace. Grace is the result of a subconscious effort. Grace is subconscious.

Like Hartmann, but instinctively, and not, in his case, by philosophic preconception, Alfred de Vigny entrusted to the subconscious the nurture of his ideas. When they were ripe, he recovered them. They came back of their own accord to offer themselves rich with all the consequences of their secret burgeoning. It may be supposed that, like Goethe, he was a subconscious whose promissory notes were on very long time, since Vigny left, between certain of his works, unusually long intervals. It is highly probable that, if there are individuals whose subconsciousness is inactive, there are others who, after a period of activity, cease suddenly to produce, either as a result of premature exhaustion, or through a modification in the relations of the brain cells. Racine offers the singular example of a twenty years' silence broken just halfway by two works which have only a formal resemblance to those of his first phase. Can it be supposed that it was through religious scruple that he so long refused to listen to the suggestions of the subconscious? Can it be supposed that religion, which had modified the nature of his perception, had, at the same time, diminished the physiological power of his brain? Such a supposition would run counter to all other observations, which go to show, on the contrary, that a new belief is a new excitant. It seems, then, probable that Racine became silent simply because he had almost nothing more to say. It is a common adventure, and he found in religion the common consolation.

A distinction should then be made between two sorts of subconscious individuals—those whose energy is short-lived and strong, and those whose force is less ardent but more sustained. The two extremes are exemplified by the man who produces a remarkable work in his early youth, then ceases, and by the man who offers for sixty years the spectacle of a mediocre, useless and continuous effort. I am speaking, of course, of those works in which the imaginative intelligence plays the major part—works in which the subconscious is always the master-collaborator.

More practically, and from a totally different point of view, M. Chabaneix, having studied the continuous subconscious, divides it into nocturnal and waking subconsciousness. If the former be a question of sleep or of the moments preceding sleep, it is oneiric or pre-oneiric. Maury, who was particularly afflicted by them, has carefully considered the hallucinations which are formed the moment the eyes close in sleep. It is not clear that these hallucinations which are called hypnagogic, and which are almost always visual, can have a special influence on the ideas undergoing elaboration in the brain. They are rather embryonic dreams which influence the course of the thought only as dreams influence it. It happens, at times, that the conscious effort of the brain is prolonged during the dream, even reaching its goal there, and that, on awaking, the dreamer finds himself, without reflection or difficulty, master of a problem, a poem, a combination, which had baffled him previously. Burdach, a Koenigsberg professor, made, in his dreams, several physiological discoveries which he was afterwards able to verify. A dream was sometimes the point of departure for an undertaking. Sometimes a work was entirely conceived and executed during sleep. It is highly probable, however, that it is the conscious reason which, at the moment of awaking, judges and rectifies the dream spontaneously, gives it its true value, and divests it of that incoherence peculiar to all dreams, even the most rational.