The Conscious and the Unconscious: From Outlines of Psychology (1881)

In the preceding account of mental life, stress has been laid on two chief distinguishing traits—on the occurrence of a change, through which new elements of consciousness emerge, and on the connection between all elements of consciousness. If this account is correct, then consciousness may cease from two causes: either because the individual elements do not possess strength enough to make themselves felt, or because the connection between them ceases.

So long as we adhere strictly to the principle that the mind is known only through the manifestations of consciousness, the province of mental life is not widely extended. Nerve-processes are not all of the kind which we have reason to think accompanied by consciousness, and even those with which this is the case may be carried on without consciousness, if their intensity is not sufficiently great.

Thus a physical stimulus may take effect on the nervous system without a sensation arising; the sensation arises only when the stimulus has reached a certain strength. The nerve-process, on the other hand, must begin at lower degrees of stimulation, and has thus already reached a certain strength when the sensation crosses the threshold of consciousness. Let x, for example, denote the degree of strength of a nerve-process, which is just strong enough for a scarcely perceptible sensation, which we will call y, to correspond to it. We then have a peculiar relation: while the degrees of strength on the physical side continuously decrease from x downwards, the psychical side remains empty, stops suddenly at y. This is how the relation presents itself, whatever fundamental conception as to the relation between the mental and material we start from. It is the same with combination as with degree of strength; for there is only a difference of degree between the structure and mode of action of the lower and the structure and mode of action of the higher cells. Now is it probable that at a certain stage of the scale a something should arise which did not exist at all at the lower stages? If the series in the one sphere is continuous, must it not be supposed to be so in the other? We have no right to assume that there are chinks or gaps anywhere in nature; at any rate the advances of knowledge principally consist in the filling up and connecting of interstices and clefts.

The question before us is, whether the unconscious can be other than a purely negative conception. In daily speech (and, more than is proper, even in the scientific use of language) we use such expressions as unconscious sensations, unconscious ideas, unconscious feelings. As, however, sensations, ideas, and feelings are elements of consciousness, the expression is in reality absurd. If by an unconscious idea is meant an idea which I have, then the predicate "unconscious" signifies only that I do not think of or pay heed to the fact that I have it. This use of the word unconsciousness is connected with a twofold use of the word consciousness. It is used to denote not only the inner presentation of our sensations, ideas, and feelings, but also self-consciousness, the attention expressly directed to our sensations, ideas, and feelings. We have, of course, many sensations and ideas without being conscious that we have them; many feelings and impulses stir within us, without our clearly apprehending their nature and direction. In this sense we can speak, for example, of unconscious love; a man who has this feeling does not know what is astir in him; perhaps others see it, or he himself gradually discovers it; but he has the feeling, his conscious life is determined in a particular way.

In desiring to examine here, however, the relation between the conscious and the unconscious, we understand by unconsciousness a state which lies below the threshold of our consciousness in general (not merely of our...