Sigmund Freud, answered from the texts and cited to the page.
The unconscious is not a poetic metaphor or a convenient shorthand for what we have merely forgotten. It is a system of the mind with its own laws, its own logic — if one can call it that — and its own relation to time and reality that differs fundamentally from anything consciousness knows. Let me begin with the most important correction to ordinary thinking on the matter.
Every psychological process, I would say, first exists in an unconscious state and only under certain conditions passes over into consciousness — much as a photographic negative need not become a print.1 The unconscious is the primary condition; consciousness is the achievement, the exception. What we ordinarily call the mind is the smaller room; the ante-chamber behind it is vast, crowded with impulses pressing against the threshold, where a watchman stands to censor what may enter.2
But the spatial metaphor, useful as it is for a first orientation, must give way to something more precise. The system of the unconscious has characteristics that set it apart not merely in degree but in kind. Its instinctual impulses exist independently side by side, exempt from mutual contradiction: when two wishes whose aims appear incompatible become simultaneously active, they do not cancel each other but combine into a compromise.3
There is in this system no negation, no dubiety, no varying degree of certainty — all that is only imported by the work of the censorship between the unconscious and the preconscious.4 The processes of the unconscious are timeless; they are not ordered temporally, bear no relation to time at all.5 And they are subject to the pleasure-principle alone, indifferent to external reality.6
Now here is the discovery that forced me to revise the theory most radically. One might suppose the unconscious and the repressed to be the same thing — that what is unconscious is simply what has been driven out of consciousness by repression. The clinical work showed otherwise. In the treatment, the resistance that the patient opposes to our efforts — the very force that keeps the repressed material from reaching consciousness — emanates not from the repressed but from the ego itself, and it operates without the ego's knowledge.7
We find ourselves confronted, therefore, with something in the ego that is also unconscious, that behaves exactly like the repressed, producing powerful effects without itself being conscious, requiring special work before it can be made conscious.8 All that is repressed is unconscious, certainly; but not all that is unconscious is repressed.
A part of the ego — and an important part — is unconscious too.9 This compelled me to abandon the old antithesis between the conscious and the unconscious as the fundamental axis of the theory. It serves better to contrast the coherent ego with what is repressed and dissociated from it.10 The unconscious ceases to be a simple container of forbidden wishes and becomes a quality that can attach to processes across the whole mental apparatus — a quality that, for all its complexity, remains the single ray of light that penetrates the obscurity of depth-psychology.11
let us assume that every psychological process first exists in an unconscious state or phase and only goes over from this into a conscious phase, much as a photographic picture is first a negative and then becomes a picture by being printed.A General Introduction to Psychoanalysis
We will compare the system of the unconscious to a large ante-chamber, in which the psychic impulses rub elbows with one another, as separate beings. There opens out of this ante-chamber another, a smaller room, a sort of parlor, which consciousness occupies. But on the threshold between the two rooms there stands a watchman; he passes on the individual psychic impulses, censors them, and will not let them into the parlor if they do not meet with his approval.A General Introduction to Psychoanalysis
When two wishes whose aims must appear to us incompatible become simultaneously active, the two impulses do not detract one from the other or cancel each other, but combine to form an intermediate aim, a compromise.Chapter VI — The Unconscious ^
There is in this system no negation, no dubiety, no varying degree of certainty: all this is only imported by the work of the censorship which exists between the Ucs and the Pcs.Chapter VI — The Unconscious ^
The processes of the system Ucs are timeless; i.e. they are not ordered temporally, are not altered by the passage of time, in fact bear no relation to time at all.Chapter VI — The Unconscious ^
The processes of the Ucs are just as little related to reality. They are subject to the pleasure-principle; their fate depends only upon the degree of their strength and upon their conformity to regulation by pleasure and pain.Chapter VI — The Unconscious ^
The resistance in the treatment proceeds from the same higher levels and systems in the psychic life that in their time brought about the repression. But since the motives of the resistances, and indeed the resistances themselves, are found in the process of the treatment to be unconscious, we are well advised to amend an inadequacy in our mode of expression.Beyond the Pleasure Principle
We have come upon something in the ego itself which is also unconscious, which behaves exactly like the repressed, that is, which produces powerful effects without itself being conscious and which requires special work before it can be made conscious.The Ego and the Id
We recognize that the Ucs does not coincide with what is repressed; it is still true that all that is repressed is Ucs, but not that the whole Ucs is repressed. A part of the ego, too—and Heaven knows how important a part—may be Ucs, undoubtedly is Ucs.The Ego and the Id
We escape ambiguity if we contrast not the conscious and the unconscious, but the coherent ego and the repressed.Beyond the Pleasure Principle
Nevertheless, we must beware of ignoring this property, for in the last resort the quality of being conscious or not is the single ray of light that penetrates the obscurity of depth-psychology.The Ego and the Id