Galton says: "I have desired to show how whole states of mental operation that have lapsed out of ordinary consciousness, admit of being dragged into light."

Montgomery says: "We are constantly aware that feelings emerge unsolicited by any previous mental state, directly from the dark womb of unconsciousness. Indeed all our most vivid feelings are thus mystically derived. Suddenly a new irrelevant, unwilled, unlooked-for presence intrudes itself into consciousness. Some inscrutable power causes it to rise and enter the mental presence as a sensorial constituent. If this vivid dependence on unconscious forces has to be conjectured with regard to the most vivid mental occurrences, how much more must such a sustaining foundation be postulated for those faint revivals of previous sensations that so largely assist in making up our complex mental presence!"

Sir Benjamin Brodie says: "It has often happened to me to have accumulated a store of facts, but to have been able to proceed no further. Then after an interval of time, I have found the obscurity and confusion to have cleared away: the facts to have settled in their right places, though I have not been sensible of having made any effort for that purpose."

Wundt says: "The traditional opinion that consciousness is the entire field of the internal life cannot be accepted. In consciousness, psychic acts are very distinct from one another, and observation itself necessarily conducts to unity in psychology. But the agent of this unity is outside of consciousness, which knows only the result of the work done in the unknown laboratory beneath it. Suddenly a new thought springs into being. Ultimate analysis of psychic processes shows that the unconscious is the theater of the most important mental phenomena. The conscious is always conditional upon the unconscious."

Creighton says: "Our conscious life is the sum of these entrances and exits. Behind the scenes, as we infer, there lies a vast reserve which we call 'the unconscious,' finding a name for it by the simple device of prefixing the negative article. The basis of all that lies behind the scene is the mere negative of consciousness."

Maudsley says: "The process of reasoning adds nothing to knowledge (in the reasoner). It only displays what was there before, and brings to conscious possession what before was unconscious." And again: "Mind can do its work without knowing it. Consciousness is the light that lightens the process, not the agent that accomplishes it."

Walstein says: "It is through the sub-conscious self that Shakespeare must have perceived, without effort, great truths which are hidden from the conscious mind of the student; that Phidias painted marble and bronze; that Raphael painted Madonnas, and Beethoven composed symphonies."

Ribot says: "The mind receives from experience certain data, and elaborates them unconsciously by laws peculiar to itself, and the result merges into consciousness."

Newman says: "When the unaccustomed causes surprise, we do not perceive the thing and then feel the surprise; but surprise comes first, and then we search out the cause; so the theory must have acted on the unconscious mind to create the feeling, before being perceived in consciousness."

A writer in an English magazine says: "Of what transcendent importance is the fact that the unconscious part of the mind bears to the conscious part such a relation as the magic lantern bears to the luminous disc which it projects; that the greater part of the intentional action, the whole practical life of the vast majority of men, is an effect of events as remote from consciousness as the motion of the planets."