Oliver Wendell Holmes says:  “Our different ideas are stepping-stones; how we get from one to another we do not know; something carries us.  We (our conscious selves) do not take the step.  The creating and informing spirit, which is within us and not of us, is recognized everywhere in real life.  It comes to us as a voice that will be heard; it tells us what we must believe; it frames our sentences and we wonder at this visitor who chooses our brain as his dwelling place.”

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.”