Scientists are peeping toms at the keyhole of eternity.

Hitherto man had to live with the idea of death as an individual; from now onward mankind will have to live with the idea of its death as a species.

The prerequisite of originality is the art of forgetting, at the proper moment, what we know.

When a person identifies himself with a group his critical faculties are diminished and his passions enhanced by a kind of emotive resonance. The individual is not a killer, the group is, and by identifying with it, the individual becomes one. This is the infernal dialect reflected in man's history.

Chemically induced hallucinations, delusions and raptures may be frightening or wonderfully gratifying; in either case they are in the nature of confidence tricks played on one's own nervous system.

Of all forms of mental activity, the most difficult to induce even in the minds of the young, who may be presumed not to have lost their flexibility, is the art of handling the same bundle of data as before, but placing them in a new system of relations with one another by giving them a different framework, all of which virtually means putting on a different kind of thinking-cap for the moment. It is easy to teach anybody a new fact...but it needs light from heaven above to enable a teacher to break the old framework in which the student is accustomed to seeing.

Conscious and unconscious experiences do not belong to different compartments of the mind; they form a continuous scale of gradations, of degrees of awareness.