To be too conscious is an illness—a real thoroughgoing illness.

Sanity is madness put to good uses; waking life is a dream controlled.

As is the face, so is the mind.

What the brain does by itself is infinitely more fascinating and complex than any response it can make to chemical stimulation.

The highest possible stage in moral culture is when we recognize that we ought to control our thoughts.

The sleep of reason produces monsters.

Don’t lose your mind unless you have paid for it.

What a torture to talk to filled heads that allow nothing from the outside to enter them.

Is there no way out of the mind?

The real question is not whether machines think but whether men do.

Strength of mind is exercise, not rest.

In psychoanalysis nothing is true except the exaggerations.

“I think, therefore I am” is the statement of an intellectual who underrates toothaches.