The brain may be regarded as a kind of parasite of the organism, a pensioner, as it were, who dwells with the body.

What is outside my mind means nothing to it.

Strength of mind is exercise, not rest.

Sooner or later if the activity of the mind is restricted anywhere, it will cease to function even where it is allowed to be free.

Your mind’s got to eat, too.

In psychoanalysis nothing is true except the exaggerations.

Madness need not be all breakdown. It may also be breakthrough.

Understanding is a very dull occupation.

Every thought is, strictly speaking, an afterthought.

The sleep of reason produces monsters.

If anything affects your eye, you hasten to have it removed; if anything affects your mind, you postpone the cure for a year.

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

Not all heads have a brain.