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

Strength of mind is exercise, not rest.

A mind lively and at ease can do with seeing nothing, and can see nothing that does not answer.

Every thought is, strictly speaking, an afterthought.

The universe is an object of thought at least as much as it is a means of satisfying needs.

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

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

Is there no way out of the mind?

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

What is outside my mind means nothing to it.

There is no female mind. The brain is not an organ of sex. As well speak of a female liver.

Imagination continually outruns the creature it inhabits.

What is the hardest task in the world? To think.