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

Understanding is a very dull occupation.

Any man could, if he were so inclined, be the sculptor of his own brain.

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.

The brain is an unreliable organ, it is monstrously great, monstrously developed. Swollen, like a goiter.

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

The human mind is an evolutionary product, just like the human body.

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

Imagination is the secret and marrow of civilization. It is the very eye of faith.

As is the face, so is the mind.

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

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