The mind of man is capable of anything.

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

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

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

Not all heads have a brain.

Strength of mind is exercise, not rest.

We need strength, we need energy, we need quickness, and we need brain in this country to turn it around.

Your mind’s got to eat, too.

Understanding is a very dull occupation.

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

Is there no way out of the mind?

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

The sleep of reason produces monsters.