Every thought is, strictly speaking, an afterthought.

The mind is not, I know, a highway but a temple, and its doors should not be carelessly left open.

Strength of mind is exercise, not rest.

Is there no way out of the mind?

Brains are the only things worth having in this world.

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

Brain, n. An apparatus with which we think that we think.

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

The most potent weapon in the hands of the oppressor is the mind of the oppressed.

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

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

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

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