As is the face, so is the mind.

What the brain does by itself is infinitely more fascinating and complex than any response it can make to chemical stimulation.

The march of the human mind is slow.

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

Strength of mind is exercise, not rest.

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

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

What is outside my mind means nothing to it.

To be too conscious is an illness—a real thoroughgoing illness.

Not all heads have a brain.

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

Is there no way out of the mind?

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