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

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

The real question is not whether machines think but whether men do.

It is far, far better and much safer to have a firm anchor in nonsense than to put out on the troubled seas of thought.

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

Strength of mind is exercise, not rest.

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

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

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

The sleep of reason produces monsters.

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

The march of the human mind is slow.

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