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

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

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

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.

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

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

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

From a man’s face, I can read his character. If I can see him walk, I know his thoughts.

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

The mind of man is capable of anything.

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

If anything affects your eye, you hasten to have it removed; if anything affects your mind, you postpone the cure for a year.

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