The march of the human mind is slow.

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

Though this be madness, yet there is method in’t.

Every thought is, strictly speaking, an afterthought.

What is outside my mind means nothing to it.

The sleep of reason produces monsters.

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

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

Brains are the only things worth having in this world.

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

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

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

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