Present opportunities are not to be neglected; they rarely visit us twice.

We admit, in geometry, not only infinite magnitudes, that is to say, magnitudes greater than any assignable magnitude, but infinite magnitudes infinitely greater, the one than the other. This astonishes our dimension of brains, which is only about six inches long, five broad, and six in depth, in the largest heads.

It is not a mistress I have lost but half of myself, a soul for which my soul seems to have been made.

Know that the secret of the arts is to correct nature.

Every one should be his own physician. We ought to assist, and not to force nature. Eat with moderation...Nothing is good for the body but what we can digest. What medicine can procure digestion? Exercise. What will recruit strength? Sleep.

The prudent man does himself good; the virtuous one does it to other men.

Heaven made virtue; man, the appearance.