Time destroys the speculation of men, but it confirms nature.

The man who backbites an absent friend, nay, who does not stand up for him when another blames him, the man who angles for bursts of laughter and for the repute of a wit, who can invent what he never saw, who cannot keep a secret -- that man is black at heart: mark and avoid him.

We should be as careful of our words as of our actions.

No phase of life, whether public or private, can be free from duty.

The following passage is one of those cited by Copernicus himself in his preface to De Revolutionibus: "The Syracusan Hicetas, as Theophrastus asserts, holds the view that the heaven, sun, moon, stars, and in short all of the things on high are stationary, and that nothing in the world is in motion except the earth, which by revolving and twisting round its axis with extreme velocity produces all the same results as would be produced if the earth were stationary and the heaven in motion. . . ."

What is impossible by the nature of things is not confirmed by any law.

Grief is not in the nature of things, but in opinion.