Every animal loves itself.

Vicious habits are so odious and degrading that they transform the individual who practices them into an incarnate demon.

Fire and water are not of more universal use than friendship.

Morals today are corrupted by our worship of riches.

People don't know the value of what they have until it is gone: Freedom suppressed and again regained bites with keener fangs than freedom never endangered.... Liberty is rendered even more precious by the recollection of servitude. Don't wait till freedom is gone before you enjoy, value, support, protect and make the most of it!

I am not ashamed to confess that I am ignorant of what I do not know.

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. . . ."