The greatest wisdom is to get to know oneself.

But some, besides allegiance to their original error, possess I know not what fanciful interest in remaining hostile not so much toward the things in question as toward their discoverer.

You may force me to say what you wish; you may revile me for saying what I do. But it moves.

Mathematics is the key and door to the sciences.

The deeper I go in considering the vanities of popular reasoning, the lighter and more foolish I find them. What greater stupidity can be imagined than that of calling jewels, silver, and gold "precious," and earth and soil "base"?

Facts which at first seem improbable will, even on scant explanation, drop the cloak which has hidden them and stand forth in naked and simple beauty.

There are those who reason well, but they are greatly outnumbered by those who reason badly.