The easy, gentle, and sloping path . . . is not the path of true virtue. It demands a rough and thorny road.

I set forth notions that are human and my own, simply as human notions considered in themselves, not as determined and decreed by heavenly ordinance.

Nature clasps all her creatures in a universal embrace; there is not one of them which she has not plainly furnished with all means necessary to the conservation of its being.

Socrates ... brought human wisdom back down from heaven, where she was wasting her time, and restored her to man.... It is impossible to go back further and lower. He did a great favor to human nature by showing how much it can do by itself.

Oh senseless man, who cannot possibly make a worm or a flea and yet will create Gods by the dozen!

There is not one of us that would not be worse than kings, if so continually corrupted as they are with a sort of vermin called flatterers.

But as Nature is the best guide, teaching must be the development of natural inclinations, for which purpose the teacher must watch his pupil and listen to him, not continually bawl words into his ears as if pouring water into a funnel. Good teaching will come from a mind well made rather than well filled.