A schoolteacher or professor cannot educate individuals, he educates only species.

Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.

Why does a suppurating lung give so little warning and a sore on the finger so much?

Prejudices are so to speak the mechanical instincts of men: through their prejudices they do without any effort many things they would find too difficult to think through to the point of resolving to do them.

He swallowed a lot of wisdom, but all of it seems to have gone down the wrong way.

What is the good of drawing conclusions from experience? I don't deny we sometimes draw the right conclusions, but don't we just as often draw the wrong ones?

With a pen in my hand I have successfully stormed bulwarks from which others armed with sword and excommunication have been repulsed.