Diogenes, filthily attired, paced across the splendid carpets in Plato's dwelling. Thus, said he, do I trample on the pride of Plato. Yes, Plato replied, but only with another kind of pride.

Virtue by premeditation isn't worth much.

The writer who cannot sometimes throw away a thought about which another man would have written dissertations, without worry whether or not the reader will find it, will never become a great writer.

Do not say hypothesis, and even less theory: say way of thinking.

There is no greater impediment to progress in the sciences than the desire to see it take place too quickly.

Libraries can in general be too narrow or too wide for the soul.

He who is in love with himself has at least this advantage - he won't encounter many rivals.