A genuinely free and educated man should be able to tune himself, as one tunes a musical instrument, absolutely arbitrarily, at his convenience at any time and to any degree, philosophically or philologically, critically or poetically, historically or rhetorically, in ancient or modern form.

In true prose everything must be underlined.

Life is writing. The sole purpose of mankind is to engrave the thoughts of divinity onto the tablets of nature.

Every uneducated person is a caricature of himself.

There is no self-knowledge except historical self-knowledge. No one knows what he is if he doesn't know what his contemporaries are.

If you want to penetrate into the heart of physics, then let yourself be initiated into the mysteries of poetry.

There are three kinds of explanation in science: explanations which throw a light upon, or give a hint at a matter; explanations which do not explain anything; and explanations which obscure everything.