All mathematical laws which we find in Nature are always suspect to me, in spite of their beauty. They give me no pleasure. They are merely auxiliaries. At close range it is all not true.

An hour-glass is a reminder not only of time's quick flight, but also of the dust to which we must at last return

The great trick of regarding small departures from the truth as the truth itself - on which is founded the entire integral calculus - is also the basis of our witty speculations, where the whole thing would often collapse if we considered the departures with philosophical rigour.

Reading means borrowing.

To make a vow is a greater sin than to break one.

We can see nothing whatever of the soul unless it is visible in the expression of the countenance; one might call the faces at a large assembly of people a history of the human soul written in a kind of Chinese ideograms.

The highest level than can be reached by a mediocre but experienced mind is a talent for uncovering the weaknesses of those greater than itself.