Analyse data just so far as to obtain simplicity and no further.

A small error in the former will produce an enormous error in the latter.

If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living

Every good mathematician should also be a good chess player and vice versa.

There are no solved problems; there are only problems that are more or less solved.

If we knew exactly the laws of nature and the situation of the universe at the initial moment, we could predict exactly the situation of the same universe at a succeeding moment.

Doubt everything or believe everything: these are two equally convenient strategies. With either we dispense with the need for reflection.