We also know how cruel the truth often is, and we wonder whether delusion is not more consoling.

What is it indeed that gives us the feeling of elegance in a solution, in a demonstration?

Thus, be it understood, to demonstrate a theorem, it is neither necessary nor even advantageous to know what it means. The geometer might be replaced by the "logic piano" imagined by Stanley Jevons; or, if you choose, a machine might be imagined where the assumptions were put in at one end, while the theorems came out at the other, like the legendary Chicago machine where the pigs go in alive and come out transformed into hams and sausages. No more than these machines need the mathematician know what he does.

All the scientist creates in a fact is the language in which he enunciates it. If he predicts a fact, he will employ this language, and for all those who can speak and understand it, his prediction is free from ambiguity. Moreover, this prediction once made, it evidently does not depend upon him whether it is fulfilled or not.

One does not ask whether a scientific theory is true, but only whether it is convenient.

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

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