science has now been for a long time - and to an ever-increasing extent - a collective enterprise. Actually, new results are always, in fact, the work of specific individuals; but, save perhaps for rare exceptions, the value of any result depends on such a complex set of interrelations with past discoveries and possible future researches that even the mind of the inventor cannot embrace the whole.

Only an indirect method is effective. We do nothing if we have not first drawn back.

In the Church, considered as a social organism, the mysteries inevitably degenerate into beliefs.

True definition of science: the study of the beauty of the world.

Official history is a matter of believing murderers on their own word.

Contradiction itself, far from always being a criterion of error, is sometimes a sign of truth.

Mathematics alone make us feel the limits of our intelligence. For we can always suppose in the case of an experiment that it is inexplicable because we don't happen to have all the data. In mathematics we have all the data, brought together in the full light of demonstration, and yet we don't understand. We always come back to the contemplation of our human wretchedness. What force is in relation to our will, the impenetrable opacity of mathematics is in relation to our intelligence.