Le cerveau du savant, qui n'est qu'un coin de l'Univers, ne pourra jamais contenir l'univers tout entier - Henri Poincaré

In general, the totality A will have nothing in common with the totality A´, nor the totality B with the totality B´. The transition from the totality A to the totality B and that from the totality A´ to the totality B´ are therefore two changes which in themselves have in general nothing in common. And yet we regard these two changes both as displacements and, furthermore, we consider them as the same displacement. How can that be? It is simply because they can both be corrected by the same correlative movement of our body.

Later generations will regard set theory as a disease from which one has recovered.

La pensée ne doit jamais se soumettre, ni à un dogme, ni à un parti, ni à une passion, ni à un intérêt, ni à une idée préconçue, ni à quoi que ce soit, si ce n'est aux faits eux-mêmes, parce que, pour elle, se soumettre, ce serait cesser d'être.