Abstract work, if one wishes to do it well, must be allowed to destroy one's humanity; one raises a monument which is at the same time a tomb, in which, voluntarily, one slowly inters oneself.

There can't be a practical reason for believing something that is not true.

Mathematics takes us into the region of absolute necessity, to which not only the actual word, but every possible word, must conform.

Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

We are faced with the paradoxical fact that education has become one of the chief obstacles to intelligence and freedom of thought.

The desire to understand the world and the desire to reform it are the two great engines of progress, without which human society would stand still or retrogress.

One eminently orthodox Catholic divine laid it down that a confessor may fondle a nun's breasts, provided he does it without evil intent.