When a contradiction is impossible to resolve except by a lie, then we know that it is really a door.

A beautiful woman looking at her image in the mirror may very well believe the image is herself. An ugly woman knows it is not.

I think that it is useless to fight directly against natural weaknesses. One has to force oneself to act as though one did not have them in circumstances where a duty makes it imperative; and in the ordinary course of life one has to know these weaknesses, prudently take them into account, and strive to turn them to good purpose; for they are all capable of being put to some good purpose.

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.

If we are suffering illness, poverty, or misfortune, we think we shall be satisfied on the day it ceases. But there too, we know it is false; so soon as one has got used to not suffering one wants something else.

The real stumbling-block of totalitarian regimes is not the spiritual need of men for freedom of thought; it is men's inability to stand the physical and nervous strain of a permanent state of excitement, except during a few years of their youth.

All sins are attempts to fill voids.