Evil being the root of mystery, pain is the root of knowledge.

The Our Father contains all possible petitions; we cannot conceive of any prayer not already contained in it. It is to prayer what Christ is to humanity.

Petroleum is a more likely cause of international conflict than wheat.

Attentiveness is the heart of prayer.

As soon as men know that they can kill without fear of punishment or blame, they kill; or at least they encourage killers with approving smiles.

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.

Our science is like a store filled with the most subtle intellectual devices for solving the most complex problems, and yet we are almost incapable of applying the elementary principles of rational thought.