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.

What a country calls its vital economic interests are not the things which enable its citizens to live, but the things which enable it to make war. Petrol is more likely than wheat to be a cause of international conflict.

Attention is the rarest and purest form of generosity.

The only hope of socialism resides in those who have already brought about in themselves, as far as is possible in the society of today, that union between manual and intellectual labor which characterizes the society we are aiming at.

We only possess what we renounce; what we do not renounce escapes from us.

Every new development for the last three centuries has brought men closer to a state of affairs in which absolutely nothing would be recognized in the whole world as possessing a claim to obedience except the authority of the State. The majority of people in Europe obey nothing else.

Never react to an evil in such a way as to augment it.