What counts can't always be counted; what can be counted doesn't always count.

A true genius admits that he/she knows nothing.

Your fervent wishes can only find fulfillment if you succeed in attaining love and understanding of men, and animals, and plants, and stars, so that every joy becomes your joy and every pain your pain.

Why does this magnificent applied science which saves work and makes life easier bring us so little happiness? ... The simple answer runs: 'Because we have not yet learned to make sensible use of it.'

One feels the insignificance of the individual, and it makes one happy.

[There is] a duty in refusing to cooperate in any undertaking that violates the Constitutional rights of the individual. This holds in particular for all inquisitions that are concerned with the private life and the political affiliations of the citizens.

The theory must not contradict empirical facts.