Censorship ends in logical completeness when nobody is allowed to read any books except the books that nobody can read.

Rich men without convictions are more dangerous in modern society than poor women without chastity.

Independence? That's middle class blasphemy. We are all dependent on one another, every soul of us on earth.

A part of eugenic politics would finally land us in an extensive use of the lethal chamber. A great many people would have to be put out of existence simply because it wastes other people's time to look after them.

Paradoxes are the only truths.

All problems are finally scientific problems.

The mathematician is fascinated with the marvelous beauty of the forms he constructs, and in their beauty he finds everlasting truth.