Idiocy: crudeness’ intellectual equivalent. - Otto Weininger

To understand a man is really to be that man.

The number of different aspects that the face of a man has assumed may be taken almost as a physiognomical measure of his … genius.

Colour-blindness always extends to the complementary colours. Those who are red blind are also green blind; those who are blind to blue have no consciousness of yellow. This law holds good for all mental phenomena; it is a fundamental condition of consciousness.