If men and women are to understand each other, to enter into each other's nature with mutual sympathy, and to become capable of genuine comradeship, the foundation must be laid in youth.

The modesty of women, which, in its most primitive form among animals, is based on sexual periodicity, is, with that periodicity, an essential condition of courtship.

What we call progress is the exchange of one nuisance for another nuisance.

Even the most scientific investigator in science, the most thoroughgoing Positivist, cannot dispense with fiction; he must at least make use of categories, and they are already fictions, analogical fictions, or labels, which give us the same pleasure as children receive when they are told the "name" of a thing.

Life is livable because we know that wherever we go most of the people we meet will be restrained in their actions towards us by an almost instinctive network of taboos.

All civilization has from time to time become a thin crust over a volcano of revolution.

At the present day the crude theory of the sexual impulse held on one side, and the ignorant rejection of theory altogether on the other side, are beginning to be seen as both alike unjustified.