All the art of living lies in a fine mingling of letting go and holding on.

Every man of genius sees the world at a different angle from his fellows, and there is his tragedy.

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

No faith is our own that we have not arduously won.

Birth-control is effecting, and promising to effect, many functions in our social life.

Socialism also brings us up against the hard rock of eugenic fact which, if we neglect it, will dash our most beautiful social construction to fragments.

The more rapidly a civilization progresses, the sooner it dies for another to rise in its place.