The commonest objection to birth control is that it is against nature.

Either man will abolish war, or war will abolish man.

To abandon the struggle for private happiness, to expel all eagerness of temporary desire, to burn with passion for eternal things-this is emancipation, and this is the free man's worship... United with his fellow men by the strongest of all ties, the tie of a common doom, the free man finds that a new vision is with him always, shedding over every daily task the light of love.

My own belief is that in most ages and in most places obscure psychological forces led men to adopt systems involving quite unnecessary cruelty, and that this is still the case among the most civilized races at the present day.

Zeno was concerned with three problems... These are the problem of the infinitesimal, the infinite, and continuity.

He will see himself and life and the world as truly as our human limitations will permit; realizing the brevity and minuteness of human life, he will realize also that in individual minds is concentrated whatever of value the known universe contains.

It will be said that the joy of mental adventure must be rare, that there are few who can appreciate it, and that ordinary education can take no account of so aristocratic a good. I do not believe this. The joy of mental adventure is far commoner in the young than in grown men and women. ...It is rare in later life because everything is done to kill it during education.