I say quite deliberately that the Christian religion, as organized in its Churches, has been and still is the principal enemy of moral progress in the world.

We know very little, and yet it is astonishing that we know so much, and still more astonishing that so little knowledge can give us so much power.

Among the Tibetans, one wife has many husbands, because men are too poor to support a whole wife.

Do not feel certain of anything.

The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken.

Continuity of purpose is one of the most essential ingredients of happiness in the long run, and for most men that comes chiefly through their work.

In action, in desire, we must submit perpetually to the tyranny of outside forces; but in thought, in aspiration, we are free, free from our fellowmen, free from the petty planet on which our bodies impotently crawl, free even, while we live, from the tyranny of death.