Without civic morality communities perish; without personal morality their survival has no value.

The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.

The only thing that will redeem mankind is cooperation.

If a Black Death could be spread throughout the world once in every generation survivors could procreate freely without making the world too full.

I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.

A truer image of the world, I think, is obtained by picturing things as entering into the stream of time from an eternal world outside, than from a view which regards time as the devouring tyrant of all that is.

We have in fact, two kinds of morality, side by side: one which we preach, but do not practice, and another which we practice, but seldom preach.