Modern life cannot be constructed on . . . physically strenuous principles. A great deal of work is sedentary, and most manual work exercises only a few specialized muscles.

Bad philosophers may have a certain influence; good philosophers, never.

What Galileo and Newton were to the seventeenth century, Darwin was to the nineteenth.

There are certain things that our age needs, and certain things that it should avoid. It needs compassion and a wish that mankind should be happy; it needs the desire for knowledge and the determination to eschew pleasant myths; it needs, above all, courageous hope and the impulse to creativeness.

The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm.

How much longer is the world willing to endure this spectacle of wanton cruelty?

The scientific attitude of mind involves a sweeping away of all other desires in the interest of the desire to know.