Only the most acute and active animals are capable of boredom.

A reader is doubly guilty of bad manners against an author when he praises his second book at the expense of his first (or vice versa) and then expects the author to be grateful for what he has done.

One has to know the size of one's stomach.

We seldom break our leg so long as life continues a toilsome upward climb. The danger comes when we begin to take things easily and choose the convenient paths.

Everyone who has ever built anywhere a "new heaven" first found the power thereto in his own hell.

When an idea is just rising on the horizon, the soul's temperature with respect to it is usually very cold. Only gradually does the idea develop its warmth, and it is hottest (which is to say, exerting its greatest influence) when belief in the idea is already once again in decline.

The moral earth, too, is round! The moral earth, too, has its antipodes! The antipodes, too, have their right to exist! There is still another world to be discovered--and more than one! Set sail, you philosophers!