All natural goods perish. Riches take wings; fame is a breath; love is a cheat; youth and health and pleasure vanish.

Only necessity understood, and bondage to the highest is identical with true freedom.

When once a decision is reached and execution is the order of the day, dismiss absolutely all responsibility and care about the outcome.

Feed the growing human being, feed him with the sort of experience for which from year to year he shows a natural craving, and he will develop in adult life a sounder sort of mental tissue, even though he may seem to be 'wasting' a great deal of his growing time, in the eyes of those for whom the only channels of learning are books and verbally communicated information.

The old question of whether there is design is idle. The real question is what is the world, whether or not it have a designer--and that can be revealed only by the study of all nature's particulars.

Science as such assuredly has no authority, for she can only say what is, not what is not.

The greatest discovery of the 20th Century is that our attitude of mind determines our quality of life, not circumstances.