Unrest is the mark of existence.

If anyone spends almost the whole day in reading...he gradually loses the capacity for thinking...This is the case with many learned persons; they have read themselves stupid

If children were brought into the world by an act of pure reason alone, would the human race continue to exist? Would not a man rather have so much sympathy with the coming generation as to spare it the burden of existence, or at any rate not take it upon himself to impose that burden upon it in cold blood?

That the outer man is a picture of the inner, and the face an expression and revelation of the whole character, is a presumption likely enough in itself, and therefore a safe one to go on; borne out as it is by the fact that people are always anxious to see anyone who has made himself famous. Photography offers the most complete satisfaction of our curiosity.

Physics is unable to stand on its own feet, but needs a metaphysics on which to support itself, whatever fine airs it may assume towards the latter.

It is in the treatment of trifles that a person shows what they are.

For, after all, the foundation of our whole nature, and, therefore, of our happiness, is our physique, and the most essential factor in happiness is health, and, next in importance after health, the ability to maintain ourselves in independence and freedom from care.