Every man has enough power left to carry out that of which he is convinced.

Mediocrity has no greater consolation than in the thought that genius is not immortal.

The affairs of the world are no more than so much trickery, and a man who toils for money or honour or whatever else in deference to the wishes of others, rather than because his own desire or needs lead him to do so, will always be a fool.

Everything factual is, in a sense, theory. The blue of the sky exhibits the basic laws of chromatics. There is no sense in looking for something behind phenomena: they are theory.

Who can think wise or stupid things at all that were not thought already in the past.

Correction does much, but encouragement does more.

To be sure, we have inherited abilities, but our development we owe to thousands of influences coming from the world around us from which we appropriate what we can and what is suitable to us.