Admiration is the daughter of ignorance.

It has seemed to be more necessary to have regard to the weight of words rather than to their number.

Criticize the act, not the person.

Intellectuals solve problems, geniuses prevent them.

Let him who would move the world first move himself.

All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.

Empty pockets never held anyone back. Only empty heads and empty hearts can do that.

Muddy water is best cleared by leaving it alone.

Tomorrow hopes we have learned something from yesterday.

Jealousy is the tribute mediocrity pays to genius.

You cannot truly listen to anyone and do anything else at the same time.

There are things known and there are things unknown, and in between are the doors of perception.

It is a wise man that does know the contented man is never poor, whilst the discontented man is never rich.

We seldom realize, for example that our most private thoughts and emotions are not actually our own. For we think in terms of languages and images which we did not invent, but which were given to us by our society.

Judge not unless you judge yourself.

What's real and what's true aren't necessarily the same.

A person who spends more than he earns is a fool

He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.

If you do not know the laws of right conduct, you cannot form your character.

Think globally, act locally.

An understanding of the natural world is a source of not only great curiosity, but great fulfilment.