Treat people the way they are and they will stay that way. Treat people the way they can become and they will become that way.

I could never have known so well how paltry men are, and how little they care for really high aims, if I had not tested them by my scientific researches. Thus I saw that most men only care for science so far as they get a living by it, and that they worship even error when it affords them a subsistence.

A well-bred carriage is difficult to imitate; for in strictness it is negative, and it implies a long-continued previous training.

Oh how sweet it is to hear one's own convictions from another's lips.

Let everyone sweep in front of his own door, and the whole world will be clean.

If a man writes a book, let him set down only what he knows. I have guesses enough of my own.

Analysis and synthesis are both as necessary to the thinking spirit as inspiration and expiration to the organism.