The greater part of human misery is caused by indolence.

I ceased in the year 1764 to believe that one can convince one’s opponents with arguments printed in books. It is not to do that, therefore, that I have taken up my pen, but merely so as to annoy them, and to bestow strength and courage on those on our own side, and to make it known to the others that they have not convinced us.

It is almost impossible to carry the torch of truth through a crowd without singeing somebody's beard.

All mathematical laws which we find in Nature are always suspect to me, in spite of their beauty. They give me no pleasure. They are merely auxiliaries. At close range it is all not true.

As I take up my pen I feel myself so full, so equal to my subject, and see my book so clearly before me in embryo, I would almost like to try to say it all in a single word.

Of all the inventions of man I doubt whether any was more easily accomplished than that of a Heaven.

Every man has his moral backside which he refrains from showing unless he has to and keeps covered as long as possible with the trousers of decorum.