Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.

Science is practical philosophy.

He who hid well, lived well.

The nature of matter, or body considered in general, consists not in its being something which is hard or heavy or coloured, or which affects the senses in any way, but simply in its being something which is extended in length, breadth and depth.

Every man is indeed bound to do what he can to promote the good of others, and a man who is of no use to anyone is strictly worthless.

I should consider that I know nothing about physics if I were able to explain only how things might be, and were unable to demonstrate that they could not be otherwise.

There is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.