Give me extension and motion and I will construct the universe.

Even the mind depends so much on temperament and the disposition of one's bodily organs that, if it is possible to find a way to make people generally more wise and more skilful than they have been in the past, I believe that we should look for it in medicine. It is true that medicine as it is currently practiced contains little of much use.

Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.

Everybody thinks himself so well supplied with common sense that even those most difficult to please. . . never desire more of it than they already have.

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.

I was convinced that our beliefs are based much more on custom and example than on any certain knowledge.

Desire awakens only to things that are thought possible.