One cannot explain words without making incursions into the sciences themselves, as is evident from dictionaries; and, conversely, one cannot present a science without at the same time defining its terms.

There are also two kinds of truths, those of reasoning and those of fact. Truths of reasoning are necessary and their opposite is impossible, and those of fact are contingent and their opposite is possible. When a truth is necessary its reason can be found by analysis, resolving it into more simple ideas and truths until we reach those which are primitive.

Natural religion itself, seems to decay very much. Many will have human souls to be material: others make God himself a corporeal being.

I don't say that bodies like flint, which are commonly called inanimate, have perceptions and appetition; rather they have something of that sort in them, as worms are in cheese.

What is is what must be.

Take what you need, do what you should, you will get what you want.

He who understands Archimedes and Apollonius will admire less the achievements of the foremost men of later times.