All men are by nature free; you have therefore an undoubted liberty to depart whenever you please, but will have many and great difficulties to encounter in passing the frontiers.
You despise books; you whose lives are absorbed in the vanities of ambition, the pursuit of pleasure or indolence; but remember that all the known world, excepting only savage nations, is governed by books.
Descartes constructed as noble a road of science, from the point at which he found geometry to that to which he carried it, as Newton himself did after him. ... He carried this spirit of geometry and invention into optics, which under him became a completely new art.
Ask a toad what is beauty....; he will answer that it is a female with two great round eyes coming out of her little head, a large flat head, a yellow belly and a brown back.
There's scarce a point whereon mankind agree - So well as in their boast of killing me; I boast of nothing, but when I've a mind - I think I can be even with mankind