René Descartes

With me everything turns into mathematics. omnia apud me mathematica fiunt

If I found any new truths in the sciences, I can say that they follow from, or depend on, five or six principal problems which I succeeded in solving and which I regard as so many battles where the fortunes of war were on my side.

Perfect numbers like perfect men are very rare.

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

I concluded that I might take as a general rule the principle that all things which we very clearly and obviously conceive are true: only observing, however, that there is some difficulty in rightly determining the objects which we distinctly conceive.