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

“I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extens...”

“Except our own thoughts, there is nothing absolutely in our power.”

“I desire to live in peace and to continue the life I have begun under the motto 'to live well you must live unseen”

“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.”

“although we very clearly see the sun, we ought not therefore to determine that it is only of the size which our sense of sight presents; and we may very distinctly imagine the head of a lion joined...”

“I should attempt to treat human vice and folly geometrically... the passions of hatred, anger, envy, and so on, considered in themselves, follow from the necessity and efficacy of nature... I shall...”

“If you can't test it, it's not theorics -- it's metatheorics. A branch of philosophy. So, if you want to think of it this way, our test equipment is what defines the boundary separating theorics fr...”

“Physicists have come to realize that mathematics, when used with sufficient care, is a proven pathway to truth.”