Scientific knowledge is an enabling power to do either good or bad — but it does not carry instructions on how to use it.
Richard P. FeynmanThe whole question of imagination in science is often misunderstood by people in other disciplines. ... They overlook the fact that whatever we are allowed to imagine in science must be consistent with everything else we know.
Richard P. FeynmanSo my antagonist said, "Is it impossible that there are flying saucers? Can you prove that it's impossible?" "No," I said, "I can't prove it's impossible. It's just very unlikely." At that he said, "You are very unscientific. If you can't prove it impossible then how can you say that it's unlikely?" But that is the way that is scientific. It is scientific only to say what is more likely and what less likely, and not to be proving all the time the possible and impossible.
Richard P. FeynmanIf you think you understand quantum mechanics, you don't understand quantum mechanics.
Richard P. Feynman