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. FeynmanWe cannot define anything precisely. If we attempt to, we get into the paralysis of thought that comes to philosophers, who sit opposite each other, one saying to the other, "You don't know what you are talking about!" The second one says, "What do you mean by know? What do you mean by talking? What do you mean by you?"
Richard P. FeynmanThe real problem in speech is not precise language. The problem is clear language.
Richard P. FeynmanAll the time you're saying to yourself, 'I could do that, but I won't,'--which is just another way of saying that you can't.
Richard P. FeynmanIt is our responsibility as scientists, knowing the great progress which comes from a satisfactory philosophy of ignorance, the great progress which is the fruit of freedom of thought, to proclaim the value of this freedom; to teach how doubt is not to be feared but welcomed and discussed; and to demand this freedom as our duty to all coming generations.
Richard P. Feynman