“The first principle is that you must not fool yourself and you are the easiest person to fool.”

“Science is a way of trying not to fool yourself. The principle is that you must not fool yourself, and you are the easiest person to fool.”

“Pompous fools drive me up the wall. Ordinary fools are alright; you can talk to them and try to help them out. But pompous fools – guys who are fools and covering it all over and impressing people as to how wonderful they are with all this hocus pocus – THAT, I CANNOT STAND! An ordinary fool isn’t a faker; an honest fool is all right. But a dishonest fool is terrible!”

“For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”

“Of course, I am interested, but I would not dare to talk about them. In talking about the impact of ideas in one field on ideas in another field, one is always apt to make a fool of oneself. In these days of specialization there are too few people who have such a deep understanding of two departments of our knowledge that they do not make fools of themselves in one or the other.”

“All 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.”

“I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously… The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.”