"The reason universities have students is so they can teach the professors, and Feynman was one of the best. Through some wonderful freak of fate, I ended up with him assigned to me. He had what so many people with a purely mathematical background lack: he had a feel for the physical world. He had worked in a paint factory, I think, in the summertime before he came to Princeton. I was very enthusiastic about the idea that in the world there are nothing but particles, with Dirac thinking that the electron is the basic particle, and that if you could understand the interaction between electron and electron, then everything else will follow, everything else would be subsidiary to that simple picture. The idea of an electromagnetic field traveling through space, that's just talk. The real thing is that this electron does something, and later that electron, affected by it, does something. Action at a distance. And we found we could express that in consistent mathematical language, although we didn't get a chance to write it up until after the war."