Information Processing points to a review by Freeman Dyson in the New York Review of Books of Perfectly Reasonable Deviations From The Beaten Track: The Letters Of Richard P. Feynman .
What I find interesting in the article is Dyson’s claim that Paul Dirac was a greater genius than Richard Feynman. Of course, judging “greater genius” seems about as silly as worrying about whether it is a “double backward doggy dare” or a “triple backwards over-the-top doggy dare.” With this caviot, I however, just have to say “huh?”
In my mind Dirac has three claims to genius: his derivation of the Dirac equation, his work on magnetic monopoles (showing that the existence of a single such monopole could explain the reason charge comes in discrete quantities), and his work unifying the early differing approaches to quantum theory. Feynman, in my mind, has four or more claims to genius: his derivation of the path integral formulation of quantum theory, his space-time approach to solving the problems in quantum electrodynamics, his work on the theory of superconductivity (showing the importance of quantum theory on a “macroscopic” level), and his model of weak decay (work with Gell-Mann which was also independently done by George Sudharsan and Robert Marshak.) So in my mind, I put Feynman just above Dirac (what, you mean you don’t have your own personal ordering of geniuses?)
And, after thinking about it for a while (too much time, perhaps!) I think I can guess why Dyson puts Dirac above Feynman (oh, to be a physicist known by your last name alone!) I believe the reason is that Dyson was originally a mathematician. Feynman’s work is filled with the sort of raw physical insight that physicists love and admire. Sure, making the path integral rigorous is a pain the rear, but it works! In Dirac’s work, we find, on the other hand, a clear mathematical beauty: the Dirac equation and the magnetic monopole are motivated more my arguments of symmetry than by any appeal to a physicist’s “calculate and run” methodologies (indeed the latter is not even known the correspond to experimental reality!)
So who is the greater genius? Well I “double dog dare you” to come up with reasons that Dirac is a greater genius than Feynman.
Update: See the comments for some fun back and forth. OK, in my head really I put Dirac and Feynman at the same level. What I find intersting is how one’s background influences this (silly) debate. If you are a particle theorist, I bet Dirac>Feynman. If you went to Caltech as an undergrad, I bet you have Feynman>Dirac. Ah, the ways theorists waste away their days.