Built on Facts

#5 - Richard Feynman

I'm probably going to take some flack for this one. Feynman was and is so popular as a scientific writer, raconteur, and honest-to-goodness celebrity that his staggering scientific accomplishments are sometimes lost in the shadow of his own popular legend. But if we want to try to make a more-or-less honest ranking of the top ten, we have to give him the vast credit he deserves.

Feynman got his start as a physicist in roughly the most dramatic way possible. Pulled fresh out of Princeton in the middle of the Second World War, he was assigned as one of the thousands of scientists and engineers working in great secrecy on what became the icon of 20th century physics - the Manhattan Project. He was not central to the project, but he quickly established a reputation as one of the most brilliant scientists working there at Los Alamos.

So how did he get to be the 5th greatest physicist? First, there's his Nobel Prize winning work on quantum electrodynamics. QED was the staggeringly successful extension of the quantum mechanics of particles to the quantum mechanics of fields. Its description of electric and magnetic fields has proved to fit the experimental reality exactly. Indeed its agreement with experiment is widely considered to be the most precisely verified theory in all of physics. Not even the great Dirac had managed to solve the problem of the quantization of fields despite his best efforts. Even after Feynman and his collaborators succeeded in formulating QED, Dirac wasn't happy with its mathematically questionable renormalization methods. Neither was Feynman, actually. But renormalization works perfectly so far as we can tell, and that's the true test of a theory.

Feynman also developed the path integral formulation of quantum mechanics, which of all the various equivalent formulations of QM is the one I personally find the most elegant. It describes the time evolution of a system in terms of an integral over all possible paths, classically possible or not. While it's not often useful for doing problems, it had great theoretical merit and it forms a foundation for many quantum field theories. In some ways it's considered more fundamental than the more common ways of formulating quantum mechanics.

He developed Feynman diagrams and worked in superfluidity, particle decay, quantum gravity, and kept up a friendly (Maybe. Sometimes I'm not sure...) rivalry with Murray Gell-Mann over their approaches to the strong nuclear force. And those are just the high points of his physics career. Aside from physics, he became well known for his successes at everything from the drums to safecracking to art and womanizing. He was, um, a bit of a ladies man. For better or worse, there's not many physicists who can say that.

He was a prolific writer. His humorous memoir Surely You're Joking, Mr. Feynman! is still a classic, and his books on physics are universally regarded as among the best of the genre. In my opinion, his best is The Character of Physical Law
, but I don't think anything he wrote is less than excellent.

When the Challenger disintegrated on launch Feynman was asked to be a menber of the investigatory commission. Had NASA brass known how this would end they might not have been so eager to invite him, but his effort was a beautiful and merciless instance of massacring bureaucracy in the service of truth. The story is well worth reading. So is his actual report.

Are there physicists who contributed more to physics? Yes. But just four, by my very unscientific ranking. Of all the scores of truly brilliant 20th century physicists, Feynman stands nearly without peer.

The list so far (click the category name for links):
5. Feynman
6. Rutherford
7. Schrodinger
8. Dirac
9. Thomson
10. Pauli