John A. Wheeler, the great physicist who coined the term ‘black hole,’ a primary architect of modern physics, and the scientist for whom the fictional “Wheeler Laboratory” is named in ‘A Beautiful Mind’, died last week. Many are calling this an end of an era; as Max Tegmark of MIT says, “For me, he was the last Titan, the only physics superhero still standing.” There’s a great write-up in the Times about his life and career.
I’m no authority on this stuff, but as an enthusiast reading about the history of physics, I was always impressed with Wheeler’s propensity toward clever speculation. Here’s an excerpt from Richard Feynman’s 1965 Nobel Lecture where he talks about one of his mentor’s crazy ideas- the idea remains unproven, but it provided the inspiration for modern Quantum Electrodynamics:
As a by-product of this same view, I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, “Feynman, I know why all electrons have the same charge and the same mass” “Why?” “Because, they are all the same electron!” And, then he explained on the telephone, “suppose that the world lines which we were ordinarily considering before in time and space – instead of only going up in time were a tremendous knot, and then, when we cut through the knot, by the plane corresponding to a fixed time, we would see many, many world lines and that would represent many electrons, except for one thing. If in one section this is an ordinary electron world line, in the section in which it reversed itself and is coming back from the future we have the wrong sign to the proper time – to the proper four velocities – and that’s equivalent to changing the sign of the charge, and, therefore, that part of a path would act like a positron.” “But, Professor”, I said, “there aren’t as many positrons as electrons.” “Well, maybe they are hidden in the protons or something”, he said. I did not take the idea that all the electrons were the same one from him as seriously as I took the observation that positrons could simply be represented as electrons going from the future to the past in a back section of their world lines. That, I stole!
And thus the Feynman Electron Diagram was born.
Still, I have to think it’d be a neat application of Occam’s Razor if Wheeler is eventually proven right that the fabric of reality is woven by just one particle, getting knocked forward and backward in time by its past and future selves.