Sometime In the Twenty-First Century I Will Understand Twentieth-Century Physics
I am optimistic that sometime in the twenty-first century I will understand twentieth-century physics.
Not that I haven't tried before. Over years—decades, really—I have enlisted some of the finest minds of the era to help me grasp relativity, quantum mechanics and superstring theory: Richard Feynman, Sheldon Glashow, Paul Davies, Stephen Hawking, and even Einstein himself, whose 1916 book "Relativity: The Special and General Theory" was the prototype for all subsequent efforts to explain the universe in words rather than equations. It marked the earliest appearance of that ubiquitous character, the man on the train, a faceless stick figure glimpsed through a coach-car window as he zooms past at nearly the speed of light. Remarkably, we can observe him as he goes about his obsessive tasks: bouncing a Ping-pong ball on a table, or shining a flashlight at a mirror on the ceiling, or holding up a clock for us to compare to the identical one we just happen to hold. Many hours have I devoted to contemplating his inertial frame of reference and trying to reconcile it to my own, standing motionless on the platform. I have engaged him in my own thought experiments, even conjuring a gedanken companion who rides a train on the adjacent track. If they each pass my position at the same instant, traveling at three-quarters the speed of light in opposite directions, then their speed relative to each other is one and a half times the speed of …wait a second, that can't be right, can it?
What I'm up against here is a problem in translation; the laws of nature are written in equations, but I read only English. I have the same problem with anything written in French, of course, but I can accept a second-hand version of Proust more easily than Einstein or Heisenberg. My understanding of the world is not dependent on Proust, the way it is on the double-slit experiment. Everything I know about the basic stuff of the universe—the very atoms I am made of myself, the gravity that glues me to my bed at night—I know second-hand, through the imperfect medium of language and metaphor. I don't even know what it means to "solve" an equation in relativity or quantum mechanics. Here's an equation involving a man on a train that I can solve: If he leaves Chicago at 6 a.m. at 70 miles an hour, when will he pass someone who left St. Louis three hours earlier at 50 miles an hour? But when physicists "solve" an equation, what emerges isn't a quantity, it's a new law of nature. How do they do that?
That's what keeps me awake at night, reading. It is much too late for me to go back and learn enough math to meet Einstein on his own terms, much less Heisenberg or Hawking. But I am sustained by optimism that someday I will transcend my own limitations, that I will achieve the conceptual breakthrough necessary to grasp relativity, quantum mechanics and the rest of it on a deep level. Someday I will understand not just the epiphenomena of physics, the trains and the slits and the cats in boxes, but their mathematical essence. Their metaphysics. I'm optimistic. Really.