The Incomplete Book of Running

by Peter Sagal

opinion, from Christine M. Korsgaard, Ph.D., a Harvard professor and a foremost expert on the moral philosophy of Immanuel Kant. Many of my critics made an argument that began with “What if everyone did what you did?” and in doing so, were unknowingly (perhaps!) relying on Kant’s seminal 1785 Groundwork of the Metaphysics of Morals. Kant called this notion “the categorical imperative,” and Professor Korsgaard proceeded to beat me about the head with it. “It’s applied as a thought experiment,” she wrote to me. “Imagine a world in which everyone acts on the same principle that you do, and ask yourself whether, in that world, you could act that way, too.” I understood this as a formal statement of the turnstile principle: If you jump a turnstile, the subway will run fine without your $2.25. If everybody jumped the turnstile, the subway would collapse for a lack of funds and nobody would go anywhere. And since you can’t stop anyone else from jumping the turnstile, you have a responsibility to at least make sure you don’t do it. The professor also took issue with my argument that I had used few public resources in my run: “Why does the public consent [to let the marathon use the roads]? Maybe the public just approves of marathons, and wants to support them. Or maybe the public gets something in return—the thrill of watching a race, caring who wins, etc. If that’s how it goes, the fact that you didn’t enter at the starting point or try to finish doesn’t excuse you: it makes it w...