In track and field, athletes compete not just against one another, but against the intrinsic barriers of human achievement. At the London Olympics, the runners and jumpers and javelin-throwers will set fewer world records than the swimmers. But the ones they do set are more likely to survive the test of time. Read more in the Sunday Review.
Nate Silver is the founder and editor in chief of FiveThirtyEight. @natesilver538