"Nobody will ever run a four-minute mile," says a character in John L. Parker Jr's Again to Carthage. "Physically can't be done. You can't drive a golf ball 300 yards. Never happen. No one can throw a hundred-mile-an-hour fast ball and no one can hit it out of the stadium. All of it is beyond human capacity."
And no one can run a two-hour marathon. Oh wait. Not long, but wait.