For example, the greatest player in the world’s most popular sport, the soccer superstar Lionel Messi, was a promising player in his native Argentina, but small. At age 13, he moved to Spain to enroll in the youth academy of the famed club Barcelona, which paid for treatments to address a diagnosis of growth-hormone deficiency. Without that enhancement, might Messi have just ended up as a terror in Sunday-afternoon recreational games rather than the world’s best soccer player?

Herr says that what will make sport fairer is “more technology, not less.” But that doesn’t really settle the Pistorius question, because no one is likely to want to trade his biological legs for artificial ones, no matter how cool and sexy Herr can make them.

Pistorius refers to himself as “a sportsman.” As we sat one afternoon in his living room, he talked about the inquiry into his eligibility in terms of a specific kind of self-discovery: is his presence on the track fair to competitors? “The purpose for me wasn’t to be able to say to everybody, ‘Look, I don’t have an advantage,’ ” he said. “I really wanted to find out, ‘Do I have an advantage?’ Because I don’t want to be competing in a sport where I feel that I’m here not on my talent and my hard work but because of a piece of equipment.”

Pistorius stresses that he is proud to compete in Paralympic competitions. But he believes the strongest argument for his participation in able-bodied events is his vast superiority over disabled athletes who run on the same Cheetah prosthetic legs in the 400 meters. “These are not guys who just came off the streets and they strapped prosthetic legs to them,” he said. “Some of them have been top athletes before their operations, and some grew up in the Paralympic movement. They’re guys who sit in the gym and go on the track as much as I do. They’re hard-core athletes, but you don’t see them running remotely the same times.”

Pistorius’s dogs — an English bull terrier, a very docile American pit bull and a dachshund mix — were at his feet, and he threw them chew toys as we talked. I asked what his goal was for the coming year and was a little surprised that his ambitions were not higher. He is aiming to run in the final heat of the 400 meters in London, after failing to advance past the semis at the world championships. “I can have my goals, and I can have my dreams,” he said. “My goal is to make the finals and improve my position. I want to run all decent races. I don’t want to look back and say I ran a terrible race. It’s not like at this level I can go out and run a low 44, just because I said this is the day I want to do that. That’s never going to happen.”

Which is probably true. But also surprising to hear from someone of Pistorius’s hellbent temperament. I wondered if there might be an element of self-protection in his thinking. If he meets his stated goal, he would continue to be well compensated, well liked and respected. His good life would get only better. If he could somehow pull off a miracle and make it to the medal stand, there might be no end of controversy.

He told me that he gets no special thrill from defeating men with two biological legs. To do so would be to dwell on his own disability. “You have to move past it,” he said. “Everyone has setbacks. I’m no different. I happen to have no legs. That’s pretty much the fact.” So what does he think as he settles into the starting block? “I just try to get my mind in the right place and think about what I want to do in that race, how I want to run it,” he said. “And then I go out and bang it.”