Michael Phelps has left us only with questions of history.
He is master of his present. No one can argue otherwise now that he has won eight gold medals and swum better than any other human ever has at the Beijing Olympics. Competitors rarely bother to call him the best anymore because, well, duh!
No, the Phelps experience comes down to a couple of questions: Are we witnessing the greatest athletic feat of recent times? And if so, is Phelps the greatest athlete we've ever watched?
It is folly to frame the thing in those terms. After all, was Abraham Lincoln a greater leader than Queen Elizabeth I? Is Yo-Yo Ma a more profound musician than Jimi Hendrix?
Adherents might claim one or the other with some ferocity, but most rational people know these questions are unanswerable. Yet we ask them. What else to do when a fellow human leaves us in bewildered awe?
Phelps has at least put himself in a class of athletes unassailably the best at their respective arts. Tiger Woods, Michael Jordan, Steffi Graf, Roger Federer and others have apartments in this pantheon. But when deciding which performer deserves the penthouse, how do you set the terms?
"He's right there in the top echelon," said National Public Radio commentator Frank Deford, who has seen his share of great ones in almost 50 years as a sportswriter.
"It's always difficult to compare him with people in team sports because it's easier to stand out in an individual sport. But I don't know that there's ever been anything like this. It's extraordinary."
Phelps' masterpiece has seemed more condensed and thus more intense to Deford than the great moments of Woods or Federer or Jordan.
"I don't know if anybody's ever owned a week like this," he said.
Phelps might be the most remarkable Olympian in memory, said Bob Dorfman, who studies the marketing potential of Olympic athletes for San Francisco-based Baker Street Partners.
"Maybe he doesn't bring the drama of Kerri Strug vaulting on a broken ankle, but in terms of sheer athletic performance, he's just jaw-dropping," Dorfman said.
"He's doing something that no one else has done, which puts him in that Tiger Woods category. His performance is really hard to top."
Just don't ask Phelps to sort all this out, at least not yet.
"I literally just get in the water and swim," he said when asked to weigh himself against other great Olympians.
"That's all I think about."
But his coach, Bob Bowman, isn't afraid to proclaim his student as the best.
"I think if it was over today, he's the greatest Olympian who ever lived," Bowman said in Beijing late last week.
"I do think it's difficult to compare [the different sports], but in terms of just sheer dominance in his events and the times he's putting up and what he's doing now in two Olympics - really three, but two where we won medals - I think it's hard to argue."
Like the other greats, Phelps rarely fails to meet the ridiculous expectations set before him. Better yet, he exceeds them. Skeptics, for example, thought he might have hit his peak at last year's world championships, where he won seven gold medals and set five world records. Too bad, they figured, that he did it at an event seen by few in the United States.
But great athletes are always upping the ante, creating possibilities for themselves that we could never fathom. Phelps was clearly in that realm last week, as he swam a full body length ahead of those little green bars that NBC uses to track world-record pace.
At a ballgame last week, some sportswriters briefly stopped to watch an Olympic water polo match. "Why isn't Phelps in this?" one cracked.
Another said, "I don't know, but I bet he'd be great."
It was a silly moment, but it illustrated the mentality Phelps has created. Put him in water and it seems nothing is beyond him. If he lined up to race a dolphin or, heck, Poseidon, would you bet against him?
"At his level, the amazing thing is not the pressure he faces but the physical demands of it," Deford said. "Woods or Federer have to play the same amount as everyone else to win a tournament. But this guy is, in effect, a racehorse with a weight handicap. Nobody else is doing the schedule he's doing, but he's still beating them."
Inspiring other greats
Like Woods, Phelps has taken a sport that was never considered cool and made it fascinating to other great athletes. LeBron James made it known that Phelps' record swim in the 400-meter individual medley inspired him. Carmelo Anthony compared the swimmer to a shark in The New York Times.
James, Anthony, Kobe Bryant and Dwyane Wade led cheers for him the night he won his 10th and 11th career gold medals.
"To be able to watch that kind of greatness in person is something I'll always remember," Wade wrote in his Olympic diary for the Associated Press.
Dorfman said Phelps has transcended swimming, a sport ignored by most Americans between Olympics.
"He's beyond the normal jock at this point," he said. "He's a superhero. He's Aquaman."