Ancient mathematicians were manically mystical, and we could stay with the number 8 a while longer. Eight is the first digit that expresses a cube of a whole number (2x2x2). With his 8 golds, Phelps has conquered the Water Cube. Had to be.

This is how desperate Phelps has made us trying to figure out what exactly it is that he’s done by winning the eight races in the way he did.

Great sportspersons are known by the competition they keep. Today four other relay teams registered records. Australia, with 3.30.04, too broke the earlier world record, and set a new standard for the Oceanic region. Bronze medallists Japan set a Asian record, the fourth placed Russians an European standard, and seventh placed South Africa an African record.

The debate had already begun, once Phelps got his seventh gold in the 100m butterfly on Saturday, about who is the greatest Olympian ever. Does his eight-fold swim this month, his career haul of 14 Olympic golds by the age of 23, make his greater than Mark Spitz? Does it take him beyond Carl Lewis, who took four golds at the 1984 Games and returned three times to reclaim the gold in the long jump?

Decoded, the questions are: do two swimmers from different eras compare? And does track allow the kind of ambition the pool clearly does, even if only to exceptional men?

Don’t, however, pose that question to Phelps. Legacies are spoken of when one’s work is done. Phelps’s is not. “There are some things, I still want to do,” he said. For his sport, for instance. He knows he has done more to popularise swimming than anybody else. NBC, holders of the broadcast rights for the US, used their clout to have the swimming finals shifted to the morning so they could catch prime time back home. “I think swimming has come a long way,” he said “and it can go even farther. That’s where I want to take it.”

He has been finding that place called Farther in the pool and in post-race press conferences. Phelps takes every question that comes his way. (This readiness had a wit in the Media Press Centre exclaim that the only person who can stop Michael Phelps is the moderator, who often cut him short by reminding him that time was up.)

Why did he display so much emotion after the races? To remember, he said: “I just wanted to make sure I took in every single moment. I didn’t want to forget anything that happened. Those are moments I’ll remember forever.”

And these seven records? “That’s like putting money in the bank,” he said. His coach, he explained, would force him through training by suggesting that this was like putting money in the bank. Now, said Phelps, every last penny has been spent, “it’s time to start redepositing.”

Then, the unexpected intimation that Phelps may actually belong to a place different from the one the rest of us inhabit. What would he do if he didn’t swim? “I have no clue. I’d probably in the real world having a job.”

If it is in the real world that his worth is being assessed, his achievement is already two-fold. One, he has taught us new things about the human body. Oh no, it is not myth-building when they refer to his metabolism, says Susan Casey, a writer with Sports Illustrated. (No, the reference is not to his 12,000 calories-a-day diet.)

She writes: “For Phelps, with his 17 races, recovery is key. Exertion creates lactic acid, the athletic equivalent of kryptonite, and there are perfectly legal ways to minimise its residency in the body. Longer warm-downs, for one. Three minutes after Phelps’s race, or theoretically when lactic acid production is at its highest, someone will prick his ear with a needle and that blood will be measured to see how many millimoles of muscular waste must be cleared from his system. Phelps will then swim easily until the readings drop to an acceptable level.”

He wears the LZR Speedo suit, that’s credited with a flurry of new records. He has a body suited to the waters, wide armspan, for instance. To these he’s added his hard work — the money deposited in the bank.

Two, Phelps matters because he’s begun what only the greatest can, a historical reassessment of everything that’s come before him. So, this month when every hero’s pedestal is reassessed for size, when the worth of everything that has ever happened at an Olympic Games before is revisited, know that this has been made possible by the extraordinary achievement of a guy with a very goofy grin.