No gills are to be found on Joseph Schooling, no fins protrude from his body, but in liquid he finds his most fluent expression. On Tuesday, as he stood knee-deep in water at Resorts World Sentosa, leopard and blue-spotted rays swam idly around him as if he was just another aquatic cousin on a visit.

Rays in the wild have a stinger; Joseph's politeness is a balm. He has no obvious ego, no evident hard streak, but it is there. Below the surface. If I am studying him, it is because he intrigues me. For at 18 he is caught in the most complex, uncertain, breathtaking enterprise: The giving of a life to a single cause. The Olympic medal.

Everyone has a theory on the chase for greatness. Malcolm Gladwell in Outliers, Matthew Syed in Bounce, David Epstein in The Sports Gene. Each one enriches our understanding but the fascination of professional sport - and the reason why it is an insecure life - is that greatness is mysterious. No formula exists, no one theory suffices. For years Gladwell's 10,000-hour rule of practice has been embraced, only for Epstein to now demolish it.

All this concerns Joseph because he, a junior swimming scientist, is just starting to solve greatness. Just returned from his first world championships with a first semi-final in the 200m butterfly, this 184cm boy-man categorises his progress and his approach in two words: "Baby steps."

In effect, he understands he cannot rush greatness; in short, he knows he has to become fast slowly. At 18, he is more mature than we ever were because this is a teenage life with purpose.

Joseph is an athlete and so of course we will judge him, but how we judge him is important. Small nations unused to sporting success react in various ways: They can be deeply proud and supportive, they can overestimate small success, they can be impatient for talent to assert itself.

Already I have heard his semi-final at the world championships was both a triumph and no big deal. The first is an exaggeration, the second is hogwash: He set a personal best and it is progress and that is all that matters. Yet if you ask him, he will tell you he wanted to go even faster. Nothing, not even a straightforward timing, is what it seems.

Judging Joseph seems easy for his life is measured in seconds: Either he is fast or too slow. But it is far more complicated. Improvement isn't just a number, not when you're so young. Improvement is tiny pieces that no one can see but your coach and no one can feel but you.

Athletes may speak to us but what they experience is deeply private and evident only to their closest circle. The delightful Marion Bartoli amused us during Wimbledon, yet her unending pain - which made her retire - was imagined by no one. Similarly, ask Joseph where he has improved and he rattles off a list we can't see, or measure, but only he can feel: "Mindset. Will power. How I approach races. I'm stronger. I start underwater better."

All these improvements don't always show in timings. Not immediately. Athletes can train for days, weeks, months, with nothing to show, yet trusting progress will come. And then suddenly all these improvements collide and fuse, like in London 2012, where Katie Ledecky knocked five seconds off her personal best in winning the 800m.

She did that at 15. Joseph is 18. Chad le Clos won Olympic gold at 20. Everyone's time comes at a different age and comparison is futile. Joseph, for instance, hasn't even started weights yet. "Only in college," he says.

And this is the fun of following Joseph, observing his building blocks, watching him grow, looking at him eat (think junior sumo wrestler), listening to him talk about a light morning workout of 3,000m. This is a boy's adventure for a small nation to enjoy.

Every meet he goes to, Olympics or SEA Games, already Singapore looks to him. Of course, we will look and, as an athlete with an ego, he'll want us to look. But it's how we look which matters: with interest, yes; with some expectation, fine; but with hasty judgment, no use. Because if building champions is a process, he is still early in the production line, so many parts of him yet to be assembled and polished. We cannot make him live up to a reputation he still doesn't possess.

Tomorrow night he returns to America and cold water, dark skies, shouting coach. He is at 18 a prisoner of a clock and a calendar: In short, he must reach a certain speed (faster than anyone) by a specific date (before he gets too old) in a particular place (the Olympics).

But that is then. For now everything is possible still and he is, like only the young can be, a creature of mad, innocent beauty: He actually believes one day he will beat the whole bloody world.