David Walsh's Museum of Old and New Art (MONA) - and it is his museum - is dug into a cliff, underground, like a lair. Outdoors, on its roof, is a tennis court where Walsh likes to play.

The two car parking spaces nearest the entrance are reserved for him and his wife. I know this because they're labelled "God" and "God's Mistress".

Before I met him, I already knew Walsh had an ego. Or a sense of humour. In fact, he has both.

Arguably, however, Walsh tells me during an hour-long interview, he's a "complete waste of space".

Extended interview with MONA founder David Walsh [Al Jazeera]

He's made tens of millions of dollars, but not from creating or producing anything, or doing anything valuable.

He made his millions gambling. That created guilt. And from that guilt came MONA.

Walsh has now created. In fact, he's produced something very special.

To talk to Walsh is to get a glimpse into his mind. It is an unusual one: not many people are suited to the discipline necessary to apply maths, and science of probability, to anything a gambling market covers.

Walsh has spent 30 years crunching data, looking for where there are discrepancies between odds offered, and the likelihood of an event occurring.

"The principle is exactly the same whatever you bet on. If the odds of the event are more likely than the payoff, in the long run you’ll win," he says.

Walsh talks about his museum in the same mathematical terms. The probability, he says, was that it would fail. Most museums do; and he didn't really know what he was doing.

But that very ignorance - that freedom - is key to his museum's success.

Today, it's the most popular paid-for tourist attraction in Tasmania and it has made an important financial contribution to the island-state's economy.

That has surprised and pleased Walsh, he says, but he claims no credit. It wasn't intended, he says, so to accept praise would be disingenuous.

Regardless, against all the odds, Walsh has become Tasmania’s favourite son.