Simon Taufel has a thing about the constant pursuit of perfection.

It's a waste of time, according to the man who is widely regarded as one of cricket's best-ever umpires.

"The game is not perfect," he says.

There is no black and white, right or wrong, sometimes not even "in" or "out" is as straightforward as it might appear.

Just ask Nathan Lyon and the rest of the Australian cricket team who screamed at umpire Joel Wilson during the final moments of the third Test to give Ben Stokes out LBW to a ball that tracking showed was going to hit middle and leg stumps.

Not out. No reviews left. Game over.

Simon Taufel was voted the world's best umpire five times. ( Reuters: Andrew Boyers )

Since then debate has raged about the pros and cons of the Decision Review System (DRS).

A system that is meant to provide definitive proof of whether a batter is in or out, is subject to all manner of vagaries.

Now, in an LBW decision, a player can be either in or out, depending on the umpire's original call and how much of the ball-tracking technology shows is going to hit the stumps.

Or, as Lyon knows only too well, a player can be seemingly demonstrably out, but given not out, because the umpire has got it wrong and the captain has gambled on a previous review.

But is that any different from any decision in cricket?

"Is 100 per cent decision making achievable? No," Taufel says.

"Are human beings perfect? No. Is technology perfect? No.

"There's no right or wrongs to these types of things, there's just a different perspective about how we want to use technology."

DRS serves to make umpiring even harder

Taufel umpired in 74 Tests between 2000 and 2012 in a career that overlapped with the first use of DRS in a Test, in 2008.

Suddenly, a difficult job was now the subject of even more intense scrutiny — even for the man voted the ICC's umpire of the year five times.

India captain Virat Kohli calls for a DRS review. ( AP: Aijaz Rahi )

Because, here's the thing: "Every time you go out on the field you feel vulnerable."

"How many commentators, how many armchair critics at home say that LBW was plumb, but you've given it not out because of an inside edge that you heard, that isn't broadcast or not explained and used to support your decision?" Taufel says.

The DRS adds yet another level of introspection.

"You have to see your decision dissected in front of thousands of people in the stadium or millions of people at home, and that can be the longest two minutes of your officiating life," he says.

"You have players telling you that they think your decision is wrong, and they basically say 'send it upstairs, we don't respect the decision, we want it reviewed'.

"It's different and it's awkward and it's confronting."

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And then there's the self-doubt that creeps in if your decision is overturned.

"You do get into that vicious cycle of self-doubt, spiralling confidence and wondering if you can actually get the next decision right.

"I saw in the recent World Cup one or two umpires had to change two decisions in an over, and then you start to think 'well gee, where's the biggest hole I can crawl into and get out of this scenario?'.

"We're human."

The great test, he says, is to move on, to get back "in the moment" because "mistakes are part of umpiring".

"You need to be looking for that next decision, wanting that next decision and being confident that you'll get it right," Taufel says.

And sometimes, he says, an umpire won't agree with the decision of their colleague up in the box.

"I'll tell you that not every third umpire makes 100 per cent an accurate decision all the time," Taufel says.

"We take the best field umpires, we put them behind a fruit machine, a monitor, link them up to a director and then say 'good luck in managing hot spot, snicko, up to 31 camera angles, slow mo, real time, audio', the whole lot.

"I now advocate for specialist third umpires."

He describes officiating in the third umpire's box as "hours and hours of observation interspersed with a few minutes of panic".

"All of a sudden, this thing happens, and someone draws a box and they say 'you're on'," he says.

"And all of a sudden, the whole world's watching you. Depending on what you've got, what might be 30 seconds seems like three hours — it's almost like time stops."

How much technology is too much?

Taufel won't say whether he's a fan of the DRS or not, but he does have some concerns with what he calls an "inconsistency of process".

Specifically, the fact that there are three different ways the third umpire can be called into play.

Umpires can themselves call for advice from the third official on run-outs, stumpings and hit-wickets without giving an on-field decision, they can give a player out caught and then check to see whether it was a fair catch, or a player can review for LBWs or caught behinds.

So, why can an umpire ask for a run-out review before giving a decision, but can't do the same for an LBW appeal, when both cases are presented as cut-and-dried decisions thanks to the use of technology?

Because, Taufel says cryptically, "conclusive evidence can be subjective — not every decision is a line decision".

The question for Taufel is how far technology should intrude into what is fundamentally a very human and very imperfect game.

"Umpires make hundreds of decisions every ball, every over, every hour, every day. If you want to break those decisions down into minute pieces and you want to isolate them, it becomes an incredibly complicated, time-consuming process.

"To what extent do we want to forensically analyse every single delivery to get that black and white outcome?"

He leaves the question hanging.

"These are day-long discussions that are not straightforward. If it was straightforward we would have done it by now," he says.

As for the future of the DRS?

"I'm a fan of getting more decisions right. I'm a fan of the role of the umpire being maintained. I'd hate for the game to get to a sterile, mechanical, send everything upstairs and let technology make all the decisions. It's a game for humans, played by humans," Taufel says.

"I think it's always a balance — the all-technology route, in my view is not good, and the all human route is not good."

"But will we always be perfect? No, the game is not perfect."