Many years ago, as part of the nonsense verse that would come to define his fighting style, Muhammad Ali said: "The hands can't hit what the eyes can't see." There are other things that one can't do when the eyes don't see. Comparing players across eras is one of them.
The other day, someone on a social-networking site suggested that he'd put Jacques Kallis, interviewed recently on Wisden India, ahead of even Sir Garfield Sobers in the allrounders' pantheon. Had he been around as long as Richie Benaud, his view would have had some credence. But he was so young that he couldn't possibly have seen even the 1980s greats in their prime.
He's hardly alone though. It's a mistake we all make frequently. What we witness in the here and now is often the 'greatest ever' or 'unparalleled'. But without a frame of reference as broad as Benaud's or Tony Cozier's, we're really in no position to make such judgments.
In some sports and certain cases, you can make an assessment based on the kind of footage available from the past. One can safely say that heavyweight boxing has never been as bereft of excitement and class as it is today. Contrast what you can see of Ali, Frazier, Foreman and Norton with the lumbering imposters of today, and it's enough to make you weep.
Athletics has gone in the other direction, at least as far as times are concerned. Usain Bolt and Johan Blake are so quick that several greats of the past -Abrahams, Owens, Borzov and Crawford - wouldn't even have got close enough to smell their aftershave. But such comparisons ignore the advances in shoe technology and also how much faster tracks are now.
It's the same reason why cricket doesn't lend itself to accurate comparison. The bat that Barry Richards used - one of them is available for the public to view at Kingsmead - is like a toothpick next to the one that MS Dhoni employed to biff the ball high into the Mumbai night on April 2, 2011. Bowlers may use the same ball, but the greats of the past didn't have to deal with these logs that allow even a mishit to clear the boundary rope.
Back to Kallis though. In a time of drought, he's a king without a rival. If your definition of an allrounder is someone good enough to bat in the top six and deliver game-changing spells with the ball, then he's the only allrounder the game has seen since the days of plenty three decades ago. Andrew Flintoff's glory years were so few that it would be illogical to include him in any debate.
Even in the '80s, however, there was a first among equals. Clive Rice had his admirers in South Africa and England and 48 first-class centuries to go with 930 wickets at 22.49 should tell you just how good he was. But it's hard to include someone in an elite list when they don't even have a Test match to their name.
Richard Hadlee, his teammate at Trent Bridge, was a magnificent bowler in most conditions. With the bat, he was more than competent, but it would be a poor team that had him in the top six. Kapil Dev, who went past his record, certainly had the ability. Even in his mid-30s, he scored a sensational hundred against Allan Donald at his quickest. But all too often, Kapil and the reckless went hand-in-hand.
With the ball, until those final two forgettable seasons, he was often India's lone warrior. Whether it was replying to searing West Indian pace at Ahmedabad  or repeatedly embarrassing the left-handers in Australia [1991-92], he truly was a bowler for all seasons.
The same can't be said of Ian Botham, whose performances with both bat and ball tailed away after the halcyon years in the early '80s. Though he finished with 14 centuries, he did little of note against the best team of that era, West Indies.
That leaves just the man who was truly Sobers' heir apparent. Imran Khan averaged 50 over the final decade of his career and took 80 wickets at 21 against West Indies. In a six-Test series against India in 1982-83, he took 40 wickets. I recall the late Rajan Bala talking about it years ago. "Some say it was bottle tops [to tamper with the ball]," he said. "Maybe. All I know is that he'd have bowled us out even with an orange."
Kallis's numbers are immense, but watching him has seldom been a visceral experience. There's little in his back catalogue that compares to Botham's onslaught at Headingley or Kapil whacking those sixes to avoid the follow-on at Lord's . As for Imran, almost everything he did quickened the pulse, whether it was that fabulous leap before delivery or the majestic straight-drive.
There's little doubt that Kallis suffers in comparison because every other great allrounder - Keith Miller preceded Sobers - was capable of the cavalier, the heroics that boys dream of before going to bed at night. By accident or design, Kallis chose a more prosaic path.
My chosen one was good enough to take the new ball for years, and possessed a batting technique far more refined than many in the top four. Add in inspirational captaincy, and you'll understand why Imran remains the greatest allrounder that I've seen. Sobers? I'll leave that debate to those who actually watched him play.