Muhammad Ali or Mike Tyson? Mike Gibson or Brian O'Driscoll? George Best or Ronaldo? Rod Laver or Roger Federer? Arkle, Flyingbolt, Kauto Star or Best Mate?
These are questions that can never be answered by way of direct engagement, but because few arguments electrify sporting debates like comparisons between stars from different eras they are always in the background, demanding some form of response.
Subjective in the extreme and invariably littered with shock that the holders of opposing views are so blindingly wrong, it's fertile territory for stubbornness.
Even a 9-1 vote in a group of 10 won't convince the sole dissenting voice that it's best left in the wilderness.
Indeed, it merely reinforces the view that the others haven't a clue. Either that or they are being swayed by the loudest spoofer.
Still, despite the uneven nature of the terrain and the possibility of never re-emerging from a maze of names and games, there are always lots of visitors.
More importantly, there's fun too in the trek back through the decades, stopping off at whatever attraction takes your fancy.
Starring on Monday, the Irish Independent is inviting everybody to join us for the week as we apply the generational test to football and hurling in our special 20-20-50 series.
We are marking an eerily strange 2020 with a celebration of the very best in GAA over the past 50 years by selecting the top 20 hurlers and footballers in each county since 1970.
We then move on to the top 20s in each of the provinces on Friday and finish by naming the top 20 nationally next Saturday.
We could have gone for the easier route by selecting the best teams in the various categories, but opted for the tougher challenge of ranking the players against each other.
Basically, we're trying to answer the question that arises so often in all counties: 'Who were our best players?'
The wipe-out of 'live' action has seen the sports media adapt and improvise in a valiant attempt to provide some respite from the Covid-19 misery, but its arrival had nothing to do with this particular project.
We planned it late last year, with the inter-county-free month of April as the target publication date. Events took a dramatic change in March when all sport ceased, so we decided to defer 20-20-50 until now.
We did so, because irrespective of how long you devote to settling on top 20s for such a long period it's never quite enough. There's always a need to revisit.
Should 'A' be included? If so, where? And at whose expense. Should 'B' be ranked higher or lower?
Who makes the top 10, top five and who's No 1? Let's start again and review the lot.
And that's just at county level before moving on to the provincial selections and, finally, the top 20 nationally.
The argument will, no doubt, will be made that it's impossible to accurately compare players from different decades.
It's a view of the unimaginative and misses the point that the basis for any successful sporting career is rooted in fundamentals that don't change.
Natural talent, ambition, application, perseverance and mental toughness are no more the preserve of the current generation than they were 30, 40, 50 years ago.
Of course they can be refined by applying new science techniques, whether in the area of greater fitness/conditioning, advanced coaching, modern medicine, improved equipment, better pitches, psychological back-up etc.
However, whether in the 1970s or now, it all starts with raw talent. So if you took players from the past and applied modern methods, they would, no doubt, be just as good as the current crop.
Similarly, if today's top players could be despatched to less sophisticated times, they would thrive too.
For example, Henry Shefflin and Eddie Keher are rightly regarded as two of the best-ever hurlers. However, the game was so much different in their respective eras.
Apart from all the other changes, Keher played at a time when players received nothing like the protection they get nowadays.
Very few games were shown on TV, there was no private videoing, so skulduggery often went unpunished, unless it was spotted by the referee.
Keher - and a great many other top forwards - had to manage their own security arrangements, whereas cameras offer extensive protection to the current generation. Quite right too.
Keher managed well in his long career, but would have had a more enjoyable time in the modern game. Shefflin, would, no doubt, be well able to look after himself in the 'old days', but probably without as much fun.
Either way, either time, both would have been exceptional performers.
Pitches are much better nowadays, which is great for hurling, while the art of hurley-making has improved too.
It all adds up a better game, but in no way proves that the top stars of previous times wouldn't be just as effective now.
Similarly in football, where the likes of Brian Fenton, Darragh ó Sé and Anthony Tohill would have been outstanding midfielders in the 1970s/'80s, just as Dermot Earley Snr, Jack O'Shea and Brian Mullins would prosper today.
Our exercise looks at the players through the prism of how they played the game at the time, recognising the qualities that made them what they were and assessing how they would fit into another era.
Since January, we have consulted widely among trusted observers all over the country.
Naturally, they often differed greatly, but it gave us a sense of local opinion before applying our own criteria to the process.
The results of our deliberations will emerge next week, county-by-county and province-by-province before settling on the list of ultimate superstars who comprise the top 20.
From next Monday our legendary GAA correspondent Martin Breheny will unveil his bumper GAA Top 20 rankings. Martin has ranked the top 20 footballers and hurlers from each county, province and nationally with the results revealed over the course of the week. And you'll get the chance have your say with a selection of polls on the results running in tandem with the series.