We grow up with one or the other, we hear things from people we love and trust, and they slowly become fact. We then repeat them to others, and that's how legends grow. There is another important factor however. Most of us haven't seen Maradona nor Pele play regularly in the flesh. At best, we've seen one or the other, or we've seen them on television or, at worst, in highlight shows.
Highlights are irrelevant.
A skilled producer could produce a highlight film of Edilson or Nwankwo Kanu or Marius Lacatus that could fool you into thinking either one of the three was better than Pele or Maradona. And I can tell you, even though I do this for a living, I have no clue who I would pick between the two. Many insiders I've spoken to don't know either. The rest are pretty evenly split. Having said all that, perhaps we can establish some kind of criteria that will allow us, at least individually, to reach some closure.