Originally Posted by mr. magoo
That's kind of dodging the question if we're honest. When doing a fantasy matchup you have to compare the two fighters as they REALLY were.
Well, if the question is 1
e.g. how would Ali, as he was in his day, deal with Lewis, as Lewis was in his own day, that's the question people should discuss.
However, there is nothing illogical about asking 2
how Ali would have done if he's have come along in Lewis's day, or vice versa, the temporally transplanted boxer developing in analogy to how he had developed in his own time (i.e., in proportion to the opportunities for development).
There are degrees of actualities. The boxers nature is an actuality which is a potential for his or her powers; their actual powers is in turn a potential for their operations. Scenario 1 requires us to consider a boxers powers (and how they may actuate as operations against one another), but not necessarily their nature (i.e., their potential for powers); scenario 2, on the other hand, requires us to consider also the fighters nature (i.e., potential to have power) as it may be actuated in various circumstances.