Board Thread:General Discussion/@comment-1312012-20161212132314/@comment-1257201-20161212223438

As Tupka points out, this is an ancient debate in fandom (and even in the DC editorial offices).

The articles that Johnny Diablo linked to are very good: they set a baseline for when certain series cannot be on E-2. For example, any story involving Superboy must be on E-1, etc.

However, it assumes -- as most such analyses do -- that every story between 1945 and 1964 actually happened on either Earth-One or Earth-Two. However, if you read DC during the height of the multiverse (1976 to 1985), this does not appear to be the case. For example, from about 1960 until early 1964, Batman's primary task was fighting aliens, robots, and strange creatures. Were these the final adventures of the E-2 Batman, or the earliest adventures of the E-1 Batman? Based on everything published from 1970 to 1985, neither of these seems possible.

To make things more complicated, the late 1970s writers sometimes took the very earliest Golden Age adventures as typical of Earth-Two: thus in the revived All-Star, the JSA members all sported their earliest costumes, and Superman was unable to fly!