"This is a total and opposite reality from the Chris Nolan movies," he said. "It’s another universe, so we couldn’t hire Christian Bale if we wanted to, because he doesn’t exist in our world. Maybe we could hire him to play another part. We did talk about that briefly. I just wanted to hire Christian to play another part to make that obvious."

"Another universe"…? That's interesting phrasing, given recent developments in DC's TV slate. The second season of the CW's The Flash has, after all, spent much of its time exploring the notion of alternate universes and parallel earths, building off an idea first explored in a 1961 Flash comic book — that of a number of parallel earths exist in which events, ideas and even identities echo without repeating exactly.

Over time, what started as a relatively lighthearted (if not exactly entirely coherent — Barry Allen, it was revealed, became the Flash because he read the adventures of the Earth-2 Flash as a child, adventures written and drawn by creators whose brains tuned into Earth-2 events while they slept) nod to the past of the DC characters became part of an increasingly complicated mythology called the DC Multiverse, with new parallel earths being added on an almost annual basis.

In addition to "Earth-1," where the Justice League lived, there was Earth-2, home of the WWII-era Justice Society; Earth-3, where the Justice League was replaced by the evil Crime Syndicate; Earth-X, where Nazis had won the Second World War; Earth-S, home to Shazam and the original Captain Marvel; and more.

Heroes and villains crossed between Earths on an irregular basis and histories became so contradictory and confusing for newcomers — at one point, there was an unofficial "Earth-B," suggested by DC editors as the home for stories with obvious continuity errors born of the parallel realities — that, in 1985, DC celebrated its 50th anniversary by doing away with the whole thing in the fan-favorite Crisis on Infinite Earths comic book mini-series. By the end of that 12-part storyline — teased with the tagline "Worlds will live, worlds will die" — there was only one Earth, and history had been rewritten so that had always been the case.

Except, of course, the idea of parallel worlds was too fun to leave alone for good. After a couple of false starts, 2005's Infinite Crisis and 2006's 52 restored the concept of the multiverse, while keeping things under control: now there were just 52 earths to consider. Well, until the climax of 2015's The Multiversity No. 2 revealed that there was, in fact, a multiverse of multiverses. (Don't think about it too hard.)

Back, then, to Snyder's comment about Christopher Nolan's Dark Knight movies taking part in "another universe." Given that DC's comic books have a long history of crossing between parallel earths, and also that The Flash has demonstrated that DC's TV properties have started to get to grips with the same concept, is it impossible to think that the DC movie properties are just happening one parallel earth over from, say, The Dark Knight, the Christopher Reeve Superman movies or any of the TV shows?

Marvel has demonstrated both the strengths and weaknesses from tying all of its output to one central timeline — audiences will feel that the stories can overlap and interconnect, but the events of one have to be reflected in the others. Could Warners be trying to build a better model with a Multiverse that allows for all the pluses of interconnectedness, but none of the drawbacks?