FAIR WARNING: this blog entry discusses the final episode of The Flash, season one. If you somehow haven't seen it and still plan to, skip this reading for your own good!
With that out of the way...if you like my content, feel free to check out my other writing related to my developing fantasy series Fire of Norea here.
I'm a member of a fun geek group online and we speculate on everything in what often amounts to funny and innovative ways (some film studio would be wise to hire us as consultants!)
After the confusing (from a multiple timeline perspective) finale of The Flash a few weeks ago, someone in the group suggested Eddie could have simply decided to get a vasectomy sometime in his future and Eobard would have disappeared just as completely without Eddie having to die. A funny and eloquent resolution to one of the issues in this episode, to be sure. This suggestion started a conversation that had to happen, though: just what is going on with the multiple time lines in The Flash? I mean, if Eobard disappeared, does that mean he never existed? And if he never existed, wouldn't that mean Barry never became the Flash??
First, let's get the obvious out of the way: time travel to the past is scientifically impossible, so it's really just a matter of figuring out if the writers remained consistent with the fantasy world they created.
My take on it is this: Reverse Flash came from, say, "timeline 1" and went back in time in timeline 1. When he killed Barry's mom, he created timeline 2. When Eddie killed himself, that created "timeline 3".
When Eobard killed Barry's mom in timeline 1, he created timeline 2 and cut himself off from the Speed Force (probably because Barry would now never become the Flash in this new timeline without Eobard's intervention)...so he further altered the timeline by recreating the events that made Barry the Flash so he could return "home", although that future would now be the future of timeline 2.
When Eddie killed himself, he eliminated Eobard's "past" in "timeline 3"'s future...but Eobard still exists in timeline 1, up until he went back in time, and the Eobard who killed Barry's mom still exists in timeline 2 as the man who helped Barry become Flash until Eddie's death. None of the events leading up to Eddie's death would be changed; only the future would be changed, as a new timeline.
There has been speculation over whether the future Eddie altered would affect the Eobard of the past, since Eddie's future is Eobard's past. The problem is Eobard shouldn't exist at all in "timeline 3" after Eddie kills himself, right? And so no one should remember that he ever existed. Barry's mother would never have been killed and Barry would probably have become the Flash according to the original timeline 1, right?
More likely, "timeline 1" exists until Barry's mother dies and then becomes "timeline 2", which exists until Eddie dies and creates "timeline 3"; and up until divergence, these timelines still serve as the "past" for the new timelines. Eobard from timeline 1 killed Barry's mother and Eobard from timeline 2 helped create the Flash. Eobard from timeline 3 never will have existed, but Eobard from timelines 1 and 2 still do, in the past leading up to the divergence that created timeline 3.
Up until those moments of divergence, the memories are not erased because they are still the past. Memories disappear only if the past is changed, leading to a different "present", as happened to Barry in the earlier episode "Out of Time."
Sounds plausible, although the showrunners are smart enough to know a little mystery goes a long way. Speculation among fans is way more satisfying (and gives the show more longevity) than any attempt to fully explain the plot (something Arrow and other superhero television shows need to employ more effectively). Bravo to that wonderful creative team!
But yeah, Eddie should have just sneaked away and found a back alley doctor to give him a quick snip, problem solved. Even so, I can't imagine we've seen the last of Eobard or Eddie, given that we know they're still alive out there, somewhere in time....
Jamie A. Duncan/www.fireofnorea.com