Spoiler Alert --- If you have not read the Chapter 66 of A New Past, don't read this blog post.
Really, I'm serious. You'll spoil the ending.
You've been warned.
Let's talk about the ending. Several readers did not follow what I tried to lay out without boring everyone to tears with technical mumbo-jumbo of plausible realism. Trust me, you don't want to read some of the crap I wrote trying to explain a multi-verse and how time flows at different rates in different universes.
Anyway, that is the core premise in the universe that Paul inhabits.
At the opening of the story, he was in universe A. The accident that appeared to send him into his past, actually transmitted his consciousness into his doppelganger's body in universe A-prime. I call it A-Prime, because to our main character's conscious mind, it is his own past in Universe A.
Once he realizes that he did not actually travel into his own past in universe A, he comes to believe that there are a multitude of universes ((B through Z) raised to infinity). A little later, working with Dr. Perdew, they conclude that the rate at which time passes in these universes is variable. That implies that Universe B may be further along the timeline than universe C.
Paul also realizes that his life and family are now in A-Prime, and that if he leaves it, all of the good he knows may be gone forever.
His grand experiment, which ends the story, transmits a portion of his consciousness outward from A-prime. He then continues to live in A-prime and proposed to Chrissy.
In universe B, he wakes up in his lab shortly before the original explosion and escapes that fate. Maybe he thinks it was a premonition, or a deja vu, or a dream. Maybe his consciousness and mental patterns are different enough that firm memories are not retained. Regardless, he escapes the original fate he experienced in universe A.
In universe C, he is fourteen again, much as when he went back to A-prime. In this universe, it was a much stronger dream, maybe even a recollection. This was possible because his mental state is less defined than his older self was in universe B. He remembers enough and knows he wants to pursue Jeryl again.
Finally, in universe D, he wakes with recollections and it is just before Jeryl and Alison's and Rose's fateful trip.
While only four snippets are shown, an infinite number of Paul's doppelgangers exist and received some impression from his broadcast. I wrote several passages (that I later cut) trying to equate the number of universes and possible reception points based on quantum states, similar to what drives how many electrons can reside within an electron shell, but decided that was detail not relevant to the story, and opened up to many possible arguments regarding feasibility, etc.
Instead of worrying about infinity and pseudo-scientific explanations, I chose to focus on the threads that would close out the story and leave the rest to the reader's imagination.
I hope this helps for anyone that was not clear on the ending.
Thanks for reading.
-Charlie