Okay, I have it ALL figured out. I started off discussing this on the FringeBloggers page after "The Day We Died," and I’ve been slowly digesting all of the ideas out there. I don't know why I didn't come to the forum first, but I'm going to go back and comb through this now as well. I'm sure most or even all of these ideas may have been shared already in the forum, but I just got done typing all this, and I'm going to post it, darn it. We’ve all been talking about different pieces of the puzzle, and I’ve just put them all together to figure out the whole story (I think). Well, not everything, but a whole darn lot. There are still many questions, and this is all speculation, of course, but a lot of it makes a lot of sense.
I agree, as has already been discussed, that we are in a time-loop continuum, and that they’ve been stuck in the loop at least six times already because of Sam Weiss’ references, and maybe more. Sam refers to his “great-great-great-great grandfather,” which would indicate that he is the seventh Sam Weiss. He implies that these previous Sam Weisses are his ancestors, but as we know from the secret anagram, “Don’t trust Sam Weiss.” He is giving us clues, but as misinformation. I think that these previous Sam Weisses were actually previous versions of himself from other timelines. I also think that the different manuscripts are each from a different loop as well. (Also remember the "numbers" channels of numbers being broadcast over radio waves in different languages from "the first people"). Furthermore, a reference was once made that there may have been more “first people” before even the "first people." I will assume then, that we are in the seventh timeline which would be appropriate since seven symbolizes completion. Even if I am wrong about that, we are, at the very least, in a second timeline, although multiple clues point to seven. If we’re in a second timeline, then Sam really was referring to ancestors before him within this timeline, but I don’t trust him, and apparently, neither should you.
I am going to use a new reference because we are now referring to not only multiple universes, but multiple universes within multiple timelines. The very first original unaltered time-line was 1.0 and our current timeline in 7.0, if our theory proves correct. Our universe within our current timeline, then, will be 7.1 and the alternate universe will be 7.2. In the original timeline, our universe was 1.1 and the alternate was 1.2. This way I can refer to Walter 1.1 or Peter 7.2 (our Peter as we know him, since he came from our current time line but the other side).
Going back to timeline 1.0, there is no machine that had been sent back because the future hadn’t happened yet at all. Time plays out, and William 1.1 and Walter 1.1 learn about the parallel universe and begin the cortexiphan trials. Then, Peter 1.1 dies as a kid, so Walter 1.1 crosses over and brings back Peter 1.2. Soon, however, Peter 1.2 falls into the lake and drowns because there was no Observer yet to save him (I’ll get to that later). This means that Peter was never supposed to exist as an adult on either side, in any timeline, and that’s what September (the Observer) meant when he says, “He never existed.” I don’t think Peter was “created” by the Observers, they just created his presence as an adult when he otherwise would not have been present. Things in 1.1 then play out in a similar fashion as we’ve seen them, just without Peter. By crossing over, Walter 1.1 begins the decaying of universe 1.2 which will eventually lead to the decaying of universe 1.1 as well, opening up the wormhole around the year 2026 (still in timeline 1.0). Perhaps Walter 1.1 never had parts of his brain removed and was never in St. Clair’s, but even if he had, he eventually figured out a way to use the wormhole to go back in time. But who can Walter send back in time who doesn’t age (or ages very slowly) to observe events to make sure things go correctly? Hmmm… did you catch the key word there?
I had always figured that the Observers were people from the future. Either that, or they were some sort of aliens or pseudo-angels, but they have the futuristic guns, gadgets, and language (probably all invented by future-Walter and the future-Fringe division), and I just always knew Fringe would get into time-travel. I just never imagined it would play such a major role over the entire plot since even the pilot episode. The writers had to have had this planned from the beginning, because the key here is Season 1 Episode 15 (S1E15), “Inner Child.” Remember, they find the little Observer-like boy underground who Walter suggests is “significantly older than he appears?” (Suggesting he’s immortal perhaps, at least in regards to aging?) The guy who at first claimed to be with Social Services says, "We may have found another one," when the boy is first found, and later reveals that he is with a classified division of the CIA Directorate of Science & Technology and he's here to take the boy so that his abilities don't slip into the wrong hands. At the end, the boy sees the Observer with whom he seems to share some unspoken connection. I, and many others, knew this kid had to be a child Observer, but he is in fact THE SAME Observer as a child! He is September!
This also dawned on me at the end of “The Day We Died,” (the second time I watched it), after Peter creates the “bridge” between the two universes, right before he disappears, he reveals to Walter that we are “the first people” and adds as an afterthought, “I don’t know who it was that took the machine back through time.” Who is it that we know have been observing events throughout time? In the episode “August” (S2E8) we see all the recorded sightings of Observers at major historical events throughout history. In the future, I predict that Walter and Olivia train all of the Observer “kids” to go back, plant the machine parts, and observe the timeline to see if they can figure out a way to save the universes which will end the time-continuum. Future-Walter also instructs them not to alter the events which could negatively affect the course of the universe even more. Remember when Future-Walter tells Ella that he would do anything to change his decisions that caused this… well, he is going to these lengths to do just that.
I’m not sure as to the source of the rest of the observers, though. Was child-September a normal kid who went through such “fringe” conditions that he developed all the Observer traits, and future-Walter just later realizes that he is the perfect candidate to go back in time to live through the entire time line until he could meet back up with Walter and report his findings? What about the other observers? How did they all get to be the same way? Maybe they were all planted in underground caves as kids to be found by the Fringe team to be trained to go back in time and observe? But then who planted them? Us as the “First People”? The Observers from the previous timeline? Aliens?
I was originally thinking that there was actually only one observer, the kid from “Inner Child,” and that the different observers were “older” versions of the same observer from all the past timelines, since I assume they are immortal in terms of aging (we know August dies). In other words, they found the kid in universe 1.1 who had, for whatever reason, become immortal (not far-fetched, the girl in Stowaway, S3E13, was similarly immortal). This Observer 1.1 was later sent by Walter 1.1 back to the beginning of universe 2.1, who then eventually teamed up with Observer 2.1, his “younger” self. They teamed up and all went back again to universe 3.1 and teamed up with Observer 3.1, and so on and so forth to get multiple Observers. I liked this idea because what are the odds that there were multiple kids who underwent the exact same rare conditions as the kid in “Inner Child” to make them have immortal Observer qualities? This also fit in with their names: each one had a different name of a month, as in they were from a different page in a calendar, each from a different timeline. This made the most sense to me, the only problem is that there are supposedly 10 observers at the end of “The Day We Died” (although I only count nine), plus August who died, making eleven past observers, meaning the kid in “Inner Child” was the twelfth Observer (with 12 months for their names), meaning we would be in a twelfth loop. I thought that this was the case and that the seven Sam Weisses must be referring to something else, but then I remembered that the agent from “Inner Child” said “We may have found another one,” seeming to indicate that they had found other observer kids in that timeline. So that kind of busted that theory, although it’s still my favorite. And yes, I know that if that were the case, all the Observers should look identical, but would they? Alternate universes mean alternate conditions. We have also not seen the faces of all the Observers clearly. Maybe some of them are identical while a couple others are not? Or perhaps they do age, or change, just extremely slowly, such that the oldest/largest looking Observer was 1.1, etc. This also ties into the way they react when August dies. I seem to remember them saying something like, “One of us has died.” But this may be a bit of a stretch, so let’s assume I’m wrong and that there are multiple unique observers.
In this case, I am instead guessing that, maybe, each time the 10 (11? 12?) Observers make it to around the year 2026 when the wormhole opens, they pass on what they have learned to the next set of Observers in that new timeline, their younger(?) selves, to go back and try again in the next timeline. Heck, I don't know. They may have tried altering slightly different variables each time to figure out a solution. In this last go-around, they somehow figured out that Peter was the answer. I don't think they “created” Peter as many people have speculated, but they just saved Peter 7.2 from drowning such that he would exist when he otherwise wasn’t supposed to.
In either case, this is how they always know when and where events are happening, and what people are going to say before they say it. They’ve observed it multiple times already, or maybe have had the knowledge of what is going to happen passed on to them.
There is a huge clue in the episode “Firefly,” and also in the Fringe graphic novel video, where the Observer talks about knowing the events that will happen, but not necessarily the results. He talks about when he rescued the Bishops from the lake, he couldn't have known that Peter would later catch a firefly, setting off a chain reaction ending with a truck skidding through the rainy intersection at Harvard Yard and killing Roscoe Joyce’s son. Because they interacted with the universe this time by saving Peter, things are similar but slightly different. The Observer has seen many possible futures but can't tell which will occur.
The only potential hang-ups here are that the Observers can apparently move through time freely, and with other people at that. At least it seems like it due to this same episode. September brings Roscoe Joyce’s son forward to talk to his father years later from the night just before he was killed. Perhaps the Observers can still interact with the wormhole that future-Walter uses to send them back in time?
Another one is that the Observers seem to be able to move freely between universes. We see the observer distract Walternate so that he does not discover the cure to save Peter, causing Walter to cross over to do it himself. Perhaps Walter treats the Observer kids with cortexiphan so they can move between universes like Olivia, but they can control it better?
I think another important key lies in S1E4, “The Arrival.” It is the first episode in which the Observer speaks, and is when the mysterious cylinder arrives from deep underground, which the Observer later calls “the beacon.” I don’t have any clue what it could be, but it much more interesting now that we know about the multiple timelines, and I think it will be a huge part of the plot making perfect sense later. This is also where we briefly hear a bit about Robert Bishop, Peter’s grandfather, who seems to perhaps be somehow involved in the story later as well. This is also when the Observer repeats what Peter is going to say as/before he says it. Either because he has been through multiple timelines, or because he is an empath just as he was as a kid in “Inner Child.”
My last thought, having reached a full three pages of text in Microsoft Word, is this. What if we're looking at this all wrong and the other universe is actually a different time-loop?
I could elaborate more, but I’ll wrap it up now to keep it brief.