Gawd, I KNEW I should have stayed out of this discussion!
As much as I LOVE science fiction, and the discussion of paradoxes and whatnot, catching up just now has my head literally spinning! And some of the episodes you folks are remembering and reposting (like the three people in Olivia's head), while I vaguely remember that, it seems like a dream or something... Not sure why I don't remember all the episodes more clearly.
I remember ENOUGH to know there have been so many different things happen over the previous four seasons that there are so many potential directions they can take the end of this show we shouldn't be surprised at just about anything that happens. I also recall a great many fans of "Heroes" after Season 1 continually saying that show "jumped the shark" after it did this or that. Well, "Fringe" has "jumped the shark," so to speak, every few episodes, but in the case of this show I think that's what keeps us coming back for more, because there really IS no boundary they can't cross or address.
I also really like the fact that as the "reality" of whatever's going on in the show has changed, the things listed as "science fiction" in the opening credits have changed. The first season or so, the list included things like multiverses, which while still unproven are a quite popular speculation amongst many physicists and cosmologists these days. Then later on, when some episodes were in the past, when Peter was a boy, the list included things like stem cells and the wireless communications, I think. There was a different list for the atlernate universe, although I can't recall any of them offhand. And now, of course, in a future dominated by Observers who appear to have NO emotions and seek to control everyone's actions, things like "individuality" and "free will" are their "science fiction."
It's really been a shame that this show has always been precisely what its name implies -- on the "Fringe," as far as audience appeal goes -- just barely enough audience to bring it back for five seasons and SO CLOSE at the end of most seasons that they ended several with maybe unnecessary cliffhangers, or possible "endings," not knowing if they'd get to really wrap things up. I guess that's better than, for instance, ABC's "Invasion," which ended Season 1 with a major cliffhanger, followed by about a 5-minute preview of a "Season 2" ABC chose not to run. All three of the original "Big 3" started the season with a new Sci-Fi show that year... "Surface," on NBC (starring Lake Bell), was a fun ride, but it was obvious near the end of the season that there was no way they COULD renew it, as it the monsters were taking over the Earth; The one on CBS (can't recall the name) LOOKED good, except for some really stupid story lines, like having to sink a sub off the EAST COAST of America that was infected by aliens "before the North Koreans?!?) got to it?!?!? Since WHEN were North Korean subs a threat to THE EAST COAST OF NORTH AMERICAN????? Had a GREAT cast, headed by Carla Gugino, which also included Brent Spiner and Chi McBride, amongs others, but doomed itself early with sucky plots like that, although the sci-fi aspect was intriguing. And then there was "Invasion," on ABC, which made it all the way through the season, and was a pretty good show. At that time, I didn't really know how to check show renewals online, so I just kept looking for it on ABC the following fall, until, by mid-October, or so, I figured ABC changed its mind (also saw one of the stars on a new Fox show -- "Prison Break").
It's uncertainty like THAT which keeps MORE decent sci-fi from being on TV, and I'm truly grateful "Fringe" has made it as long as it has, and has provided the high-quality television it has for now more than 100 episodes! When I saw promos for "Revolution" this fall, I didn't even bother to watch. I'm not longer seeing promos. I assume it's gone. Even Spielberg couldn't pull off a renewal for his compelling show "Terra X," and that was with it running in the summer! I'm amazed "Falling Skies" has now made it through two seasons. I think that's on AMC, though, so I may not get it next summer unless they and DISH iron out their issues (or I change providers). I'm currently missing the third season of "The Walking Dead," and NOT enjoying that one bit! Were I not behind on watching shows I have DVRd, I may have done something about it already.
At any rate, I'll really miss "Fringe" when it's gone. Although I sort of feel like they've used up most of their ideas, this has been a great ride!
P.S. -- Anyone ever watch John Noble's show on the Science Channel called "Weird Science," I think, about scientists who did strange things? He provides really creepy narration. Also, "Fringe" is about to start running there, beginning with Episode 1, I think -- This coming Tuesday.