I think we could argue about the proposition that "everything has to be caused by something," both in a larger ontological sense and in the specific linear-causation sense that you seem to be implying here.But, again, everything has to be caused by something. What would cause a single timeline to branch off into a "Y"?I find diagrams can be helpful when time travel is involved, and I look at it like this: imagine the timeline (relevant to this episode) as a "Y". Things are flowing unbroken up until the branching point, which is the ENT-C's battle with the Romulans.
At that moment, things go two ways: (1) the ENT-C disappears into the future, the Klingons get angry, and a war results; (2) the ENT-C sacrifices itself in battle, the Klingons are impressed, and no war results.
Branch (1) is the one experienced for the bulk of the episode. Branch (2) is the one we know from TNG episodes before and after this one.
But to keep it relatively simple, let's just look at the obvious thing about the branching point: either the anomaly opens up and the ENT-C disappears... or it doesn't. Options 1 and 2, again. "2" is the one we're more familiar with, and self-evidently the one more likely to occur in any stable universe. Still, whatever may have "caused" option 1 is kind of beside the point (and certainly a photon torpedo battle by itself is not ordinarily sufficient to produce such results); all we really need to know is that in one line of probability, it does indeed happen.
See, that's where I think you're making an unwarranted assumption. In fact, I don't think the word "always" even applies here, since it implies a definite before-and-after chronology that can't actually be imposed. The outcomes are parallel but mutually exclusive, and each is equally valid.(My answer... The Enterprise-C always had fought the Romulans, always fired torpedoes, and always had created the rift, which always sucked it into the future.)
IF one accepts your proposition that it "always" disappears, then this would logically follow... but it's hairsplitting, really, since it's still the same moment.From the episode, it would seem that the only branching point forming a "Y" in the timeline would be AFTER the Enterprise-C returns from the future (or fails to return -- those are the two branches of the "Y").
Are you proposing an outcome where it merely disappears, but doesn't "pop out" in the future? I see no evidence for that. It is possible to imagine an outcome where it "pops out" but doesn't return, and thus the "war" timeline (branch A) continues to exist rather than sealing itself off, but again that's entirely speculative. (Indeed, IMHO that would represent a second branching, 20 years later than the first.)But the branch of the "Y" where the Enterprise-C fails to return (resulting in the Klingon war) is the branch where the Enterprise-C pops out of the rift 20 years later, and from which future Yar comes from.
What I'm disputing here is the way you're using the word "creating." I would agree only insofar as the chain of events anomalously allows Tasha of branch 1 (and thus later Sela) to survive in branch 2. Call it 2B. (But that's really no different than any time-traveler visiting the past and then living on into a future different from what he/she recalls.)And from that future, the Enterprise-C is sent back to the branching point, thus CREATING the other branch, in which Yar is captured, has a half-Romulan daughter, and Worf joins Starfleet.
Listen to yourself. You're proposing a scenario in which events are simultaneous (on which I agree), and yet (somehow!) don't happen "at once," because one "causes" the other. That's a logical pretzel. Isn't it simpler (Occam's Razor) merely to suppose a timeline split, a quantum branching, in which the anomaly both does and doesn't appear?Therefore, the timeline branch would more resemble a "4" than a "Y," because the two branches are not spontaneously created at once -- the existence of one causes the existence of the other. They only seem spontaneous because they are simultaneous.
At any rate, we're arguing over how many angels can dance on the head of a pin here. If it's important to you to see the "war" timeline as "first," the fact remains that it seals itself off and continues from a moment 20 years in its own past. The important point to keep in mind, IMHO, is that however one cares to parse the causation, from the narrative point of view the Star Trek timeline flows unbroken through that branching point and forward along one particular path... just as it does at all other such branching points in the canon. (We've occasionally been shown the "alternatives," but never for so long as to get attached to one or mistake it for the primary.) There is no point at which the timeline incontrovertibly backs up and starts in a different direction, like what we're being told happens in this movie.