re. Martha--
I think Adam does know about her, does he not? All he doesn't know is that she's found the loophole and has been exploiting it. I could be misremembering because it's really easy to miss stuff in this show.
re. breaking the circle--I think that holds true if there's only one world. But in a quantum interpretation in which multiple states can exist simultaneously, it's surely possible. One quantum conclusion is that every single potentiality plays out in different realities, and so somewhere the loops must be broken--possibly even in several realities the loops are broken. This scenario still doesn't break with the notion of predetermination though, which I think is one of the show's themes: i.e. that people are already doomed to what they'll do. The creation of the worlds is derived from a set of prior conditions (in the "original" world), and all the possibilities that might happen within the splinter worlds are determined by those conditions.
In essence, I take what happened at the end of S3 to be akin to going back to the "Big Bang." The key to dissolving everything was to find the fissure out of which their worlds were created and seal it. If we're in a quantum framework (insofar as the show interprets it), then there has to be at least one world where that's possible. There's nothing about that that goes against any of its laws. It just chose to introduce those laws over the course of the narrative.
re. the final comment, I'm not sure I follow--"you have to question how can a show based in quantum physics not recognize or address the influence of DIRECT INCEST." I don't understand the connection between quantum physics and incest. I mean, incest has always been one of the most common tropes when discussing the paradoxes of time travel, i.e. a man goes back and becomes his own grandfather... which means he fucked his grandmother. I don't see what's quantum about it. Also, the quantum framework introduces the possibility of alternate worlds/realities; time travel is generally derived from theories of general relativity. That doesn't mean it's not possible in quantum theory, just that quantum theory doesn't (historically speaking) add that much.
It's only in the past 15-20 years or so that quantum physics has begun to yield insights into time, and this might be some of what
Dark is trying to get into. Effectively, at a quantum scale, time doesn't exist--or rather, time exists ubiquitously: "elementary processes cannot be ordered along a common succession of instants," according to
Carlo Rovelli. I think this was the point of H.G.'s speech about quantum effects applying to large objects (like human bodies). At the quantum level, changes don't occur sequentially but simultaneously. If this applied at the macroscopic level, then people could be doing entirely different things at the same moment. I think that's the implication of the final season. Time doesn't really exist.
Also, as I mentioned above, I think all this was already implicit in S1. I don't think the showrunners pulled it out of their asses. S1 opens with the Einstein quote: "The distinction between past, present and future is only a stubbornly persistent illusion." H.G.'s overdubbed speech also says that "Yesterday, today and tomorrow are not consecutive, they are connected in a never-ending circle." This could be interpreted as meaning that time is relative and nonlinear (i.e. general relativity), and that it loops back into itself--i.e. the perspective until the end of S2. But it could also be interpreted as meaning that
time doesn't exist (i.e. quantum physics)
--which doesn't mean nothing happens, but rather that everything happens at the same "time." This is the perspective of S3.
