TL4, or at least (TL4+some measure theory that gives calculable and sensible answers), is not entirely unfalsifiable. For instance, it predicts that a random observer (you) should live in a very “big” universe. Since we have plausible reasons to believe TL0-TL3 (or at least, I think we do), and I have a very hard time imagining specific laws of physics that give “bigger” causal webs than you get from TL0-TL3, that gives me some weak evidence for TL4; it could have been falsified but wasn’t.
It seems plausible that that’s the only evidence we’ll ever get regarding TL4. If so, I’m not sure that either of the terms “testable” or “untestable” apply. “Testable” means “susceptible to reproducible experiment”; “untestable” means “unsusceptible to experiment”; so what do you call something in between, which is susceptible only to limited and irreproducible evidence? Quasitestable?
Of course, you could still perhaps say “I ignore it as only quasitestable and therefore useless for justifying anything interesting”.
TL4, or at least (TL4+some measure theory that gives calculable and sensible answers), is not entirely unfalsifiable. For instance, it predicts that a random observer (you) should live in a very “big” universe. Since we have plausible reasons to believe TL0-TL3 (or at least, I think we do), and I have a very hard time imagining specific laws of physics that give “bigger” causal webs than you get from TL0-TL3, that gives me some weak evidence for TL4; it could have been falsified but wasn’t.
It seems plausible that that’s the only evidence we’ll ever get regarding TL4. If so, I’m not sure that either of the terms “testable” or “untestable” apply. “Testable” means “susceptible to reproducible experiment”; “untestable” means “unsusceptible to experiment”; so what do you call something in between, which is susceptible only to limited and irreproducible evidence? Quasitestable?
Of course, you could still perhaps say “I ignore it as only quasitestable and therefore useless for justifying anything interesting”.