I’m hardly claiming that if we find some true future unified theory of physics, every physical proposition we current believe is false. To assert that would be absurd. The interesting question is which of the propositions that are part of the current packages (at least one of which is false) are in fact false.
If you want to pick some of those propositions and rely upon them, you’d better have independent evidence for their truth (the accurate predictions made by the package isn’t going to count). So rely on that as your evidence, and not on the false package. This is what less wrong people would do.
Barbour is engage more in philosophy than in hard science, and his work is published in either published in poor journals or book form. I could care less whether Eliezer endorse Barbour’s views, if he does. And if he does, then maybe he’d do better to rely upon them than upon QM. If Eliezer does advocate for Barbour’s views, one must wonder why. On the basis of some nice hard scientific evidence? Or on the basis of lots of wishful thinking?
I’m not very interested in getting into a debate about how to properly taxonomize physical theories. That’s irrelevant to any of the points I’ve made, and the debate would be even more irrelevant. Two paragraphs of your response are on this irrelevant subject matter.
It is perfectly acceptable for me to bundle the whole of QM into one proposition, if Eliezer is baselessly relying upon QM. If Eliezer wants to rely on something OTHER than QM, then he can. Something OTHER than QM would be a part of the theory (but not the whole of the theory), or something else like a theory of quantum gravity. If he wants to rely on those things, fine. Then we’ll see what the evidence is for what he relies upon. What, for example, is the evidence for treating Barbour’s odd-ball theories to be more likely true than, say, a fixed-foliation quantum gravity? Well, there isn’t really much evidence. Bad Eliezer.
Your last comment is well worth remarking on. By “very probably false”, I roughly meant that there is a 50% probability that it is false. If there is a 50% epistemic probability that P is false, and your belief that Q is based solely upon your belief that P, then you are irrational if you believe that Q.
This post demonstrates a deep misunderstanding of modal logics, and of the notions of possibility and necessity. one would expect that misunderstanding given that Eli can’t really get himself to read philosophy. For example:
“I have to make an AI out of electrons, in this one actual world. I can’t make the AI out of possibility-stuff, because I can’t order a possible transistor.”
What? What kind of nonsense is this? No contemporary philosophers would ever say that you can make something out of “possibility stuff”, whatever the hell that is is supposed to be.
Or this:
“It’s going to be because the non-ontologically-fundamental construct of “possibility” turns out to play a useful role in modeling and manipulating the one real world, a world that does not contain any fundamentally possible things.”
Eli, everything that is actual is trivially possible, according to every single contemporary analytic philosopher. I have no idea what you mean by “fundamentally possible”, but I doubt you mean anything useful by it. If x exists, then it’s possible that x exists. If x is an actual object, then x is a possible object. If you want, you can treat those claims as axioms. What’s your beef with them? Surely you don’t think, absurdly, that if x actually exists then it’s not possible that x exists?
One also has to wonder what your beef with meaning is. I mean, surely you mean something and mean to communicate something when you string lots of letters together. Is there nothing you mean by “reductionism”? If you don’t mean anything by using that linguistic term, then nobody should pay attention to you.,