On Tue, May 14, 2019 at 1:50 AM Jason Resch <[email protected]> wrote:
> On Mon, May 13, 2019 at 7:45 AM Bruce Kellett <[email protected]> > wrote: > >> >> I am not sure I have the time to delve into Muller's paper to find out >> his reasons. He is clearly misguided, because there are many viable >> cosmological theories that do not have a beginning of time (such as eternal >> inflation and related ideas) -- even if time is universally defined, which >> is very doubtful. >> > > To be clear, his result does not rule out inflation, he finds only that > observers can expect that there we will find a beginning in history where > if we try to penetrate more deeply into what happened before, it devolves > into a multitude of indistinguishable possibilities. > So he is not proposing an absolute beginning to time after all! ...... No they didn't. Zeh's ideas of decoherence go some distance, but Everett is >> totally irrelevant to this. >> > > Do you think something more than decoherence is needed to get there? > Yes. You need to reduce the superposition to a mixture. .... > You seem to be using the old scholastic notion of nominalism. >> "In more recent usage, 'nominalism' is often employed as a label for any >> repudiation of abstract entities, whether universals or particulars, and >> thus embraces the rejection of such things as propositions, sets, and >> numbers." (Oxford Companion to Philosophy, OUP, 2005) >> > > But then what is arithmetical truth? We have no label for it. It cannot be > derived from or defined by labels. > What is truth? (Pontus Pilate). Arithmetical statements are true if they are theorems derived from the axioms. "Snow is white" (Brent) is true because it corresponds with the facts. These are different notions of truth. ..... > >> We might discover some of their properties, but we can never know the >> "thing" in itself. Theoretical entities are generally dealt with by >> nominalism, as above. >> > > Most scientists would say quarks are real, because they are part of > successful theories which have explanatory power. > That is the semantic part of scientific realism -- the entities in our most successful theories correspond to elements of reality. That is just to acknowledge that the ontology is theory dependent -- not mind independent. So quarks may or may not be real -- we will probably never know. Calabi-Yau manifolds are mathematical constructs, depending on the >> definitions of topological manifolds. They are certainly theoretical items >> that have no mind-independent existence. >> > > Most string theorists would guess that Calabi-Yau manifolds are real, > because they are part of successful theories which have explanatory power. > Most stirring theorist are hooked on a failed theory. String theory is not a successful theory, and it has no explanatory power. > The more you keep pushing this, the closer you get to seeing there is some > truth to the Quine Putnam indispensability argument. You can't remove > mathematical objects and numbers from our scientific theories. > Why would I want to? Mathematics is useful for describing the results of our observations and experiments. It is a convenient language. Do you think that English sentences are part of a mind-independent reality? What separates the existent from the non-existent? >>>>> >>>>> >>>>> It might be that at a certain level of description it becomes >>>>> impossible to adequately represent the world other than mathematically. >>>>> ... >>>>> So yeah, you might think, if we eventually did have a one-to-one >>>>> mapping, what could be the grounds for denying that reality was >>>>> mathematical? I'm not really sure. I suppose I'm very skeptical of >>>>> anything >>>>> in philosophy that purports to explain the difference between abstract >>>>> maths and maths that's substantiated. Because in the end, what could >>>>> possibly explain that difference in terms of? Like, I reject the question >>>>> 'What breathes fire into the equations?' Because anything you say is just >>>>> gonna be figurative, right? Because you'd say, 'Well, there's the abstract >>>>> maths and then the actual universe is a sort of substructure of all the >>>>> possible structure there could be. So what's the difference between the >>>>> uninstantiated structure and the instantiated structure?' Well, the >>>>> philosopher will say there's a primitive instantiation relation or >>>>> something--you could invent some metaphysical language to talk about it, >>>>> but to me that's no different from saying that some of the maths has pixie >>>>> dust in it. It's not going to do any work. Because what could it possibly >>>>> connect to that would have any meaning? If you ask questions in science >>>>> like 'What causes an earthquake?' you appeal to conceptual resources and >>>>> those are non-empty because they're tied to observation. But maths--pure >>>>> maths isn't tied to observation. If the theory of everything id a >>>>> mathematical theory, how would you test it? It would have to have some >>>>> content that has to do with something other than mathematics. -- James >>>>> Ladyman, when asked "Does that mean the physical world is made of math?" >>>>> >>>>> >>>> That sounds confused. But if anything, Ladyman is arguing for >>>> scientific realism >>>> >>> >>> He's saying any attempt to draw a boundary between "instantiated >>> possibility" and "uninstantiated possibility", or between "physical >>> structure" and "mathematical structure" is doomed to be ad hoc. >>> >> >> He has a very good point, then. The problem with identifying "things" in >> terms of their relations to other things, as Muller seems to do, is that >> you make things into mathematical structures, and that is what Ladyman is >> rejecting as ad hoc. This is a straight rejection of such ideas as >> Tegmark's 'Mathematical (or Computable) Universe Hypothesis'. The universe >> has its inherent physical structure, which is part of the 'ding an such', >> which is not identified with any 'mathematical structure'. >> > > You think there is no mathematical structure that can be identical to our > physical universe with?! This is very surprising to me, why would this not > be the case? > We must be careful not to identify the map with the territory. Mathematical models are descriptions, not the reality itself. ...... That does not follow. The sets of axioms that we can employ is effective >> unlimited, but all invented. >> > > I know, I said as much. But arithmetical truth does not come from the > axioms we invent. That was my point. > It does, you know. There is no other explanation that makes sense. Arithmetical realism does not make sense. ..... Why do you think arithmetical or mathematical realism does not qualify as > an external mind-independent reality? > > The answer of "*No*" to my question "*Is it possible that the physical > universe could be explained from something more primitive?*" signals a > quasi-religious belief. There is little point in trying to debate any > further on this question while you hold so firmly to this belief. > Your belief in arithmetical realism is also a quasi-religious belief. One has to start somewhere. Numbers are a poor starting point . Believing that there is something mind-independent to explain is better -- as long as one explores what this might mean, rather than assuming the answer from the start. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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