Some of the discussion on the “Edward Feser and Vincent Torley” thread seems to have drifted way off topic. So I’m starting a new thread for further discussion on realism.
I’ll just quote part of a recent comment by BruceS:
1. A complete description of the world is a scientific description (or has a large component that is a scientific description).
2. Science is in principle reducible to physics.
3. Physics requires mathematics.
4. Mathematics is “unreasonably effective” when used in physics, which is saying that somehow the world is describable by mathematical concepts.
5. The (parts of the) any two separate complete description of the world (eg by us and some alien species) in mathematical physics will hence involve the same (or at least mathematically equivalent) concepts.
I realize all of these statements are quite questionable, although I would have thought that #3, the need for mathematics in physics, would have been among the least questionable premises!
My own contribution to the thread will be in the comments.
For reference — HERE is a link to an earlier comment by walto that started the discussion of realism
Since GR and QM are incompatible, and taking them conjointly yields contradictions, then a theory which insists on taking them together would rely on one further premise that neither GR nor QM contain: that dialetheism is true.
Thanks, Bruce. It may be that my argument depends on math generally–as it does logic in particular–being true in all possible worlds. I’m not sure–throw untranslatable conceptual schemes on top of possible worlds and I get too confused to get very far. Maybe someone else can suss this all out. Can math that is (exactly) true in one conceptual scheme be literally false (not just useless or incomprehensible) in another?
Couldn’t one also say that neither is exactly true on its own? I mean, is the situation like the non-Euclidean geometries, where one of the postulates has to go by the boards or something?
Oh, of course — and that is the reasonable view! I know nothing of the search for quantum gravity but from what I understand it’s not entirely hopeless.
I only raised dialetheism to be cute. (Don’t know if it worked or not.) To be honest, paraconsistent logics (including dialetheism) seems interesting to me for dealing with certain kinds of semantical paradoxes, but that’s it. If dialetheism is true of the physical world, then I don’t know what I would do. If it turned out that dialetheism holds of the physical world, then it would mean that it’s impossible to reliably track or model the world’s objective modal structure, since all incompatible models would be equally true of the world. I’d quit philosophy and do something else with my life. Maybe become a pastry chef, like my mom wanted me to be.
That geometry example occurred to me, but the limitation is that Euclidean and some form of non-Euclidean geometries have different consequences for how the world would be. Since the hypothetical complete descriptions would both the talking same metaphysical reality, they could not both apply.
At least, not without using some unfamiliar (to me) concept of truth, as KN suggests.
I guess “descriptions of the world” and how one might combine them are too vague for me to understand well enough to discuss to a conclusion. It is interesting that Putnam the mathematician (at one time at least) thought differently.
Any, it was good intellectual exercise.
And it helps me to understand where L&R might be coming from.
Bruce, I have no doubt I could resolve these issues of inter-translatability of conceptual schemes, ultimateness, and completeness to absolutely everyone’s satisfaction, but, alas, I have a pressing social engagement…..
🙁