MBlume comments on Logical Pinpointing - Less Wrong

62 Post author: Eliezer_Yudkowsky 02 November 2012 03:33PM

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Comment author: MBlume 02 November 2012 12:57:20AM 0 points [-]

I've seen some (old) arguments about the meaning of axiomatizing which did not resolve in the answer, "Because otherwise you can't talk about numbers as opposed to something else," so AFAIK it's theoretically possible that I'm the first to spell out that idea in exactly that way, but it's an obvious-enough idea and there's been enough debate by philosophically inclined mathematicians that I would be genuinely surprised to find this was the case.

If memory serves, Hofstadter uses roughly this explanation in GEB.

Comment author: DavidS 02 November 2012 06:33:40PM 0 points [-]

This is pretty close to how I remember the discussion in GEB. He has a good discussion of non-Euclidean geometry. He emphasizes that originally the negation of Parallel Postulate was viewed as absurd, but that now we can understand that the non-Euclidean axioms are perfectly reasonable statements which describe something other than plane geometry we are used to. Later he has a bit of a discussion of what a model of PA + NOT(CON(PA)) would look like. I remember finding it pretty confusing, and I didn't really know what he was getting at until I red some actual logic theory textbooks. But he did get across the idea that the axioms would still describe something, but that something would be larger and stranger than the integers we think we know.

Comment author: Peterdjones 02 November 2012 01:20:09AM 0 points [-]

???

IRC, Hofstadter is a firm formalist, and I don't see how that square with EYs apparent Correspondence Theory. At least i don't see the point in correspondence if hat is being corresponded to is itself generated by axioms.