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Ideas for 'What is Logic?st1=Ian Hacking', 'Explanation and Reference' and 'Putnam's Paradox'

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2 ideas

5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms

14212	A consistent theory just needs one model; isomorphic versions will do too, and large domains provide those [Lewis]
	Full Idea: A consistent theory is, by definition, one satisfied by some model; an isomorphic image of a model satisfies the same theories as the original model; to provide the making of an isomorphic image of any given model, a domain need only be large enough.
	From: David Lewis (Putnam's Paradox [1984], 'Why Model')
	A reaction: This is laying out the ground for Putnam's model theory argument in favour of anti-realism. If you are chasing the one true model of reality, then formal model theory doesn't seem to offer much encouragement.

5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems

13843	If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
	Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic.
	From: Ian Hacking (What is Logic? [1979], §13)
	A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos.