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Ideas for 'Axiomatic Theories of Truth', 'Four Dimensionalism' and 'De Mundo Praesenti'

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3 ideas

5. Theory of Logic / K. Features of Logics / 3. Soundness
You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach]
     Full Idea: One cannot just accept that all the theorems of Peano arithmetic are true when one accepts Peano arithmetic as the notion of truth is not available in the language of arithmetic.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1)
     A reaction: This is given as the reason why Kreisel and Levy (1968) introduced 'reflection principles', which allow you to assert whatever has been proved (with no mention of truth). (I think. The waters are closing over my head).
Normally we only endorse a theory if we believe it to be sound [Halbach]
     Full Idea: If one endorses a theory, so one might argue, one should also take it to be sound.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1)
Soundness must involve truth; the soundness of PA certainly needs it [Halbach]
     Full Idea: Soundness seems to be a notion essentially involving truth. At least I do not know how to fully express the soundness of Peano arithmetic without invoking a truth predicate.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1)
     A reaction: I suppose you could use some alternative locution such as 'assertible' or 'cuddly'. Intuitionists seem a bit vague about the truth end of things.