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Single Idea 14669

[filed under theme 4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T ]

Full Idea

Insofar as modal logic is concerned exclusively with the logic of metaphysical modality, ..T may well be the one and only (strongest) correct system of (first-order) propositional logic.

Gist of Idea

For metaphysics, T may be the only correct system of modal logic

Source

Nathan Salmon (The Logic of What Might Have Been [1989], Intro)

Book Ref

Salmon,Nathan: 'Metaphysics, Mathematics and Meaning' [OUP 2005], p.130

A Reaction

This contrasts sharply with the orthodox view, that S5 (or at the very least S4) is the correct system for metaphysics.

The 4 ideas with the same theme [version imposing one condition on accessibility]:

16960 If possibilitiy is relative, that might make accessibility non-transitive, and T the correct system [Dummett]
14669 For metaphysics, T may be the only correct system of modal logic [Salmon,N]
9744 The system T has the 'reflexive' conditon imposed on its accessibility relation [Fitting/Mendelsohn]
14607 T adds □p→p for reflexivity, and is ideal for modeling lawhood [Schaffer,J]