more from Nathan Salmon

Single Idea 14688

[catalogued under 10. Modality / A. Necessity / 5. Metaphysical Necessity]

Full Idea

If one confines one's sights to genuinely possible worlds, disavowing the impossible worlds, then metaphysical modality emerges as the limiting case - the 'unrestricted' modality that takes account of 'every' world - and S5 emerges as its proper logic.

Gist of Idea

Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic


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

Book Reference

Salmon,Nathan: 'Metaphysics, Mathematics and Meaning' [OUP 2005], p.142

A Reaction

He observes that this makes metaphysical modality 'restricted' simply because you have restricted what 'all worlds' means. Could there be non-maximal worlds? Are logical and metaphysical modality coextensive? I think I like the S5 view.