more from Robert C. Stalnaker

Single Idea 16468

[catalogued under 4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / a. Systems of modal logic]

Full Idea

One can make sense of necessary versus contingent necessities in a non-S5 modal semantics.

Gist of Idea

Non-S5 can talk of contingent or necessary necessities


Robert C. Stalnaker (Mere Possibilities [2012], 4.3 n17)

Book Reference

Stalnaker,Robert C.: 'Mere Possibilities' [Princeton 2012], p.112

A Reaction

In S5 □φ → □□φ, so all necessities are necessary. Does it make any sense to say 'I suppose this might have been necessarily true'?