Single Idea 14667

[catalogued under 4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B]

Full Idea

Even the conventionally accepted system B, which is weaker than S5 and independent of S4, has not been adequately justified as a fallacy-free system of reasoning about what might have been.

Gist of Idea

System B has not been justified as fallacy-free for reasoning on what might have been

Source

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

Book Reference

Salmon,Nathan: 'Metaphysics, Mathematics and Meaning' [OUP 2005], p.129


Related Idea

Idea 14668 In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N]