My Approach to Modal Logic - Axioms

by Dennis J. Darland
February 17, 2008
Last revised 22.04.2008 07.37 time
Copyright © 2008 Dennis J. Darland

NOTE:

I expect that working all this out is too difficult for me. I think in My modal system - definitions , I have indicated how my approach would go. I have insufficient training in logic and to work all this out will take me a long time - if at all. I encourage anyone else interested to work on these ideas.

More Thoughts

For a universal point of view [S=God] there would be no difference from usual logics. I.e. B(God,t,p) iff p. But for any other S, no new consequences would follow, as other S's need not be logical! But I would point out it is still true:
(∀ x)(∀ y)((x = y) ⇒ B(S,t,...,x,...) ⇔ B(S,t,...,y...)) [ where x and y are in the same position.]
But that this position is for names and that 'Tully' ≠ 'Cicero' even if Tully = Cicero.

Preliminary Axioms

I am using Blackwell's Guide to Philosophical Logic ed. Lou Goble as a guide.
  1. Axioms from Classical First Order Logic
    1. Φ⇒(Ψ⇒Φ)
    2. (Φ⇒Ψ)⇒((Φ⇒(Ψ⇒Χ))⇒(Ψ⇒Χ))