[FOM] Possible worlds
neilt at mercutio.cohums.ohio-state.edu
Tue Dec 19 08:44:26 EST 2006
On Tue, 19 Dec 2006, Ignacio Nattochdag wrote:
> I quote from Lukasiewicz's paper:
> "The following definition was discovered by Tarski in 1921, when he
> was attending my seminars as student of the university of Warsaw. The
> definition of Tarski is as follows:
> Mp = CNpp (This should be read : "p is possible equals if not p then p") "
> The fundamental result in the paper is the following theorem:
> All the traditional theorems for modal propositions are established
> free of contradiction in the trivalent propositional calculus, using
> as base the definition "Mp = CNpp".
What is the "trivalent" calculus?
In the classical calculus, this definition would render every possibilium
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