[FOM] The Derivability Conditions

[Panu Raatikainen]

"Richard Heck" <richard_heck at brown.edu>:

> In any event, it occurred to me the other day that there is a direct  
> argument > for G2 from Löb's three conditions that does /not/ go via  
> Löb's Theorem, and > in no way involves the sort reasoning that is  
> involved in the proof of that theorem.

Such a proof is given at least in Smullyan's book, and sketched in  
Detlefsen's entry in the Routledge Encylopedia of Philosophy, as well  
as in various surveys by Smorynski.

So a bit more than just folklore...


Best

Panu



-- 
Panu Raatikainen

Ph.D., University Lecturer
Docent in Theoretical Philosophy

Theoretical Philosophy
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