[FOM] Deflationism and the Godel phenomena
Aatu Koskensilta
aatu.koskensilta at xortec.fi
Thu Feb 17 02:45:32 EST 2005
On Feb 16, 2005, at 12:58 PM, Joseph Vidal-Rosset wrote:
> Jeffrey Ketland a écrit :
>
> | (ii) The Adequacy Condition (adding truth axioms should give a proof
> of
> | reflection principles, and in particular "All theorems of S are
> true").
>
> Do we need at this point to grow up to the second order? I believe it.
Only if we want to be able to define the truth predicate explicitly.
Otherwise it suffices to add a predicate True to the language of the
theory T under consideration. To the axioms of T one adds axioms saying
that True is a truth predicate (for the original language of T) - these
are the usual inductive clauses of Tarski's definition of truth - and
extends all schemata of T to apply to formulae in the extended
language.
--
Aatu Koskensilta (aatu.koskensilta at xortec.fi)
"Wovon man nicht sprechen kann, daruber muss man schweigen"
- Ludwig Wittgenstein, Tractatus Logico-Philosophicus
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