[FOM] Only one proof

[Charles Silver]

On Aug 31, 2009, at 2:41 PM, Aatu Koskensilta wrote:
>
> Another example: Gödel's proof for the first incompleteness theorem
> understood as the result that the set of Pi-1 truths is productive.
> I'm not aware of any way of proving this result without going through
> essentially the recursion theoretic contortions found in the original
> proof. (I may well be just ignorant.)

	I may too, but I don't recall Kripke's proof as presented by Putnam  
(Notre Dame, 2000?) as having "recursion theoretic contortions".