zahidi at logique.jussieu.fr
Mon Nov 6 04:52:02 EST 2006
I was asked the following question:
"PA does not prove its own consistency. Are there other formal systems
which do prove their own consistency?"
I had to admit that I did not know the answer to this question, but that
it seemed unlikely to me. It seems that just to formalize the sentence
"i'm consistent" one would need a lot of coding techniques, which in their
turn would require the fact that the formal system under scrutiny has
elementary arithmetic inside it.
Do any of the FOM-members know more about this question and/or the
validity of the above sketched argument.
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