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libeclipse | 1 year ago

It would tell you that the system is inconsistent

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skhunted|1 year ago

It would not. If a system can prove (I know sufficiently rich systems can’t do this but suppose it could) its own consistency you still can't conclude it is consistent.

EDIT: I'm working under the hypothetical situation in which PA could prove its consistency. I know it can't but assuming that it could prove it's own consistency you still couldn't conclude that it was consistent since an inconsistent system can prove it's consistency.

roywiggins|1 year ago

GP is (I think correctly) stating that a system that can "prove" its own consistency is definitely inconsistent. Inconsistent systems can "prove" anything; if a system can appear to prove its own consistency, it isn't.