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Comment by weinzierl

> there exist some true theorems that you can't prove.

Emphasis mine.

Are all unprovable theorems true? I googled "are all Gödel sentences true", but came up with nothing. Also: Are all unprovable theorems Gödel sentences or are there other kinds?

EDIT: Lots of good answers to my first question, thanks a lot to everyone. For the second one I think I also found an answer:

According to the Wikipedia article about the incompleteness theorems [1]: "The Gödel sentence is designed to refer, indirectly, to itself." So the question really is if there are non self-referential unprovable statements, and the answer seems to be yes[2].

[1] https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_...

[2] https://www.quora.com/Are-there-true-but-unprovable-statemen...

parent weinzierl 10 years ago

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