Today’s chapter is optimistically entitled ‘Proving the Second Incompleteness Theorem’. Of course we don’t actually do that! But we do say something more about what it takes to prove it (stating the so-called derivability conditions, and saying what it takes to prove them). As an extra, we say how it can be that there are consistent theories which ‘prove’ their own inconsistency. The post Gödel Without Tears, slowly, 16 appeared first on Logic Matters.