 That is, Wittgenstein’s Gödelian constructs a proposition that is semantically self-referential and which specifically says of itself that it is not provable in PM. With this erroneous, self-referential proposition P [used also at (§10), (§11), (§17), (§18)], Wittgenstein presents a proof-sketch very similar to Gödel’s own informal semantic proof ‘sketch’ in the Introduction of his famous paper (1931: 598).