Before revision: Gaetano Licata (2011) rejected the slingshot argument showing that the concept of identity (=) employed in the Davidson's and Gödel's demonstration is very problematic, because Gödel (following Russell) uses the Leibniz's principle of indiscernability of identicals , which suffer from the criticism proposed by Wittgenstein: to state that x=y when all properties of x are also properties of y is false because y and x are different signs, while to state that x=x when all properties of x are also properties of x is a nonsense.
After revision: Gaetano Licata (2011) rejected the slingshot argument showing that the concept of identity (=) employed in the Davidson's and Gödel's demonstration is very problematic, because Gödel (following Russell) uses the Leibniz's principle of the identity of indiscerniblesG. W.Ludwig , which suffer from the criticism proposed by Wittgenstein: to state that x=y when all properties of x are also properties of y is false because y and x are different signs, while to state that x=x when all properties of x are also properties of x is a nonsense.