In September of 1930, at the Königsberg conference on the epistemology of the exact sciences, Gödel made the first, tentative announcement of his incompleteness results. Von Neumann immediately saw the implications, and, as he wrote to Gödel on November 30, 1930, “using the methods you employed so successfully … I achieved a result that seems to me to be remarkable, namely, I was able to show that the consistency of mathematics is unprovable,” only to find out, by return mail, that Gödel had got there first.
