Ludwig Wittgenstein me." Wittgenstein had only maintained contact with Fouracre from Guy's hospital who had joined the army in 1943 after his marriage, only returning in 1947. Wittgenstein maintained frequent correspondence with Fouracre during his time away displaying a desire for Fouracre to return home urgently from the war. In May 1947, Wittgenstein addressed a group of Oxford philosophers for the first time at the Jowett Society. The discussion was on the validity of Descartes' Cogito ergo sum where Wittgenstein ignored the question and applied his own philosophical method. Harold Arthur Prichard who attended the event was not pleased with Wittgenstein's methods;Wittgenstein:
Cogito, ergo sum ("If I am mistaken, I am") (book XI, 26), and also anticipates modern refutations of the concept. Furthermore, in the "Enchiridion" Augustine attempts to refute skepticism by stating, "[B]y not positively affirming that they are alive, the skeptics ward off the appearance of error in themselves, yet they do make errors simply by showing themselves alive; one cannot err who is not alive. That we live is therefore not only true, but it is altogether certain as well" (Chapter 7 section 20). In 1640 correspondence, Descartes thanked two colleagues for drawing his attention to Augustine and notes similarity and difference.