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 of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that "if he thinks", then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the "cogito", as a foundation upon which to build