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 familiar form of the phrase in his 1641 "Meditations on First Philosophy". The earliest written record of the phrase in Latin is in his 1644 "Principles of Philosophy", where, in a margin note (see below), he provides a clear explanation of his intent: "[W]e cannot doubt of our existence while we doubt". Fuller forms of the phrase are attributable to other authors. The phrase first appeared (in French) in Descartes's 1637 "Discourse on the Method" in the first paragraph of its fourth part: In 1641, Descartes published (in Latin) "Meditations on first philosophy" in which he referred to the proposition,