An outspoken pacifist during the interwar years, C. E. M. Joad was head of the Department of Philosophy and Psychology at Birkbeck during the 1930s.

While at Birkbeck, Joad played a leading role in The King and Country debate. The motion, debated on Thursday 9 February 1933, was “that this House will in no circumstances fight for its King and Country.”  His ardent pacifism resulted in political controversy, and he became unpopular with many who were trying to encourage men to enlist as soldiers to fight for their country.

Joad was also involved in the National Peace Council, which he chaired, 1937–38. With his two books, Guide to Modern Thought and Guide to Philosophy, he became a well-known figure. He also appeared on The Brains Trust, a BBC Radio wartime discussion programme.