German philosopher Hanno Sauer argues that class hierarchies are a permanent feature of human societies. So if true equality is elusive, how do we live with class? Plus new revelations on the Cambridge Five - the young men who spied against Britain from the 1930s to the 1950s. Guests: Hanno Sauer, Associate Professor of Philosophy at the Department of Philosophy & Religious Studies at Utrecht University. Guest of the Festival of Dangerous Ideas in SydneyAntonia Senior, author, journalist and co-host of the History Book Buffs podcast.  New book is Stalin’s Apostles: The Cambridge Five and the Making of the Soviet Empire