With Karl Mannheim, Arnold Hauser and Ervin Szabó he was also involved in the Budapest Free School of Humanities, founded by Lukács.
A December 1915 lecture on historical materialism to the Hungarian Philosophical Society criticized economic determinism.
[2] In December 1918 he joined the Hungarian Communist Party and was appointed as editor of Vörös Újság (The Red Journal).
After the Republic fell he emigrated to Vienna, and from 1921 to 1930 lived in Berlin, where he was a member of the Communist Party of Germany.
[5] In 1923 he lectured, alongside Lukacs, at the Marxist Work Week, out of which later grew the Institute for Social Research.