Participants over the years have included Heinrich Zimmer (Indian religious art), Karl Kerényi (Greek mythology), Mircea Eliade (history of religions), Carl Jung and Erich Neumann (analytical psychology), Alfons Rosenberg (symbolism), Gilles Quispel (gnostic studies), Gershom Scholem (Jewish mysticism), Henry Corbin (Islamic religion), Adolf Portmann (biology), Herbert Read (art history), Max Knoll (physics), and Joseph Campbell (comparative mythology).