 The focus of Hook’s concern in ethical theory over several decades was the continuing defense of Deweyan ethical naturalism. During the decade of the 1940s, a number of ethical and political works were written that represented reactions to the historical evils that had emerged into public consciousness after the Second World War. These works involved reconsiderations of the causes for the phenomena of human evil and of historical regression that were identified with the institutions of “the concentration camp universe” and of mass murder. These works generally involved a rejection of ethical naturalism and the recurrent claim that the Deweyan approach reflected an excessively optimistic and unrealistic interpretation of human nature.