Eclipse of Reason

Horkheimer's book, Eclipse of Reason deals with the concept of "reason" within the history of Western philosophy. Horkheimer defines true reason as rationality. He details the difference between objective and subjective reason and states that we have moved from objective to subjective. Objective reason deals with universal truths that dictate that an action is either right or wrong. Subjective reason takes into account the situation and social norms. Actions that produce the best situation for the individual are "reasonable" according to subjective reason. The movement from one type of reason to the other occurred when thought could no longer accommodate these objective truths or when it judged them to be delusions. Under subjective reason, concepts lose their meaning. All concepts must be strictly functional to be reasonable. Because subjective reason rules, the ideals of a society, for example democratic ideals, become dependent on the "interests" of the people instead of being dependent on objective truths.

Horkheimer is writing in 1946 and is influenced by Nazi power in Germany. He is outlining how the Nazis were able to make their agenda appear "reasonable". He is also issuing a warning against this happening again. Horkheimer believes that the ills of modern society are caused by the misuse and misunderstanding of reason. If people use true reason to critique their societies, they will be able to identify and solve their problems.