Horkheimer was born in Stuttgart to an assimilated Jewish family; due to parental pressure, he did not initially pursue an academic career, leaving secondary school at the age of sixteen to work in his father's factory. After World War I, however, he enrolled in München, where he studied Philosophy and Psychology; he subsequently moved to Frankfurt am Main, where he studied under Hans Cornelius. There he would meet Theodor Adorno, many years his junior, with whom he would strike a lasting friendship and one of the most fruitful collaborative efforts in contemporary philosophy.
In 1925 he was habilitated with a dissertation on Kant's Critique of Judgement as Mediation between Practical and Theoretical Philosophy under Cornelius' direction. He was appointed as Privatdozent the following year; when the Institute for Social Research's direction became vacant in 1930, he was elected for the position; among the founding members of the Institute were also Friedrich Pollock, Leo Löwenthal, and Erich Fromm. The following year publication of the Institute's Zeitschrift für Sozialforschung was begun, with Horkheimer as its editor. Besides the Institute's members, contributors included Adorno and Walter Benjamin.
In 1933 his venia legendi was revoked by the Nazi government, and the Institute closed. Horkheimer emigrated to Switzerland, from where he would leave for the USA the following year. The generous offer of Columbia University to host the Institute in exile allowed for the continued publication of the Institute's journal.
In 1940 Horkheimer received American citizenship and moved to Pacific Palisades, California, where his collaboration with Adorno would yield the Dialectic of Enlightenment. Unlike Adorno, Horkheimer was never a prolific writer, and in the following twenty years he published little, although he continued to edit Studies in Philosophy and Social Science as a continuation to the Zeitschrift. In 1949 he returned to Frankfurt, where the Institute was reopened the following year. Between 1951 and 1953 Horkheimer was Rektor of the University of Frankfurt.
He would return to America between 1954 and 1959 to lecture at Chicago. He retired in 1955. He remained an important figure until his death in Nürnberg in 1973.
Philosophy and writings
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.
Writing in 1946, Horkheimer was strongly influenced by the Nazi legacy in Germany. He outlined how the Nazis had been able to make their agenda appear "reasonable", but also issued a warning about the possibility of this happening again. Horkheimer believed 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.