Arthur Oncken Lovejoy (October 10, 1873 – December 30, 1962) was an American philosopher and intellectual historian, who founded the discipline known as the history of ideas with his book The Great Chain of Being (1936), on the topic of that name, which is regarded as 'probably the single most influential work in the history of ideas in the United States during the last half century'.

Eighteen months later, his mother, a daughter of Johann Gerhard Oncken, committed suicide, whereupon his father gave up medicine and became a clergyman.

Lovejoy studied philosophy, first at the University of California at Berkeley, then at Harvard[3] under William James and Josiah Royce.

[4] He did not earn a Ph.D.[5] In 1901, he resigned from his first job, at Stanford University, to protest the dismissal of a colleague who had offended a trustee.

Thus, at the height of the McCarthy Era (in the February 14, 1952, edition of the Journal of Philosophy) Lovejoy stated that, since it was a "matter of empirical fact" that membership in the Communist Party contributed "to the triumph of a world-wide organization" which was opposed to "freedom of inquiry, of opinion and of teaching," membership in the party constituted grounds for dismissal from academic positions.