Greg L. Bahnsen (September 17, 1948 – December 11, 1995) was an American Reformed philosopher, apologist, and debater. He was a minister in the Orthodox Presbyterian Church and a full-time Scholar in Residence for the Southern California Center for Christian Studies (SCCCS). He is also considered a contributor to the field of Christian apologetics, as he popularized the presuppositional method of Cornelius Van Til.
n 1970 Bahnsen graduated magna cum laude from Westmont College, receiving his B.A. in philosophy as well as the John Bunyan Smith Award for his overall grade point average. From there he went on to Westminster Theological Seminary in Philadelphia, where he studied under Cornelius Van Til. The two became close friends. When he graduated in May 1973, he simultaneously received two degrees, Master of Divinity and Master of Theology, as well as the William Benton Greene Prize in apologetics and a Richard Weaver Fellowship from the Intercollegiate Studies Institute. His next academic stop was the University of Southern California (USC), where he studied philosophy, specializing in the theory of knowledge. In 1975, after receiving ordination in the Orthodox Presbyterian Church, he became an associate professor of Apologetics and Ethics at Reformed Theological Seminary (RTS) in Jackson, Mississippi. While there, he completed his studies at USC, receiving his Ph.D. in 1978. Bahnsen's four years at RTS were fraught with contention, centered around his particular version of theonomic postmillennialism.