Mordecai KaplanRabbi Mordechai Menahem Kaplan (June 11,1881- November 8, 1983) founded Reconstructionist Judaism. He was born in Lithuania and was ordained as a rabbi at the Jewish Theological Seminary of America (JTS), in New York, in 1902. While JTS was affiliated with Conservative Judaism, rabbis at that time found it easier to move between denominations than they do today; as such Kaplan began his career as an Orthodox rabbi at Kehillath Jeshrun, a synagogue in New York. He helped to create the Young Israel Modern Orthodox movement with Rabbi Israel Friedlander. Due to Kaplan's evolving position on Jewish theology, he was later condemned as a heretic by Young Israel and the rest of Orthodox Judaism, and his name is no longer mentioned in official publications as being one of the movement's founders.
In 1909 Kaplan joined the staff at JTS, where he had his greatest impact by teaching Conservative Jewish students over a 50 year period. His central idea of understanding Judaism as a religious civilization was accepted within Conservative Judaism, but his naturalistic conception of God was not as accepted. His view of God and rejection of the concept of Israel as a Chosen people led to him being excommunicated by the Orthodox. In 1968 his followers induced him to formally leave Conservative Judaism, and set up the Reconstructionist Rabbinical College (RRC) in which his philosophy, Reconstructionist Judaism, would be promoted as a separate religious denomination.
Rabbi Mordecai Kaplan held that in light of the advances in philosophy, science and history, it would be impossible for modern Jews to continue to adhere to many of Judaism's traditional theological claims. Kaplan's naturalism theology has been seen as a variant of John Dewey's philosophy. Dewey's naturalism combined atheist beliefs with religious terminology in order to construct a religiously satisfying philosophy for those who had lost faith in traditional religion. Kaplan was also influenced by Emil Durkheim's argument that our experience of the sacred is a function of Social Solidarity.
In agreement with the classical medieval Jewish thinkers, Kaplan affirmed that God is not personal, and that all anthropomorphic descriptions of God are, at best, imperfect metaphors. Kaplan's theology went beyond this to claim that God is the sum of all natural processes that allow man to become self-fulfilled. Kaplan wrote that "to believe in God means to take for granted that it is man's destiny to rise above the brute and to eliminate all forms of violence and exploitation from human society."
It should be noted that not all of Kaplan's writings on the subject were consistent; his position evolved somewhat over the years, and two distinct theolgies can be discerned with a careful reading. The view more popularly associated with Kaplan is strict naturalism, a la Dewey, which has been criticised as using religious termonology to mask a non-theistic (if not outright atheistic) position. However a second strand of Kaplonian theology exists which makes clear that at times Kaplan believed that God has ontological reality, a real and absolute existence independent of human beliefs. In this latter theology Kaplan still rejects classical forms of theism and any belief in miracles, but holds to a position that in some ways is neo-Platonic.