Rabbis Mordecai Kaplan (1881-1983) and Ira Eisenstein over a period of time spanning from the late 1920s to the 1940s. It formally became a distinct denomination within Judaism with the foundation of the Reconstructionist Rabbinical Seminary in 1968.
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.
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 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.
Most Reconstructionist Jews reject traditional forms of theism. Many are deists; a small number accept Kabbalistic views of God.
All Orthodox Jews, most Conservative Jews, and some Reform Jews find Kaplan's theology incompatible with that of classical Judaism. Some within the Reconstructionist movement, while accepting many of Kaplan's other ideas, refused to accept Kaplan's theology. Instead they affirm a theistic view of God.
Judaism is the result of natural human development. There is no such thing as divine intervention; Judaism is an evolving religious civilization; Zionism and aliyah (immigration to Israel) are encouraged; Reconstructionist Judaism is based on a democratic community where the laity can make decisions, not just rabbis; The Torah was not inspired by God; it only comes from the social and historical development of Jewish people; The classical view of God is rejected. God is redefined as the sum of natural powers or processes that allows mankind to gain self-fulfillment and moral improvement; The idea that God chose the Jewish people for any purpose, in any way, is "morally untenable", because anyone who has such beliefs "implies the superiority of the elect community and the rejection of others".
Most Reconstructionists do not believe in revelation (the idea that God, in some way, can reveal His will to man). This is dismissed as supernaturalism. Mordecai Kaplan instead posits that revelation "consists in disengaging from the traditional context those elements in it which answer permanent postulates of human nature, and in integrating them into our own ideology...the rest may be relegated to archaeology." ("The Meaning of God in Modern Jewish Religion").
Reconstructionism promotes many traditional Jewish practices, while also holding that personal autonomy has precedence over Jewish law. Thus, mitzvot (commandments) have been replaced with "folkways", non-binding customs that can be democratically accepted or rejected by the congregations. Folkways that are promoted include keeping Hebrew in the prayer service, studying Torah, daily prayer, wearing kipot (yarmulkas), tallitot and tefillin during prayer, and observance of the Jewish holidays.
The role of women in Reconstructionist Judaism is the same as that held by Reform Judaism.
The role of non-Jews in Reconstructionist congregations is a matter of ongoing debate. Practices vary widely between synagogues. Most congregations strive to strike a balance between inclusivity and integrity of boundaries. The JRF has issued a non-binding statement attempting to delineate the process by which congregations set policy on these issues, and sets forth sample recommendations. These issues are ultimately decided by local lay leadership. [See "Can Halakha Live" by Rabbi Edward Feld, "The Reconstructionist", Vol.59(2), Fall 1994, p.64-72]