Reform Judaism (also known as Liberal Judaism or Progressive Judaism) is a major Jewish denomination which emphasizes the evolving nature of the faith, the superiority of its ethical aspects to the ceremonial ones, and a belief in a continuous revelation not centered on the theophany at Mount Sinai. A liberal religion, it is characterized by a lesser stress on ritual and personal observance, regarding Jewish Law as non-binding and the individual Jew as autonomous, and openness to external influences and progressive values. The origins of Reform Judaism lay in 19th-century Germany, where its early principles were formulated by Rabbi Abraham Geiger and his associates; since the 1970s, the movement adopted a policy of inclusiveness and acceptance, inviting as many as possible to partake in its communities, rather than strict theoretical clarity. Its greatest center today is in North America.
The various regional branches sharing these beliefs, including the American Union for Reform Judaism (URJ), the Movement for Reform Judaism (MRJ) and Liberal Judaism in Britain, and the Israel Movement for Reform and Progressive Judaism, are all united within the international World Union for Progressive Judaism. Founded in 1926, the WUPJ estimates it represents at least 1,800,000 people in 50 countries: close to a million registered adult congregants as well as numerous unaffiliated individuals who identify with it.
Its inherent pluralism and great importance placed on individual autonomy impede any simplistic definition of Reform Judaism; its various strands regard Judaism throughout the ages as derived from a process of constant evolution. They warrant and obligate further modification and reject any fixed, permanent set of beliefs, laws or practices. A clear description became particularly challenging since the turn toward a policy favouring inclusiveness ("Big Tent" in the United States) over a coherent theology in the 1970s. This largely overlapped with what researchers termed as the transition from "Classical" to "New" Reform in America, paralleled in the other, smaller branches across the world. The movement ceased stressing principles and core beliefs, focusing more on the personal spiritual experience and communal participation. This shift was not accompanied by a distinct new doctrine or by the abandonment of the former, but rather with ambiguity. The leadership allowed and encouraged a wide variety of positions, from selective adoption of halakhic observance to elements approaching religious humanism.