The Reconstructionist Movement is a twentieth-century reaction from within the Conservative movement. It generally accepts the conclusions of philosopher Mordechai Kaplan as its axioms. It rejects the concept of a deity, and regards Judaism as �an evolving civilization�; whereas Reform regards Judaism as �a religion� in the Western sense, and whereas Orthodox communities and the Conservative Movement see Judaism as �a people� who happen to be bound by a specific covenant with God.
These philosophies differ over how a mitzvah becomes a mitzvah, and conversely what makes any behavior a transgression. Reform theology regards each individual Jew as the sole arbiter of what Jewish tradition demands of them. Orthodox and Conservative theologies regard the community�s rabbi as the authority. Reconstructionism regards the local Jewish community as the arbiter of what is (or is not) a mitzvah. But Reconstructionism does require the community to reach certain conclusions. For example, identical roles for men and women is a fundamental tenet of Reconstructionism. It was this movement that first introduced the public Bat Mitzvah celebration.