Mordecai Kaplan's formulation — Judaism as an evolving religious civilization — reframed the whole question: Judaism is not primarily a set of beliefs but a people's entire culture, including language, art, food, and land, and it changes as the people change. That let Reconstructionism affirm Jewish practice while abandoning supernatural claims, and it explains the movement's early emphasis on the synagogue-center with a gym and a theater as well as a sanctuary.