Badāʾ , literally, "emergence, appearance," refers in theology to the advent of a divine decree that changes a previous divine decree in response to new circumstances. Hence, the term is sometimes translated as "versatility or mutability of God." The concept is found mainly in Shīʿī theology, among the "extremist" Badāʾiyya, about whom we know nothing except for allusions by heresiographers, but especially the "moderate" Twelver Imāmīs (van Ess, Frühe , 64, Arabic text, 75; van Ess, TG , index). The idea seems to have originated with the Kaysānīs (one of the oldest Shīʿī