ORTHODOXY AND HETERODOXY. The concepts of orthodoxy and heterodoxy are found within all the major religious traditions, expressed by a variety of terms. In relation to religious life, orthodoxy means correct or sound belief according to an authoritative norm; heterodoxy refers to belief in a doctrine differing from the norm. The two terms originated in the patristic period of Christian history, when emphasis on belief rather than practice distinguished the concerns of Christian theologians.

Each of the major religious traditions has its own modes of determining orthodoxy. The extent to which heterodoxy is considered a serious deviance varies across traditions, and also within traditions at different phases of their history. From the perspective of an overview of the history of each tradition, one can discern that differing beliefs and/or practices have been considered of vital significance over the course of time. Further, some...