Heresy and Apostasy

Heresy is not an idea known to Christian civilization alone. The Islamic concept equivalent to heresy may be bid'a, meaning literally "deviation": the counterconcept of sunna, meaning the tradition established by Muhammad. Unlike heresy, bid'a does not always have negative denotation; departure from the tradition may be tolerated as innovation, and the extreme deviation alone may be subject to condemnation. Zandaqa—the idea that rejects the existence or omnipotence of God, as in Zoroastrianism and Manichaeism—exemplifies Islamic heresy. The Islamic concept equivalent to apostasy is called irtidat or ridda, which is according to the Koran subject to death penalty or life imprisonment.

Heresy seems to be an idea whose application is overwhelmingly confined to monotheistic religions. While occasional attempts have been made to regularize the teachings of Confucianism, and thus to create a division between orthodoxy and heresy, these have not succeeded for long. The revealed word of a single god implies heterodoxy in a way that the assumptions about supernatural belief in other religions do not.