When used of a religion, this word implies the doctrine of two divine powers or principles in opposition within the universe. Such is found in Zoroastrianism and Manichaeism. In the field of philosophy the term describes the existence of two essentially different constituents in the worlde.g., the Cartesian bifurcation of reality into material substance and mental substance. Within Christian theology, Nestorians were accused of dualism because they supposedly taught the doctrine that Jesus was two Persons linked together and not truly one Person. In general the word dualism describes any system of belief or thought which contains two opposing principles.