Dualism designates “two parts” and is the position that the universe consists of two opposing principles -- though not limited to only two. There are variations within dualism. Moral dualism would see the opposites of good and evil. Personal dualism would deal with the human being as consisting of mind and body. There are property dualists (the mind is a property of physical matter), and substance dualists (the mind is a different substance than physical matter). Religious dualism is the belief that there are two opposite powers in the universe: good and evil. Some say that this is manifested in the biblical revelation of God versus Satan. A common representation of these opposites is known from the Taoist religion as Yin and Yang.
Dualism is unbiblical since Scripture does not teach that the universe consists of opposites, nor does it affirm that Satan and God are equal and opposing forces. God, according to Scripture, is infinitely greater than Satan and will eventually cast Satan into hell. This could not be done if they were equal and opposing forces.