dualism

noun

• 1the division of something conceptually into two opposed or contrasted aspects, or the state of being so divided:a dualism between man and nature
• Philosophy a theory or system of thought that regards a domain of reality in terms of two independent principles, especially mind and matter ( Cartesian dualism). Compare with idealism, materialism, monism.
• the religious doctrine that the universe contains opposed powers of good and evil, especially seen as balanced equals.
• (in Christian theology) the doctrine that Christ had two coexisting natures, human and divine.

• 2the quality or condition of being dual; duality.