dualism

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The condition of being double; duality.
2. n. Philosophy The view that the world consists of or is explicable as two fundamental entities, such as mind and matter.
3. n. Psychology The view that the mind and body function separately, without interchange.
4. n. Theology The concept that the world is ruled by the antagonistic forces of good and evil.
5. n. Theology The concept that humans have two basic natures, the physical and the spiritual.

Century Dictionary and Cyclopedia

1. n. Division into two; a twofold division; duality.
2. n. In philosophy, in general, that way of thinking which seeks to explain all sorts of phenomena by the assumption of two radically independent and absolute elements, without any continuous gradation between them: opposed to monism. In particular, the term is applied — To the doctrine that spirit and matter exist as distinct substances, thus being opposed both to idealism and to materialism.
3. n. To the doctrine of a double absolute, especially a principle of good and a principle of evil, or a male and a female principle.
4. n. In theol.: The doctrine that there are two independent divine beings or eternal principles, one good and the other evil: characteristic especially of Parsism and various Gnostic systems.
5. n. The heretical doctrine, attributed to Nestorius by his opponents, of the twofold personality of Christ, the divine logos dwelling as a separate and distinct person in the man Christ Jesus, and the union of the two natures being somewhat analogous to the indwelling of the Holy Spirit in the believer; that view of the personality of Christ which regards him as consisting of two personalities.
6. n. In chem., a theory advanced by Berzelius which assumed that every compound, whether simple or complex, must be constituted of two parts of which one is positively and the other negatively electrified. Thus, for example, sodium sulphate is put together not from sulphur, oxygen, and sodium, but from sulphuric acid and soda, which can themselves be separated into positive and negative constituents. Muir, Principles of Chemistry.
7. n. In general, any system or theory involving a duality of principles

Wiktionary

1. n. Duality; the condition of being double.
2. n. philosophy The view that the world consists of, or is explicable in terms of, two fundamental principles, such as mind and matter or good and evil.
3. n. theology The belief that the world is ruled by a pair of antagonistic forces, such as good and evil; the belief that man has two basic natures, the physical and the spiritual.

GNU Webster's 1913

1. n. (Philos.), (Theol.) A view of man as constituted of two original and independent elements, as matter and spirit.
2. n. A system which accepts two gods, or two original principles, one good and the other evil.
3. n. The doctrine that all mankind are divided by the arbitrary decree of God, and in his eternal foreknowledge, into two classes, the elect and the reprobate.
4. n. (Physiol.) The theory that each cerebral hemisphere acts independently of the other.

WordNet 3.0

1. n. the doctrine that reality consists of two basic opposing elements, often taken to be mind and matter (or mind and body), or good and evil