- the state of being dual or consisting of two parts; division into two.
- Philosophy.
- the view that there are just two mutually irreducible substances.
- the view that substances are either material or mental.
- Theology.
- the doctrine that there are two independent divine beings or eternal principles, one good and the other evil.
- the belief that a human being embodies two parts, as body and soul.
- the state of being twofold or double
- the doctrine, as opposed to idealism and materialism, that reality consists of two basic types of substance usually taken to be mind and matter or two basic types of entity, mental and physical
- the theory that the universe has been ruled from its origins by two conflicting powers, one good and one evil, both existing as equally ultimate first causes
- the theory that there are two personalities, one human and one divine, in Christ
