n. [ From Gr. mo`nos single. ] 1. (Metaph.) That doctrine which refers all phenomena to a single ultimate constituent or agent; -- the opposite of dualism. [ 1913 Webster ]

☞ The doctrine has been held in three generic forms: matter and its phenomena have been explained as a modification of mind, involving an idealistic monism; or mind has been explained by and resolved into matter, giving a materialistic monism; or, thirdly, matter, mind, and their phenomena have been held to be manifestations or modifications of some one substance, like the substance of Spinoza, or a supposed unknown something of some evolutionists, which is capable of an objective and subjective aspect. [ 1913 Webster ]

2. (Biol.) See Monogenesis, 1. [ 1913 Webster ]

3. The doctrine that the universe is an organized unitary being or total self-inclusive structure.

Monism means that the whole of reality, i.e., everything that is, constitutes one inseparable and indivisible entirety. Monism accordingly is a unitary conception of the world. It always bears in mind that our words are abstracts representing parts or features of the One and All, and not separate existences. Not only are matter and mind, soul and body, abstracts, but also such scientific terms as atoms and molecules, and also religious terms such as God and world. Paul Carus. [ Webster 1913 Suppl. ]