Monism is the philosophical view that a variety of existing things can be explained in terms of a single reality or substance. The wide definition states that all existing things go back to a source which is distinct from them (e.g. in Neoplatonism everything is derived from The One). A commonly-used, restricted definition of monism asserts the presence of a unifying substance or essence. Monism is contrasted with Dualism (philosophy) and Pluralism (philosophy).

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