universe of discourse the usually limited class of individuals under discussion, whose existence is presupposed by the discussants, and which in some sense constitutes the ultimate subject matter of the discussion. Once the universe of a discourse has been established, expressions such as ‘every object’ and ‘some object’ refer respectively to every object or to some object in the universe of discourse. The concept of universe of discourse is due to De Morgan in 1846, but the expression was coined by Boole eight years later. When a discussion is formalized in an interpreted standard first-order language, the universe of discourse is taken as the ‘universe’ of the interpretation, i.e., as the range of values of the variables. Quine and others have emphasized that the universe of discourse represents an ontological commitment of the discussants. In a discussion in a particular science, the universe of discourse is often wider than the domain of the science, although economies of expression can be achieved by limiting the universe of discourse to the domain. See also DOMAIN, FORMAL LOGIC , MODEL THEORY, ONTOLOGICAL COM – MITMENT, VARIABL. J.Cor.