domain of a science, the class of individuals that constitute its subject matter. Zoology, number theory, and plane geometry have as their respective domains the class of animals, the class of natural numbers, and the class of plane figures. In Posterior Analytics 76b10, Aristotle observes that each science presupposes its domain, its basic concepts, and its basic principles. In modern formalizations of a science using a standard firstorder formal language, the domain of the science is often, but not always, taken as the universe of the intended interpretation or intended model, i.e. as the range of values of the individual variables. See also AXIOMATIC METHOD, FORMAL- IZATION , FORMAL LOGIC , MODEL THEORY, ONTOLOGICAL COMMITMENT, UNIVERSE OF DISCOURSE , VARIABL. J.Cor.