Abstract

Often when a new scientific theory is introduced, new terms are introduced along with it. Some of these new terms might be given explicit definitions using only terms that were in currency prior to the introduction of the theory. Some of them might be defined using other new terms introduced with the theory. But it frequently happens that the standard formulations of a theory do not define some of the new terms at all; these terms are adopted as primitives. The audience is expected to come to grasp the meanings of the primitive terms by learning the role they play in the theory and its applications. I shall call such new and undefined terms, as well as new terms that are defined using them, theoretical terms. 1 If T is a theory, the T-terms are the theoretical terms introduced by T. A theoretical term need not be a word new to human language; it might be an old term that is employed in a new and specialized sense, not equivalent to any of its familiar senses; e.g. “color” in quantum chromodynamics.