Abstract

Tryon advises psychologists to construct theories as physicists do, and claims that a theory of physics is a system of algebraic relations which constitute the definitions of new concepts and their units of measurement in terms of existing ones, at least two basic units being initially adopted. He says that these algebraic relations create a knowledge hierarchy, which he considers a theory. In reality, only some of the mathematical relations of physics are definitions, which introduce new tools, while the rest of them express the "laws of nature," the discovery of which is the primary objective of science. Tryon also says that these algebraic relations express quantitative, logical, and conceptual equivalences. He is wrong again, because only the relations that constitute definitions express conceptual equivalences, while the laws of nature are discovered either by making measurements or by constructing theories. Tryon says nothing about the discovery of the laws of nature either way, and appears to consider the concept of "law of nature" as unscientific. He also believes that measurements serve only to determine the characteristic properties of substances. In this article, the usefulness of the concept of "law of nature" is illustrated, and more importantly, the method of theory construction used in physics and the way in which it can be adapted to psychology are explained.