The document discusses theories in behavior science research. It defines theory as an explanation for how things work together that can make predictions. A good theory can be tested and either supported or discarded based on the evidence. The major goal of science is to generate and verify theories, as theories predict and explain natural phenomena. The document provides examples of theories like Marx's theory and Freud's theory. It distinguishes theories from hypotheses, noting that a proven hypothesis becomes a theory. It outlines several functions and roles of theories in research, such as guiding research, classifying concepts, summarizing knowledge, and predicting facts. The document also discusses deductive, inductive, and adaptive approaches to relating theory and research. Finally, it outlines several characteristics of