This dialectical method is built on the Principles of Expression and Differentiation. The first breaks with both logical and causal analysis, emphasizing relationships within a whole. The second stresses that development is often multilinear and discontinuous. Both principles deny the Aristotelian logic which deals with reality as built on abstract theoretical entities. Dialectics can be traced from Socrates through Hegel to pragmatism and contemporary general systems theory. The method is sensitive to linguistic, social, and cultural issues and is much more sociological than its critics have grasped. When applied to functionalism, the dialectical method demonstrates the inadequacy of ends-means logic. It also shows that functionalism has rested on a limited, social control viewpoint based on an identification of equilibrium with negative feedback models. A dialectical approach can subsume functionalism through a balanced perspective which stresses latent potentials as much as latent functions and treats equilibrium as homeorhesis rather than homeostasis.