This article is a critical analysis of Maturana's recent works as applied to the social and behavioral sciences. It proposes that there is a major contradiction in Maturana's “structure determinism” which prevents a consistent epistemological and ontological perspective. The concept of change is viewed as crucial to understanding Maturana's work and to extending his ideas to form a consistent philosophical viewpoint, which is defined as the third epistemology for the social and behavioral sciences. Accordingly, the idea of structure is abdicated. It is proposed that the new perspective on Maturana's work has practical application to the social and behavioral sciences, in general, and family therapy, in particular.