This article presents a formal reconstruction of James D. Thompson's classic contribution to organization theory, Organizations in Action. The reconstruction explicates the underlying argumentation structure for Thompson's propositions - literally, theorems or problems to be demonstrated. This allows Thompson's propositions to be derived as theorems in a deductive theory. As it turns out, the formal theory is based on general assumptions using only few primitive concepts. In addition, this theory explains why Thompson's propositions do not hold for noncomplex or "atomic" organizations (a restriction on the domain of application). Furthermore, this study reveals that organizations attempt to reduce constraints in their environment - a heretofore unknown implication of the theory.