Relying on Niklas Luhmann's systems theoretical redescription of modern society, this article aims at questioning the basic theoretical notions of the ongoing inclusion/exclusion debate. The most remarkable aspect of Luhmann's reassessment of the inclusion/exclusion relationship within functionally differentiated societies is that individuals are basically situated within the exclusion domain of society, and thus cannot but partially be included within society's function systems and organizations. This reassessment not only allows Luhmann to raise fundamental questions with respect to the implicit norm of (...) full inclusion which still dominates the debate on inclusion and exclusion, but it also directs his attention to the different inclusion/exclusion conditions within function systems, organizations and interaction systems. Eventually Luhmann's position comes down to the idea that exclusion rather than inclusion is the rule, and, moreover, that inclusions differ from one another. The article closes off with a critical evaluation of Luhmann's redescription of the inclusion/exclusion debate. It is argued that systems theory might suffer from empirical deficiency, as it seems to have difficulties to detect and to depict the actual mechanisms of social exclusion without resorting to theories that are more geared to empirical reality and that are of help in observing it. Key Words: evolution • function systems • inclusion/exclusion • Niklas Luhmann • networks • organizations. (shrink)