Abstract
Constitution is the relation between something and what it is made of. Composition is the relation between something and its parts. I examine three different approaches to the relation between constitution and composition. One approach, associated with neo-Aristotelians like Mark Johnston and Kathrin Koslicki, identifies constitution with composition. A second, popular with those sympathetic to classical mereology such as Judith Thomson, defines constitution in terms of parthood. A third, advocated strongly by Lynne Baker, takes constitution to be somehow inconsistent with relations of parthood. All of these approaches, I argue, face serious problems. I conclude, tentatively, that constitution and composition have nothing to do with each other.