This paper presents a reading of Metaphysics Z.10–11 according to which both chapters outline two main definienda: forms and material substances or compounds, each of which is governed by its own peculiar constraints. Forms include formal parts alone; furthermore, they are the main definable items and enjoy the strictest possible unity. However, this does not preclude Aristotle from upgrading material compounds to the status of definable items in their own right. Z.10 explains this contention by making the compound’s sensible functional (...) matter dependent on its form. This dependence affords the resulting compound an unusually tight form-matter relationship, strong enough to ensure its definability, despite falling short of the highest kind of unity that only forms display. (shrink)

Aristotle analyses a large range of objects as composites of matter and form. But how exactly should we understand the relation between the matter and form of a composite? Some commentators have argued that forms themselves are somehow material, that is, forms are impure. Others have denied that claim and argued for the purity of forms. In this paper, I develop a new purist interpretation of Metaphysics Z.10-11, a text central to the debate, which I call 'hierarchical purism'. I argue (...) that hierarchical purism can overcome the difficulties faced by previous versions of purism as well as by impurism. Roughly, on hierarchical purism, each composite can be considered and defined in two different ways: From the perspective of metaphysics, composites are considered only insofar as they have forms and defined purely formally. From the perspective of physics, composites are considered insofar as they have forms and matter and defined with reference to both. Moreover, while the metaphysical definition is a definition in the strict sense of 'definition', the physical definition is a definition in a loose sense. Analogous points hold for intelligible composites and geometry. Finally, neither sort of definitional practice implies that, for Aristotle, forms are impure. (shrink)

La place qu’occupe la matière dans la définition de la substance sensible évolue au cours des livres Z et H de la Métaphysique : là où les chapitres 10 et 11 du livre Z affirment que la matière doit être exclue du definiens de la substance sensible, le chapitre 2 du livre H affirme, au contraire, qu’il se doit de l’inclure. Le présent article montrera que cette différence de doctrine est issue d’un approfondissement de la manière dont la priorité causale (...) de la forme est exprimée dans la définition. Elle l’est d’abord, dans le livre Z, au moyen d’une réduction des termes du definiens aux seules « parties de la forme », réduction qui est d’emblée jugée superflue et insatisfaisante. Elle le sera ensuite, dans le livre H, par la position de prédicat de la matière qu’elle occupe et qui a précisément vocation à exprimer sa priorité. En ce sens, les deux ensembles de textes ne constituent pas une volte-face théorique de la part d’Aristote, mais l’approfondissement d’un seul et unique modèle de définition visant à exprimer la priorité de la forme. (shrink)