Abstract

This thesis argues that Metaphysics ZH$\Theta$--the crux of Aristotle's metaphysics--are not, as the tradition takes it for granted, a unity which hosts a consistent doctrine of substance; rather they contain two distinct approaches to substance. I call them respectively the formal approach and the synthetical approach. They present two kinds of hylomorphism, with Z17 as a demarcation. ;The formal approach takes form or essence as a separate substance from matter and the composite and demonstrates that form is the primary substance over them. In this approach Aristotle views form or essence to be an essential property of an individual material substance. The locus of this approach is mainly in Z3-16 which host two conflict schemes for avoiding Plato's Third Man Argument. One is in Z7-9 which claims that form as primary should be toionde and not separate, and the other is in the program outlined in Z3 which rejects the notion of the Categories that primary substance is primary subject and proposes that it should be tode ti and separate. Each of these two schemes has internal difficulty. The former's claim that substance is universal is criticised in Z13, and the latter's claim that substance is particular is in conflict with the universality of knowledge. Thus the formal approach is an aporematic investigation into the ontological status of form on the basis of the dichotomy of tode ti-toionde. ;The synthetical approach associates the matter/form relation with the potentiality/actuality relation. Form and matter become relative conceptions, and are not separated from each other in definition. In this approach, Aristotle views form or essence to be the formal cause or the unifying principle which makes the material substance a unity rather than a heap. The locus of this approach is Z17 and H$\Theta$. ;The formal approach leads to the science of being qua being , and the synthetical approach leads to theology . Since two approaches are distinct, Aristotle's two notions of first philosophy cannot be reconciled