アリストテレス『形而上学』Θ巻におけるアナロギアと二つのデュナミス

抄録

In the Metaphysics Θ Aristotle introduces two types of dynamis (dynamis as ability (DA) and dynamis as potentiality (DP)). It has been often pointed out that his distinction between DA and DP is confusing. In this paper, I examine the difference between them and the significance of his detailed explanation of DA in the first half of Θ (ch.1-5), and thereby I show the following.
In the first half of Θ, Aristotle basically understands DA as an external (objective) principle of motion. This characterization is neutral with regard to the framework of hylomorphism and whether relevant motion happens or not. But in his criticism against the Megarians who deny dynamis, he indicates that dynamis can be regarded as potentiality. This criticism serves as a point of contact between of ability and potentiality. On the other hand, in the latter half of Θ, the notion of potentiality implies that dynamis is only conceivable as energeia (actuality). However, DA and DP are not exclusive kinds, the difference consists in that of perspective and there is no genuine confusion.
Further, DA plays an important role in introducing DP by analogy. In Θ6, DA functions as the starting point of an analogical argument. That is, there is an analogical progression which proceeds from the scheme of <ability-motion> to that of <matter-substance (form)>. In this respect DA has a methodological significance in Aristotle's potentiality-actuality theory.