抄録
In Physics II 9, Aristotle argues the concept of necessity which apply to natural generations. So far on the crucial problem found in the argument of this chapter, interpreters have mainly examined Part A (199b34-200a15). In this paper, however, I attempt to find out a viewpoint from which the unity of II 9's three parts including Part B (200a15-30) and Part C (200a30-38) could be seen. At the beginning of Part A, a question is raised; does 'of necessity' mean hypothetical necessity (HN) or simple necessity (SN) as well? (199b 34-35). Answering the question, Aristotle introduces HN and explains his notion of it that something (some kind of material) is necessary if some goal is to be attained. This explanation clearly shows us HN to be a teleological concept of necessity that is contrary to a mechanical concept of material necessity, which I call Democritean necessity (DN) following Cooper. According to the context of his explanation, it seems that DN is identical with SN. But we must consider if it is truly so because a key-term 'simple' (απλως) is never seen in the place of the exemplification of DN. Moreover, although HN was introduced as an opponent of DN, it should not be forgotten that HN basically depends upon DN. Thus we reexamine those problems. The point I especially want to make is that 'the necessary thing as a goal' (το αυαγχαιου ως τελος, 200a13-14) shown at the end of Part A should be identified with not DN but SN which corresponds to the necessity of eternal things suggested in PA (639b23-27). Judging from the place where the phrase in question is located, 'the necessary thing as a goal' may have something to do with the theory of deductive syllogism developed in Part B, C. Namely the concept of SN presented by that phrase is pertinent to the manner in which the principle (αρχη) of deductive syllogisms exists without both generating and perishing. Aristotle probably tried to propose the necessity of knowledge (επιστημη) that natural philosophy as well as geometry should have as a theoretical philosophy. In order to show that, he compares natural philosophy with geometry in respect of their logical necessity, i.e. HN in Part B. DN of mechanists or materialists who don't have philosophical understanding about the natural world doesn't have fully explanatory force, whereas HN has relevant explanatory force. Therefore the concept of DN is refuted by teleological theory though its existence is rightly admitted.
