アリストテレスのシュロギスモス体系 : 最近の諸研究によって

Abstract

§1 In J. Corcoran 〔4〕, 〔5〕 and T. Smiley 〔16〕, it has been shown that Aristotle's syllogistic in Prior Analytics, Book I, Chapters 1, 2 and 4 through 7 is not an axiomatic system as previously construed in 〔9〕, 〔3〕, 〔18〕, 〔11〕, but a natural deduction system. (See further 〔7〕, 〔14〕.) I agree with their interpretations on substantial points. §2 It is shown according to Aristotle's text that his assertoric syllogistic can be formalized as a natural deduction system. §3 It is clear from Prior Analytics, 41 a 13-18, that Aristotle recognized only three figures and not the fourth figure. Why? The reason is that he seems to represent the basic structure of the syllogism with a linear array of three letters (for example, ABΓ) and he recognized the figure "by the position of the middle." In Appendix, I present a symbolization in natural deduction style of Aristotle's proofs of the fourteen syllogisms which closely corresponds with the original text.