Abstract

Three major problems continue to perplex every interpreter of Stoic logic since Lukasiewicz's [[sic]] revolutionary studies in 1932: the alleged opposition of Stoic dialectic to Aristotelian syllogistic; the baffling status of "implication" in Diodorus and Chrysippus; the questionable completeness of the Stoic system based on the five "indemonstrables." Expanding on Lukasiewicz's [[sic]] findings, Benson Mates and Mary Kneale argued for interpreting Stoic logic in terms of a logic propositions formally analogous to our propositional calculus. Furthermore Mates and, to a less extent, Kneale cast doubts on the accepted opinion that Diodorus' "implication" was the ancient version of what C. I. Lewis calls "strict implication," and opted for B. Russell's "formal implication," while attributing the first type of implication to Chrysippus alone. Finally Mates, Kneale, and Reymond questioned the alleged completeness of the Stoic logic system. Among recent logicians this very question still calls for an answer. In form and content, Mignucci's knowledgeable study on the meaning of Stoic logic is a lucid restatement of his predecessors published conclusions. With the exception of the first chapter devoted to a résumé of the main contributions in the field, the remaining sections of his essay are organized around Mates' topical structure of Stoic epistemology and semantics, the doctrine of the proposition, and the theory of the five "anapodictics." Mignucci makes, however, two relevant additions which may raise suspicion among the most rigorous of logicians. In the first chapter and again in the conclusion of his essay, he analyzes carefully the alleged opposition of Aristotle's logic of classes to the Stoic logic of propositions. For Mignucci, the acceptance of the logic of propositions implies one's commitment to an ontological domain which is incompatible with the metaphysical discourse of the logic of classes. He argues that the two logics are complete and formally analogous only in the sense that from the Stoic first axiom and from the Aristotelian Barbara one can deduce all the rules which constitute their respective logics. This completeness is, however, logically dependent upon the Aristotelian and Stoic view of reality.--L. M. P.