George Boger

Studies of Aristotle’s syllogistic system, since Corcoran’s deductionist interpretation supplanted Łukasiewicz’ axiomaticist interpretation, misrepresent Aristotle’s logic in two important respects. Following Corcoran, they take indirect deduction to occur only once in a deduction discourse; they then obviate the system having a reductio rule. Second, they represent reduction as a deductive process for deriving ‘imperfect’ syllogisms from ‘perfect’ syllogisms to impose an axiomatic interpretation on the logic. Denying that Aristotle's logic admits of a reductio rule results from this misrepresentation of reduction. This discussion shows that the defects imputed to Aristotle's logic, and systems devised to resolve them, result from misunderstanding reduction, which itself results from misapprehending Prior Analytics expressly to identify in a metadiscourse deduction rules and not deductions per se.

Not until the early 1920’s was it possible to distinguish Aristotelian or traditional logic from Aristotle’s own ancient logic. We can now recognize many aspects of his logical investigations that are themselves modern, in the sense that modern logicians are making discoveries that Aristotle had already made or had anticipated. Here we gather five salient features of Aristotle’s logical investigations that reveal a striking philosophical modernity: 1) Aristotle took logic to be that part of epistemology used to establish knowledge of logical consequence; 2) Prior Analytics is a metalogical treatise on the syllogistic deduction system; 3) Aristotle recognized the epistemic efficacy of certain elemental argument patterns, and he explicitly formulated them as rules of natural deduction in corresponding sentences; 4) Prior Analytics is a proof-theoretic treatise in which Aristotle describes a natural deduction system and demonstrates certain of the logical relationships among syllogistic deduction rules ; and finally, 5) Aristotle worked with a notion of substitution sufficient for distinguishing logical syntax and semantics. In this connection he also distinguished validity from deducibility sufficiently well to note the completeness of his logic.

Contemporary logicians continue to address problems associated with the existential import of categorical propositions. One notable problem concerns invalid instances of subalternation in the case of a universal proposition with an empty subject term. To remedy problems, logicians restrict first-order predicate logics to exclude such terms. Examining the historical origins of contemporary discussions reveals that logicians continue to make various category mistakes. We now believe that no proposition per se has existential import as commonly understood and thus it is unnecessary to restrict first-order predicate logics to non-empty classes. After introducing the problem, we trace some nineteenth century treatments of the issue to locate a source of misconstruing propositional import in misconceptions of ‘implies’ and ‘affirms’ and name the process/product fallacy, along with the translation of categorical sentences using quantifiers and accommodating an empty class. Next we treat some metalogical matters to orient our discussion by which we provide a more precise nomenclature about ‘sentence’ and ‘proposition’ to correct previous misconceptions; here we uncover a common category mistake in respect of a proposition’s efficacy. The semantic distinction between agent and force is helpful in this connection. We conclude by showing that logicians have reinserted existence as a predicate, a position previously excised by Kant, and that the Frege-Russell ambiguity thesis applies only to relationships within a categorical sentence between grammatical predicate and subject.

Infusing logic with new rhetoric, dialogical pragmatics, and emphasizing argument context revolutionized the practice of logic. Critiquing oppressive practices and promoting justice, argumentationists empower participants to mediate their own argumentative situations. Against relativism to rescue the normative utility of good argument, argumentationists invoke the universal audience. Still, context-concerns eclipse its independence or resurrect rationalist absolutism. This vacillation imposes an external mediation that subverts establishing theoretical ground for promoting an empowering culture of justice.

The obstacle to more objective knowledge of early Pythagoreanism is the ideological conflict over the proper mission of historiography. Not only the confusing evidence, but also the different investigative procedures and theories of history employed, make solving the Pythagorean problem difficult. I analyze the historiographic methodologies of some modern historians of Pythagoreanism in respect to the kinds of historical explanation they provide. Immediately ideological controversy arises between idealist and materialist historians. ;My critical evaluation proceeds from two theses. The content of ideas reflects their social referents. Consequently, one must identify the class interests of early Pythagoreans. Writing history is a contemporary undertaking by which historians reflect their own social interests. Therefore, historiographic methodology continually must be objectified to overcome the subjectivism of historical relativism. ;I review the reconstructions of six historians. John Burnet, an empiricist, held that the Greeks entirely broke from their religious past to develop philosophy. F. M. Cornford, a Durkheimian, used anthropology to reveal philosophy's totemic content. J. E. Raven is a philologist; he maintaned that ancient philosophy was the Eleatic-Pythagorean debate. W. K. C. Guthrie, an eclectic, held that science served Pythagorean religious interests. These idealist historians attributed the Greek achievement to absolutized temperaments or racial factors; the development of ideas is not mediated by practical necessity. George Thomson and Alban Winspear are historical materialists. They explained ancient philosophy by showing the class interests of philosophers in a mercantile economy based on slave labor. ;After introducing the Pythagorean problem, I present, by chapter, first an exposition of each historian's account of the causes of Greek philosophy and then his exposition of early Pythagoreanism. My analyses follow each section. In the first part of the final chapter I discuss each historian in the context of the ideological controversy. In the second part I present a general outline of procedure for scientific historiography

Argumentation logicians have recognized a specter of relativism to haunt their philosophy of argument. However, their attempts to dispel pernicious relativism by invoking notions of a universal audience or a community of model interlocutors have not been entirely successful. In fact, their various discussions of a universal audience invoke the context-eschewing formalism of Kant’s categorical imperative. Moreover, they embrace the Kantian method for resolving the antinomies that continually vacillates between opposing extremes – here between a transcendent universal audience and a context-embedded particular audience. This tack ironically restores the very external mediation they thought to obviate in their aim to ‘dethrone’ the absolutism and totalitarianism of formal logic with a democratic turn to audience adherence, the acceptability of premises and inferential links, and a contextual, or participant-relative, notion of cogency.

Three distinctly different interpretations of Aristotle’s notion of a sullogismos in Prior Analytics can be traced: (1) a valid or invalid premise-conclusion argument (2) a single, logically true conditional proposition and (3) a cogent argumentation or deduction. Remarkably the three interpretations hold similar notions about the logical relationships among the sullogismoi. This is most apparent in their conflating three processes that Aristotle especially distinguishes: completion (A4-6)reduction(A7) and analysis (A45). Interpretive problems result from not sufficiently recognizing Aristotle’s remarkable degree of metalogical sophistication to distinguish logical syntax from semantics and, thus, also from not grasping him to refine the deduction system of his underlying logic. While it is obvious that Aristotle most often uses ‘sullogimos’ to denote a valid argument of a certain kind, we show that at Prior Analytics A4-6, 7, 45 Aristotle specifically treats a sullogismos as an elemental argument pattern having only valid instances and that such a pattern then serves as a rule of deduction in his syllogistic logic. By extracting Aristotle’s understanding of three proof-theoretic processes, this paper provides new insight into what Aristotle thinks reasoning syllogistically is and, moreover, it resolves three problems in the most recent interpretation that takes a sullogismos to be a deduction

Aristotle studies syllogistic argumentation in Sophistical Refutations and Prior Analytics. In the latter he focuses on the formal and syntactic character of arguments and treats the sullogismoi and non-sullogismoi as argument patterns with valid or invalid instances. In the former Aristotle focuses on semantics and rhetoric to study apparent sullogismoi as object language arguments. Interpreters usually take Sophistical Refutations as considerably less mature than Prior Analytics. Our interpretation holds that the two works are more of a piece than previously believed and, indeed, that Aristotle's treatment of fallacious reasoning presupposes the results of the formal theory.

We can now recognize Aristotle's many accomplishments in logical theory, not the least of which is treating the deduction process itself as a subject matter and thus establishing the science of logic. Aristotle took logic to be that part of epistemolo gy used to establish knowledge of logical consequence. Prior Analytics is a metalogical treatise on his syllogistic system in which Aristotle modelled his deduction system to demonstrate certain logical relationships among its rules. Aristotle's n otion of substitution distinguishes logical syntax from semantics and enabled him to distinguish validity from deducibility sufficiently to note the completeness of his logic.

Humanist concerns to empower human beings and to promote justice inspired the modern argumentation movement. Turning to audience adherence and acceptability of inferential links raised a spectre of pernicious relativism that undermines concerns for justice. Invoking Perelman’s universal audi-ence as a remedy only begs the question with ‘whose universal audience?’ and frustrates fulfilling the jus-tice commitment. Turning discourse toward the common good better addresses concerns of justice and social justice.

The word pro-tasis is etymologically a near equivalent of pre-mise, pro-position, and ante-cedent—all having positional, relational connotations now totally absent in contemporary use of proposition. Taking protasis for premise, Aristotle’s statement (24a16) A protasis is a sentence affirming or denying something of something…. is not a definition of premise—intensionally: the relational feature is absent. Likewise, it is not a general definition of proposition—extensionally: it is too narrow. This paper explores recent literature on these issues.