Sweet Analytics, ‘tis thou hast ravish'd me,Bene disserere est finis logices.Is to dispute well logic's chiefest end?Affords this art no greater miracle?(Christopher Marlow, Doctor Faustus, Act 1,...

In Posterior Analytics 1.3, Aristotle advances three arguments against circular proof. The third argument relies on his discussion of circular proof in Prior Analytics 2.5. This is problematic because the two chapters seem to deal with two rather disparate conceptions of circular proof. In Posterior Analytics 1.3, Aristotle gives a purely propositional account of circular proof, whereas in Prior Analytics 2.5 he gives a more complex, syllogistic account. My aim is to show that these problems can be solved, and that (...) Aristotle’s third argument in 1.3 is successful. I argue that both chapters are concerned with the same conception of circular proof, namely the propositional one. Contrary to what is often thought, the syllogistic conception provides an adequate analysis of the internal deductive structure of the propositional one. Aristotle achieves this by employing a kind of multiple-conclusion logic. (shrink)

In the Posterior Analytics, Aristotle imposes some requirements on scientific propositions: (i) they must be susceptible of syllogistic articulation, (ii) they must have universal terms as subjects of predication and (iii) their subjects must be primary, i.e. they cannot “be said of a distinct underlying subject”. However, it is problematic to meet those three requirements together. If associated with the theory of predication in Categories, the requirement (iii) shall prescribe names or descriptions of individuals within the category of substance as (...) subjects of predication, which are primary insofar as they cannot play the logical role of predicate. Nevertheless, if the requirement (i) is satisfied, then the terms of scientific proposition would be able to perform the function of subject as well as of predicate since the rules of conversion and syllogistic moods presuppose the interchangeability among terms of predication. The requirement (ii), by its turn, withdraws all particular subjects from scientific propositions and a fortiori individual substances. We offer as a solution for the aforementioned dilemma the association of theses from the Posterior Analytics, not with the treatise Categories, but with the new ontology of predication emerged in the Metaphysics, which, by introducing the hylomorphic analysis of compound substances, admits primary and notwithstanding universal subjects of predication: the specific forms. (shrink)

ABSTRACTIn this paper, I explore the contrast drawn by Aristotle in two parallel passages of the Posterior Analytics between ‘signs’ and ‘demonstration’. I argue that while at APo. I.6 Aristotle contrasts demonstration proper with a deductively valid sign-syllogism, at APo. II.17 the contrast is rather between a demonstration proper and a deductively invalid sign-syllogism.

Aristotle's theory of demonstration, developed in the Posterior Analytics, is not restricted to determining the formal requirements for formulating probative arguments that establish properly the results of scientific investigation. To the probative aspect of demonstration it shall be added its primarily explanatory character, orientated by theses of strong ontological and metaphysical content and involving notions like substance, essence and causation. We shall analyze the relation between those two ranges of Aristotle's philosophy of science and investigate how the formal features of (...) demonstration maintain an affinity with the metaphysical background to which scientific activity is conditioned. (shrink)

My dissertation is devoted to an examination of the resolution of fallacy in Plato's Euthydemus. It is a familiar claim that the Euthydemus champions Socratic argumentation over sophistical or eristic reasoning. No consensus however exists regarding either the nature or philosophical significance of Socrates’ treatment of the fallacies he confronts. I argue that a careful reading of the dialogue reveals that the Socratic response to fallacious reasoning is conducted at two different levels of philosophical sophistication. Socrates relies upon the resources (...) of Socratic dialectic in responding to sophisms due to ignorance of refutation. Insofar as Socratic dialectic is grounded in a grasp of the nature of genuine refutation, the objections it raises to false refutation are fully explanatory. On the other hand, Socrates employs various self-refutation arguments against theses which depend on false assumptions regarding the nature of predication---for example, the thesis that false speaking is impossible. It is however characteristic of Socratic dialectic that this method of examination cannot explain why the sophists’ theses are false. The Socratic response to fallacy in these cases is non-explanatory in this sense. On the other hand, these limitations on Socratic expertise are overcome in other passages in the dialogue which are replete with clues to the reader that point to a genuine explanation and resolution of the sophists’ arguments for their various theses. In particular, the reader is invited at every turn to modify, clarify, or reject various assumptions made by the brothers regarding the nature of predication. Here Plato implicitly relies on the results of what I call higher dialectic. This theory, which receives explicit formulation in the Sophist, is conceptually rich enough to expose and dispose of the various false assumptions upon which the sophists’ theses rest. I conclude that the Euthydemus is concerned to identify Socratic dialectic as only a part of philosophy, and to locate and strictly delimit its epistemological status as lying above eristic and the rhetorical arts, but below that of dialectic as that is conceived in the Republic and even later dialogues---thus anticipating the Sophist’s conception of Socrates as the practitioner of a ‘noble sophistry’, and the elenchus as a propaedeutic to philosophy, which purges the soul of false beliefs. (shrink)