A natural reading of Hume’s distinction between impressions and ideas is that impressions are forceful perceptions whereas ideas are faint. A problem emerges, however, when Hume countenances the possibility of faint impressions and forceful ideas. In this paper, I attempt a resolution to the problem. I argue that Hume characterizes impressions and ideas intensionally and extensionally, and sometimes uses the term in only one of the two senses. I argue that Hume intensionally defines impressions and ideas as forceful perceptions and weak perceptions, respectively, but takes these to be extensionally equivalent to original and copied perceptions, respectively. Hume recognizes that his two characterizations—the intensional and extensional—don’t perfectly match up, and that there are exceptions to the purported equivalences (the exceptions being disease, sleep, madness, and enthusiasm). Nonetheless, I argue that Hume’s willing to proceed with his definitions.
Over the last thirty years, a group of philosophers associated with the University of Pittsburgh—Robert Brandom, James Conant, John Haugeland, and John McDowell—have developed a novel reading of Kant. Their interest turns on Kant’s problem of objective purport: how can my thoughts be about the world? This paper summarizes the shared reading of Kant’s Transcendental Deduction by these four philosophers and how it solves the problem of objective purport. But I also show these philosophers radically diverge in how they view Kant’s relevance for contemporary philosophy. I highlight an important distinction between those that hold a quietist response to Kant, evident in Conant and McDowell, and those that hold a constructive response, evident in Brandom and Haugeland. The upshot is that the Pittsburgh Kantians have a distinctive approach to Kant, but also radically different responses to his problem of objective purport.
Immanuel Kant states that indirect arguments are not suitable for the purposes of transcendental philosophy. If he is correct, this affects contemporary versions of transcendental arguments which are often used as an indirect refutation of scepticism. I discuss two reasons for Kant’s rejection of indirect arguments. Firstly, Kant argues that we are prone to misapply the law of excluded middle in philosophical contexts. Secondly, Kant points out that indirect arguments lack some explanatory power. They can show that something is true but they do not provide insight into why something is true. Using mathematical proofs as examples, I show that this is because indirect arguments are non-constructive. From a Kantian point of view, transcendental arguments need to be constructive in some way. In the last part of the paper, I briefly examine a comment made by P. F. Strawson. In my view, this comment also points toward a connection between transcendental and constructive reasoning.
Kant influentially distinguished analytic from synthetic a priori propositions, and he took certain propositions in the latter category to be of immense philosophical importance. His distinction between the analytic and the synthetic has been accepted by many and attacked by others; but despite its importance, a number of discussions of it since at least W. V. Quine’s have paid insufficient attention to some of the passages in which Kant draws the distinction. This paper seeks to clarify what appear to be three distinct conceptions of the analytic (and implicitly of the synthetic) that are presented in Kant’s Critique of Pure Reason and in some other Kantian texts. The conceptions are important in themselves, and their differences are significant even if they are extensionally equivalent. The paper is also aimed at showing how the proposed understanding of these conceptions—and especially the one that has received insufficient attention from philosophers—may bear on how we should conceive the synthetic a priori, in and beyond Kant’s own writings.
According to Philoponus, the activity of drawing syllogisms is a dynamic operation. Following the classical idea that actions are specified by their objects and habitual powers by their actions, Philoponus concludes that only a dynamic power can elicit the act of syllogizing. This power is identified with discursive reasoning (dianoia). Imagination, on the contrary, is a static power, that cannot elicit that particular motion of drawing a syllogistic inference. The issue, however, is not entirely uncontroversial, because Ammonius maintains that sophistical syllogisms can only be formed by imagination, since they involve “empty concepts” as terms and only imagination can form such concepts. In this paper I will reconstruct Philoponus’ and Ammonius’ theories about the “activity” of syllogizing, and I shall explain how Philoponus can deal with sophistical syllogisms in a consistent way.
Damascius has become well-known in recent scholarship for his unique, radical use of the aporetic method, both to highlight the inherent limits of human thought and to reveal crucial tensions in Neoplatonic metaphysics. Though much attention has been paid to the subjective or skeptical aspects of Damascius’ aporiai, little has been noted of the parallels between Damascius’ aporetic strategy in the De Principiis and Aristotle’s own in Metaphysics B. This article analyzes the parallel by looking at Aristotle’s aim for aporiai in Metaphysics B.1 and closely comparing, as a case study, the De Principiis’ first aporia alongside Metaphysics B’s first aporia. Despite Damascius’ aporia dealing with different principles compared to Aristotle’s, the aporetic method for both ultimately exposes the limitations of thought and, exactly in the domain of these limitations, clarifies our concepts in relating to reality and attaining determinate understanding of principles.
The present paper investigates the question as to how and for what purposes the Middle Platonic author of the Anonymous Commentary on Plato’s Theaetetus uses Aristotelian and Stoic syllogistic in his interpretation of the Platonic text. This investigation shows that the commentator employs Aristotelian categorical syllogistic as an exegetical tool for reconstructing arguments in the Platonic text, enabling him not only to uncover doctrinal statements that are in his view hidden in the Platonic text, but also to dissociate Plato from unwelcome propositions. By contrast, the commentator uses Stoic hypothetical syllogistic as a polemical tool for constructing ad hominem arguments against the Stoics. More precisely, the author exploits the Stoic type of deductive reasoning to draw anti-Stoic conclusions from premises that are accepted by the Stoics, and in doing so, he manages not only to refute Stoic doctrines, but also to corroborate the corresponding Platonic theories.
In this paper I explore the ways in which Alexander of Aphrodisias employs and develops so-called ‘common notions’ as reliable starting points of deductive arguments. He combines contemporary developments in the Stoic and Epicurean use of common notions with Aristotelian dialectic, and axioms. This more comprehensive concept of common notions can be extracted from Alexander’s commentary on Metaphysics A 1–2. Alexander puts Aristotle’s claim that ‘all human beings by nature desire to know’ in a larger deductive framework, and adds weight to Aristotle’s use of the common understanding of the notion of ‘wisdom’. Finally I will indicate how these upgraded common notions are meant to play an important role in the general framework of metaphysics as a science.
Olympiodorus led the Platonist school of philosophy at Alexandria for several decades in the sixth century, and both Platonic and Aristotelian commentaries ascribed to him survive. During this time the school’s attitude to the teaching of Aristotelian syllogistic, originally owing something to Ammonius, changed markedly, with an early tendency to reinforce the teaching of syllogistic even in Platonist lectures giving way to a greater awareness of its limitations. The vocabulary for arguments and their construction becomes far commoner than the language of syllogistic and syllogistic figures, and also of demonstration. I discuss the value of these changes for the dating of certain works, especially where the text lectured on does not demand different emphases. The commitment to argument rather than to authority continues, but a greater emphasis eventually falls on the establishment of the premises than on formal validity.
In late antiquity, logic developed into what Ebbesen calls the LAS, the Late Ancient Standard. This paper discusses the Neoplatonic use of LAS, as informed by epistemological and metaphysical concerns. It demonstrates this through an analysis of the late ancient debate about hypothetical and categorical logic as manifest in the practice of syllogizing Platonic dialogues. After an introduction of the Middle Platonist view on Platonic syllogistic as present in Alcinous, this paper presents an overview of its application in the syllogizing practice of Proclus and others. That overview shows that the two types were considered two sides of the same coin, to be used for the appropriate occasions, and both relying on the methods of dialectic as revealing the structure of knowledge and reality. Pragmatics, dialectic, and didactic choices determine which type or combination is selected in syllogizing Plato. So even though there is no specific Neoplatonic logic, there is a specific Neoplatonic use of LAS.