Medieval Logic

Roger Swyneshed, in his treatise on insolubles (logical paradoxes), dating from the early 1330s, drew three notorious corollaries of his solution. The third states that there is a contradictory pair of propositions both of which are false. This appears to contradict the Rule of Contradictory Pairs, which requires that in every such pair, one must be true and the other false. Looking back at Aristotle's treatise De Interpretatione, we find that Aristotle himself, immediately after defining the notion of a contradictory (...) pair, gave counterexamples to the rule. Thus Swyneshed's solution to the logical paradoxes is not contrary to Aristotle's teaching, as many of Swyneshed's contemporaries claimed. Dialetheism, the contemporary claim that some propositions are both true and false, is wedded to the Rule, and in consequence divorces denial from the assertion of the contradictory negation. (shrink)

It is universally acknowledged that, for St. Thomas, there is a distinction between human persons or supposits and their natures or essences. But it is usually thought that there is no parallel distinction between the angelic person or supposit and its nature. Yet, as this paper argues, Aquinas consistently puts forward just such a distinction. This paper surveys Aquinas’s arguments for the unique identity of God with his essence and the corresponding distinctions between created persons and their essences, showing in (...) the process how the distinction found in angels differs from that found in material substances. It is important to recognize the distinction between supposit and nature in angels not only for its own sake as it touches on his understanding of created persons—human or angelic—but also insofar as it sheds light on Aquinas’s understanding of divine simplicity and of other act-potency compositions in creatures. (shrink)

I propose an approach to liar and Curry paradoxes inspired by the work of Roger Swyneshed in his treatise on insolubles (1330-1335). The keystone of the account is the idea that liar sentences and their ilk are false (and only false) and that the so-called ''capture'' direction of the T-schema should be restricted. The proposed account retains what I take to be the attractive features of Swyneshed's approach without leading to some worrying consequences Swyneshed accepts. The approach and the resulting (...) logic (called ''Swynish Logic'') are non-classical, but are consistent and compatible with many elements of the classical picture including modus ponens, modus tollens, and double-negation elimination and introduction. It is also compatible with bivalence and contravalence. My approach to these paradoxes is also immune to an important kind of revenge challenge that plagues some of its rivals. (shrink)

If an argument is valid, it is impossible for its premises to be true, and its conclusion false. But how should we understand these notions of truth and impossibility? Here, I present the answers given by John Buridan (ca. 1300-60), showing (i) how he understands truth in his anti-realist metaphysics, and (ii) how he understands modality in connection with causal powers. In short: if an argument exists and is valid, there does not exist a power capable of making the premises (...) true and, at the same time, making the conclusion false. (shrink)

The Formalist tradition in late-scholastic philosophy has gone unnoticed in standard historiography. This article’s overall objective is to add the Formalist tradition to what we know about Renaissance philosophy. I first show how the Formalist tradition was born out of some innovative considerations of hierarchies of distinctions in the wake of the Franciscan John Duns Scotus’s teaching on the formal distinction in the beginning of the fourteenth century (especially Francis of Meyronnes’s model of four distinctions and Petrus Thomae’s more elaborate (...) doctrine of seven kinds of distinctions). I then trace how Formalist literature developed from being an exclusively Franciscan affair to becoming a much more widespread phenomenon. Thus, from the decades up to 1500 and onwards, authors from various late-scholastic schools (Thomism, Lullism, Averroism, and others) produced Formalist literature, i.e., treatises on multiple kinds of distinctions. I highlight particularly how one Franciscan philosopher of the sixteenth century, Jean Du Douet, proposed to view the Formalist preoccupation with distinctions as a discipline in its own right, a proper scientia formalitatum. I finally argue that while this proposal met with dismissive reactions, Du Douet’s idea does in fact reflect the role Formalism played in the scholastic curriculum in the late sixteenth century, at least in Franciscan milieus. (shrink)

This essay addresses two preeminent figures in the study of the doctrine of signs. The first is John Poinsot (9 July 1589 – 15 June 1644). The second is John Deely (26 April 1942 – 7 January 2017). In many ways, the academic lives of these two noteworthy scholars are forever intertwined because of their scholarly contributions to the doctrine of signs. On the one hand, John Poinsot authored a very significant, but long neglected document, Tractatus de Signis, which articulated (...) a comprehensive analysis of the doctrine of signs. Moreover, his work constituted a significant link between Christian theology, philosophical Latinity, and modern and postmodern scholarly matters. In this regard, John Deely resurrected Poinsot’s neglected text by providing a detailed, annotated translation of the original Latin version together with a meticulous account of its implications for the doctrine of signs. As a result, we now possess the “missing link” between these philosophical and intellectual epochs. Deely further addressed the role that Charles Sanders Peirce played in the study of the doctrine of signs. Finally, there is a discussion of the “International Open Seminar on Semiotics: A Tribute to John Deely on the Fifth Anniversary of His Passing” available at the University of Coimbra website. (shrink)

The prologue of the Sophistici elenchi is as close an Aristotelian text gets to dealing with language as a subject matter in its own right, only in reverse. Language and its features bear consideration to the extent that they account for some major predicaments discursive reasoning is prone to, both as a separate and as a common endeavour. That being said, the linguistic pitfalls that trick us into thinking that whatever is the case for words and word-compounds is also the (...) case for the things and facts linguistic items stand for reveal as much about good linguistic habits and sound argumentation as they themselves are revealed by the principles and rules our argumentation goes by. In this connection, Aristotle resorted to a curious (or not so curious) analogy between words and counters which played a major role in explaining why language is such a powerful source of illusion and deception. As it happens, Aristotle accounting analogy is a case in point for showcasing the level of sophistication medieval Latin literature on fallacies achieved as early as the first half of the twelfth century. As a matter of fact, Western commentators managed to build compelling cases both in favour of and against the understanding that was to become and still is the standard story – which, of course, speaks volumes about their exegetical proficiency and technical expertise. On the one hand, trusting implicitly Boethius’ translation and well aware of his views on disputational hazards as opposed to computational reliability, they usually understood Aristotle’s comparison as if it was an analogy in name only. On the other hand, despite Boethius’ translation put them at a considerable disadvantage, Latin commentators were able to construe Aristotle’s analogy as bringing together two sets of symbolic variables (words and counters) that are neither entirely free nor entirely bound – which expose them to subtle but critical shifts in value and meaning. (shrink)

This paper explores an idea of Stoic descent that is largely neglected nowadays, the idea that an argument is valid when the conditional formed by the conjunction of its premises as antecedent and its conclusion as consequent is true. As it will be argued, once some basic features of our naıve understanding of validity are properly spelled out, and a suitable account of conditionals is adopted, the equivalence between valid arguments and true conditionals makes perfect sense. The account of validity (...) outlined here, which displays one coherent way to articulate the Stoic intuition, accords with standard formal treatments of deductive validity and encompasses an independently grounded characterization of inductive validity. (shrink)

Deely's chief orientation, in his Medieval Philosophy field days, was to frame the field's thematic concern in light of the gestation of semiotic awareness. He argued that semiotic awareness was expressed fully for the first time in history by Poinsot, although he said that the process of gestation only resulted in a community-binding Way after the arrival of the Semiotics of Peirce. Between Poinsot and Peirce, a period of darkness preceded a full dawn. In this paper, we provide an introductory (...) picture of Deely's understanding of Medieval Philosophy and strive to convey a preview of the angle adopted by the semiotician. (shrink)

This paper has been presented at the Charles S. Peirce Society’s 10-Minute Thesis Initiative: “His Glassy Essence in Relation” on February 18, 2023, where papers were also presented by Professor Doctor António Manuel Martins and Professor Doctor Mohammad Shafiei, respectively affiliated to the Coimbra Institute for Philosophical Studies and Shahid Beheshti University. -/- The edition “His Glassy Essence in Relation” of the Charles S. Peirce Society’s 10-Minute Thesis Initiative has been jointly organized by Aaron Wilson, António Manuel Martins, Mohammad Shafiei, (...) Richard Kenneth Atkins, and Robert Junqueira. The second, the third, and the last all presented papers, while the first one presided over the proceedings. The second to last was responsible for creating the bridge that enabled it all to take place. -/- The 10-Minute Thesis Initiative is an ongoing cycle of the Charles S. Peirce Society. This edition in particular benefited from the collaboration of the Coimbra Institute for Philosophical Studies and the Shahid Beheshti University. This text has been published in PhicaRe (Philosophy & Care Repository) of the Institute for Philosophical Studies of the Faculty of Arts and Humanities of the University of Coimbra. -/- How to cite (Chicago Manual of Style 17th Edition): Junqueira, Robert. “Peirce and the Coimbra Jesuit Course: A Bond Far More Pervasive Than Commonly Believed.” In PhicaRe (Philosophy & Care Repository), 1–12. Coimbra: Institute for Philosophical Studies, 2023. DOI: 10.5281/zenodo.7607786. (shrink)

Charles S. Peirce (†1914) is often referred to as the founder of contemporary semiotics. Peirce provided the community of inquiry with a very convincing explanation of what a sign is. Peirce's definition of the sign bears a striking resemblance to that proposed in the 1606 volume of the CJC, the Coimbra Jesuit Course, authored by Sebastião do Couto (†1639). The community of inquiry holds the belief that Peirce drew from the writings of Couto to arrive at his triadic conception of (...) the sign. Could it be that the effect of the CJC on Peirce is restricted to the definition of the sign? What can anyone say so far on the Peirce-CJC relation? Our ultimate purpose here is to provide a contribution to settling such doubts. (shrink)

In the first of the Insolubles in Chapter 8 of his Sophismata, Buridan contends that the inference Omnis propositio est affirmativa; ergo, nulla propositio est negativa (PS) is valid, even though it appeals to the self-reference in the conclusion to show that what we (following Read 2001) call the classical conception of validity (CCV) fails. This requires that we accept that there are good inferences in which a false conclusion follows from true premises. Partially following Hughes’ proposal (1982), we argue (...) that the First Sophism (PS) involves three different notions of validity. Two of them correspond to the ones described by Hughes (1982, 80–86), who calls them Theory A and Theory B. The third one—that will we call Theory C—is not mentioned by Hughes; instead, it is suggested by Buridan himself in the first three arguments in favor of the validity of PS. We show that: a) from what Buridan says in his Theory C it follows that PS is a formal and material consequence, and hence, a valid one. Then we show that: b) the rejection of CCV and the acceptance of Nulla propositio est negativa (NPN) as a (formal) consequence of Omnis propositio est affirmativa (OPA) leads to a paradox that bears similarities with the one put forward by Pseudo Scotus—which has been studied by Read (2001) and is related to Curry’s paradox. However, there are enough differences to merit considering this paradox separately, especially in relation to the so-called validity paradoxes. Interestingly, our work suggests that Buridan was aware of these problems, which explains why he introduced a new criterion for validity, one that is not based on truth-preservation but on what Spade (1988) calls firmness, and Klima (2016) correspondence. (shrink)

Aristotle divided arguments that persuade into the rhetorical (which happen to persuade), the dialectical (which are strong so ought to persuade to some degree) and the demonstrative (which must persuade if rightly understood). Dialectical arguments were long neglected, partly because Aristotle did not write a book about them. But in the sixteenth and seventeenth century late scholastic authors such as Medina, Cano and Soto developed a sound theory of probable arguments, those that have logical and not merely psychological force but (...) fall short of demonstration. Informed by late medieval treatments of the law of evidence and problems in moral theology and aleatory contracts, they considered the reasons that could render legal, moral, theological, commercial and historical arguments strong though not demonstrative. At the same time, demonstrative arguments became better understood as Galileo and other figures of the Scientific Revolution used mathematical proof in arguments in physics. Galileo moved both dialectical and demonstrative arguments into mathematical territory. (shrink)

The phrase _secundum quid et simpliciter_ is the Latin expression translating and labelling the sophism described by Aristotle as connected with the use of some particular expression “absolutely or in a certain respect and not in its proper sense.” This paper presents an overview of the analysis of this fallacy in the history of dialectics, reconstructing the different explanations provided in the Aristotelian texts, the Latin and medieval dialectical tradition, and the modern logical approaches. The _secundum quid_ emerges as a (...) strategy that is based on the pragmatic dimension of arguments, and in particular the complex passage from an utterance (what is said) to its logical form (a proposition in an argument). The medieval and modern logical theories attempted to explain from different philosophical perspectives how the pragmatically enriched semantic representation can be achieved, justified, and most importantly manipulated. The different analyses of this fallacy bring to light various dimensions of the pragmatics of arguments, and the complex interdependence between context, meaning, and inferences. (shrink)

Multiple generality has long been known to cause confusion. For example, “Everyone has a donkey that is running” has two readings: either (i) there is a donkey, owned by everyone, and it is running; or (ii) everyone owns some donkey or other, and all such donkeys run. Medieval logicians were acutely aware of such ambiguities, and the logical problems they pose, and sought to sort them out. One of the most ambitious undertakings in this regard is a pair of massive (...) diagrams (magnae figurae) which map out the logical interrelations of two sets of doubly-general forms. These appear in a fourteenth-century MS of John Buridan’s Summulae de Propositionibus. In this paper, I present these diagrams, and determine the truth conditions of their different forms. To that end, I have developed a bespoke system of diagrams to display their truth conditions. As we will see, such forms present significant difficulties for an all-encompassing account of the role form plays in logic. Accordingly, they can tell us important things about the role logical form plays in Buridan’s account of logical foundations. (shrink)

Johannes Steuchius’ disputatio uses Arabic logic to present an historical account of the development of philosophical thought in Arabia before and after the emergence of Islam. Steuchius first proposes that philosophy drew its origins from the East. His evidence for this claim is that many of the Greek philosophers, considered the forefathers of European philosophy, began cultivating their philosophical thinking as a result of exposure to ancient Eastern philosophy. After the introduction of Greek philosophy, it is agreed that dialectic was (...) among the first of the arts the Arabs practiced. (shrink)

This paper attempts to bring the traditional theodicy on the question of evil and the Divine Providence, to its logical conclusion, in such a way that a believer is challenged to totally accept the implication of his or her faith in God. To have faith is to completely surrender to Divine Providence. It is to completely surrender ones free will to the rational conclusions or consequences of faith in the Divine Providence. Hence, this paper is for those who are perplexed (...) due to the Pandemic. Especially for Christians whose faith in God is perplexed because of their existential experience of the COVID 19 pandemic as evil. The existential reality of dread and misery caused by this pandemic is globally and more subjectively experienced due to the digitalization of this age. This shows how disastrously powerful the digitalization of our world can be in the proliferation of dread, misery and hopelessness. (shrink)

What makes a valid argument valid? Generally speaking, in a valid argument, if the premisses are true, then the conclusion must necessarily also be true. But on its own, this doesn’t tell us all that much. What is truth? And what is necessity? In what follows, I consider answers to these questions proposed by the fourteenth century logician John Buridan († ca. 1358). My central claim is that Buridan’s logic is downstream from his metaphysics. Accordingly, I treat his metaphysical discussions (...) as the key to his logic. As has been often noted, Buridan’s metaphysics are radically anti-realist about universals, though I think the depth and scope of his anti-realism has at times been papered over. Buridan constructs his logic on an amazingly spartan ontology, and this accomplishment is overdue for reconsideration. To the foregoing questions: truth is a feature of propositions, and of propositions only—not of proposition-like states of affairs, or anything like that. It is a function of the reference or supposition (suppositio) of their terms, which depends on predication in a propositional context. And necessary truth is grounded in causation: a predication is necessary if it cannot be falsified by any power, natural or supernatural, without ii annihilating what its terms stand for. “Socrates is a human”, for instance, can only be falsified by annihilating Socrates, and so it is a necessary truth. -/- These considerations provide an ample theoretical basis for a thorough examination of Buridan’s modal logic. This is what the thesis culminates with. In the final chapter, I set forth some novel and surprising findings, chief of which is this: Buridan’s modal syntax and semantics are nothing like Kripke’s—and indeed are incompatible with them. This has significant implications not only for modal logic and metaphysics, but for how we think about medieval logic and philosophy more generally. -/- Throughout the thesis, I advocate a methodology of emphasising the differences, rather than the similarities, between past and present thought. Buridan is wildly unlike what we’re used to, and we should let him speak for himself. (shrink)

L'elaborato intende analizzare lo statuto ontologico dell'ente a partire dal binomio esse e id quod est, sviluppato da Tommaso nel commento al De Hebdomadibus di Boezio, specificando i concetti di partecipazione come causalità forte, e di essere come massimo estensivo e più generale.

Marsilius of Inghen’s account of imaginable impossibilities became paradigmatic in logic, semantics, and metaphysics throughout the later Middle Ages and well into the early modern period. The present study focuses on imaginable impossibilities in 14th-century logic, underlining the relevance of Marsilius of Inghen’s innovative approach through a comparison with the semantic accounts proposed by other mid-14th-century Parisian nominalists, namely John Buridan and Albert of Saxony. In particular, this paper tracks the specific issue of the admissibility of absolute impossibilities – such (...) as the chimera – within Marsilius of Inghen’s semantic analysis, proving that there is a sense in which the chimera is indeed treatable. The present study does so by analysing the issues involved in impossibilities on the levels of signification, supposition, and extended reference. In doing so it provides a clearer picture of the problems involved, where they emerge and why, as well as of the significance and range of Marsilius of Inghen’s approach. (shrink)

This paper seeks to articulate the relationship between medieval logic and theology. Reviewing modern scholarship, we find that the purpose of medieval logic, when it is even inquired about, has proven difficult to articulate without reference to theology. This prompts reflection on the metaphors of logic as a “tool” and a “game”: a tool is not merely instrumental, insofar as it can have its own intrinsic goods and can shape and be shaped by that which it serves; likewise a game, (...) with its own intrinsic goods, may yet contribute to extrinsic goods as well. After reviewing some distinctive ways in which theology shaped developments of medieval logic, this paper summarizes key examples from the work of Thomas Aquinas where medieval logic shaped the articulation of, and is therefore crucial to a proper understanding of, theological arguments and claims. The conclusion suggests implications for future philosophical and theological work. (shrink)

North-American philosophy was bolstered with the doctrines of the Jesuits. The penetration of the Coimbra Jesuits in the United States of America can be examined through the paradigmatic case of Charles Sanders Peirce. The extent to which Peirce was affected by the Coimbra Jesuits has not yet been researched. However, it is known that Peirce was acquainted with the Coimbra Jesuit Aristotelian Course.

In this essay, I consider some logical treatises and commentaries from the first decades of the 12th century (many of which are still unedited) which contain a discussion on modalities and modal logic. After presenting a short catalogue of these sources and a description of their common features, I shall focus on some definitions of the modal term “necessarium” which are provided in them. As we will see, Abelard and logicians of his time advanced three different characterizations of this term: (...) necessity was either defined in terms of unavoidability (ineuitabilitas), or in terms of immutability and omnitemporality (impermutabilitas, sempiternitas), or again in terms of absolute necessity as opposed to conditioned one (necessitas absoluta vs. determinata). I argue that the temporal understanding of necessity in terms of omnitemporality, inherited from ancient sources and extensively used by Abelard and others in the first years of the twelfth-century, started to disappear in texts datable from around the 1120, perhaps due to several difficulties that were related to this definition when applied in logical contexts. I also discuss how the notion of necessitas determinata was used by Abelard’s contemporaries to qualify the modal status of present and past events, which were generally believed to be necessary only in a “weak” and harmless sense that did not prevent them from being contingent. -/- . (shrink)

A sound historiographical account of the role of logic in the development of medieval philosophical and theological reflection requires a thorough examination of its historical roots and its theoretical implications. An apparent historiographical bias, due to the idea that only the development of contemporary formal logic enables a proper reconstruction of the whole history of logic, can be exposed by taking into account the case of the medieval discussions on the topics, starting from their late-antiquity legacy. An attentive inspection of (...) the successive stages of the gradual formalisation process of medieval topical logic brings to the fore significant theoretical aspects in the philosophy of logic, all too often left aside in common contemporary discussions. In particular, the distinction between topical maxims and topical differences, or principles according to and principles from which an inference is drawn, highlights the specific nature of a major part of medieval logic, that deals with meta-logical issues by means of higher-order logical resources. It is precisely this special character of medieval logic that proves to be of the highest significance in the discussion of the most subtle theological—and just as well philosophical—questions that engaged medieval authors, thus testifying to the essential role of logic in the overall development of medieval thought. (shrink)

This paper makes two main arguments. First, that to understand analogy in St. Thomas Aquinas, one must distinguish two logically distinct concepts he inherited from Aristotle: one a kind of likeness between things, the other a kind of relation between linguistic functions. Second, that analogy (in both of these senses) plays a relatively small role in Aquinas's treatment of divine naming, compared to the realist semantic framework in which questions about divine naming are formulated and resolved, and on which the (...) coherence of the doctrine of divine simplicity—which is what gives rise to the questions of divine naming in the first place—depends. (shrink)

We reconstruct as much as we can the part of al-Fārābī's treatment of modal logic that is missing from the surviving pages of his Long Commentary on the Prior Analytics. We use as a basis the quotations from this work in Ibn Sīnā, Ibn Rushd and Maimonides, together with relevant material from al-Fārābī's other writings. We present a case that al-Fārābī's treatment of the dictum de omni had a decisive effect on the development and presentation of Ibn Sīnā's modal logic. (...) We give further evidence that the Harmonisation of the Opinions of Plato and Aristotle was not written by al-Fārābī. (shrink)

In the Categories Aristotle defines the analytic relationship of ‘being said’ in terms of ordinary categorical predication. The interpreters found themselves facing different interpretative problems, among others the meaning of categorial terms, how to understand the predication relation or the predication relations, what properties these relations have, etc. In the present brief contribution I consider two questions concerning transitivity and the metaphysical meaning of Aristotelian definitions.

Till just few decades ago, scholars used to use the label ‘Ockhamism’ to mark a turning-point in the history of mediaeval philosophy, above all in the history of natural philosophy. That turning-point was exemplified by the once so-called ‘Buridanian school’, today known simply as ‘Parisian school of natural philosophy’, whose leading representative was for sure John Buridan. But looking carefully at some crucial points of the Picard master’s idea of ‘nature’, concerning specifically the relationship between God and secondary causes on (...) one side, and the role played by free will, both the divine and the human one, on the other side, one will find out that Buridan’s ‘Ockhamism’ is at least questionable: Scotus’ modal logic is the conceptual framework, within which he redetermines the boundaries of natural laws, but the ‘pure ockhamist’ idea of the prevalence of the will on the intellect in God’s nature is the source of an image of the world in which voluntary behaviours and natural laws are intertwined. Therefore, Buridan’s natural philosophy results as a peculiar synthesis of two of the main divergent lines of thinking of late mediaeval philosophy. (shrink)

Aquinas has been labelled “the greatest advocate of dispositional modality”, by one contemporary power theorist. This paper’s goal is to critically analyse this claim. Before doing so, however, it first explicates some components of Aquinas’s ontology of powers, putting him in dialogue with contemporary discussions. Next it explicates the two competing views of the modality of powers, dispositional modality and conditional necessity, and proceeds to examine the textual basis as to which of the two Aquinas held. Ultimately the paper finds (...) evidence in favour of the latter. The paper then concludes with a suggestion as to how Aquinas would explain examples given by those who advocate the dispositional modality position. In answer to the title, therefore, the paper argues that thinking of Aquinas as the greatest advocate of dispositional modality is a fiction, and that this award belongs to someone else. (shrink)

Ockham holds what nowadays would be characterized as a “higher-order perception” theory of consciousness. Among the most common objections to such a theory is the charge that it gives rise to an infinite regress in higher-order states. In this paper, I examine Ockham’s various responses to the regress problem, focusing in particular on his attempts to restrict the scope of consciousness so as to avoid it. In his earlier writings, Ockham holds that we are conscious only of those states to (...) which we explicitly attend. This view, I go on to argue, is inadequate on both phenomenological and philosophical grounds. Interestingly, and perhaps for this very reason, in later works, Ockham goes on to develop an alternative explanation for his account of the limited scope of consciousness. (shrink)

This paper is the written version of my contribution to the International Conference «30 years Logica modernorum» held in Amsterdam in November 1997 in honor of the late prof. Lambertus M. de Rijk. Research on Oresme’s modi rerum theory was in the first stage, while now we can read the critical edition of Oresme’s Physics commentary, where modi are introduced and widely used. In this paper I shall consider Oresme’s polemical use of modi rerum, trying to set it in the (...) larger context of both his ontology and his epistemology. Oresme’s challenge to either a realist or terminist ontology by means of modi rerum conceals probably an attack to William of Ockham; Oresme refers explicitly to Ockham concerning exclusive propositions, but I think that on many other occasions the polemical target of Oresme’s criticism can be reasonably identified in William of Ockham or in some unnamed followers of the Venerabilis Inceptor. Some hints are reserved also to the possible sources of Oresme’s modi rerum. (shrink)

Les commentateurs latins ont rencontré pour la première fois le « Troisième homme » d’Aristote dans le chapitre vingt-deux des Sophistici elenchi. Cette rencontre illustre bien à la fois leur respect de la lettre et la radicalité de certaines de leurs innovations. Influencée par la traduction de Boèce, leur exégèse de l’argument a tenu compte de l’ensemble des indications du texte tout en lui conférant une tournure inédite.

The common view that Aquinas changed his mind about analogy (before and after De Veritate 2.11) is unwarranted. Dialectical context, and clarifications about the logic of analogy and the implications of proportionality, reveal consistency in Aquinas's teaching on the analogy of divine names.

Rondo Keele makes a foray into what he calls 'applied logic', investigating a complex argument strategy employed against Ockham by his greatest contemporary opponent, Walter Chatton. Chatton conceives a two-part strategy which attempts to force a kind of iteration of conceptual analysis, together with an infinite explanatory regress, in order to establish that one particular philosophical analysis is ultimately dependent on another. Chatton uses this strategy against Ockham in order to show that the latter's reductionist metaphysics depends ultimately upon a (...) deeper level of realist assumptions that he can neither evade nor explain away. Keele then shows how, earlier in his career, Chatton found himself on the receiving end of this same strategy, defending his own highly original solution to the problem of future contingents from the very iteration-regress attack he would subsequently use on Ockham. Keele concludes with an examination of Chatton's attempts to avoid the consequences of his own strategy, and draws some connections between this argument strategy and modal collapse in modern logics. (shrink)

The focus of the paper is a sophism based on the proposition ‘This is Socrates’ found in a short treatise on obligational casus attributed to William Heytesbury. First, the background to the puzzle in Walter Burley’s traditional account of obligations (the responsio antiqua), and the objections and revisions made by Richard Kilvington and Roger Swyneshed, are presented. All six types of obligations described by Burley are outlined, including sit verum, the type used in the sophism. Kilvington and Swyneshed disliked the (...) dynamic nature of the responsio antiqua, and Kilvington proposed a revision to the rules for irrelevant propositions. This allowed him to use a form of reasoning, the “disputational meta-argument”, which is incompatible with Burley’s rules. Heytesbury explicitly rejected Kilvington’s revision and the associated meta-argument. Swyneshed also revised Burley’s account of obligations, formulating the so-called responsio nova, characterised by the apparently surprising thesis that a conjunction can be denied both of whose conjuncts are granted. On closer inspection, however, his account is found to be less radical than first appears. (shrink)

Latin commentators came across the « Third Man » in Aristotle’s Sophistici elenchi. The way they dealt with the argument is a fair illustration of how they were both faithful to the text and innovative in their understanding of its most challenging issues. Besides providing a detailed survey of all manuscript sources, the introductory essay shows that Latin interpretation originates from a mistake in Boethius’ translation which radically transformed the argument. The edition makes available for the first time a considerable (...) amount of new documentary evidence which made it possible to solve the riddle of the Latin « Third Man ». (shrink)

This paper offers an analysis of a hitherto neglected text on insoluble propositions dating from the late XiVth century and puts it into perspective within the context of the contemporary debate concerning semantic paradoxes. The author of the text is the italian logician Peter of Mantua (d. 1399/1400). The treatise is relevant both from a theoretical and from a historical standpoint. By appealing to a distinction between two senses in which propositions are said to be true, it offers an unusual (...) solution to the paradox, but in a traditional spirit that contrasts a number of trends prevailing in the XiVth century. It also counts as a remarkable piece of evidence for the reconstruction of the reception of English logic in italy, as it is inspired by the views of John Wyclif. Three approaches addressing the Liar paradox (Albert of Saxony, William Heytesbury and a version of strong restrictionism) are first criticised by Peter of Mantua, before he presents his own alternative solution. The latter seems to have a prima facie intuitive justification, but is in fact acceptable only on a very restricted understanding, since its generalisation is subject to the so-called revenge problem. (shrink)

We describe the earliest occurrences of the Liar Paradox in the Arabic tradition. e early Mutakallimūn claim the Liar Sentence is both true and false; they also associate the Liar with problems concerning plural subjects, which is somewhat puzzling. Abharī (1200-1265) ascribes an unsatisfiable truth condition to the Liar Sentence—as he puts it, its being true is the conjunction of its being true and false—and so concludes that the sentence is not true. Tūsī (1201-1274) argues that self-referential sentences, like the (...) Liar, are not truth-apt, and defends this claim by appealing to a correspondence theory of truth. Translations of the texts are provided as an appendix. (shrink)

Review of the English translation of Bernard Montagnes' influential 1963 monograph on analogy in Aquinas. (Pre-publication copy -- please cite final version.).

What role does Scotus‘s understanding of univocity play in Cajetan‘s development of a theory of analogy? In this paper I examine three relevant texts from Cajetan (question 3 of his commentary on Aquinas‘s De Ente et Essentia, his treatise De Nominum Analogia, and his commentary on question 13, article 5 of Aquinas‘s Summa Theologiae) in which Cajetan articulates his understanding of analogy at least in part through dialectical engagement with Scotus‘s arguments about univocity.

This paper addresses the question of whether there is a proper analogy of being according to both meaning and being. I disagree with Ralph McInerny’s understanding of how things are named through concepts and argue that McInerny’s account does not allow for the thing represented by the name to be known in itself. In his understanding of analogy, only ideas of things may be known. This results in a wholesale inability to name things at all and thereby forces McInerny to (...) relegate naming to a purely logical concern. As a consequence, for McInerny, since naming becomes only a logical concern, being itself cannot be known as analogous according to being and meaning since naming only involves the naming of ideas, not of things. (shrink)

The influence of Cajetan’s De Nominum Analogia is due largely to its first three chapters, which introduce Cajetan’s three modes of analogy: analogy of inequality, analogy of attribution, and analogy of proportionality. Interpreters typically ignore the final eight chapters, which describe further features of analogy of proportionality. This article explains this neglect as a symptom of a failure to appreciate Cajetan’s particular semantic concerns, taken independently from the question of systematizing the thought of Aquinas. After an exegesis of the neglected (...) chapters, which describe the semantics of analogy through the three levels of cognition (simple apprehension, composition and division, and discursive reasoning), the article concludes with observations about the relationship between Cajetan and Aquinas and the philosophical and historical signifi cance of Cajetan’s approach to the semantics of analogy. (shrink)

Cajetan's treatment of analogy in De Nominum Analogia is well known as the most influential and sophisticated theory of a central issue in Thomistic philosophy. The late twentieth century saw that theory subject to a family of criticisms. If the critics are correct, Cajetan's analogy theory is also significant historically for exposing weaknesses latent in medieval semantic assumptions. According to the critics, the Aristotelian assumptions that words signify by means of discrete “concepts,” and that the meaning of propositions depends on (...) the significations of its component terms, cannot do justice to the complexity, variety, and flexibility of actual human discourse; in De Nominum Analogia they see the elegant structure of classical semantics collapsing under the pressure of analogical language. In this article, I examine these criticisms of Cajetan's analogy theory, and argue that, in light of both Cajetan's semantic principles and his hermeneutic practice, they fall short. The conclusion not only implies a defense of Cajetan's project, but clarifies the general philosophical alternatives available within the traditional Aristotelian semantic framework. (shrink)