Gyula Klima

This chapter provides a comprehensive survey of Buridan’s conception of logical validity in a semantically closed token-based system, as he conceives of natural languages. The chapter argues first that Buridan has very good logical, as well as merely metaphysical, reasons to conceive of natural languages as compositional systems of significative token-symbols. Next, the chapter discusses the peculiar Buridanian conception truth and validity, according to which validity must not be based on truth, and truth need not always follow upon correspondence. These results are presented as the consequences of Buridan’s pursuit of a consistently nominalist semantics for natural languages, able to handle the Liar Paradox and its kin involving reflective uses of language without the Tarskian distinction between object-language and meta-language, rejected for systematic reasons in the seventh chapter.

The sixth chapter discusses the issue of how the reconstruction of the relevant parts of Buridan’s logic and medieval logic in general, using restricted variables, validates the attribution of existential import to affirmative propositions, in turn establishing the validity of all relations of the traditional Square of Opposition. The chapter also discusses how Buridan’s theory of natural supposition handles some objections to this conception concerning law-like statements, and, in general, how his theory of ampliation handles the issue of existential import in intensional contexts.

This collection of readings with extensive editorial commentary brings together key texts of the most influential philosophers of the medieval era to provide a comprehensive introduction for students of philosophy. Features the writings of Augustine, Thomas Aquinas, Boethius, John Duns Scotus and other leading medieval thinkers Features several new translations of key thinkers of the medieval era, including John Buridan and Averroes Readings are accompanied by expert commentary from the editors, who are leading scholars in the field.

The first chapter presents a brief summary of the little we know about Buridan’s life, and the somewhat more we know about his immediate historical influence. But this brief survey of known facts only sets up the main argument of the chapter intending to show Buridan’s “modernity” in more than one sense of the word. Buridan is “modern” in the medieval sense, being “the great architect” of what would become in late-medieval philosophy the nominalist via moderna, but he is also “modern” from our perspective, having many of the same concerns as contemporary analytic philosophers. Indeed, his philosophy can be the best key to understanding the major paradigm shifts between medieval and modern philosophy.

The second chapter spells out Buridan’s conception of logic as a practical science, teaching us, as logica docens, to heed the valid rules of reasoning embedded in our logical practice, logica utens. The chapter also deals with the particular difficulties of Buridan’s approach, considering his idea of the radical conventionality of written and spoken languages, consisting of token-symbols that owe their meaningfulness to the natural representational system of the human mind. This is the fundamental idea that naturally leads to the nominalist conception of a mental language. On this conception, mental language itself is a compositional semantic system of naturally representative token-symbols, the singular mental acts of singular human minds.

The final chapter provides a summary account of Buridan’s essentialist nominalism, showing how Buridan can successfully claim to be both a nominalist denying the existence of real shared essences and an essentialist endorsing the possibility of discovering truly essential attributes of things, which allows valid scientific generalizations. The concluding critical part of the chapter, however, points out a fundamental conflict between Buridan’s abstractionist cognitive psychology of absolute concepts and his logical semantics of the corresponding absolute terms that grounds his nominalist essentialism.

This chapter compares the modern reliabilist strategies, including Buridan’s antiskepticism, considered in the previous chapter with a premodern form of antiskepticism, exemplified by Aquinas’s doctrine of “the formal unity of the knower and the known”, which, as the chapter argues, simply does not allow the emergence of “Demon-skepticism.” In fact, the chapter further argues that the emergence of “Demon-skepticism“ in its most extreme form, allowing an impossibility to appear as a possibility, indicates a serious flaw in the nominalist conception of mental representation. Nevertheless, the chapter further argues that this flaw is easily masked by the apparent success of Buridan’s reliabilist strategy, not requiring the elimination of Demon-skepticism, but rather presenting reasonable ways for us to learn to live with it.

This paper is not going to offer any criticism of the way Gaven Kerr treats Aquinas’ argument. Instead, it offers an alternative way of reconstructing Aquinas’ argument, intending to strengthen especially those controversial aspects of it that Kerr’s reconstruction left untreated or in relative obscurity. Accordingly, although the paper’s treatment will have to have some overlaps with Kerr’s, it will deal with issues essential to adequate replies to certain competent criticisms of his argument untreated by Kerr. For the sake of the “formally inclined” reader, the paper’s treatment will also include an Appendix offering a formal reconstruction of both the main argument and its sub-arguments to demonstrate the formal rigor of Aquinas’ original.

In this paper, I will primarily argue for the consistency of Aquinas’ conception, according to which the human soul, uniquely in God’s creation, is both the inherent, material, substantial form of the human body, and the subsistent immaterial substance underlying the immaterial operations of its immaterial, rational powers, namely, intellect and will. In this discussion, I will point out that typical challenges to Aquinas’ conception usually rely on semantic or ontological assumptions that can plausibly be denied in Aquinas’ own conceptual framework. Since the issue of consistency merely assumes the less than self-evident claim of the immateriality of the human intellect, I will also provide a brief sketch of what I take to be Aquinas’ most promising proof of this claim.

This volume features essays that explore the insights of the 14th-century Parisian nominalist philosopher, John Buridan. It serves as a companion to the Latin text edition and annotated English translation of his question-commentary on Aristotle's On the Soul. The contributors survey Buridan's work both in its own historical-theoretical context and in relation to contemporary issues. The essays come in three main sections, which correspond to the three books of Buridan's Questions. Coverage first deals with the classification of the science of the soul within the system of Aristotelian sciences, and surveys the main issues within it. The next section examines the metaphysics of the soul. It considers Buridan's peculiar version of Aristotelian hylomorphism in dealing with the problem of what kind of entity the soul (in particular, the human soul) is, and what powers and actions it has, on the basis of which we can approach the question of its essence. The volume concludes with a look at Buridan's doctrine of the nature and functions of the human intellect. Coverage in this section includes the problem of self-knowledge in Buridan's theory, Buridan's answer to the traditional medieval problem concerning the primary object of the intellect, and his unique treatment of logical problems in psychological contexts.

It is supposed to be common knowledge about the history of ideas that one of the few medieval philosophical contributions preserved in modern philosophical thought is the idea that mental phenomena are distinguished from physical phenomena by their intentionality, their directedness toward some object. As is usually the case with such commonplaces about the history of ideas, this claim is not quite true. Medieval philosophers routinely described ordinary physical phenomena, such as reflections in mirrors or sounds in the air, as exhibiting intentionality, while they described what modern philosophers would take to be typically mental phenomena, such as sensation and imagination, as ordinary physical processes. Still, it is true that medieval philosophers would regard all acts of cognition as characterized by intentionality, on account of which all these acts are some sort of representations of their intended objects. This course is going to provide a broad survey of the conceptual relationships between intentionality, cognition and mental representation as conceived by some of the greatest medieval philosophers, including Aquinas, Scotus, Ockham and Buridan, and some of their lesser known contemporaries. The clarification of these conceptual connections sheds some light not only on the intriguing historical relationships between medieval and modern thought on these issues, but also on some fundamental questions in the philosophy of mind as it is conceived today.

This paper confronts a certain modern view of the relation between semantics and ontology with that of the late-medieval nominalist philosophers, William Ockham and John Buridan. The modern view in question is characterized in terms of what is called here “the thesis of onto-semantic parallelism,” which states that the primitive (indefinable) categorematic concepts of our semantics mark out the primary entities in reality. The paper argues that, despite some apparently plausible misinterpretations to the contrary, the late-medieval nominalist program of “ontological reduction” was not driven by considerations that try to “read off” ontology from semantic analysis or those that try to identify semantic primitives in their search for ontological primitives. The medieval authors presented a much more flexible, dynamic view of “Aristotelian naturalism,” which challenges both of the unappealing modern alternatives of “conceptual tribalism” and “conceptual imperialism.”

The lectures presented here are the by-product of my teaching in Yale's Directed Studies program from 1991 through 1993 (hence the title, for want of a better). In fact, being what they are, lecture notes for an introductory philosophy course, they present rather elementary material. Yet, I flatter myself, they do not lack certain originality in the treatment of some of the basic questions of traditional metaphysics and epistemology. In any case, over the past couple of years they proved to be quite useful in teaching my several other courses, especially in medieval philosophy. Thus, being too elementary for transforming them into scholarly papers, on the one hand, yet, containing what I think to be both philosophically interesting and pedagogically useful ideas, on the other, I decided to publish them here, in the Net's formally less stringent medium. Here they can easily be accessed by people who think what they need is a clear and simple discussion of the intriguing philosophical points themselves, rather than the meticulous and sometimes cumbersome scholarly discussions of the texts that raised them (a description which fits, at least, the majority of my students). Given these considerations (as well as the author's lack of time), the lectures are presented here basically unedited, in the form as they were actually delivered, without any notes or references (disregarding the occasionally inserted page numbers, serving as reminders for myself, referring to the texts we used in class). However, anyone who is interested in the more detailed scholarly discussion of some of the topics touched upon here may wish to check some of the papers listed on my..

Anthony Kenny's book is one of the best of its genre, exemplifying the kind of introduction into (some field of) Aquinas's thought that endeavors to make his ideas accessible to the philosophically interested contemporary reader in terms of such philosophical, scientific and everyday concepts with which the reader can safely be assumed to be familiar. Indeed, Kenny's book provides us with such a good example of this genre that it brings into sharp focus the problems of the genre itself. Therefore, while duly acknowledging the book's virtues of clarity of presentation, and its highly readable, almost conversational style, let me concentrate in this brief review on this problematic aspect of Kenny's book, as someone who is just as much concerned with making Aquinas accessible to a contemporary audience as the author is.

Is Aquinas a representationalist or a direct realist? Max Herrera’s (and, for that matter, Claude Panaccio’s) qualified answers to each alternative show that the real significance of the question is not that if we answer it, then we can finally learn under which classification Aquinas should fall, but rather that upon considering it we can learn something about the intricacies of the question itself. In these comments I will first argue that the Averroistic notion of “intentional transfer”, combined with the Avicennean idea of the indifference of nature, yielding the Thomistic doctrine of the formal unity of the knower and the known renders the question moot with regard to Aquinas, indeed, with regard to the pre-modern epistemological tradition in general. These considerations will then lead to a number of further, both historical and philosophical questions, which I will offer in the end for further discussion.