Buridan's life, works, and influence -- Buridan's logic and the medieval logical tradition -- The primacy of mental language -- The various kinds of concepts and the idea of a mental language -- Natural language and the idea of a formal syntax in Buridan -- Existential import and the square of opposition -- Ontological commitment -- The properties of terms (proprietates terminorum) -- The semantics of propositions -- Logical validity in a token-based, semantically closed logic -- The possibility of scientific (...) knowledge -- Buridan's anti-skepticism -- Buridan's essentialist nominalism. (shrink)

This volume is the first annotated translation in any language of the entire text of the Summulae de dialectica, by the Parisian master of arts John Buridan (1300-1358). One of the most influential works in the history of late medieval philosophy, the Summulae is Buridan's systematic exposition of his nominalist philosophy of logic. Buridan's doctrine spread rapidly and for some two hundred years was dominant at many European universities. His work is of increasing interest today not only to historians of (...) medieval philosophy but also to modern philosophers, several of whom find in Buridan's ideas important clues to problems of contemporary philosophy. Gyula Klima provides a substantial introduction to Buridan's life and work and discusses his place in the history of logic. Through extensive notes Klima assists philosopher and medievalist alike to read Buridan with understanding and insight. Those with a philosophical interest in the relations among the structures of language, thought, and reality will find much to ponder in the Summulae. (shrink)

An argument with roots in ancient Greek philosophy claims that only humans are capable of a certain class of thought termed conceptual, as opposed to perceptual thought, which is common to humans, the higher animals, and some machines. We outline the most detailed modern version of this argument due to Mortimer Adler, who in the 1960s argued for the uniqueness of the human power of conceptual thought. He also admitted that if conceptual thought were ever manifested by machines, such an (...) achievement would contradict his conclusion. We revisit Adler’s criterion in the light of the past five decades of artificial-intelligence research, and refine it in view of the classical definitions of perceptual and conceptual thought. We then examine two well-publicized examples of creative works produced by AI systems and show that evidence for conceptual thought appears to be lacking in them. Although clearer evidence for conceptual thought on the part of AI systems may arise in the near future, especially if the global neuronal workspace theory of consciousness prevails over its rival, integrated information theory, the question of whether AI systems can engage in conceptual thought appears to be still open. (shrink)

This is a brief, accessible introduction to the thought of the philosopher John Buridan (ca. 1295-1361). Little is known about Buridan's life, most of which was spent studying and then teaching at the University of Paris. Buridan's works are mostly by-products of his teaching. They consist mainly of commentaries on Aristotle, covering the whole extent of Aristotelian philosophy, ranging from logic to metaphysics, to natural science, to ethics and politics. Gyula Klima argues that many of Buridan's academic concerns are strikingly (...) similar to those of modern philosophy and his work sometimes quite directly addresses modern philosophical questions. (shrink)

“The problem of universals” in general is a historically variable bundle of several closely related, yet in different conceptual frameworks rather differently articulated metaphysical, logical, and epistemological questions, ultimately all connected to the issue of how universal cognition of singular things is possible. How do we know, for example, that the Pythagorean theorem holds universally, for all possible right triangles? Indeed, how can we have any awareness of a potential infinity of all possible right triangles, given that we could only (...) see a finite number of actual ones? How can we universally indicate all possible right triangles with the phrase ‘right triangle’? Is there something common to them all signified by this phrase? If so, what is it, and how is it related to the particular right triangles? The medieval problem of universals is a logical, and historical, continuation of the ancient problem generated by Plato's (428-348 B.C.) theory answering such a bundle of questions, namely, his theory of Ideas or Forms. (shrink)

“The expression ‘free logic’ is an abbreviation for the phrase ‘free of existence assumptions with respect to its terms, general and singular’.”1 Classical quantification theory is not a free logic in this sense, as its standard formulations commonly assume that every singular term in every model is assigned a referent, an element of the universe of discourse. Indeed, since singular terms include not only singular constants, but also variables2, standard quantification theory may be regarded as involving even the assumption of (...) the existence of the values of its variables, in accordance with Quine’s famous dictum: “to be is to be the value of a variable”. (shrink)

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.

This paper primarily aims to provide a coherent interpretation of several, apparently conflicting claims made by Aquinas concerning the semantic function of the copula. The paper also argues that these claims can properly be understood only if they are interpreted as forming a coherent part of Aquinas' larger theory of the analogy of being. The Appendix sketches a model theoretical semantics for the reconstruction of Aquinas' relevant ideas, providing the technical means for setting apart the various senses of the verb (...) 'est' and its cognates distinguished by Aquinas. (shrink)

Contemporary "essentialism", if we want to provide a succinct, yet sufficiently rigorous characterization, may be summarized in the thesis that some common terms are rigid designators. [1] By the quotation marks I intend to indicate that I regard this as a somewhat improper (though, of course, permitted) usage of the term (after all, nomina significant ad placitum [2]). In contrast to this, essentialism, properly so-called, is the Aristotelian doctrine summarizable in the thesis--as we shall see, no less rigorous in its (...) own theoretical context--that things have essences. (shrink)

This paper argues that three characteristic modern positions concerning intentionality – namely, (1) that intentionality is ‘the mark of the mental’; (2) that intentionality concerns a specific type of objects having intentional inexistence; and (3) that intentionality somehow defies logic – are just three ‘modern myths’ that medieval philosophers, from whom the modern notion supposedly originated, would definitely reject.

This paper argues that Aquinas's conception of the human soul and intellect offers a consistent alternative to the dilemma of materialism and post-Cartesian dualism. It also argues that in their own theoretical context, Aquinas' arguments for the materiality of the human soul and immateriality of the intellect provide a strong justification of his position. However, that theoretical context is rather "alien" to ours in contemporary philosophy. The conclusion of the paper will point in the direction of what can be done (...) to render Aquinas's position more palatable to contemporary philosophers. (shrink)

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. (shrink)

Saint Anselm’s proof for God’s existence in his Proslogion, as the label “ontological” retrospectively hung on it indicates, is usually treated as involving some sophisticated problem of, or a much less sophisticated tampering with, the concept of existence. In this paper I intend to approach Saint Anselm’s reasoning from a somewhat different angle.

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. (shrink)

This paper argues for two principal conclusions about natural language semantics based on John Buridan's considerations concerning the notion of formal consequence, that is, formally valid inference. (1) Natural languages are essentially semantically closed, yet they do not have to be on that account inconsistent. (2) Natural language semantics has to be token based, as a matter of principle. The paper investigates the Buridanian considerations leading to these conclusions, and considers some obviously emerging objections to the Buridanian approach.

Thomas of Sutton was one of the earliest, and by all measures one of the most astute defenders of St. Thomas Aquinas’ characteristic theological and philosophical doctrines. As usual with medieval thinkers, we have little information regarding Sutton’s life..

This paper analyses the import of three claims extracted from Geach's works concerning theories of predication and the reference of common terms, the notions of being or existence, and the force/content distinction and theories of valid inference, respectively. The paper highlights the theoretical and historical errors involved in these claims as well as their enormous influence and inspiration in the field of the philosophical study of medieval logic and metaphysics.

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. (shrink)

To many contemporary philosophers, the phrase “essentialist nominalism” may appear to be an oxymoron. After all, essentialism is the doctrine that things come in natural kinds characterized by their essential properties, on account of some common nature or essence they share. But nominalism is precisely the denial of the existence, indeed, the very possibility of such shared essences. Nevertheless, despite the intuitions of such contemporary philosophers,2 John Buridan was not only a thoroughgoing nominalist, as is well-known, but also a staunch (...) defender of a strong essentialist doctrine against certain skeptics of his time. But then the question inevitably arises: could he consistently maintain such a doctrine? (shrink)

Summary: The aim of this paper is to explore the relationships between Buridan’s logic and the ontology of modes modi). Modes, not considered to be really distinct from absolute entities, could serve to reduce the ontological commitment of the theory of the categories, and thus they were to become ubiquitous in this role in late medieval and early modern philosophy. After a brief analysis of the most basic argument for the real distinction between entities of several categories (“the argument from (...) separability”), I point out that despite nominalist charges to the contrary, “older realists”—that is, authors working before and around Ockham’s time—were not committed to such real distinctions, and thus to an overpopulated ontology, by their.. (shrink)

This paper argues in the first place that nominalists are right in insisting against ontological realists that semantic universality does not require commitment to universal entities. However, Ockham, in his zeal to get rid of Scotus’s universal entities, swept under the carpet the issue of universal representational content of genuinely universal symbols, conflating it with the mere indifference of the information content of non-distinctive singular representations. Buridan did come up with an abstractionist theory of the formation of genuinely universal representational (...) content to solve the resulting issues, however, the paper argues further, his solution is committed to attributing the sort of “aspectuality” to universal absolute concepts that his Ockhamist semantics denies to them. The conclusion of the paper suggests how Aquinas’s “moderate realism” can provide a consistent solution without the ontological extravaganza of ontological realists, without conflating the mere indifference of singular representation with genuine universality, and without having to deny aspectuality to our quidditative universal concepts formed by abstraction. (shrink)

Lo studio intende mettere in evidenza l'ambiguità della nozione di unità, intesa come entità numerica, con la nozione di unità quale sinonimo di essere. Sul primo concetto verte la parte iniziale dello studio, alla quale segue l'esame del significato ontologico di «uno». Le considerazioni fatte guidano l'A. a valutare i rapporti di relazione fra le nozioni di essere e uno, e quelle di sostanzialità, identità e semplicità in Tommaso. La gerarchia ontologica che ha al vertice l'essere assoluto e l'assoluta unità (...) implica la paradossale impossibilità di «significare» e definire la divinità. (shrink)

This paper contrasts the Thomistic and Cartesian interpretations of what the substantial unity of the body and mind can consist in. A detailed discussion of the Thomistic account of the substantial unity of body and soul identifies especially those principles of the presupposed hylomorphist metaphysical background of this account that Descartes abandoned. After arguing for the consistency of the Thomistic view, briefly outlines how certain developments in late-medieval scholasticism prepared the way for the abandonment of precisely these principles. Finally, the (...) paper shows why from the perspective of the Thomistic principles identified in the first part, Descartes has to appear as someone paying mere lip-service to the thesis of the substantial unity of body and mind. (shrink)

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. (shrink)

1st GPMR Workshop on Logic and Semantics: Medieval Logic and Modern Applied Logic, Reinische Friedrich Wilhelms Universität Bonn, Germany, 2007.

This paper examines the multiple semantic functions Aquinas attributes to the verb ‘est’, ranging from signifying the essence of God to acting as a copula of categorical propositions to expressing identity. A case will be made that all these apparently radically diverse functions are unified under Aquinas’s conception of the analogy of being, treating all predications as predications of being with or without some qualification (secundum quid or simpliciter). This understanding of the multiplicity of the semantic functions of this verb (...) as conceived by Aquinas will enable us to have a better understanding of the meaning of his metaphysical claims and arguments. In particular, with this understanding of Aquinas’ conception of being, we will be able to see how Aquinas’s famous “intellectus essentiae” argument for the thesis of the real distinction between essence and existence in creatures can work, despite Anthony Kenny’s arguments to the contrary in his recent book Aquinas on Being. (shrink)

Of those that exist, some are said of a subject, but are in no subject: as man is said of some subject, namely of some man, but is in no subject. Others, however, are in a subject, but are said of no subject. And I say that to be in a subject which, while it is in something not as a part, cannot exist apart from the thing in which it is. For example, some particular literacy is in a subject, (...) namely in the soul, but is not said of any subject, and this whiteness is in a body as in its subject, for any color is in a body. Others both are said of and are in a subject. For example, knowledge is in the soul, and is said of a subject, say, of literacy. Still others neither are in a subject, nor are said of a subject, for example, some particular man, or some particular horse: for none of these is either in or is said of a subject. In general, individuals, and what are numerically one are said of no subject, but nothing prevents them from being in a subject, for some particular literacy is in a subject. (shrink)

This paper provides a comparison of three fundamentally different approaches to the issue of ontological commitment. It argues that despite superficial similarities on either side, Buridan’s approach provides an intriguing third alternative to the two commonly recognized modern approaches. Keywords: ontological commitment, existence, meaning, reference..