Gyula Klima

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.

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 chapter provides a brief survey of Buridan’s reliabilist epistemology, contrasting it with skeptical challenges of his time, and comparing it with modern responses to similar skeptical challenges in modern philosophy, arguably stemming from the controversies of Buridan’s time. In particular, the chapter argues that the sort of “Demon-skepticism” modern readers are familiar with from Descartes was made conceptually possible precisely by the emergence of late-medieval nominalist semantics, and that the modern strategies responding to the skeptical challenge, exemplified by the works of Thomas Reid and most recently John Greco, originate in the epistemic principles of Buridan.

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.

Common representational content allows the Buridanian classification of human concepts discussed in the fourth chapter, which provides the first thoroughgoing, systematic survey of Buridan’s conception of a mental language. The chapter discusses the divisions of concepts into syncategorematic and categorematic, simple and complex, absolute and connotative, and singular and common concepts. Besides presenting these classifications, the chapter provides a detailed discussion of the idea of conceptual complexity as semantic compositionality, its role in Buridan’s nominalist program of “ontological reduction,” and his precarious positioning of his account of the distinction between the representational contents of universal and singular concepts “somewhere between” those of Ockham and Aquinas. The discussion relates the emerging issues to contemporary concerns in the philosophy of mind and language, such as the possibility of forming genuinely singular concepts and simple substantial concepts that would allow some terms of our language to function as rigid designators; the differences between consciousness and mental content; and the problem of universal representation without real universals.

The third chapter discusses how Buridan’s conception of mental language provides the grounding for the objectivity and universality of logic despite the radical conventionality of written and spoken languages. Buridan’s conception, since it is based on the Aristotelian idea of the uniformity of natural human capacities in all individual humans, is nothing like modern psychologism, the kind heavily criticized by Frege. Indeed, Buridan’s mental language is not a “private language” criticized by Wittgenstein. On Buridan’s conception, the naturally representative units of human mental language, namely, human concepts, are not inter-subjectively inaccessible private mental states; on the contrary, they are common to us all in our thinking. Of course, our concepts, being individual acts of individual minds are singular token-symbols, but they are common in their representational content: in what and how they represent for all humans. This is precisely the ground for their intersubjective accessibility as well as for the objectivity and universality of logic.

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.

After a brief analysis of the specifics of teleological explanations as opposed to causal explanations, the paper seeks to establish the irreducibility of the former to the latter by arguing that teleological explanations are inextricably tied to our notion of intentionality. Since this result undermines the very possibility of “a physicalist reduction” of the explanation of teleological phenomena, especially of human beha- vior, the rest of the paper develops an argument against the perceived need of any such reduction. According to the conclusion of the paper, a more promising program is the development of a “modern, scientific Aristotelianism”, one that can provide a consistent conceptual framework that accommodates both types of explanation