Many things can be other than they are. Many other things cannot. But what are statements like these about? One answer to this question is that we are speaking of possible worlds: if something can be other than it is, then it actually is that way in some possible world. If something cannot be otherwise, it is not otherwise in any world. This answer is presently dominant in analytical philosophy of language and logic. What are these worlds? David Lewis famously (...) claimed that every world exists, just like ours does: there is no difference between the other worlds and ours. In contrast, the medieval thinker John Buridan understands modal logic in terms of objects and causal powers in this world: if something can be other than it is, then there is a causal power that can make it that way. If it cannot, then no causal power—not even God—can alter it, at least without destroying its nature. As we’ll see, the Lewisian plurality is not possible on Buridan’s account; accordingly, a basic tenet of classical theism is untenable on Lewis’s metaphysics. In short, either the Lewisian plurality is incoherent, or a core monotheistic tenet is impossible. (shrink)

Scholastic philosophers can be quite funny. What’s more, they have good reason to be: Aristotle himself lists ready wit (eutrapelia) among the virtues, as a mean between excessive humor and its defect. Here, I assess Scholastic discussions of humor in theory, before turning to examples of it in practice. The last and finest of these is a joke, hitherto unacknowledged, which Aquinas makes in his famous Five Ways. Along the way, we’ll see (i) that the history of philosophy is not (...) so hostile to humor as is commonly supposed; and (ii) that the competing theories of humor like the Incongruity Theory and the Release Theory are not altogether incompatible. We’ll also see at least one example of an apparent attempt by modern translators to excise humor from a medieval text. Our considerations will open a window into what oral discussion and debate at medieval universities was actually like, and how we should understand the relationship between the texts we have now and the exchanges that actually occurred then. (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)

Spoken sentences have parts. Therefore they take time to speak. For instance, when you say, “Socrates is running”, you begin by uttering the subject term ("Socrates"), before carrying on to the predicate. But are the corresponding predications in thought also composite? And are such thoughts extended across time, like their spoken counterparts? Peter Abelard gave an affirmative response to both questions. Alberic of Paris denied the first and, as a corollary, denied the second. Here, I first set out Abelard’s account. (...) I then present a series of arguments against Abelard, reconstructed from (sometimes fragmentary) manuscripts associated with Alberic’s school. I conclude with an observation about present philosophy of language: this twelfth-century debate points to some undefended (and largely unstated) assumptions common to our latest thinking about propositions. I highlight this by presenting recent accounts of two philosophers with radically different outlooks: Jeffrey King and Peter Hanks. Both their accounts take many of the same things for granted, as the Alberican criticisms make plain. (shrink)

It may come as a surprise to readers familiar with the life and work of the Arts Master that he discusses the Eucharist at all. As he likes to remind us, theological topics are generally out of his wheelhouse. Even so, in his Questions on the “Metaphysics” of Aristotle (QM) 4.6, Buridan takes the sacrament of the Eucharist as a key data point in his discussion of Aristotle’s Categories. In the Eucharist, the accidents of the bread and wine—their color, texture, (...) and so on—remain intact, but the underlying substance is transubstantiated into the body and blood of Christ. Accordingly, God can preserve accidents independent of their underlying substance. Therefore, for our part we can use accidental terms, like whiteness, without connoting any substances, like communion bread. Moreover, it follows that, contrary to Aristotle, substance and the accidental categories are not the most general genera. Instead, being (ens) is, as Buridan concludes. Here, I trace Buridan’s thought on the metaphysical and semantic matters of substance in light of the Eucharist. The Eucharist is for him not only a theological truth, but a metaphysical and semantic datum as well. I conclude by asking why Buridan did not take any and all questions about the Eucharist to be out of his ken. What does this tell us about his attitude toward theology? This paper also includes, as an appendix, the first ever English translation of the question under discussion (QM 4.6): “Does the term being (ens) signify substances and accidents by one single concept or notion?”. (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)

In the major French and German etymological dictionaries of Latin, there is some puzzlement over the semantics of exāmen: how can one word refer to a measurement or examination, but also to a swarm of bees? Walde and Hofmann suggest these two dis-parate meanings stem from the diverse meanings of the verb exigō (<*ex-agō, ‘to drive out’), from which exāmen derives. They claim these two senses of exāmen become two words in the Latin Sprachgefühl. Ernout and Meillet agree: there is (...) more than one exāmen in the Latins’ sentiment linguistique. I, too, agree. But this approach does not tell us why these terms derive from exigō, nor does it give any hint of an underlying concept which measurements and swarms of bees share, which makes a derivation from exigō appropriate to both. The present paper addresses this puzzle by reducing the two meanings of exāmen to one meaning of the parent term *ex-agō: ‘to drive out.’ In sum: a swarm of bees is a ‘driving out’ or outpouring, and a measurement or examination is a ‘driving out’ or setting out for scrutiny. This interpretation is moreover supported by semantically parallel uses of cognate terms in other Indo-European languages, notably Greek and Old Irish, and by semantic parallels in English and in the Slavic language family. Along the way, I touch upon a philosophical puzzle: at what point do evolving linguistic items with a common source become distinct from one another? (shrink)

What does success in online teaching look like? There are two ways to answer this question. The first defines success in terms of replacement of educational means: for example, how closely does an online lecture approximate its offline counterpart? The second defines success in terms of educational goals: for example, how well does an online lecture facilitate learning, compared with its offline counterpart? The first is a trap: it commits us to an endless online game of catch-up with offline models (...) of teaching. Instead, we should adopt a goal-oriented approach, mindful of obstacles to online teaching. As a case study, I present practices developed using this approach to teach philosophy online in 2020. An important upshot is that this approach leaves us open to ways in which online teaching is actually better than its offline counterpart. I conclude with some examples of these, and discuss their future implementation. (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)