It is relatively well known that Buridan’s nominalist semantics changed “the rules of the game” in practically all fields of philosophy and science. For instance, in his semantics, the traditional distinction between essential and accidental predicates is mapped onto the Ockhamist distinction between absolute and connotative terms and concepts. It is, however, still not quite well understood what impact these “new rules” had in particular philosophical disciplines. This essay offers a case study of the late-medieval paradigm change brought about by nominalist “semantical innovations.” In particular, it contrasts Aquinas’ “semantics-driven mereology” with Buridan’s, set against the background of Buridan’s new, nominalist semantics, arguing that the two authors’ differences in their mereological considerations are rooted in the differences between their diverse semantic intuitions. The conclusion of the essay will provide a brief logical and historical evaluation of the paradigmatic changes brought about by these diverse intuitions.

John Buridan devotes an extensive discussion to final causality in two questions of his commentary on Book ii of the Physics: one asks whether the end is a cause (q. 7) and the other asks whether the necessity in natural operations derives from the end or from matter (q. 13). These two questions are the focus of this essay, which provides a detailed presentation of Buridan’s view, explaining its philosophical significance and setting it in the context of the medieval debate about final causality. It also points out the originality of Buridan’s view. Departing from the dominant medieval interpretation of Aristotle’s concept of the final cause, Buridan does not try to defend the idea that the end to which an action or change is directed is properly speaking a cause of that action, and in doing so he undermines the main assumptions at work in the Aristotelian account of finality in nature.

The Quaestiones de secretis mulierum of MS Erfurt-Gotha, Universitäts- und Forschungsbibliothek, Dep. Erf., CA 4º 299, ascribed to John Buridan and recently edited for the first time, are an incomplete set of questions on Pseudo-Albert the Great’s De secretis mulierum. The text contains an extensive treatment of the topic of human generation, with a particular focus on male and female roles in reproduction. This essay retraces Buridan’s view on the generative aspects of female physiology as it emerges in his commentary on Pseudo-Albert’s text. By analyzing this unexplored feature of Buridan’s thought, the essay aims to contribute to the growing research on the biological aspects of Buridan’s natural philosophy.

Bertrand Russell famously remarked that “a logical theory may be tested by its capacity for dealing with puzzles, and it is wholesome plan, in thinking about logic, to stock the mind with as many puzzles as possible.” John Buridan, like many medieval logicians, adopted the same methodology: he developed and refined his theories of truth and other semantic notions against an array of paradoxes. Indeed, in an appendix to his Summulae de dialectica Buridan gave a succinct but comprehensive introduction to his logical philosophy in the form of responses to a collection of sophisms (his Sophismata). Among these sophisms are the logical paradoxes, the so-called “insoluble,” such as the Liar Paradox (is one who says he is lying, lying or telling the truth?). But before he comes to these especially difficult examples, Buridan tackles puzzles which lead him to reject standard accounts of meaning, truth, logical consequence, tense, hyperintensionality, and other semantic notions. In the final chapter of the Sophismata, he deals with various problems involving self-referential propositions, not all of them insolubles. When he turns at last to the insolubles, he elaborates a revision he had already suggested in his Questions on the Sophistical Refutations to the general solution he had developed for them over a long career in the arts faculty at the University of Paris dealing with philosophical puzzles.

Ethical Aristotelianism, with happiness at its core, is enjoying a resurgence. The revival of this view has been driven in large part by historically minded philosophers, who believe that the best versions of this general outlook were developed many centuries ago by some of our astute philosophical forebears. John Buridan shares a similar approach. Like these historically minded philosophers today, he both attempts to reconstruct others’ views – especially those of Aristotle and Seneca – and attempts to respond to potential concerns that one might have through a sensitive and creative development of those inherited views. This sort of creative development is on full display in Buridan’s work on happiness and the good life, as he clarifies, expands, and reshapes Aristotle’s basic conception of happiness.

This essay reconstructs the account that results. It begins with Buridan’s account of happiness understood as the best single human good. It then turns to Buridan’s account of happiness understood as the best collection of human goods, which he takes to be unqualified human happiness. Finally, since unqualified happiness is extremely demanding and thus exceedingly rare, the essay considers varieties of happiness in various restricted senses that Buridan seems to countenance, namely, being happy for a time, being happy within the confines of one’s non-ideal situation in life, and being happy in a domain of one’s life. The author hopes that even in this short span it will become clear that Buridan is among those astute philosophical forebears worth taking seriously as an ethicist, especially for those invested in the project of Ethical Aristotelianism.

The essay studies four aspects of Buridan’s use of principles in his logic. (1) Some principles, such as being said of all or of none, are taken over from the tradition but applied with some qualifications: for example, certain modal syllogisms governed by this principle are said to be “quasi-perfect.” (2) Some principles not used by Buridan’s realist predecessors are introduced, for example, Things that are identical with one and the same thing are identical with each other. (3) Some principles familiar from the tradition are put to powerful new uses, for example, In every pair of contradictories, one is true and the other false, and it is impossible for both to be true together or for both to be false together; again, every proposition is true or false, and it is impossible for the same proposition to be true and false together. (4) Some principles, taken from Porphyry, the Categories, and the Posterior Analytics, which were used by realist logicians to connect the theory of genus and species with the theory of modal syllogisms, are no longer used in that way. It seems that (1)–(3) have the effect of making the theory of consequences (and thus the syllogistic) more “scientific,” while (4) has the effect of separating the theory of consequences from the logical theories contained in the books of the Organon other than the Prior Analytics. If this is so, then Buridan’s logic marks an important stage in the emergence of modern conceptions of logic. A further question is how all of this relates to Buridan’s professed humanistic conception of logic as an art – not a science – “just as the leader is the savior of the army, so reasoning with learning is the leader in human life, whether that life be contemplative, namely, speculative, or active.”

This essay surveys John Buridan’s writings on logic and temporality, arguing that while Buridan’s earliest writings on the Organon show acceptance of a temporal analysis of modality, Buridan’s later writings reflect a plurality of modalities, two based on the power to falsify, and two based on time.

How was Buridan’s thought shaped by its institutional setting and by pedagogical practice in the faculty of arts at the University of Paris? This essay argues that local circumstances are crucial not only for interpreting Buridan’s arguments, but also for understanding his larger contribution to the history of philosophy. Thus, we find that even working within the constraints of the arts curriculum, Buridan was always able to segue from established modes of instruction and prescribed topics to discuss philosophical problems of interest to him; in this he was no different from other arts masters of the period, and indeed, from university lecturers even today. But he also used his independence to embody, in ways he himself may not have fully understood, a new way of being a philosopher. Whereas a century earlier, Thomas Aquinas saw himself as a theologian and regarded philosophy as an activity proper to pagans such as Plato and Aristotle, Buridan sought to define what he was doing in contradistinction to theology, and on grounds we would now recognize as secular.

In the first two books of his massive commentary on Aristotle’s Physics (in the third and final redaction), Buridan pays ample attention to the composition of natural substances. Natural substances are composed of matter and (substantial) form. But what exactly does Buridan mean by the notions of “matter” and “(substantial) form”? Does matter possess some kind of being of its own? Is it pure potency? Does matter somehow possess a disposition (or “appetite”) to receive substantial forms, and what precisely are such forms? Buridan also offers a detailed account of the relation between natural substances and artificial things. How do artificial things (such as houses, tables, and axes) relate to the natural substances of which they are (somehow) made? What kind of change is involved in making an artifact and what kind of form makes an artifact the thing it is?

The prevailing view of Buridan’s theory of cognition and his epistemology is that he is a kind of externalist as well as a reliabilist. This essay argues that this reading is mistaken and that Buridan instead must be seen as a semantic and epistemic internalist. The essay develops the arguments for both these views. The first part of the essay supplements an argument already made by Claude Panaccio, but the second part is a new argument for why Buridan must be seen as an epistemological internalist. The essay also compares Buridan to later empiricists such as David Hume.

Scholars agree that Buridan’s commentary on the Nicomachean Ethics gives far more attention to Seneca’s works than other commentaries of the period do. Buridan cites Seneca on one topic after another, always respectfully and often with praise. But did his study of Seneca lead him to a generally negative view about the role of emotions in morality? On this topic scholars clearly disagree. One claims that there are hardly any positive references to the emotions in Buridan’s entire Ethics commentary. Buridan emphasizes instead that emotions must be repressed by the will. Another scholar claims, to the contrary, that Buridan is in no sense a disciple of Seneca. For example, he follows Aristotle in arguing that anger can have genuine value and should not be completely eliminated. This essay examines Buridan’s account of anger and his discussions of some other emotions to clarify his views on how emotions contribute to a virtuous life.