As many commentators have noticed, medieval views on the relation of mind and body occupy a strange territory somewhere between substance dualism, on the one hand, and some form of materialism, on the other. On the one hand, the medievals were convinced that the soul is an immaterial agent, causally responsible for our intellectual activities - causally responsible independently of the body - on the other hand, they were all convinced that body and soul are united in such a way as to form one (composite) substance. While there was widespread agreement about the correct understanding of the first of these two claims - that the soul is an individual immaterial object - there was considerable disagreement about the correct understanding of the second. The consensus was that the soul is in some sense an (Aristotelian) form of the body. But there was no corresponding consensus about what it is to be a form.

THE IMMATERIALITY OF THE SOUL

Scotus’s account of the immateriality of the soul springs from a discussion of the immateriality of human cognition and will. The argument from cognition focuses on an argument proposed by Aquinas in defence of the immateriality of the soul. According to Aquinas, we can infer the immateriality of the soul from the immateriality of mental acts.

The traditional philosophical category of epistemology serves medieval philosophy poorly. The medievals were concerned with most of what now falls within the theory of knowledge, but they never thought of knowledge as the sort of integrated topic around which one might construct a philosophical theory. Much the same might be said about philosophy today. In place of knowledge, philosophers now focus their energies on cognition; in place of the theory of knowledge, we now have cognitive theory. This way of dividing up the philosophical terrain turns out to be well suited to the study of medieval philosophy. The medievals, rather than focusing on how knowledge differs from mere true belief, focus on how we manage to form true beliefs: How does the process work? To answer this question is to develop a theory of cognition.

As in most matters, John Duns Scotus does not distinguish himself in cognitive theory by adopting a radically new perspective. Scotus accepts the general cognitive framework set out by his most distinguished recent predecessors, Thomas Aquinas and Henry of Ghent; where he disagrees, he does so in ways that reinforce the broader contours of the theory. Scotus is interesting, then, not because he offers any startlingly new ideas about cognition, but because he gives a careful and penetrating analysis of the field as it stood at the end of the thirteenth century. In many ways, he sees the issues in more depth than had anyone before him.

Recent interest in John Duns Scotus’s modal theory derives largely from the suggestion that Scotus was the first in the Middle Ages, and perhaps the first ever, to employ a synchronic conception of modality, one that allowed for alternative possibilities at a given time, and from the debate about whether Scotus introduced a notion of logical possibility divorced from any question of what powers there are. These issues interact in the question of whether Scotus had any analogue of the notion of possible world in either the Leibnizian or the late twentieth-century sense. Late medieval interest in Scotus’s modal theory derived largely from its role in his account of divine and human freedom and from the debate about whether possibility itself depended in any way upon God. This discussion attempts to shed some light on these issues and to locate them in the context of the issues in the theory of modality with which Scotus and his contemporaries were themselves concerned.

It would be desirable in an essay of this kind to present a picture of the development of Scotus’s thought about modality, but in the current state of scholarship that is not possible. Despite nearly a century of work by the Scotus Commission and by a number of very able scholars outside it, our understanding of the textual tradition of Scotus’s works remains radically incomplete. In such a situation any hypothesis about the development of Scotus’s modal theory must be highly speculative. In what follows I will not attempt to trace such a development but will attempt to limn the modal theory with which Scotus seems to have been working at the end of his (unfortunately short) life.

Scotus’s natural theology has the following distinctive claims:

1. That we can reason demonstratively to the necessary existence and nature of God from what is actually so but not from imagined situations or from conceivability-to-us; rather, only from the possibility logically required for what we know actually to be so.

2. That there is a univocal transcendental notion of being.

3. That there are disjunctive transcendental notions that apply exclusively to everything, like 'contingent/necessary', and such that the inferior cannot have a case unless the superior does.

4. That an a priori demonstration of the existence of God is impossible because there is nothing explanatorily prior to the divine being; thus, reasoning must be a posteriori from the real dependences among things we perceive to the possibility of an absolutely First Being (The First Principle).

5. That such a being cannot be possible without existing necessarily.

6. That the First Being (God) is simple, omni-intelligent, free (spontaneous), omnipotent, and positively infinite.

7. That there is a formal distinction, which is more than a distinction within our concepts or definitions, among the divine attributes.

Unlike many thirteenth- and fourteenth-century authors, Scotus never wrote a grammar or logic handbook. Nor did he compose a treatise dealing explicitly with the grammatical and semantic issues that were eagerly debated at his time - for instance a treatise about the famous “properties of terms” or the “modes of signifying.” The only work concerning grammar and semantics, entitled Tractatus de modis significandi sive Grammatica speculativa, that was attributed to him until the beginning of the twentieth century, proved to be inauthentic; it was written by his contemporary Thomas of Erfurt, a leading representative of the school of the “modistae.” Given such an apparent lack of writings dedicated to grammatical and semantic problems, one may have the impression that Scotus was not particularly interested in linguistic analysis and that he should be regarded as a theologian, metaphysician, and moral philosopher, but not as a philosopher of language.

Yet such an impression would be quite misleading. Although Scotus never wrote a grammar or logic handbook, he had a keen interest in linguistic theory. This interest is most obvious in his commentaries on the Isagoge, on the Categories, and on Peri hermeneias. In these early writings, Scotus does not confine himself to paraphrasing Aristotle’s and Porphyry’s view. He rather uses their opinion as a starting point for a thorough discussion of fundamental issues in philosophical semantics – a discussion that allows him to critically examine various linguistic theories of his contemporaries and to develop his own theory. Such a discussion can also be found in some parts of his later works, especially in his metaphysical and theological writings.

The theory of natural law is the heart of the ethics of John Duns Scotus. Unlike other approaches in medieval ethics, Scotus’s framework is not that of an ethics of virtue. One reason for this is Scotus’s innovative concept of will, which diverges significantly from its classical and medieval predecessors. This new conception of will, and the assumptions for action theory that arise from it, require a different systematic role for the concept of virtue, one that accords greater weight to the judgment of reason than to the natural goal-directedness of purposive action. What takes center stage in Scotus’s ethics is the obligation on the part of reason to what is apprehended in the natural law as a practical truth, rather than what befits the agent’s end-directed nature as it is manifested in the virtues.

A second theme that determines the fundamental orientation of Scotus’s practical philosophy arises from the twofold task that confronted Scotus as a theologian. On the one hand, because of the influence of the Aristotelian conception of science, he had to show that the claim of theology to be a science could be made good. On the other hand, because he belonged to the Franciscan tradition, he also had to emphasize the practical character of theology. As a result, Scotus was faced with the task of developing an understanding of practical science that would show how both demands could be consistently met1 As I show in detail in this chapter, Scotus’s theory of natural law is precisely a response to this higher standard for rational acceptability.

By the end of the thirteenth century, it was clear that Aristotle’s physics and cosmology presented claims that were incompatible with God’s omnipotence. According to Scotus, “whatever does not evidently include a contradiction and from which a contradiction does not necessarily follow, is possible for God.” But many states of affairs, treated as impossible by Aristotle, seemed to involve no contradiction. Already in 1277, Stephen Tempier, Bishop of Paris, had issued his influential condemnation of, among other things, several key claims of Aristotle’s physics and cosmology precisely because they implied limitations on God’s absolute power. This condemnation did not lead to a wholesale rejection of Aristotelian thought, however. Aristotle had provided the most detailed and powerful conception of the physical universe known to medieval thinkers, and Scotus, like most of his contemporaries, was deeply wedded to this conception in its broad outlines and in a great deal of its detail. But he formed part of a movement, beginning in the late thirteenth century, and gathering momentum in the fourteenth, in which this conception was intensely scrutinized and modified in a number of fundamental respects. Nowhere did Aristotle’s thought pose greater problems than in doctrines concerning space and time. Scotus’s writings were an important chapter in the reexamination and modification of Aristotelian doctrines on these issues.

Work on Scotus’s moral psychology and action theory has been concerned almost exclusively with questions about the relationship between will and intellect and in particular about the freedom of the will itself. In this chapter I broaden the scope of inquiry. For I contend that Scotus’s views in moral psychology are best understood against the background of a long tradition of metaethical reflection on the relationship between being and goodness. In the first section of this chapter, therefore, I sketch the main lines of that tradition in medieval thinking and examine the novel and sometimes daring ways in which Scotus appropriated them. In the sections that follow I elaborate on three areas of Scotus’s action theory, very broadly conceived, in which his modifications of the medieval metaethical tradition can be seen bearing philosophical fruit. Thus, in the second section I examine his account of the goodness of moral acts, in the third his understanding of the passive dispositions of both sensitive appetite and will, and in the fourth his account of the active power of will.

This chapter discusses Scotus’s metaphysics under six headings: the nature of metaphysics itself as a discipline (Section I); identity and distinctness (Section II); the extent and scope of the Aristotelian categories (Section III); causality and essential orders (Section IV); matter, form, and the composite of matter and form (Section V); and a brief return to the nature of metaphysics (Section VI). Some metaphysical topics are not treated here but in other chapters of this volume: space and time (Chapter 2), universals and individuation (Chapter 3), and modality (Chapter 4). Scotus’s proof of God’s existence, discussed in Section IV, is examined in Chapter 6.

METAPHYSICS AS THE SCIENCE OF BEING

Theoretical Science

Scotus holds that there are exactly three real theoretical sciences, pursued for their own sake, that are open to us in our present life: metaphysics, mathematics, and physics (In Metaph. 6, q. 1, nn. 43–6). Each qualification is important. The requirement that such sciences be “real” – that is, concerned with things in the world rather than our concepts of them – excludes logic, which is the normative science of how we are to think about things, and thus concerned with concepts. The requirement that such sciences be pursued for their own sake excludes ethics, whose primary goal is to direct and regulate the will. The requirement that we can attain such knowledge in the condition of our present life, where we can only know things through sense perception and hence have no direct epistemic access to principles or to immaterial beings, rules out theology in the strict sense as well as a properly axiomatic metaphysics; we can however construct a ‘natural’ theology and metaphysics within our limitations. Mathematics and physics are defined in terms of material substance. Mathematics deals with material substances in their material aspect, namely, in terms of their purely quantitative features (which they have in virtue of their matter) and whatever is consequent upon those features.

Scotus’s teachings on moral virtue have attracted little attention, in part because there is no single text where he presents them systematically, in part because scholars tend to associate Scotus with the ethics of freedom and right reason. Even those sympathetic to his views report, with apparent regret, his move away from the virtue-centered Aristotelian model of ethics. This chapter attempts to explain the various roles that virtues do and do not play in his ethical theory. While Aristotle receives his share of criticism, so, too, does Augustine.

THIRTEENTH-CENTURY ETHICS: A LARGE, CONFUSING LEGACY

Ancient ethics takes as its starting point questions about the happiest human life and the virtues needed to live such a life. Virtues are thought to be dispositions developed only through many years of learning and practice, beginning in childhood. Vices, too, are dispositions; and like virtues, they gradually become “second nature” to the individual. For this reason Aristotle describes moral character as impossible, or at least exceedingly difficult, to change. His definition of moral virtue as a disposition concerned with choice does not imply, then, that people always remain free to choose actions “out of character.”

Both present-day historians of philosophy and those working in the past two centuries have considered the thought of Duns Scotus regarding the philosophical problems of universals and individuation as laying the groundwork for much of the philosophical speculation of the fourteenth and fifteenth centuries. Their judgment is well founded, being based on numerous texts in writers such as William of Ockham, Adam Wodeham, Walter Burley, and a host of others whose starting points in discussing both universals and individuation were often the views of Duns Scotus. Furthermore, as the problem of justifying and delimiting the range of natural knowledge became more and more central to philosophical as well as theological investigation, the influence of Duns Scotus on the two problems under discussion continued to grow. Realists as late as the sixteenth and seventeenth centuries looked to Scotus’s works for supporting arguments and conceptual tools whereby to salvage their claims that universals exist outside the mind, whereas the conceptualists and nominalists of later centuries often began their critique of contemporary opponents by pointing out the weaknesses in Scotus’s theories. The historical importance of Scotus’s thought on the subjects being considered here is then clear enough. But the systematic value of his solutions to the problems of universals and individuation should not be overlooked. Several contemporary philosophers working in the areas of metaphysics and epistemology appeal to distinctions bearing striking resemblances to those advanced by Scotus and his followers, especially regarding the problem of individuation.

The Earnest Professor begins the lecture by announcing that today we are going to investigate what we can know about God. The Artless Student immediately asks how it is possible that we finite minds can comprehend anything about the infinite. The Professor groans inwardly, resisting the temptation to retort by asking how the finite mind of the Student is so certain that God is infinite, given the Student’s avowal of doubt about the adequacy of finite minds.

Eager to maintain classroom civility, the Professor might congratulate the Student on fastening on a question discussed at length by John Duns Scotus. It is a sign of the seriousness with which Scotus takes this and related issues that he tackles them immediately in the Ordinatio version of his monumental Commentary on the Sentences of Peter Lombard. The title of the first question in the Prologue to the First Part is “Whether It Is Necessary for Man in His Present State to Be Supernaturally Inspired with Some Doctrine.” The title of the first question of the First Part of the Third Distinction is “Whether God Is Naturally Knowable to the Wayfarer’s Intellect.” God’s existence is not at stake in these questions. Scotus thinks that God’s existence can be established as an item of natural theology, that part of theological speculation that can be developed by reason alone, independent of any kind of revelation. Scotus takes himself to be in agreement with Aristotle that human sense experience and natural reason are adequate to provide a demonstration of God’s existence.