Chapter 7 examines medieval theories of the first cause of evil. Although Augustine denied that something good is the cause of evil, medieval thinkers routinely attributed to him the view that something good – the will understood as a power of the soul – causes something evil. The majority of the thinkers considered in this chapter use Aristotle’s notion of accidental causality to argue that the will can cause evil not per se – that is, not intending evil as evil – but incidentally. Nevertheless, if the will causes evil, they face the dilemma that a good will cannot cause evil at all, and an evil will cannot cause the first evil will. Medieval thinkers deal with this dilemma in different ways. For example, Bonaventure and others hold that the created will is naturally defectible, and hence not entirely unflawed, and so it can do evil. Aquinas argues that the will causing evil for the first time presupposes a momentary nonculpable deficiency, which becomes culpable at the moment of the evil choice. For Scotus, the will is so free that it can do evil even if it is unflawed. Although all these views trace evil to the will as its cause, they hold that evil is ultimately unexplainable.

Chapter 10 studies theories of demonic obstinacy, the state in which the fallen angels or demons are unable to avoid sinning and have a limited ability to do good. The external cause of obstinacy is God’s refusal to offer them the grace of repentance and of justification. Beginning with Aquinas, theologians searched in addition for an internal, psychological cause of their obstinacy – a great challenge, given their shared belief that the angels’ will is by nature oriented to the good. Aquinas traces their obstinacy to the fixity of their cognition, and Henry of Ghent to the forcefulness of their will. Certain Franciscan thinkers explain the demons’ obstinacy by means of a divine intervention, binding their will to evil (Olivi), causing their immoderate self-love (Scotus), causing in them a habit of wickedness (Auriol), or even causing in them hatred of God (Ockham). Durand of St. Pourçain returns to the standard account prior to Aquinas, which explains the demons’ obstinacy by a divine decision, with no reference to their psychological condition. In addition to the cause of obstinacy, theologians discussed whether the demons, though necessarily obstinate, are nevertheless free.

Chapter 5 concerns the free will debate in the early fourteenth century. It thoroughly discusses the Franciscans Duns Scotus and William of Ockham, who make a sharp distinction between will and nature, that is, between a free power or cause that controls its act and one whose act is determined by external circumstances. Scotus and Ockham make the will more independent from a cognized good than previous thinkers. Using unedited texts, the chapter also presents what may well be the strongest statement of intellectualism at the time, by John of Pouilly, who builds on Godfrey of Fontaines to explain why, although our choices are moved by the cognized object, we control our choices. More briefly, the Dominicans Hervaeus Natalis and Durand of St. Pourçain are considered, whose general approach resembles Pouilly’s. As a thinker developing an intermediary theory, the chapter studies Peter Auriol, according to whom the will controls directly which judgment considered during deliberation becomes the final judgment that causes one’s choice. The dividing issue among these thinkers is, at bottom, whether the will controls its acts directly or only by means of deliberation.

Chapter 9 examines explanations of the angelic fall by voluntarists and thinkers holding an intermediary theory of free will. These nonintellectualist accounts agree – contrary to intellectualists – that there was deficient willing before there was deficient cognition. For some voluntarists, the discussion of angelic sin serves above all as confirmation of their own theories of free will (e.g., Henry of Ghent) or as proof that their adversaries are wrong (e.g., John Pecham). Others go further and try to give a plausible account of how the evil angels could intentionally make their choice (Peter Olivi), and to explain how their will could be defective while their cognition was unflawed (Duns Scotus). Among thinkers professing an intermediary theory of free will, the chapter considers Giles of Rome, whose account of angelic sin fits nicely with his general theory of the relation of ignorance and evil, and Peter Auriol, whose explanation of angelic sin does not sit comfortably with his theory of free will.

This chapter on participation in goodness, and on ethics or a good life, has been prepared for by the previous chapter, on beauty and desire. Like the chapter on truth and epistemology before that, this chapter on goodness is robustly realist: it sees what would be morally good for a person, community, or situation to align with the reality and good of the thing considered, which it has by participation in God. The twin focuses here are virtue ethics (which is explored in terms of the alignment of the good-as-moral with the good-as-excellent) and natural law (which is explored in terms of the alignment of the good-as-moral with the good-as-beneficial). No firm wedge, however, is driven between those two approaches, which are both related to God as source and goal in participatory terms. The chapter moves to a discussion of the expectation of the coherence of the good in a participatory framework, such that the goodness that creatures have (and, here, especially human beings) is expected naturally to align with the nature of the good as communicated, for instance, in revelation. This is explored in contrast with the thought of John Duns Scotus. The chapter ends with a participatory discussion of the nature of law in its various forms, including the participatory and theological backdrop to notions of international law.

The final chapters of this book look at how a participatory outlook can inform and has informed a vision of the world and what it means to live, act, pray, and seek God in it. This, the first of these chapters, considers knowledge and knowing in participatory terms. Knowledge is seen as a participation of the knower in the known, or a sharing from the known to the knower. This undergirds a 'realist' epistemology, in that knowing rests on the reality of the thing that is known. That said, it also stresses the creaturehood and particularity of the knower and the manner of knowing: that which is known comes to be in the knower in the manner of the knower, whether we are talking about our knowledge of an animal, of a plant, or of God. In the case of God, most of all, the knower never exhausts the depths of what is known. That also applies, however, although to a different degree, in the knowledge of even mundane things, since their deepest reality is a participation in God, which confers a creaturely form of inexhaustibility. In these ways, much of this chapter is an exploration of 'intra-finite participation': about how one creature participates in, or donates to, another. It closes with a discussion of the relation between reason and revelation.