In this chapter I trace the problem of killing in Christian thought. I then raise the question of whether any intentional killing can be justified; in the remainder of the book I argue that the answer to this question is “no”.

The ‘framing’ goods of life, sociality and rationality constitute necessary formal conditions of all the other, namely non-formal, goods. They are also intrinsically good; indeed, without any one of them, one ceases to be a human altogether. Life has absolute priority as a framing good, and is distinct from health (since one can be living and ill). After canvassing Aquinas’s and Finnis’s justification of life as a basic good, I offer my own bipartite justification in terms of life as both a ‘transcendent’ and ‘immanent’ human function. As to sociality, humans are essentially animals who live-in-relation, in the rich sense of developing various intentional relations to the world. If they fail to develop these, they become disabled (disability being a dysfunction and hence natural bad). I then detail various forms of sociality (which Aristotle calls philia, often translated ‘friendship’), along with the perfections or goods they embody. Last, I broach the framing good of rationality. This should be understood not as a virtue (either practical or theoretical), but rather as the ‘immanent character of human being and its form or mode of living-in-relation’. I explore its content in detail in Chapter 7.

According to Charles Taylor, the modern notion of the self is closely related to the notion of inwardness, for the self is taken to be something inside of us, accessible through introspection. Some medieval authors paved the way for this conception by identifying the self with the immaterial soul that somehow resides in the body. However, other authors clearly rejected an interiorization of the self, as this chapter argues. They took it to be a set of powers that is essentially related to external things and that becomes manifest in this relation. The chapter presents two case studies to spell out this alternative conception. It first analyzes Thomas Aquinas’s thesis that the self is present in bodily activities: whenever we perceive material objects, we become aware of ourselves as being directed toward them. The chapter then examines Peter of John Olivi’s thesis that the self is present in emotions: whenever we experience them, we cognize ourselves as being related to other people. It is therefore a bodily, relational, and social self that is at the core of two medieval theories.

Drawing from both the medieval Scholastic philosophical-theological tradition and Aristotelian virtue ethics, Thomas Aquinas offers a comprehensive and nuanced account of the virtuous life – one that suggests fruitful relationships not only with contemporary philosophical and theological discussions but also with recent empirical work. In this short chapter, I sketch the big picture using an Aristotelian, four-causes approach. Section 1 mainly addresses the final cause or telos of virtue: ultimately, perfect happiness in eternal life – although a good earthly life affords “a certain participation” in happiness. Section 2 considers virtue’s quasi-material causes: reason and the appetites, including the intellectual appetite or will. Section 3 focuses on the formal causes (modes) of virtue in general and of the cardinal and theological virtues in particular, as well as the relationships between various virtues in the larger structure of Thomistic virtue ethics – including the possibility of a unity of the virtues. And Section 4 discusses proposed efficient causes of such virtues, drawing on the various ways in which virtues are developed and related to each other in the Thomistic picture. Throughout, I consider connections between Aquinas’s account of the virtuous life and contemporary work in ethics, psychology, and education.

At first glance, Thomism and feminism seem like unlikely bedfellows. In spite of the apparent incongruity, I argue that a fruitful dialogue can exist between Aquinas and feminism, particularly regarding the relationship between the body and reason. To this end, I make three points. First, I argue that Aquinas’s anthropology provides a fertile ground for a discussion of women’s nature and flourishing. Second, I argue that there is surprising degree of similarity between the attitude of Thomas toward the female body and the attitude of certain contemporary feminists, such as Simone de Beauvoir and Shulamith Firestone. All three of these authors recognized that women are more affected by their bodies than men are, and all three saw this as a source of inequality between men and women. Third, I argue that, while Aquinas is wrong to conclude that women are less rational than men, it may nonetheless be true that women experience more frequent interruptions to their ability to exercise fully their highest powers because they experience more pain and fatigue related to their biology. Finally, I consider how the nature of the female body may dispose women to exercising their reason slightly differently than men do.

Divine Truthmaker Simplicity (DTS) avoids collapsing God into a metaphysical property by arguing that, to identify God with God’s wisdom, goodness (etc.) is not to identify God with a property, but rather to claim that God is the truthmaker for the predication “God is wise” (etc.). DTS has been the target of a number of recent objections. This chapter explains how Aquinas’s often overlooked distinction between two ways in which a thing can have a perfection – essentially and by participation – enables a response to these objections.

The earth’s shadow darkens the initial Heavens of Dante’s ascent, the shadow waning the nearer a Heaven is to that of the Sun.The inhabitants of the last earth-shadowed Heaven turn to that Heaven hoping to be free from the imperfections of terrestrial existence.But these Heavens’ vestigial earthiness exerts an effect.Each focuses on a particular imperfection: the fragility of moral vows; the defect of human law as a vehicle of justice; and the reign of “mad love.”These produce an urge to transcend this region.

But Dante has readers assess the losses as well as the gains that accrue when we leave our world behind.This assessment puts reason on trial, its inadequacies seeming to sanction reason’s subordination to faith as provided in the vision that beckons above.But these Heavens ask not only whether that’s possible but desirable.Reason’s inadequacies are shown to be inseparable from moral responsibility, from more just politics, and from the desires that generate the Comedy.Asking whether the transcendence of terrestrial existence makes for a happier life, Dante gives readers cause to consider the possibility that these earth-shadowed Heavens are more than merely a necessary step on the way to perfection.

Dante encounters a convention of famous minds moving circularly in unison, like the sun, an image of perfect intelligibility. He focuses on Aquinas’s synthesis of faith and reason, which purports to resolve those perplexities that vex previous Heavens. Dante’s doubts disrupt the harmony; he wonders how it’s possible to err, to “wander” from “the straight way,” as he had done. “Thomas of Aquino” addresses Dante’s wonder.

Dante’s verdict on Aquinas’s synthesis turns on the difference between the “Angelic Doctor” and Solomon. Their relative rank reflects the capacity of prudence and poetry versus law and deduction from abstract principle to understand and guide humanity. These alternative views of wisdom rest, in turn, on the question of happiness or the true good, the prior, shared concern that both faith and reason address. Aquinas’s thought answers to a particular view of good, one that makes this Heaven’s inhabitants exult on hearing that their “desire for their dead bodies” will be fulfilled.Dante thus brings readers to ask if the intrinsically individual good of resurrection can be the supreme good for a being that can ask the question of happiness, a being that can “wander.”

According to Suárez, unlike the properties that an Aristotelian science standardly demonstrates of its subject, being’s passions or properties – transcendental unity, truth and goodness – are distinguished only rationally from their subject. Despite the real identity of being and its properties, the conception of a being as one, true or good involves a conceptual addition, according to Suárez: one formally signifies, over and above being itself, a negation of internal division, while true and good formally signify, over and above being itself, aptitudinal extrinsic denominations from intellect and appetite. The paper explains how each of the latter denominations, according to Suárez, serves to explain, point to, or make clear something about being itself, namely, its aptitude to be an object of intellect or appetite.

This chapter begins the more speculative part of the book. It responds to two objections to the instrument doctrine. The first objection is that a person cannot use a nature distinct from him as his instrument, even a divine person, because the created nature would lack some necessary feature for it to exist concretely. With the help of John Duns Scotus’s theology of the hypostatic union, the chapter argues that Christ’s humanity can be an instrument of his person because created personality is an extrinsic feature to the constitution of human nature. If Scotus is right, then a divine person can use a really distinct human nature as his instrument without any loss to the fullness of his humanity. The second objection argued that the instrument doctrine amounts to nothing other than the attribution of secondary causality to Christ’s humanity. The chapter argues that the hypostatic union means that the actions of Christ in the flesh are irreducibly distinct from ours, belonging as they do to a divine person.

The argument of this chapter is that the instrument doctrine, if held, sharpens our understanding of other mysteries of the Christian faith, including the hypostatic union, the Church, and the sacrament of the Eucharist. One reason that Aquinas held to the doctrine was the clarity it brought to these other mysteries. With Christology, the benefits are grammatical and speculative. Calling Christ’s humanity an instrument leads us to think of the one who possesses it, namely, the Logos, and so it can render single-subject Christology clearer to the intellect. If Christ’s humanity is held to be an instrument, it also implicates in our understanding the divine power through which the Logos works. With the theology of the Church, the instrument doctrine supports the biblical idea that Christ sends the Holy Spirit on the Church as a human being, and not only as God. And with the theology of the Eucharist, the instrument doctrine assists Catholic faith in perceiving how Jesus gives us a share of the divine life through sacramental communion.

Chapter 1 introduces the instrument doctrine in Aquinas’s thought and explores its foundations in Scripture, focusing on Aquinas’s biblical commentaries. In his commentaries on Romans and 1 Corinthians, among others, Aquinas argues that the logic of scriptural teaching suggests that Christs’ humanity causes divine effects as instrument of the divinity, including our resurrection. The chapter shows how Aquinas interpreted the Scriptures as coherent with the Catholic tradition, especially the conciliar teaching on Christ in the early ecumenical councils. Aquinas thinks that the doctrine should be understood within the conceptual matrix of these early councils’ teaching on Christ.