As our study draws to a close, we can make a few final observations. We need not re-present each of our conclusions here. We have devoted a great amount of time to those conclusions in their respective chapters, especially at the end of Chapters 6 and 9. The general contour of our study has been a presentation of Aquinas’s account of the virtue to reveal its inner logic. That account’s interconnection with theological topics becomes obvious when we attend to his own language and various senses of virtue. The reasons by which Aquinas presents his account of virtue are inextricably woven together with his account of grace, sin, and God’s divine providence and governance of creation.

The last aspect of our analysis of virtue secundum quid falls to determining its end and conditions.1 Before broaching the conditions that enable us to speak of the end of pagan virtue, we must briefly lay out some metaethical points. Chapter 6 revealed that virtue simpliciter’s end meant considering the perfect happiness of the one who has arrived at journey’s end, the status comprehensoris. Now we take up that sort of end that is had by the one on earth, the status viatoris. This agent is propelled on his journey by desire. Because a desire for the good in general is hardwired into the human agent and constitutes the catalyst of agency itself, we must begin by examining what Aquinas holds to be the metaethical connections between goodness, goods, desirability, and ends.

Seeking to understand the necessary conditions of grace for virtue simpliciter, we have demonstrated that such virtue both begins and continues only through the supernatural grace of God. Not only that, but as his thought matures Thomas Aquinas comes to recognize that the human agent can, in virtue simpliciter’s beginning and continuance, do little to guarantee her obtaining and perseverance in that grace. Principally, the life of grace that founds and helps continue that life of virtue simpliciter lies locked within God’s providential wisdom. The agent’s choices, even perfectly virtuous choices, are only secondary, in terms of efficacious causality. At best, the human agent is able to cooperate with what God has begun and continues of God’s own gratuitous initiative. Having considered the beginning and continuance of virtue simpliciter’s necessary conditions, we consider the conditions pertaining to its end.

Virtue in the writings of Thomas Aquinas is inseparable from his understanding of sin, grace, and God’s presence in human life and action. The logic inherent to his account of virtue, virtue both with and without grace, requires us to speak of grace and sin. Because it pertains to the very logic of virtue to address these theological topics, it becomes impossible to treat them as mere addenda or to bracket them in favor of a supposedly complete philosophical account. This last point comes into greater relief when we acknowledge, with centuries of other readers of Aquinas, that his theology of grace underwent development throughout his writings. Yet little attention has been given to the effects this development exercises on both his understanding of virtue and the role it can take up in our moral lives. This is largely because readers of Aquinas, friends and adversaries alike, have become satisfied addressing the intersection of grace and virtue in terms of the infused and acquired virtues alone. While such a vector is certainly an interesting and demanding study, it fails to acknowledge the effects his developments in topics like operative grace, God’s influence in human action, and sin have for his account of virtue.

Since we wish to examine the conditions under which Aquinas thinks one can possess virtue, we must attend to the momentous shifts that occurred within his theology of grace. To ignore these changes would only be done to the peril of our inquiry. Because of the nature of the shifts, the issues they address, and the direction in which Aquinas moves, they are particularly important to understand accurately the place Thomas allots to virtue in the moral life.

While investigating the sources from which pagan virtue can spring, we distilled three necessary conditions for that virtue to count as authentic virtue: ordainability, good source, right reason. Each of these three conditions is necessary, without any one alone sufficient to establish the graceless agent in a virtuous life. Perhaps because Aquinas explicitly discusses it in relation to pagan virtue, most contemporary attention focuses on the ordainability condition. But it is not fair to say this is the only one to which he attends. Not only does he treat of the right reason condition, but it is easily foreseen given the role recta ratio serves in Aquinas’s moral science. It is certainly one of the ways his moral science is so indebted to Aristotelian ethics.

Contemporary authors have expressed their appreciation for Thomas Aquinas’s holistic approach to our ethical lives. In an age when virtues are often emphasized without an explicit and well-worked-out moral psychology, scholars find solace in panoptic treatments like that of Aquinas. This medieval mendicant has girded his conception of virtue with a profound anthropological depth. That account begins with why humans need the virtues. The human person is capable, by his own free will, to become so many different things. He is free to shape, hone, and altogether determine his various human powers in a multitude of ways. Just as a doctor can use his knowledge to either save life or take it, so too each person can mold his or her own natural powers for either good or evil deeds. Over time, these natural powers can become inclined toward such deeds and aims. By this inclination, the power becomes a determining force among the other powers of the human person.

The essence and principles forming virtue give rise to polyvalent meanings of virtue in Aquinas’s oeuvre. The highlighting of his language and use, therefore, ought not be thought an unimportant task. It constitutes a vital aspect of the larger question: In what way, if at all, can Aquinas’s account of virtue distinguish itself from the theological context in which that language of virtue was used? Before we can bring that larger question into sharper focus, we require an understanding of both Aquinas’s actual language and the relations pertaining among his various meanings of virtue.

Chapter 4 discusses Thomas’s account of original guilt. Infants are guilty only in an analogical sense. A human being with the use of reason is guilty in the proper sense when she commits a sinful act of her own volition; an infant is guilty in an analogical sense when she fails to receive original justice by Adam’s volition. The infant is in a moral middle ground, between the state of mortal sin and sanctifying grace (Scriptum II, d. 35, q. 2, a. 2, ad 2). She has not turned away from God, yet she needs grace nonetheless. Thomas’s explanation of infant guilt developed. He initially compared the guilt of original sin to an inherited disease (Scriptum II, d. 30, q. 1, a. 2). He later abandons this analogy and compares the infant to a homicidal hand. I defend Thomas’s view that the infant’s will is positioned between mortal sin and sanctifying grace. But I criticize his view of analogical guilt, arguing that receiving the effect of another’s sinful act cannot increase one’s own guilt.

Chapter 5 engages proposals that deny the importance of a historical Fall. I begin with Kant’s account of radical evil. An influential reading is this. Every human being who reaches the age of reason freely subordinates the moral law to self-interest. Next is Karl Barth’s “christologized” version of radical evil: the Fall is the universal act of unbelief in Christ. I argue that the reduction of original sin to the universality of actual sin is insufficiently inclusive. Neither infants nor the severely mentally disabled choose wrongdoing. Schleiermacher separated original sin from the Fall in a different way. Original sin is the corporate act of humanity. The “force” of sin is present in infants, albeit in germinal form, and when they mature they lack God-consciousness and tend to sinful self-love. Schleiermacher’s view leads to a problematic conclusion. Either sin is numerically one, or sin is merely environmental, external to the will. Schoonenberg defends a similar view but stresses human freedom. McFarland intriguingly proposes a synthesis of Maximus’s and Augustine’s accounts of the fallen will, while arguing that we can avoid etiological explanations of sin altogether. I argue, however, that we have to choose: we need either to explain why original justice is theologically unnecessary or to defend it in some form.

Chapter 1 puts Thomas’s account in its historical context by discussing Augustine and his medieval reception. The first part of the chapter focuses on Augustine’s mature account of original sin, drawing on The City of God and his anti-Pelagian works. I argue that Augustine’s account contained several fruitful ambiguities which would be the basis for medieval reflection. How should we understand the transmission of original sin and the origin of the soul? In what sense are infants guilty of sin? How can we make sense of the claim that human nature has been “corrupted”? The second major part of the chapter discusses Anselm of Canterbury, Peter Abelard, and Peter Lombard. Each of these theologians defended original sin while challenging at least one important aspect of Augustine’s teaching. Anselm claimed that concupiscence cannot be sinful. Abelard denied original guilt. The Lombard emphatically denied traducianism and insisted that infants who die unbaptized are guilty only in a highly mitigated sense.