The Cambridge Companion to Aquinas, edited by Eleonore Stump and her friend and former teacher Norman Kretzmann († 1998), appeared almost thirty years ago. In the time since the publication of that volume, an enormous amount of research on Aquinas’s thought has appeared. The time is right, then, for a redoing of that Companion volume. But because so much time has elapsed since the first Companion volume appeared, it was not feasible just to revise it and reissue it as a second edition. Instead, it was necessary to start over completely. With the exception of Eleonore Stump, all the contributors to The New Cambridge Companion to Aquinas are new and have written original papers for this volume; and even Stump’s paper in the first Companion volume has been replaced by an entirely fresh essay.

When it comes to God’s creation of and interaction with the universe, it has sometimes been suggested that Christian revelation tells us nothing about the world and its origins, restricting itself to questions of value and not to matters of fact.1 Thomas Aquinas, by contrast, argued that a false account of creation implies false opinions about God.2 Aquinas consistently held that there were a number of truths about the creation of the universe that are central to Christian revelation: first, the truth that the world causally depends on God for its existence and all of its operations. Given the way in which Aquinas conceives of this dependence, this first truth implies that the universe is guided by God’s intelligent ordering or providence. The second truth is that God created the world with no constraints of any kind, including the necessity of creating from pre-existing matter, the necessity of employing causal intermediaries, or a necessity imposed by his reasons (such that he was not free to do otherwise). The third is that the universe was created in time: that is, having a definite beginning in the finite past. Of these three central truths about creation, Aquinas held that only the third is a revealed truth strictly inaccessible to human philosophical discovery, whereas the first and second are truths for which we can give conclusive, independent philosophical demonstrations even though they are also taught by Scripture. Beginning with his theological motivations, I will explain Aquinas’s commitments in regard to God’s creation, the universe’s dependence upon God, and its beginning in time.

The introduction explains the significance of the study’s topics, efficient causation and causal powers. It explains why a study on Aquinas’s views of these topics is needed. It also describes the methodology for reconstructing Aquinas’s views and the organization of the book.

Freedom is, without a doubt, an important component of Aquinas’s worldview. The drama of salvation, in which humans respond to God’s offer to redeem them from sin and give them everlasting happiness, would make no sense if humans were not free.1 But commentators have found it difficult to agree on the details of Aquinas’s views.

Following Aristotle, Aquinas posited three virtues of the speculative intellect: science, wisdom, and understanding. Aquinas’s accounts of the virtues of science and wisdom have received a great deal of attention, as has his notion of intellectual virtue in general. But understanding as an intellectual virtue has received almost no attention at all. Part of the difficulty stems from Aquinas himself: Aquinas uses intellectus broadly, and typically without specifying whether he means to refer to our natural habitual knowledge of first principles, the act of understanding, or a developed virtue. At the same time, however, Aquinas clearly considers the virtue of understanding to be both important in its own right and fundamental to the virtues of science and wisdom. This chapter seeks to examine understanding as an intellectual virtue in Aquinas and to propose a hypothesis about what, given Aquinas’s account, it would mean to develop the intellectual virtue of understanding. I will argue that Aquinas’s account implies that we can develop the virtue of understanding only insofar as we can come to increase what we habitually know and thereby pave the way for our understanding to operate more readily and more effectively. In this way, the virtue of understanding is importantly different from the other intellectual virtues.

This chapter provides an introduction to Aquinas’s views on efficient causation and causal powers, as well as some background and context necessary for appreciating his views. The chapter first introduces Aquinas’s views on the nature of the relationship between an efficient cause and its effect and the various elements involved in paradigm cases of efficient causation. After presenting an overview of Aquinas’s theories, the chapter next contrasts Aquinas’s views with competing historical theories of causation. Comparison with these other theories helps to highlight what is philosophically significant in Aquinas’s theories. The chapter also discusses Aquinas’s sources and situates his views relative to medieval debates about causation. This background provides some context for appreciating what is original or controversial in Aquinas’s theories. Finally, the chapter includes an introduction to the technical terminology that Aquinas uses to express his views on efficient causation and causal powers.

The doctrine of the transcendentals is a truly medieval doctrine. Up until the thirteenth century, philosophers and theologians were familiar with the study of being through the ancient philosophers and their schools, particularly Plato and Aristotle. What was important for Plato, Aristotle et al. was to offer an account of being in terms of those constitutive principles without which nothing would be. So, for example, being was taken to be accounted for in terms of participation in the forms (Plato), or through the dichotomies of substance and accident, matter and form, act and potency (Aristotle). What such projects seemed to exclude, or at least did not address explicitly, was the character of being itself. The question of the character of being itself was not explicitly elaborated until the thirteenth century, when the chancellor of the University of Paris, Philip, produced his Summa de bono (1225–8), the first eleven questions of which elaborate the doctrine of the transcendentals or what he called the communissima. Philip was quickly followed in this project by the Franciscans at the University of Paris, notably Alexander of Hales, whose Summa theologica or Summa fratris Alexandri (1245) contained a treatise on the transcendentals in Book 1.

Powers explain how agents are able to act. Yet, Aquinas thinks that we must posit something further in a natural agent to account for why it exercises its power whenever it is possible to do so. Natural inclination is that impetus within natural agents that determines them toward action. This chapter examines Aquinas’s understanding of natural inclination and the role it plays in efficient causation. The chapter first considers Aquinas’s views on what natural inclinations are and why they are necessary. The chapter next considers his views on how natural inclinations explain how natural agents act for the sake of ends. Even though natural agents cannot know the ends for which they act, Aquinas thinks that they nevertheless act for the sake of goals through their natural inclinations. Lastly, the chapter examines Aquinas’s views on the ultimate cause of natural inclinations. Aquinas maintains that natural inclinations, and the natures upon which they follow, must have their ultimate causal source in a being with cognition, namely God. The chapter analyzes Aquinas’s rationale for this view.

Aquinas thinks that not all instances of efficient causation are equivalent. Certain instances of efficient causation, namely per se cases, are the most fundamental and proper. Other instances of efficient causation happen in virtue of these cases. The chapter reconstructs Aquinas’s views on per se efficient causation. The chapter next examines Aquinas’s views on the temporal and modal relationship that obtains between per se natural efficient causes and their effects. The chapter shows that Aquinas thought that per se causes are simultaneous with their effects. Contemporary scholars debate whether Aquinas thought that natural efficient causes necessitate their effects. The chapter brings greater clarity to Aquinas’s views by examining his distinctions between different types of natural efficient causes and different types of necessity. Finally, the chapter considers Aquinas’s views on important relational conditions for efficient causation: the agent and the patient must be distinct and they must be in contact with each other. The chapter analyzes Aquinas’s arguments against self-motion and action at a distance.

Toward the end of his life, Aquinas delivered a series of catechetical talks in the vernacular on the Apostles’ Creed to an Italian audience, which were preserved in Latin by his secretary, Reginald of Piperno. Its eschatological themes, including the resurrection, would have been of huge importance to Aquinas’s audience.1 His exposition shows his commitment in faith to the future resurrection of all the dead for judgment, and to an eternal reward bestowed on those who die in a state of grace and an eternal punishment for those who die in sin. In our own times there has been widespread theological debate over whether an eternal hell will ever be populated, especially in view of those passages in Scripture that suggest a renewal of creation. In Aquinas’s time and place there was no such controversy about hell. But while the beatitude of heaven enjoyed priority over hell in his theological thinking, with infernal punishment understood to consist primarily in the eternal loss of the beatific vision, fundamental to each was the bodily resurrection common to both the blessed and the wretched.

Matter and form are two notions lying at the very heart of Aquinas’s broadly Aristotelian conception of reality. Aquinas inherits these notions from Aristotle (hyle and morphe in Greek), and his understanding of each is shaped to a large extent by the various uses to which Aristotle himself puts them. Even so, the precise nature of Aquinas’s hylomorphism, as well as its centrality in his thought, are of independent significance. Indeed, it would be impossible to understand Aquinas’s fundamental divisions of reality – including the division of God and creature, substance and accident, body and spirit – apart from his own particular conception of matter and form. It would also be impossible, apart from this same conception, to appreciate the elements of an explanatory framework that Aquinas deploys in almost all his writings – including potentiality and actuality, principles and causes, and the fourfold division of causes into material, formal, efficient, and final. In short, to acquire a familiarity with the details of Aquinas’s understanding of matter and form is almost to become accustomed to his distinctive vision of reality.

Thomas Aquinas was born to an aristocratic family in Roccasecca, near Naples, probably in 1226.1 At an early age, he was sent to be schooled by the Benedictine monks at the famous abbey of Monte Cassino.2 It seems that his family planned that he would one day become its abbot – a fitting position of honor and prestige for the youngest son of Italian nobility.3