Chapter 3 A Tour of the Summa theologiae
A Tour of the Summa theologiae
The basic structure of the three parts of the Summa theologiae has been laid out in . The present chapter is, in essence, a guided tour of its contents. No survey of the Summa can pretend to convey the richness of Thomas’s exposition and the wealth of the distinctions, qualifications, insights, arguments, and conclusions he brings to the thousands of theological issues and problems he treats. In what follows I try to give a sense of the range of doctrines considered and to sample a few of the important sections in some detail. This chart gives an initial overview of Thomas’s sacra doctrina and a sense of the sequential arrangement of each of the parts.
The Structure of the Summa theologiae
Prima Pars, Ia (1266–68)
1. Introduction: sacra doctrina (q. 1)
2. Proving God’s existence (q. 2)
a. Essential attributes (qq. 3–11)
b. How God is known (q. 12)
c. How God is named (q. 13)
4. Divine operations (qq. 14–26)
a. God’s knowledge (qq. 14–18)
b. God’s will (qq. 19–24)
c. God’s power (q. 25)
d. God’s beatitude (q. 26)
5. The Trinity (qq. 27–43)
a. The procession of the divine persons (q. 27)
b. The divine relations (q. 28)
c. The three persons (qq. 29–43)
— Persons in general (qq. 29–32)
— Persons in particular: Father, Son, and Spirit (qq. 33–38)
— Comparisons of the persons (qq. 39–43)
6. The production of creatures from God (exitus) (qq. 44–119)
a. The notion of creation (qq. 44–46)
b. The various kinds of creatures (qq. 47–102)
— Creatures in general (q. 47)
— Creatures in particular (qq. 48–102)
* Good and evil (qq. 48–49)
* Spiritual creatures, or angels (qq. 50–64)
* Corporeal creatures (qq. 65–74)
* Mixed corporeal and spiritual creatures, i.e., humans (qq. 75–102)
c. Providence (qq. 103–19)
The return of creatures to God
Prima Secundae, IaIIae.
Human acts in general in the return process
1. Introduction: Beatitude as the goal of humanity (qq. 1–5)
2. Human acts in themselves (qq. 6–48)
a. Acts peculiar to humans (qq. 6–21)
b. Acts common to humans and other animals, i.e., passions (qq. 22–48)
3. The principles of acts (qq. 49–114)
a. Intrinsic principles: Powers and habits
— Habits in general (qq. 49–54)
— Habits in particular (qq. 55–89)
* Good habits, i.e., virtues (qq. 55–70)
* Bad habits, i.e., vices (qq. 71–89)
b. Extrinsic principles: God as
— Instructing man through Law (qq. 90–108)
— Aiding man by Grace (qq. 109–14)
Secunda Secundae, IIaIIae.
Human acts in particular in the return process
1. Acts pertaining to all conditions of humanity (qq. 1–170)
a. Theological virtues
— Pertaining to the intellect: Faith (qq. 1–16)
— Pertaining to the will: Hope (qq. 17–22) and charity (qq. 23–46)
— Prudence (qq. 47–56)
— Justice (qq. 57–122)
— Fortitude (qq. 123–40)
— Temperance (qq. 141–70)
2. Acts pertaining to some or given in a special manner (qq. 171–89)
a. Graces gratuitously given, i.e., spiritual charisms (qq. 171–78)
b. The active and contemplative lives (qq. 179–82)
c. Various ecclesiastical offices (qq. 183–89)
Tertia Pars, IIIa (1272–73).
Christ as the way, or the consummation of the theological task
1. Christ in himself (qq. 1–59)
a. Introduction: The fittingness of the Incarnation (q. 1)
b. The mode of the union (qq. 2–15)
— The union and the Person assuming (qq. 2–3)
— The human nature assumed (qq. 4–6)
— What was co-assumed (qq. 7–15):
* Christ’s grace (qq. 7–8)
* Christ’s knowledge (qq. 9–12)
* Christ’s power (q. 13)
* Christ’s weaknesses of soul and body (qq. 14–15)
c. Consequences of the union (qq. 16–26)
— Concerning Christ himself (qq. 16–19)
— Christ in relation to the Father (qq. 20–24)
— Christ in relation to us (qq. 25–26)
d. The mysteries of Christ’s life and death (qq. 27–59)
— Christ’s birth (qq. 27–36)
— Circumcision (q. 37)
— Baptism (qq. 38–39)
— Life in the world and miracles (qq. 40–45)
— Passion (qq. 46–52)
— Resurrection and exaltation (qq. 53–59)
2. Christ active in the sacraments (qq. 60–90)
a. Sacraments in general (qq. 60–65)
b. Sacraments in particular (qq. 66–90)
— Baptism (qq. 66–71)
— Confirmation (q. 72)
— Eucharist (qq. 73–83)
— Penance (qq. 84–90)
Supplementum, Supp. 99 qq., put together by Thomas’s disciples after his death, mostly drawn from his earlier Writing on the Sentences of Peter Lombard
1. The sacraments in particular, continued (qq. 1–68)
a. Penance, continued (qq. 1–28)
b. Extreme unction (qq. 29–33)
c. Holy orders (qq. 34–40)
d. Matrimony (qq. 41–68)
2. The last things and eternal life (qq. 69–99)
a. The resurrection of the body and last judgment (qq. 69–91)
— The place of souls after death (qq. 69–72)
— The signs of the last judgment (qq. 73–74)
— The resurrection itself (qq. 75–78)
— The condition of the resurrected (qq. 79–87)
— The last judgment (qq. 88–91)
b. Heaven (qq. 92–96)
c. Hell (qq. 97–99)
The Prima Pars
After discussing sacra doctrina in article 1, the Prima Pars begins with Thomas’s teaching about God and includes sections on the divine essence in itself (qq. 2–26), the Trinity of Persons (qq. 27–43), and the procession of creatures from God (qq. 44–119). Like a series of Chinese boxes, each of these sections opens up to reveal other boxes and yet smaller boxes within. In investigating many of the doctrines treated in the Summa, Aquinas follows a pattern of asking three questions: (1) whether the thing in question exists (an sit); (2) what the thing is (quid sit); and (3) how the thing functions (qualis sit). Thus, the section on the essence of God deals with three issues: whether God exists (q. 2); how God exists, “or rather, how God does not exist,” as Thomas tellingly puts it (qq. 3–13); and finally how God acts (qq. 14–26).
Analysis I. The God Question (Ia, qq. 2–13)
Question 2 of the Summa, with its “five ways” (quinque viae) or proofs, for the existence of God, is perhaps the most read portion of the whole book. What was Thomas trying to do in the three articles that make up this brief question? Many argue that he was constructing a demonstration in what we today call philosophical theology, that is, a natural proof of God’s existence. Others contend that the Summa is not a philosophical exercise as such but rather a series of reflections based in revealed truth on the role of reason in faith. This is why at the start Thomas cites a biblical, not a philosophical authority, Exodus 3:14, “I am who am” (q. 2.3). A second point of contention is whether or not Thomas is in fact giving his own proofs for God’s existence. There is disagreement here, too, as some contend that he is not so much providing his own proofs as reflecting on the types of arguments philosophers have made for God’s existence.
It is important to pay attention to the location of the five modes for arguing for God’s existence in the structure of question 2. Thomas begins (art. 1) by ruling out any a priori, or self-evident, proofs for God’s existence, that is, demonstrations based on the nature of the term God or on the mind’s ability to conceive of truth as demanding a “First Truth.” Thomas insists that God’s existence is self-evident to God (quoad se), but not to the limited human mind (quoad nos) that cannot know the divine essence. Here Thomas is taking a stance against some important strands in Christian thought. The second article rules out the opposing error of fideism, the view that God’s existence can be affirmed on the basis of faith alone because of its superiority to reason. Thomas contends that while we cannot prove God’s existence by demonstrating why God must exist, because we do not know God’s nature, we can still demonstrate that God exists from his effects. In article 3 then, he investigates “whether God exists” through five ways, or lines of argument.
In investigating five arguments for the existence of God, Thomas follows previous philosophers—especially Aristotle—but the arguments are condensed and adapted for his purposes. Each of the five ways follows a similar structure. Thomas begins from observations about the world around us, then investigates the nature of the phenomenon by invoking metaphysical principles. In the first way, for example, Thomas argues that change cannot be fully understood in the realm of physics alone; it demands a metaphysical explanation. Change—that is, a transition from potentiality to actuality (e.g., the transition from being cold to being hot)—demands a catalyst of change outside the being that is changing, because “a thing in the process of change cannot itself and in the same way be both the cause of motion and what is moved; it cannot change itself. Everything that is changed [in this sense] must be changed by something else.” With regard to necessary causes, where the cause of change must be presently active for the change to take place (e.g., the stick has to be present for it to move the stone), Thomas argues that an infinite regress of causes is impossible. He therefore concludes that there must be “a First Cause of change, which everyone calls God.”
A full explanation of Thomas’s five ways of proving God’s existence is beyond the purview of this book. Each has elicited a large literature, with many Thomists upholding the validity of the arguments, and other philosophers and theologians denying them. Since the five ways reflect the arguments of previous thinkers, some students of Thomas have wondered if there is a more properly “Thomist” proof, either implicit in them, or developed in some other place in Thomas’s writings. Such questions cannot delay us here. It is important to note, however, that the five ways must be seen within the perspective of the whole program of the Summa.
Having determined “that God is” (an sit), Thomas turns to exploring “what God is” (quid sit) in questions 3 to 13. The exercise is paradoxical, because God is not a “what,” that is, a being like any of the beings we can know and define. God does not fall under the general notion of being (ens commune) at all. Thomas again reminds us that he treats God from the perspective of revealed truth by citing John 4:24, “God is spirit” (q. 3.1). The questions that follow in this part of the Summa are exercises in the logic of speaking about the unknowable God.
The key to Thomas’s doctrine of God is found in question 3 on the divine simpleness (simplicitas). Everything we know in the created world has some kind of composition, for example, the composition of parts in a body, the composition of formal and material principles, and the composition of essence and existence—that is, between what something is and the fact that it is. (Knowing what a dinosaur is does not mean that dinosaurs have to exist, as we know from experience because there are no more dinosaurs.) God is not a body, nor any kind of composite thing, because there is no difference between God and whatever things we truly ascribe to him, such as divinity, life, goodness, and so on. God is his goodness. In article 4 Thomas poses the question, “Whether in God essence (essentia, i.e., what God is) is the same as his act of existence (esse)?” He answers in the affirmative. Every being whose essence is not its existence—that is, every being that does not need to exist—must have its existence caused by a being that necessarily exists. Since God is the First Cause of all, “it is impossible … that his existence is one thing and his essence another.” Thomas continues, “Because existence is the actuality of every form and nature … , it is necessary that existence itself (ipsum esse) be compared to the essence that is different from it, as act is compared to possibility.” Whereas in Aristotle’s universe all beings were composed of possibility for a form and its actuation, in Thomas’s universe, by contrast, the relations of possibility and actuality in creatures are rooted in a deeper distinction, namely, the difference between the God who must be, because what he is is nothing other than his existence, and all other things, which need not have been, but have been called into being by God’s creative will.
For Thomas, when we think about the world we are confronted by the question, “Why is there anything?” One might be tempted to reply, “Who cares? That’s just the way it is.” Thomas, of course, does care. His search for ultimate answers led him to conclude that all the beings we know need not have been. They are, in other words, contingent. But the fact that they do exist requires a being whose essence (what it is) is identical with existence (it is), and that such a being is one and the same as the God of Exodus 3:14, who said, “I am who am.” God, therefore, is not the highest of beings in a hierarchy of good, better, and best within the category of “being in general.” Instead, he is totally outside any genus or hierarchy of being (q. 3.5) in a realm beyond our ability to conceptualize. Thomas is far from subscribing to the view that theologians later called “ontotheology,” that is, the notion that God can be spoken of within the categories we use for other beings. As Etienne Gilson and others have shown, for Thomas ultimate reality is not substance, or the One, or essence, or some other of the transcendental terms explored by philosophers. The pure act of existence is not a concept, a property or an attribute. Rather, it is what we affirm when we make the judgment that God is. In this sense, questions 3 to 13 of the Prima Pars are an exercise in transcendental tautology in which we learn that our attempts to capture the absolute simpleness of God in human language simply cannot apply to God. Because there is no difference in God between his essence and his existence, or between his perfections and his nature, all statements such as “God is good” or “God is perfect” can be reduced to the formula, “To be God is to be.” In Thomas’s view, the wisdom of sacra doctrina is not learning more of what can be said about God, but in coming to appreciate more and more fully the mystery of God’s unknowable existence by exploring how language falls short of knowing or naming God.
Further on in this initial God section of the Prima Pars (qq. 4–11), Thomas conducts a survey of the traditional “divine names,” that is, terms or predicates ascribed to God. Here he takes up a theme explored by early Christian thinkers, especially Pseudo-Dionysius. Thomas distinguishes between the negative names (God’s lack of composition, lack of end, lack of change) and positive ones (God’s perfection, goodness, omnipresence, eternity, and oneness). God’s absolute simpleness, states Thomas, expresses his transcendent difference from created reality, while naming God as the perfection of all perfections shows that he is immanent in his creation. The different expositions in this section of Prima Pars each reveal something of the richness of Thomas’s theology of the divine names.
Thomas caps his treatment of the divine essence with two questions of great import. Question 12 explores how we can be said to know God, that is, the modes in which our intellect relates to knowledge of God, while question 13 asks what exactly we do when we name God. Question 12 begins by noting that because God is infinite, we can never know God essentially, that is, the way he knows himself, although faith teaches us that our “natural desire to know the cause from the effect” means that our final happiness rests in the vision of God. Nor can we know God through any created likeness or illumination. Even the vision of God in heaven, although it will involve a direct beatifying sight, will not be a comprehensive vision in which we will see God as God sees God. Here Thomas also denies that anyone in this life could see God’s essence save by a brief miraculous exception, and closes by arguing that in our present limited condition grace grants us higher knowledge of God than reason does.
Question 13 is a reflection on speaking about God as simple, perfect, good, one, and the like. What rules ought to govern such speaking, and what do they tell us about the limits of language about God? What terms are appropriate for speaking about God? Thomas begins with the issue of whether any names could really fit God. Thomas approaches the question by invoking a central motif of his thought, the three modes of predicating terms of God. “Because God cannot be seen by us in this life through his essence, he is known by us through creatures, [1] insofar as he is their source, and [2] by way of eminence [i.e., as surpassing them all], and [3] by negation.” Here he takes exception to the negative view of Maimonides, according to which all true statements about God are essentially negative, such that names like “goodness” can signify only that God is not like the evil or privation found in created things. Thomas, on the contrary, holds that words indicating perfections—like goodness—really do signify that God is good, but also that the manner of God’s goodness goes beyond anything we could ever know. To say that God is living, for example, “signifies God as the source in whom life pre-exists, although in a higher way than we can understand or signify.” Certain words (e.g., goodness and wisdom) can be used of God directly (proprie), and not just because God is the cause of these realities in creatures. “Words like this signify the divine perfection, but imperfectly, just as creatures represent him in an imperfect way.” Although these names/words can be used properly of God, what does this mean given the imperfection of all our terms in relation to God? How is radical imperfection compatible with proper predication? At this point Thomas introduces an important distinction: “In the names we give to God there are two things to be considered, first, the perfections themselves, such as goodness, life, and the like, and the second, the mode of signifying” (a. 3 corp.). What Thomas means is that we can be sure that goodness is true of God, but that we have no idea of how transcendent goodness is realized in God. Once again, there is no knowledge of God’s essence, or of the perfections that are identical with it.
Thomas’s line of argument reaches its culmination in article 5, which asks, “Whether things said of God and creatures are expressed univocally?” Univocal speaking means that when we use a term like “being” of God and a creature we are using it in one and the same way (i.e., both God and creature are beings). Equivocation, on the other hand, means that the same word (e.g., “tart”) is used of two totally different things, that is, a dessert and a woman of dubious repute. Thomas argues against both these positions, defending the middle path of analogy: “words of this kind [i.e., perfection terms] are spoken about God and creatures by way of analogy, that is, according to a kind of proportion.” Thomas’s teaching on analogy has been the subject of a large literature. He employed analogy as a tool for talking about God and God’s relation to creatures—for saying how God and creatures are “differently the same.” The sameness resides in the fact that both God and creatures are affirmed as truly good; the difference is based on the fact that we can understand how creatures are good, but not how goodness is transcendentally realized in God. Speaking by way of analogy is central to the Summa. Many of the more than two thousand articles that follow make use of analogy, because any time we use words both of God and created reality, they have to be employed in an analogical way.
Having finished his consideration of God’s essence (quid sit), Thomas turns to how God acts in questions 14 to 26, that is, how God knows and wills. With his treatment of God’s nature as one then completed, the next major section of the Prima Pars (qq. 27–43) treats God as Trinity. Thomas insisted that revelation teaches two kinds of truths: those that are accessible to human reason, but with difficulty, and those that surpass the powers of reason. Among the latter is the doctrine that the one God is a Trinity of persons. The Trinity was central to the Christian reading of both the Old and the New Testaments. Thomas’s task was (1) positively, to synthesize the scriptural teaching about the Father, Son, and Holy Spirit, that is, to construct an ordered account of the Trinitarian doctrine found in the Bible and ecclesiastical tradition, as well as (2) negatively, to answer objections that for God to be one and three is nonsense or a logical contradiction. Treating the Trinity after the divine unity, as Thomas does, is not the only way to organize the data of sacra doctrina, but it need not be taken as somehow devaluing or minimizing Trinitarian doctrine. For Thomas, the Trinity is central—the God from whom all things come and to whom they return is a communion of shared knowing and loving, a transcendent divine “friendship” beyond our powers of understanding. Organizing his account around four fundamental categories (procession, relation, person, and mission), Thomas’s theology of the Trinity has remained influential in the West down to the present.
Analysis II. What Is Creation? (Ia, qq. 44–46)
Having completed his consideration of God’s nature in itself, Thomas takes up God as the creator of the universe under three headings: (1) the notion of creation (qq. 44–46), (2) the kinds of creatures in God’s dominion (qq. 47–102), and (3) the providence by which God governs creation (qq. 103–19).
An essential difference between the worldviews found in ancient philosophy and the belief systems of the three monotheistic faiths concerns the notion of creation. This is the difference between a view of the universe as something that always was and a quite different picture of a contingent universe brought into being by the free decision of the Creator God. From the perspective of creation, God is utterly transcendent to the world, not merely its best or highest part. Aquinas’s understanding of creation is a systematic expression of this foundational truth.
Thomas’s treatment of the notion of creation was novel and was attacked from many sides both in his lifetime and afterward. For the “Radical Aristotelians,” like Siger of Brabant, Aristotle and his commentators had rationally demonstrated that the world must be eternal; its existence in time was based on faith. To the traditional theologians who followed Augustine, such as Bonaventure, the temporal existence of the universe was not only taught by scripture, but was also a fact that could be demonstrated by reason. Thomas took his stance between both camps, thereby satisfying neither. For Aquinas, the fact of creation—the notion that the world depended absolutely on God—was a truth of faith, but also something demonstrable by reason. On the other hand, the duration of the universe—whether it was temporal or eternal—was something reason could not decide on its own.
Thomas’s maneuvering between these opposed positions can be approached through a consideration of four Ds that help clarify his position: dependence, distinction, decision, and duration. The Christian view of “creation from nothing” (creatio ex nihilo) means that the world is totally dependent on God. It always remains, however, distinct from its divine source. Creation also indicates that God creates the world freely by his own decision and that therefore the duration of its existence depends on his will. God decides to make a universe marked by temporality. From the point of view of reason, however, there is nothing impossible in the idea of a universe eternally dependent on God.
In further elaborating his view of creation, Thomas employs three important distinctions. The first is that creation cannot be thought of according to the Aristotelian concept of change (motus), because change presupposes some underlying reality (a passive potency in Aristotle’s terms), something to be changed, whereas creation has no prior something to be worked on (q. 46.2). Creation is not change; it is the beginning of a relation of absolute dependence (q. 44.1–2). The second distinction is the difference between a natural cause that has to act in a certain way (e.g., fire has to burn) and an intellectual agent, such as God, who acts on the basis of intellect and will (q. 46.1). Furthermore, as the third distinction argues, there is an essential difference between the particular intellectual agents we know and God as the universal intellectual agent, one who not only causes some condition or change, but also causes the total reality of all things in every aspect (qq. 45.2–3, 46.1). Aquinas’s notion of God as the universal creative agent goes far beyond Aristotle’s view of the four kinds of cause (efficient, formal, material, and final), once again revealing his analogical thinking at work.
Thomas’s theology of creation is an exercise in showing how revelation can use reason while also demonstrating its limits. He draws on Aristotle’s understanding of act and potency, but expands it into his own distinction between existence and essence to demonstrate that God must be absolutely different from the universe: God’s essence is existence, while in all creatures there is a distinction between essence and existence. “Everything that is other than God is not its act of existence, but participates in existence” (q. 44.1). The notion of participation invoked here is crucial in showing the dependence of all things on God. Participation was not prominent in Aristotle’s thought, but was a Platonic category developed by the Neoplatonist philosophers. The Neoplatonists, however, analyzed participation in terms of form; Thomas Aquinas’s universe is a hierarchy of participated existences. Thus, Thomas puts together key themes from the thought of both Aristotle and Plato and his followers in crafting a theology of creation that is different from anything found in the ancient world.
Thomas’s treatment of the different kinds of creatures takes up almost half of the Prima Pars (55 of 119 questions). The reason for this extended discussion, especially about human creatures (qq. 74–102), lies in the necessity of understanding our nature and its place in the order of the universe as a way to grasp how to return to God. Here Thomas makes considerable use of Aristotle’s teaching about human nature in general and the soul in particular. It would be a mistake, however, to think of this section of the Prima Pars as a purely philosophical treatise. It is intended to show how sacra doctrina can make use of the truths that reason has explored.
Thomas’s anthropology has rightly attracted much attention, especially with regard to his epistemology, that is, his account of how human knowing works. It is important to remember that, for all his use of Aristotelian teaching on the soul, his teaching is fundamentally biblical, as can be seen in question 93 on humans as made in the image and likeness of God (Gen. 1:26). Because God created man in his image and likeness, there is implanted in both the human intellect and will a tendency toward God as the final end, the true source of blessedness; but, since God’s infinite mode of being surpasses the powers of every creature, this end can be attained only by grace, the supernatural gift by which God freely shares his own divine life. This finality is true of both the intellect’s desire to attain the vision of God’s essence (e.g., q. 12.4) and the will’s desire toward ultimate happiness (e.g., q. 82.2). Thomas’s notion of the person as a dynamic intellectual being, for all its Aristotelian elements, is actually nearer to Augustine than it is to Aristotle in its emphasis on the material and historical destiny of each human.
How does Thomas conceive of human knowing? Perhaps no aspect of the Dominican’s thought has produced more disagreement. A few issues seem generally agreed upon; others are still contested. For Thomas, because the human intellect exists in a being that is both spiritual and material, “its proper object is an essence (quidditas) or nature existing in a material body” (q. 84.7). Therefore, human knowing begins in the senses and consists of a process whereby the intellect abstracts from, and eventually separates out, material sense knowing in order to gain an abstract idea, or insight, into what a thing is (quid sit), and then to ask whether or not this thing exists (an sit). Attaining truth consists in an identification of the knower and the known (“the understanding in act is the thing understood in act”: q. 87.1, ad 3), as contrasted with knowing conceived of as kind of gazing on truth found in the Platonic tradition (q. 84.1). Thomas employed the analysis of knowing found in Aristotle’s On the Soul (q. 79), especially its distinction between the intellect’s natural capacity to know (the possible intellect) and the active power of questioning that empowers humans to actually arrive at knowledge (the active intellect). For Thomas, however, the active intellect, or light of knowing, is the soul’s created participation in God’s knowing. So while Aquinas made use of Aristotle, his epistemology goes beyond the Greek philosopher’s in important ways. Following Augustine’s introspective analysis of the human subject found in the Confessions and On the Trinity, Thomas attends to the act of understanding as an internal conscious operation (e.g., q. 84.7). While Thomas spends a good deal of time discussing how the concepts that answer the question “What is it?” are formed in the mind by insight, he insists that the goal of understanding is not just forming concepts about things, but the act of judging whether or not these concepts are true. Unfortunately, conceptualist accounts of Thomas’s view of knowing that neglect the importance Thomas accorded to the act of judgment were to be a feature in the Thomist tradition for many centuries.
The Secunda Pars
The Secunda Pars, despite its length, has a symphonic consistency, featuring as its main theme how humans move toward or away from God through habits and actions. Here Thomas draws on his view of human nature as spiritual-corporeal being as set out in the Prima Pars and expands on it with a meticulous study of human intentionality and action. The Secunda Pars opens with a brief Prologue emphasizing the connection between the first two parts of the Summa rooted in the notion of humans as image of God: “Because … man is said to be made to the image of God insofar as the image is ‘an intellectual being with free choice and in control of its actions,’” declared Thomas, “it now remains to consider his image, i.e., man, insofar as he is the source of his actions, having free choice and control over his actions.” Just as God freely created the universe, so too humans exercise their freedom by acting according to God’s plan and making their way toward God as the goal of the universe.
The vast exercise in moral theology that follows is, once again, teleological, based on the question, “What is the purpose of human living?” Other questions that are directed to the goal of life flow from this, such as, “What are the powers and acts that humans share with animals, and what are those that are distinctive of human nature?” “What are habits and how do we distinguish between good and bad habits, that is, virtues and vices?” “What is the difference between virtues that we can gain by our own efforts and those that are God’s gift?” “What is the role of the law given by God in the Old Testament and the grace made available by Christ in the New Testament?” These are some of the larger issues of the Secunda Pars. Embedded within them is a forest of questions and hundreds of articles. We will touch on only a handful below.
1. The Prima Secundae
The first five questions of the Prima Secundae are the key for all that comes after, because here Thomas analyzes happiness (beatitudo) as the goal of human freedom. All the questions that follow deal with attaining that goal. For Thomas moral theology is based on the search for happiness, not on law or obligation. The Incarnation of the Word in history is the ultimate expression of the divine love that makes it possible for us to reach happiness. This locates Thomas within the tradition of what is called eudaimonistic ethics, in which moral action is determined by its relation to happiness, although there are many forms of eudaimonism.
Thomas begins by treating the ultimate end of humanity (q. 1.1–8). Properly human actions (actus humanus), as contrasted with those acts humans share with other animals (actus hominis), depend on intellect and will. Although all actions take place in view of some end or purpose, human acts are special, because they are characterized by the choice of the will concerning a goal or end, the good that the agent desires. Thomas argues that our individual choices of good outcomes, when closely analyzed, demand the existence of a single final goal, namely supreme happiness. He dismisses the usual claimants for the status of real happiness (wealth, honors, power, pleasure, etc.), things that—while good in themselves—constitute at best imperfect forms of happiness. Question 3 argues that only the uncreated Good, that is, the divine essence, can be the ultimate happiness humans strive after. As Thomas puts it, “for perfect happiness, it is necessary that the intellect attain to the very essence of the First Cause. And thus it will have its perfection through union with God as its object, in which alone happiness is found.” Although happiness consists essentially in an act of the intellect, it also involves the will insofar as the will reaches the fullness of delight when it attains the final intellectual goal. Everything that comes after this in the Summa exists under the sign of final beatitude—the activities that aid in the journey are good and the actions that impede it are bad.
A long analysis of human acts follows. Once again, Thomas makes use of the philosophical treatment of human action found in Aristotle, but within the perspective of the relation between nature and grace revealed in sacra doctrina and from the supernatural finality of the desire for the vision of God. In the prologue to question 6 he briefly introduces the rest of the Secunda Pars, saying that he will first treat human acts in general (IaIIae) and then move on to consider human acts in particular (IIaIIae). Concerning human acts in general, he distinguishes between the treatment of acts in themselves (qq. 6–48) and then the consideration of the principles of acts (qq. 49–114). Human acts in themselves can be further divided into acts that are distinctive of humans as possessed of intellect and rational will (qq. 6–21), and the acts that humans share with other animals, that is, the emotions, passiones in Latin (qq. 22–48). After treating the internal principles of acts, that is, powers and habits in questions 49–114, Thomas closes the Prima Secundae with two treatises once again illustrating his program of using Aristotelian thought to help understand revelation. They treat the two major extrinsic principles of human activity as directed to God: first, the instruction God gives to humans through the various forms of law, and then the supernatural gift, or grace, that provides humans with the power they need to attain the goal of the beatific vision. Here we will briefly look at what he says about grace.
Analysis III. What Is Grace? (IaIIae, 109–14)
Thomas’s understanding of grace interweaves Aristotle and Augustine under the aegis of what the New Testament, especially Paul, has to say about “the surpassing grace of God that has been given to you” (2 Cor. 9:14). The Dominican took his fundamental stance about the nature and necessity of grace from Augustine, but he drew upon Aristotle’s theory of human action as a form of change (motus), that is, a movement from possibility to actuality, to provide a deeper understanding of the action of grace in the life of the believer. Thomas also argues that grace as the participation in God has a history, so a theology of grace must treat its role in three states: (1) the time of innocence before the Fall, (2) the stage of fallen humanity, and finally (3) grace after the Incarnation.
Thomas insists that “[t]he gift of grace exceeds every faculty of created nature, since it is nothing else but a kind of participation in the divine nature that exceeds every other nature” (q. 112.1). This is why he uses the term “supernatural” more often in Secunda Pars than elsewhere in the Summa, as when he says that both Adam before the Fall and all humans afterward need a special divine help “to will and to work towards the supernatural good” (q. 109.2). Thomas’s use of the term supernatural was not meant to suggest that we live in some kind of two-story universe, consisting of a natural basement and a supernatural edifice placed on top. For Thomas the universe is one, but there are two ways of conceiving of action within it: acts directed to the good proportionate to our finite created nature, and acts aimed at the final goal of human nature, the eternal vision of God (q. 109.5). The term “supernatural” provided Thomas with a way to talk about God’s action in everyday human life. As he put it later in the Tertia Pars, “The final goal of grace is the uniting of the rational creature to God” (IIIa, q. 7.12).
The forty-four articles that make up the grace treatise deal with a number of interrelated themes. Some come from scripture and tradition, especially from Paul (as read by Augustine) on the strict necessity of grace. For Thomas, as for Augustine, grace not only was necessary for any saving action, but also was needed for the first movement toward God. Thomas’s reading of Augustine also led him to the conclusion that even the person who has received grace as a habit in the soul needs further grace as an impetus to perform saving actions. To explain this, the Dominican turned to Aristotle and his view of human action in, for example, the way he employs the Philosopher’s notion of habit and human operation to help understand how to talk about grace. Of particular interest in Thomas’s teaching is the care with which he analyzes the relation of the divine and human wills in the process of justification by grace conceived of as both operative (i.e., God alone acts) and cooperative (i.e., where the human will has a role to play). Thomas concludes his treatise on grace with a discussion of merit. If salvation depends on God’s free gift, in what sense can humans be said to merit the beatific vision? Thomas answers in terms of a traditional distinction, but with a new twist. Merit, he says, can be considered in two ways: merit is truly earned (ex condigno) insofar as an act really deserves a reward; merit is appropriate (ex congruo) insofar as it is fitting for God in his generosity to reward our efforts even though they are not commensurate with the goal. Saving acts come from two sources for Thomas: from the Holy Spirit as the source of grace, in which case merit is fully earned (ex condigno), and from us as cooperative agents to whom God gives merit as a fitting (ex congruo) reward for our efforts (q. 114.3). Thomas’s treatise on grace is a concise and original example of his theological method.
2. The Secunda Secundae
Although grace is never absent from the Summa, its explicit treatment at the end of the Prima Secundae allows Thomas to make the transition to the Secunda Secundae where he turns from considering human acts in general to acts in particular. Here Thomas is targeting acts insofar as they are salvific, that is, those that proceed from grace as their primary cause, though also involving the human will as cooperating with God. His treatment here is so detailed that all but the most devoted Thomists may be excused from reading the 916 articles that constitute the Secunda Secundae.
Thomas begins with a Prologue, distinguishing two ways of treating moral matters (moralia): first, from the material in itself, as when we consider a particular virtue or vice; and second, from the perspective of different situations in life that come with their own particular moral obligations. (For example, one can treat the moral obligations that concern everyone separately from the obligations that belong to special groups.) Since virtues and vices consider the same object (e.g., chastity and lust both concern sexual activity), he considers vices along with the virtues they oppose, as well as both positive and negative commandments relating to each. Furthermore, he argues that all the virtues can ultimately be reduced to seven: the three theological virtues of faith, hope, and charity (qq. 1–46), and the four cardinal virtues of prudence, justice, fortitude, and temperance (qq. 47–170). A look at his analysis of charity, the most important of the theological virtues, provides a sense of how he proceeds in this section of the Summa.
Analysis IV. The Virtue of Charity (IIaIIae, qq. 23–46)
Thomas devotes twenty-four questions to charity. Perhaps the most remarkable thing about his treatment is that he places it in the category of friendship (amicitia), citing Jesus’s words in John 15:15: “I do not call you servants any longer, but my friends” (q. 23.1). Because grace perfects nature, Thomas weaves all the natural designations concerning love into his account of caritas, not only friendship, but also love (amor), delight (delectatio), and benevolence (benevolentia). They are all subsumed into this most excellent of virtues, the virtue that for Thomas is the form, or inner reality, of all the virtues.
Thomas begins with Aristotle’s definition of friendship as a love of mutual benevolence founded on a sharing of goods (Nicomachean Ethics 8.2). Again, however, Thomas has to stretch Aristotle, because the friendship between God and humans consists in God’s sharing his own blessedness, something beyond any human communication. Thomas first turns his attention to the question of charity in itself, that is, how charity is infused into the will and can be increased, diminished, or even lost. Then he considers its objects, namely, how we are to love God, our neighbor, and ourselves with God’s own love. Thomas then asks what the order and the relationship of the different objects of love should be and whether it is more proper to charity to love or to be loved. For Thomas, to love belongs to charity insofar as it is charity in action; to be loved belongs to charity only in a secondary way insofar as a friend desires good for his or her friend.
Following the pattern set up for the other virtues, Thomas then turns to the effects of charity, distinguishing between internal effects (joy, peace, mercy) and external effects (beneficence, almsgiving, and fraternal correction). Next comes a long treatment of the vices opposed to charity: hate, which is opposed to delight; sloth and envy, opposed to joy; a list of vices opposed to peace (discord, contention, schism, war, quarreling, and sedition); and scandal, opposed to beneficence. Thomas argues that both love of God and love of neighbor belong to charity and that its two acts are integrally related: “The love of God is the goal to which the love of neighbor is directed” (q. 44.2–3). Just as charity is the supreme virtue, so wisdom, the highest of the gifts of the Holy Spirit, is partnered with it. Question 45 is Thomas’s most expansive treatment of divine wisdom, which presupposes both faith and charity (aa. 1, 4, 5).
The treatment of the theological virtues in the first section of the Secunda Secundae, lengthy as it is, pales in comparison with the expanse of his discussion of the four cardinal virtues of prudence, justice, fortitude, and temperance. Employing the same format in talking about them as he did with the theological virtues, Thomas asks once again, (1) what the virtue in question is in itself; (2) what are its parts, general and particular; (3) which of the gifts of the Holy Spirit correspond to it; (4) what are the opposed vices; and (5) what positive and negative precepts relate to it. Prudence, for Thomas, is the main regulating virtue, a cognitive habit that “applies universal principles to the particular conclusions of practical matters, … and regulates the things that relate to the goal” (q. 47.6). The virtue of justice is the subject of the longest treatise on any topic in the Summa (qq. 57–122). After this lengthy treatment Thomas notes (q. 123.1) that the virtues that make humans good can be impeded from following right reason in two ways: by being drawn to an object of pleasure in an irrational way, or by not following reason because of some difficulty that lies in the way. The virtue of temperance deals with the first impediment and the virtue of fortitude treats the second. Their consideration closes his monumental treatise on the virtues.
The third and last part of the Secunda Secundae deals with acts pertaining to particular classes of people, or associated with people in special ways (qq. 171–89). As usual in his moral theology, Thomas considers these special virtues and vices in a threefold manner. There are some activities that are based on special graces that pertain only to some people; actions that belong to particular states of life—including those associated with active and contemplative lives; and finally actions specific to the particular offices in the church.
In Thomas’s time the two modes of Christian existence that had become traditional in the life of the church were allegorically figured in Martha, representing the active life of service to others, and Mary as the contemplative life of dedication to God (Luke 10). Thomas’s analysis of the two lives (qq. 179–83) is among the most complete of the Middle Ages, bringing together insights from Aristotle and the teachings of the masters of Christian mystical thought, especially Augustine and Gregory the Great. His teaching is largely traditional. Although the contemplative life is higher, as a good Dominican he argued that the best life was not the purely contemplative life of the monks (q. 182.1–2), but instead the life exemplified by friars whose task it was “to hand on to others the things gained in contemplation” (contemplata aliis tradere: q. 188.6). Thomas never wrote a treatise on what today we would call the mystical life; this section in the Summa is as close as he came. The last part of this third section of the Secunda Pars (qq. 184–89) is ecclesiastical, presenting Thomas’s view of the responsibilities of church office in its treatment of the “states of perfection,” or modes of ecclesiastical life (different from the perfection of the individual).
The Tertia Pars
Here the topic is Christ. An in-depth treatment of Christ, we are told, “is necessary for the consummation of the whole work of theology” (Prologus). The first part, consisting of fifty-nine questions, treats Christology explicitly in two sections: the mystery of the Incarnation (qq. 1–26) and the events of Christ’s life and death (qq. 27–59). The second part deals with the sacraments. Introducing this part (qq. 60–90), Thomas notes that “[a]fter the consideration of the things that belong to the mystery of the Word Incarnate, we must deal with the sacraments of the church, which have their efficacy from the Word himself.” The sacraments have a Christological function in making the Redeemer’s saving work available to us.
Thomas intended to finish the Tertia Pars with a consideration of “the happiness of eternal life to which we come by rising again through him [i.e., Christ].” Sickness and death prevented this, so his disciples, probably under the guidance of Friar Reginald, put together the Supplement dealing with the last four sacraments—penance (begun by Thomas), extreme unction, holy orders, and matrimony (qq. 1–68), and closing with eschatology, that is, the last events of the human pilgrimage: the resurrection of the body, the last judgment, heaven, and hell. These materials were drawn from Thomas’s earlier Writing on the Books of Sentences.
Analysis V. The Incarnation (IIIa, qq. 1–26).
Treatments of Christology are found in many of the summae and scholastic syntheses. These accounts tend to mix historical treatments of the events from Christ’s life with theoretical considerations concerning the union of the human and divine natures in the Redeemer. The clear division between the theoretical (qq. 1–26) and the historical (qq. 27–59) sections in Thomas’s Christological treatise is original, as is his wide range of sources. While the use of scripture is richer in the second section than in the first, Thomas’s whole presentation is based on the truths about Christ found in sacra doctrina. The theological insights gained in the consideration of the union of the divine and human natures in the person of the Word provide guiding principles that help the Dominican draw out how Christ’s life is both the cause of our salvation and a model for our imitation. As he says, “Every act of Christ is an instruction for us” (q. 40.1, ad 3). Thomas’s Christology reveals him as a teacher, marshalling scriptural and theological authorities, principles, arguments, both deductive and fitting, to reach conclusions to deepen the reflective understanding of faith.
Christology deals with a truth that surpasses human understanding—specifically, the mystery of the Incarnation. Thomas does not attempt to uncover the secrets behind the mystery of how the divine Word took human form. Rather, his main goal is to work out a theological grammar that shows which expressions of the meaning of the Incarnation are coherent with faith and which are erroneous or heretical. Incarnation was a free act of God, as was Christ’s choice to die on the cross. Therefore, the foundations of Christology are not in necessary reasons or arguments. Much of what is contained here is argument from what Thomas calls convenientia, that is, showing the “fittingness” of God’s action in history. Of course, there are also some strictly deductive arguments that can be made from principles held by faith. The interplay between the various modes of argument in Thomas’s Christology is one of its distinctive features.
Thomas had already treated the Incarnation at length in Book 3 of his Writing on the Sentences and in the Summa contra Gentiles IV.27–55. This may account for the fact that few of the topics treated in questions 1 to 26 are new (only 14 articles out of 151). Still, on several issues the treatment of the Incarnation in the Tertia Pars is original. The first question deals with the fittingness of the Incarnation. Article 3 asks whether the Word would have become incarnate even if Adam had not sinned. Various scholastic teachers had answered this question in different ways, and there was a tradition of cosmic Christology, arguing on the basis of passages in John and Paul that the perfection of the universe made it fitting that God should become man even in the absence of human sin. Others followed Augustine in saying that the scriptures teach that the Incarnation took place in order to repair the damage caused by Adam’s sin. In the Writing on the Sentences and the Summa contra Gentiles Thomas held that either view was possible. Here he argues that “it is more fittingly said that the work of the Incarnation was ordained by God as a remedy for sin, so that had sin not existed there would not have been an Incarnation.” As ever, Thomas sticks close to scripture. He was convinced that the biblical passages about Christ’s primacy deal with final causality only, that is, they teach about the fittingness of the Incarnation in relation to the return of sinful humanity to its goal, not about a Christology implicit in creation itself. Others, such as Duns Scotus, disagreed.
Questions 2 to 6 investigate what the union of God and man in Christ actually is (quid sit). The union cannot take place in either the divine or human nature as such (otherwise one nature would be changed into the other), so it must take place in the person (Greek: hypostasis) of the Word (q. 2.2). In technical terms, it is a “hypostatic union.” A person, understood as “an individual substance of a rational nature,” possesses a nature but is distinct from it (e.g., we do not say “John is humanity,” but “John is a man”). Therefore, says Aquinas, “If human nature is not united to the Word of God in the person, it is not united at all and faith in the Incarnation is totally removed and the whole Christian faith is uprooted.” The hypostatic union involves a special kind of grace, the grace of union which Thomas defines as “the personal existence itself that is freely and divinely given to human nature in the person of the Word and is the term of the act of assumption.” Thomas makes a distinction between “union,” which signifies the fact that Christ is both God and man, and “assumption,” which is the action by which the Person of the Word takes up human nature into himself (q. 6.6).
In considering knowledge as one of the perfections of Christ, Thomas differentiates Christ’s different kinds of knowledge: his divine knowledge, his beatific knowledge, the knowledge infused in him by the gift of the Holy Spirit, and finally that which he acquired by the exercise of his human intellect (q. 9.4, and the whole of q. 12). Even before the Resurrection, Thomas insists that Christ had the special privilege of existing both as a comprehensor, one who possessed the vision of God, and as a viator, one who existed as a human learner. Thomas holds that on the human level Christ advanced in knowledge with regard to both intellectual habits and acts of knowing (q. 12.2), thus paying more attention to Christ’s acquired knowledge than other scholastics did. The final perfection that Thomas investigates is Christ’s “power,” that is, the range of his ability to act (q. 13). He shows that as a human being, Christ had to respect certain limits to his power—God alone is truly omnipotent. Christ had real human emotions (passiones), such as physical pain, sadness, fear, wonder, and anger (q. 15.5–9). While Thomas qualifies the extent to which Christ possessed these human emotions more than theologians would today, this section of his Christology was original in its time.
The first twenty-six questions of the Tertia Pars are among the most sustained accounts of Christology in all of scholastic theology, but Thomas decided that even this was not enough, so he crafted a treatment of the “deeds and sufferings” (acta et passa) of Christ’s life, death, resurrection, and exaltation in questions 27 to 59. Though often neglected, this detailed and existential treatment of Christ’s life is original and important. Thomas divided it into four parts: Christ’s entry into the world (qq. 27–39), the course of Christ’s life (qq. 40–45), Christ’s exit from the world (his death on the cross; qq. 41–52), and finally his exaltation after this life (qq. 53–59). Here Thomas draws extensively on the patristic authors, especially their biblical commentaries. Especially impressive is the way Thomas develops the theology of Christ’s work of redemption, coordinating the notion of satisfaction for sin with other biblical motifs, such as reconciliation, merit, sacrifice, obedience, and especially love, the primary motivation for our salvation. At the end of his massive treatment of Christology, Thomas concludes in a typically laconic way, “Enough for now about the mystery of the Incarnation” (q. 59.6, ad 3).
After finishing the Christological treatise, in question 60 Thomas turns to a consideration of the sacraments. He divides the section into a treatment of sacramentum in general (qq. 60–65) and a consideration of what by his time had become the doctrine of the seven specific sacraments of the church (qq. 66–90). The understanding of “sacrament” underwent a shift in the twelfth century, away from a broad notion of sacrament as the full range of rituals and practices used in Christian life toward a carefully defined concept of seven rites ordained by Christ and handed on by the apostles as the means by which Christ and his grace become present to believers. Thomas had considered the sacraments in his two previous syntheses, but there are new accents in his treatment in the Summa. The scholastics had inherited two understandings of the term sacramentum—Augustine’s stress on sacrament as a “sacred sign,” and Isidore of Seville’s notion of a “sacred secret.” By the time of Peter Lombard (d. 1160), the Augustinian notion of the sacred sign had prevailed, but with a growing emphasis on the idea that the seven “true sacraments” were signs that caused grace. This concern with causality was not just an academic conceit; it was an attempt to do justice to Paul and John’s depiction of the power inherent in baptism and the Eucharist. But how can a sign be a cause? And how are the divine and human agents related in the administration of the sacraments? What is the difference between the “sacramental” signs of the Old Testament, especially circumcision, and the sacraments of the New Testament? Why and how do some sacraments, such as baptism and holy orders, effect a permanent change in the recipient so that they are not to be repeated, while others, such as penance and the reception of the Eucharist, are repeatable? These and other questions led Thomas to devote considerable attention to this aspect of sacra doctrina.
Thomas places the notion of sacrament “in the category of sign” in question 60.1, before providing his specific understanding in article 2: “A sacrament is a sign of a sacred thing insofar as it sanctifies people.” The Christological core of Thomas’s teaching is set forth in article 3 where he discusses the triple signification of sacrament as including (1) the effective cause of our sanctification, namely, Christ’s Passion understood as the whole Paschal mystery; (2) the form (formal cause) of our sanctification, that is, the grace of Christ and the Holy Spirit and the virtues attendant upon it; and (3) the final cause, namely, eternal life. A sacrament, therefore, is a unique kind of causal sign that is simultaneously commemorative of the past, demonstrative of what is taking place in the present, and prognostic of the future. The acts of worship that constitute the sacraments as saving signs require the use of both a material element (e.g., washing with water in baptism) and verbal formulas, the words of faith that express the meaning of the action (q. 60.4–8). After investigating the necessity of the sacraments, Thomas takes up the question of how the sacraments function as causes of grace in question 62. In questions 27 to 59 Thomas showed how Christ’s human nature functioned as an instrumental cause of our salvation insofar as this human nature was joined to the person of the Word (i.e., an attached instrument). In question 62 he extends this insight by arguing that the sacraments are detached instrumental causes of salvation: “And therefore, the sacraments of the New Law are at one and the same time a cause and a sign. Hence, as is commonly said, ‘They bring about what they signify’” (62.1, ad 1; and a. 5). Question 63 considers the nature of the permanent effect (character) of the sacraments, which is the reason why some sacraments can only be received once. This, as Thomas explains, is because the character is a deputation that enables the recipient to take a specific role in Christian worship. Question 64 takes up the respective roles of God, Christ, and the human minister in administering the sacraments in terms of the distinction between God’s originating causality and the instrumental causality of the human minister. Finally, question 65 shows why it was fitting that Christ instituted seven sacraments. In Thomas’s understanding of the sacramental system there is both a movement from above by which God in Christ brings down saving grace to humanity, and a movement upward in the church’s worship of its God and Savior, so that, in Liam Walsh’s words, “[the sacraments] allow God to act humanly in signs made by humans.”
Having established the nature, efficacy, and number of the sacraments, Thomas proceeds with his investigation of each sacrament, beginning with baptism (qq. 66–71), proceeding to confirmation (q. 72), and moving on to the Eucharist (qq. 73–83), which he argues is the most important sacrament (q. 65.3). Thomas finally took up the sacrament of penance, which was always much discussed in scholastic literature. He managed to write only seven questions (qq. 84–90) before the incident of December 6, 1273.
Thomas’s death left his students and colleagues with the vast but unfinished Summa theologiae. The work was already circulating in some of its separate parts, and there is no question that the world of scholastic theology—not just the Dominicans—was eager to examine the book. But Thomas’s views, at least in some areas, were controversial. What was to become of his great effort to provide a sapiential ordering to the whole of sacra doctrina?