17.2 Reasoning Concerning the Incarnation (SCG 4,40–49)
17.2 Reasoning Concerning the Incarnation (SCG 4,40–49)
With all of these thoughts in mind, Aquinas acknowledges that if Christ is both human and divine, it will be necessary to say things of him that are in opposition to each other. He also concedes that “opposites cannot be said truly of the same thing in the same way.”11 It would be absurd to claim that, for example, I am, without qualification, both suffering and incapable of suffering, or that I am unqualifiedly, both dead and immortal. So, Aquinas notes, “it is necessarily in different ways that the divine and human are predicated of Christ.”12
In that last quotation, from SCG 4,39, Aquinas is working up to the view that we should distinguish between what can be truly said of Christ while paying attention to the distinction of natures in him. On the one hand, he thinks, we can say what is true of Christ insofar as he is divine. On the other, we can say what is true of Christ insofar as he is human. According to Aquinas, what we say of Christ insofar as he is divine is going to conflict with what it makes sense to say of a human being. If, for example, Christ is God, then Christ is omnipotent. But human beings are not by nature omnipotent. Again, if Christ is human, then Christ walked around and was capable of suffering. But the divine nature, which, for Aquinas, is God, is not able to walk around or suffer. What, though, if Christ is one subject with two distinct natures? Then, thinks Aquinas, it can make sense to say both that Christ walked around and was capable of suffering with respect to his human nature and that Christ was omnipotent or anything else that God is by nature.
Suppose that I am a US citizen and a car mechanic. My being a US citizen entitles me to vote in the United States while my being a car mechanic does not come with this right. Again, suppose that I am a professor of philosophy and a qualified dentist. As a professor of philosophy I am not entitled to extract people’s teeth. Yet I am so entitled considered as a qualified dentist. Given certain qualifications, therefore, we can make sense of the idea that contraries might be consistently ascribed to one and the same thing, which is the thought that Aquinas has in mind when thinking about the Incarnation. He holds that we can consistently ascribe contraries to Christ while bearing in mind the distinction of natures in him, while noting what is true of Christ as God and what is true of him as a human being.
Obviously, the examples I have just given are going to be of only limited value when thinking about the Incarnation as Aquinas understands it. My being a US citizen and my being a car mechanic do not amount to me having two natures as Aquinas understands the word “nature.” Generally speaking, he thinks that “nature” is equivalent to “essence.” So he would say, for example, that something having a human nature is essentially human (has a human essence), though he would not say that anybody is essentially a US citizen or a car mechanic or a philosophy professor or a qualified dentist. Be that as it may, however, he does claim that, when it comes to the Incarnation, we can distinguish between what Christ is as God and what Christ is as human, or between what the Word is as God and what the Word is as human.
As I have noted, Aquinas accepts that the Incarnation, as a work of God, “most especially exceeds the reason.”13 But he is aware of certain arguments to the effect that the doctrine of the Incarnation, as he understands it, is positively unreasonable. In SCG 4,40, therefore, he lists them. Then he presents what he takes to be a true account of what should be said about the Incarnation (SCG 4,41) while going on to elaborate on certain aspects of the Incarnation (SCG 4,42–48). Finally, he explains why he takes the arguments noted in SCG 4,40 to be misguided.
17.2.1 Arguments against Belief in the Doctrine of the Incarnation (SCG 4,40)
Here are the arguments to which Aquinas refers in SCG 4,40:
1. If God is not corporeal, then God cannot become corporeal.
2. Something that acquires a new nature undergoes substantial change. So if God the Son acquired a new nature with the Incarnation, God the Son is, impossibly, substantially changed.
3. “If the hypostasis of the Son of God becomes by the Incarnation the hypostasis of human nature, the Son of God is not everywhere after the Incarnation since the human nature is not everywhere.”14
4. To have a nature is to be something of a certain kind and not another. So one individual cannot subsist in two natures.
5. In God, nature and individuality are the same. God is the divine nature and the divine existence. “But human nature cannot be identified with a divine hypostasis. Therefore, it seems impossible that a divine hypostasis subsist[s] in human nature.”15
6. A nature is more simple and formal than the thing that exists with a nature since something existing with a nature is material and, therefore, complex: it is composed of form and matter. If what is divine exists in human nature, therefore, that human nature is more simple and formal than a divine hypostasis, which is impossible on the assumption that God is entirely simple.
7. Every human individual is material; yet a divine being cannot be this.
8. Christ’s soul and body were the equal of those of other human beings. But in other human beings soul and body make up one thing. So, given the orthodox doctrine of the Incarnation, the soul and body of Christ make up one thing: the person of the eternal Word. Yet this seems to mean that there are two persons in Christ if God is incarnate in him.
9. The soul and body of a human being make someone to be a particular human being. We should, therefore, conclude that, if Christ is God incarnate, God is two individual subsisting things.
10. Considered as having a soul and a body, Christ is a particular substance. So, just by being that, Christ is a hypostasis, and we do not need to talk about the Word as the only hypostasis present in the Incarnation.
11. If in Christ, considered as both human and divine, there is only one individual, “then in one’s understanding of the man who is Christ there ought to be a divine hypostasis.”16 Yet particular human beings are not divine individuals. Therefore, and given the doctrine of the Incarnation, “___ is human” can be affirmed of Christ and other people only equivocally.
12. According to the doctrine of the Incarnation, in Christ there are body, soul, and divinity. But the soul informs the body or is the form of the body. So the soul is not the individual human being. In that case, however, neither is something divine an individual of human nature; “it is, rather, formally related to that nature.”17
13. What comes to be in something after the thing has come into being is an accident of that thing. So if the Word comes to be flesh, this must amount to the Word acquiring an accident. Yet there are no accidents in God.
17.2.2 How to Understand the Incarnation (SCG 4,41)
The key thought in SCG 4,41 is that Christ is one individual with two natures. Aquinas holds that, in Christ, there is one subject with two natures. The subject is the Word: the Second Person of the Trinity. The natures are divine nature and human nature.
Aquinas begins to develop this understanding of the Incarnation by noting that the word “nature” is used in different ways. However, he settles on an understanding of “nature” that takes something with a nature to have an essence. He then argues that “nothing prevents some things not united in nature from being united in hypostasis or person.”18 He suggests that members of a species cannot conceptually or in reality have anything added to them that leaves them to be members of that species if what is added results in them becoming members of another species. So, for example, “if to animate substance one adds only sensible, one will have another species.”19 Aquinas nonetheless goes on to say that it is possible for something belonging to a species to have what other members of it do not. One human being, for example, might have musical talents while another might not. So, says Aquinas, “nothing prevents some things being made one in the individual which are not united in one integrity of species.”20
I take it that Aquinas is at this point thinking with an eye on the fact that if Christ is one subject with two natures, then we will ascribe to him properties or attributes that do not all belong to something with one nature, properties or attributes that might even be thought to conflict with each other. Hence, if Christ is divine, then Christ is eternal and omnipotent. But if Christ is human, Christ is physical, changeable, mortal, and subject to things acting on him. Yet how can all of this be true? Aquinas replies that it can be true since it is possible for a subject to be more than what its nature implies and that Christ, who is human, can be more than what a human being essentially is. Christ could not be more than what a human being essentially is if Christ were merely human. Yet, thinks Aquinas, if Christ has two natures belonging to one subject (the Word), there is nothing to prevent him having properties or attributes that belong essentially to things of different natures (i.e., the divine nature and human nature). He recognizes that if, say, a particular dog has something that is not included in an understanding of what it takes to be canine (if, say, it has black hair), that something will be an accident. He does not, though, want to suggest that being human is an accident in God since he denies that God has accidents. He does, however, think that there can be a subject of which we can predicate what does not belong to a particular nature, which would seem to leave open the possibility of there being a subject that is both human and divine and of which different things can be said with an eye to different natures had by it.
When it comes to the Incarnation, therefore:
The union of the Word and the man was such that one nature was not breathed together out of the two; and the union of the Word to the human nature was not like that of a substance—a man, say—to those externals that are accidentally related to him. … But let the Word be set down as subsisting in a human nature as in one made his very own by the Incarnation; and in consequence that body is truly the body of the Word of God, and the soul in like manner, and the Word of God is truly man.21
According to Aquinas, the Incarnation involves a union of two natures in one subject or person: the Word. The Word is divine, and Christ is both human and divine since Christ is the Word incarnate. Aquinas, of course, acknowledges that statements like “My cat is feline and canine” are self-contradictory. He agrees that things having only one nature cannot be what things having another nature are unless they can be subsumed under one genus. Obviously, if X is a mammal and if Y is a mammal, X and Y might be thought to be the same in some respect even though they differ when it comes to nature (differ when it comes to what Aquinas would call substantial form). Hence a cat and a whale, though both mammals, are different things with different natures. Nevertheless, Aquinas thinks that something with distinct natures can consistently be spoken of in seriously different ways because it is one subject of which we can assert all that might be properly asserted of things with different natures. So, he says, if Christ is divine, then all that is true of the divine essence can be affirmed of him. And if Christ is human, all that is true when it comes to what is human can also be affirmed of him. In Aquinas’s view, the apparent conflict in what we might say of Christ with a view to his human and divine natures does not amount to self-contradiction since these natures are had by one subject. In his view, “Christ is God” and “Christ is human” affirm that one subject has two natures, not that one nature can be what another one is.
As he continues with SCG 4,41, Aquinas admits that the Incarnation presents us with something both unique and hard to fathom. He holds that the Incarnation is unique since, apart from Christ, there is nothing we can refer to that is one subject with two distinct natures. We can, he thinks, refer to things that are similar in nature. But things like these are not single subjects having two distinct natures. As for it being hard to fathom what is involved in the Incarnation, Aquinas holds that this is inevitable given our ignorance when it comes to what God is. As I have shown, he agrees that we can make various true statements concerning God (see chapters 5–9 here). As I have also shown, however, he denies that we have a grasp of what God is as we might have a grasp of what, for example, a cat is (see chapter 4 here). Given what we find in his SCG discussion of the Trinity (see chapter 16 here), Aquinas does not even think that we have some full-blown understanding of the persons of the Trinity comparable to our knowledge of three things in the world. Toward the end of SCG 4,41, however, he offers an analogy when it comes to the Incarnation. It is one that he derives from the Athanasian Creed, which he takes to teach that “as the rational soul and flesh are one man, so God and man are one in Christ.”22
Aquinas obviously has to deny that the Second Person of the Trinity is just the soul of Jesus of Nazareth, a living human being. He thinks that our bodies are united to our souls as matter is united to form; but he does not want to say that Christ is just matter informed by God the Son. He believes that this suggestion would mean that there is but one nature made of God and what is human. Yet, he says, when thinking about human beings with souls, we might usefully note how the bodies of people can be united to their souls as instruments of them.
Suppose that I am driving a car. In that case, who is driving the car? It would obviously seem to be me. Yet how does the car stand to me as I drive it? It would seem to be something that I use as a means for traveling around. So let us say that my car is an instrument that I use so as to achieve an end that I have in mind.
But now let us suppose that I scratch my neck so as to get rid of an itch. If I scratch my neck to relieve an itch, I will use my hand, and my will is working through my hand. The movements of my hand seem directly under my control in a way that a car is not as I fiddle around with it. So might we plausibly think that Christ was God incarnate as united to God as I am united to my body as I will to act and to choose? Aquinas clearly thinks that there is something in this suggestion.23 He writes:
A pick-axe is not the soul’s very own instrument, as one’s hand is, for many people can wield one and the same pick-axe, but one’s hand belongs to one’s soul in its very operation. For this reason the hand is an instrument of the soul united to it and its very own, but a pick-axe is an instrument both external and common. This is the way, then, in which even the union of God and human nature can be considered. For all people are related to God as instruments of a sort, and by these God works. … But people in general are related to God as extrinsic and separated instruments, so to say; for God does not move them only to operations which are his very own, but to the operations common to every rational nature. … But the human nature of Christ is assumed with the result that instrumentally he performs the things which are the proper operation of God alone. … The human nature of Christ, then, is compared to God as a proper and conjoined instrument is compared (sicut instrumentum proprium et coniunctum), as the hand is compared to the soul. … Therefore, nothing prevents our putting the union of the human nature to the Word in this way: that the human nature is, so to speak, an instrument of the Word—not a separated, but a conjoined, instrument: and the human nature, nonetheless, does not belong to the nature of the Word, and the Word is not its form; nevertheless, the human nature belongs to the person of the Word.24
One should notice, however, that having said all that, Aquinas observes that the comparison he has in mind at this point is not and cannot be exact. “One should understand,” he says, “that the Word of God was able to be much more sublimely and more intimately united to the entire human nature [sc. of Christ] than the soul to its very own instrument of whatever sort.”25
17.2.3 Some Elaboration on SCG 4,41 (SCG 4,42–48)
In drawing to the end of his account of the Incarnation, Aquinas makes six points.
1. It was fitting for the human nature of Christ to be united to the Second Person of the Trinity (SCG 4,42).
2. Christ’s human nature did not preexist Christ’s coming-to-be in time (SCG 4,43).
3. Christ’s human nature was perfect in soul and body (SCG 4,44).
4. Christ had no human father (SCG 4,45).
5. The coming-to-be of Christ can fittingly be ascribed to the Holy Spirit, though not as a matter of physical generation (SCG 4,46 and 47).
6. Christ must not be called a creature (SCG 4,48).
As he presents these conclusions, Aquinas, more than anything else, seems to be intent on bringing into his discussion what he takes to be stated or implied by Scripture, while reasoning concerning what he takes Scripture to teach.
Scripture tells us that the Word became flesh. Since Aquinas takes the Word to be the Second Person of the Trinity, he argues that it is the Second Person of the Trinity who assumed the human nature of Christ. Or, rather, he argues that, for several reasons, it was fitting or suitable that it should have been the Second Person of the Trinity who assumed this nature. Aquinas does not claim to be able to demonstrate that it was the Second Person of the Trinity and not the First or the Third who became incarnate.
He does, however, claim to demonstrate that Christ’s human nature could not have preexisted the Incarnation in time. Basically, he argues that Jesus of Nazareth could not possibly have preexisted himself. “Since the Word assumed the human nature,” he says, “necessarily the human nature did not pre-exist before its union with the Word.”26 It had to be the case that the Incarnation did not involve a union between God and a human being who preexisted the Incarnation.
When it comes to Christ’s perfect human nature in soul and body, Aquinas seems to be reasoning with an eye on his view of when it is that a fully formed human being comes into being. He did not believe that people begin to exist with a rational soul and a body straight upon conception. He thought that quite a bit of time elapsed between conception and the conceived having both a rational soul and a body.27 Yet, he reasons, it must have been a fully formed human being with whom the Word became incarnate. In the very beginning of the conception of Christ, therefore, “the rational soul was united to the body.”28 Aquinas finds it unbelievable that anything less than a fully formed human being with a rational soul could be united to the Word so as to make for one subject with two natures: divine and human. He says: “Anything corporeal that comes into being is, before its animation, formless and still lacking the perfection of nature. It was therefore not fitting for the Word of God to be united to a body not yet animated. Thus, from the moment of conception, the soul of Christ had to animate Christ’s body.”29
Yet how could this have been if, as Aquinas thought, human conception does not immediately result in a fully formed human being? In SCG 4,45 Aquinas suggests that the conception of Christ must not have been an ordinary conception but one lacking a human father. Ordinary human conception, he says, depends on sexual intercourse, and it does not immediately result in there being a fully formed human being with a rational soul.30 So, he reasons, if Christ was fully formed as a human being when conceived, there is a miracle to be acknowledged. The human mother of Christ cannot have conceived him as human mothers conceive their (not fully formed) offspring following sexual intercourse. Aquinas makes this point by saying that Christ was born of a virgin. That Mary, the mother of Jesus, was literally a virgin when she conceived him is not something that he attempts to demonstrate in SCG 4,45. He does, however, suggest that it was fitting that she should have been. Or as he puts it himself: “It became the Word of God, by whom all things are established and by whom all things are preserved in his wholeness, to be born so as to preserve his mother’s wholeness in every way. Therefore, suitably this generation was from a virgin.”31
In SCG 4,46, Aquinas proceeds to say that Christ was born of the Holy Spirit. I have shown how he maintains that everything that comes to pass in the created order is the work of the whole Trinity. Hence his objection to the claim that one can prove the doctrine of the Trinity with reference to what has been created by God (see chapter 16, section 3 here). All the same, Aquinas thinks that the Incarnation can be fittingly thought of as arising from what love is in God: this being the Holy Spirit. Here I assume that, though he does not quote it, Aquinas has in mind Luke 1:35, in which Mary, the mother of Jesus, is told: “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be holy; he will be called the Son of God.” Aquinas does conceive of the Trinity as a society or group of individuals acting so as to produce different things given the abilities or status of its members. So he does not believe that God the Father has a job in which God the Son is not involved. Nor does he think that God the Holy Spirit is somehow “doing his own thing” apart from what God the Father and God the Son are up to. But he does think that the Incarnation is a matter of love: love of God for people. Since he takes the Holy Spirit to be love as it exists in God, therefore, he finds it natural to say that Christ was born of the Holy Spirit, though not, for obvious reasons, with the Holy Spirit being a physical parent of Christ as Mary was.
Aquinas takes Mary, the mother of Jesus, to be a creature. He also supposes that Christ’s human nature was a creature: something in time and space created by God. In that case, however, should Christ not simply be referred to as a creature? With this question in mind, Aquinas again appeals to the idea that Christ is one person with two natures. When we speak of Christ, we are not referring to what is merely human. We are talking about the Word, and the Word is not a creature even though what the Word assumed in the Incarnation was creaturely. “In Christ,” Aquinas observes, “there is no other hypostasis or person save that of God’s Word, and this person is uncreated. … Therefore, one cannot say without qualification: ‘Christ is a creature,’ although one may say it with an addition, so as to say ‘so far as human’ or ‘in his human nature.’”32
17.2.4 Replies to the Arguments in SCG 4,40 (SCG 4,49)
With this general account of the Incarnation in place, in SCG 4,49 Aquinas finally returns to the arguments he noted in SCG 4,40. He maintains that these arguments are refuted by the discussion of the Incarnation in SCG 41–48. More precisely, he argues as follows.
1. The doctrine of the Incarnation does not assert that God was changed into something corporeal or that God is the form of what is bodily.
2. The doctrine of the Incarnation does not ascribe substantial change to the Word. It teaches that the Word came to be united to what is changeable (the human nature of Christ), not that the Word itself was in any way modified by the Incarnation.
3. “Nothing prevents the Word of God from being everywhere, although the human nature assumed by the Word is not everywhere.”33
4. The Second Person of the Trinity exists just by being divine, not by being human as God incarnate.
5. The Word and the divine nature of the Word are the same, and the Word exists by virtue of the divine nature, not the human nature assumed in the Incarnation. So we do not have to think of the human nature of Christ as identical with the person of the Word.
6. “It is not necessary that the human nature [sc. of the Word] be more simple than the Word so far as the Word is the Word, but only in so far as the Word is this man.”34
7. Considered simply as the Second Person of the Trinity, the Word does not have physical dimensions. Such dimensions can only be ascribed to the Word in the light of the Incarnation.
8. The doctrine of the Incarnation does not entail that the soul and body of Christ are anything other than what is united to or assumed by the one person of the Word. As assumed by the Word, the soul and body of Christ are united to what is better than a merely human person.
9. Christ, indeed, had a soul and a body. In the Incarnation, however, there was only one person, hypostasis, or suppositum: that of the Word.
10. Christ was a particular thing. But if we ask who Christ was, the answer is “the person of the Word.” The hypostasis of Christ is just the Second Person of the Trinity, who in the Incarnation took on a human nature in the particular man Jesus.
11. We do not use “man” equivocally when saying that Christ is a man and Socrates is a man. But we do hold that Christ is a man the person or hypostasis of which is the uncreated Word.
12. The Second Person of the Trinity does not exist as being what makes a particular human being to be a particular human being. The Second Person of the Trinity is the eternal God who does not need to create anything. In the Incarnation, however, the Word takes on a human nature and is united to this as being one subject in two natures. “The hypostasis of the Word is the subject of the human nature so far as he draws this latter into his own subsistence.”35
13. There can be no question of the human nature of the Second Person of the Trinity being an accident that God comes to possess. For God is eternal and, therefore, unchangeable. In the Incarnation, the Word is unchangeably united to what is human by becoming what is human without being essentially human.