16.3 Is Aquinas Right on the Trinity?
16.3 Is Aquinas Right on the Trinity?
SCG 4,2–26 raise many questions. To start with, we might wonder whether Aquinas’s citations of Scripture suffice to show that the doctrine of the Trinity is true in the sense that he understood it to be from his reading of the Nicene Creed, the Nicene-Constantinopolitan Creed, and the teaching of the Council of Chalcedon. Is what Aquinas believes to be the orthodox doctrine of the Trinity confirmed by the Bible? People who do not regard the Bible or church councils as having any authority will be unconcerned with this question. More likely, they will ask whether the doctrine of the Trinity can be proved philosophically or whether it is coherent. But Aquinas does take seriously the authority of the Bible and church councils. So one can reasonably ask whether he is right to hold that what church councils have said concerning the Trinity is a correct representation of what we find in the Bible.
We might think that it is not, since the doctrine of the Trinity as it emerges in the Nicene Creed, the Nicene-Constantinopolitan Creed, and what comes from the Council of Chalcedon is just not there in the Bible. These councils purported to be correctly clarifying the teaching of Scripture in opposition to readings of the Bible at odds with their understanding of it, and they would not have been doing that if the Bible unambiguously taught what the councils did concerning the Trinity. Yet Aquinas thinks that their reading of the Bible was correct insofar as it resulted in a formally stated doctrine of the Trinity. So was he right to think this?
I raise this as a serious question. Yet I am not able to offer an answer to it in this book. To do so would require me to present detailed analyses of the biblical texts Aquinas appeals to in SCG 4,2–26. Here, I think, we need to look to contemporary biblical scholars who have worked on the texts he cites and who have, drawing on the best historical and textual research now available, tried to understand what their authors might have meant when writing them. You might think, as I suspect Aquinas did, that we can lift verses from the Bible and correctly understand them as saying just what they seem to read to us as saying when taken in isolation and as so many words on paper.66 And if you think that, then you might well find Aquinas to be victorious every time he cites Scripture in defense of the doctrine of the Trinity as found in the conciliar texts governing his discussion of it. If you do not think that, however, you will suppose that a lot of work needs to be done so as to show that Aquinas’s many biblical references in defense of what he takes to be the doctrine of the Trinity show what he takes them to show. You might say that they do exactly this since Aquinas is reading the Bible in the light of orthodox church teaching and since that teaching should govern our understanding of what biblical texts mean. If you take that view, however, you will have little or no interest in how various biblical texts came to be written or in what their authors, in their various historical contexts, might have meant when composing them: a lack of interest that has been defended by some and castigated by others.
Abstracting from matters of biblical interpretation, however, there is another question that might be raised concerning what we find in SCG 4,2–26. This is a question that has been pressed by theologians who think that philosophy should not be governing theology as they take it to do for Aquinas.
As obvious as it is that SCG 4,2–26 is written by a Christian, and as obvious as it is that Aquinas never claims to demonstrate the truth of the doctrine of the Trinity, it is equally obvious that what this Christian says about the Trinity relies on a number of conclusions he holds to be philosophically demonstrable. The SCG is shot through with the conviction that, without benefit of revelation, we can reasonably conclude that God is entirely simple (see chapter 4 here) and that our best “name” for God is “He Who Is” (see chapter 5 here). Yet, one might ask, why should Aquinas turn to the doctrine of the Trinity in the light of conclusions that he has arrived at philosophically? Should he not have started with divine revelation and discarded his philosophy of God as presented in SCG 1?
This question has often been pressed, with respect not only to what Aquinas says about the Trinity in SCG 4,2–26 but also to what he writes about the Trinity in works other than the SCG—the Summa Theologiae, for instance.67 But, I think, it is obvious how Aquinas would reply to it. First, he would say that truth cannot contradict truth. Then he would say that there are truths that we can know about God apart from divine revelation, truths that have to be borne in mind when reflecting on revelation. Perhaps he would add that we should not abandon what we know to be true about God when reflecting on what we believe to be true of God.
It is easy to sympathize with Aquinas as he thinks along these lines. If the natural theology presented by him in the SCG and elsewhere is sound, how else could he think? You might argue that Aquinas’s natural theology is not sound, and if that conclusion is correct, then, perhaps, he should indeed rest what he says about the Trinity only on divine revelation as identified in some way and as contrasted with what can be known by reason or philosophical argument of the kind that he respected, this being deductive argument leading from evidently true premises to true conclusions entailed by them. Yet Aquinas thought that his natural theology was sound. So why should he not take it for granted when turning to the doctrine of the Trinity? Why should any people who think that they have established truths about God by reason not take these truths for granted when reflecting on the Trinity? Some would reply that we need to acknowledge that human beings are fallen and that their reason is always clouded and unreliable. If one really believes that, however, then one ought always to doubt what reason seems to declare, whether about God or anything else. If our reason is always clouded, then we have achieved no advances in knowledge since we first appeared on earth. But why believe that? And, if we do believe it, should we not refrain from trying to argue a case for it?
That said, however, is Aquinas right to speak about God while abstracting from the doctrine of the Trinity? He obviously does this. Hence, for example, the conclusions defended in SCG 1 are not ones that he takes to establish the existence of the Trinity. It is only in SCG 4 that he turns to the Trinity directly. But if God is Father, Son, and Spirit, does not talk of God that is not grounded in this doctrine effectively fail to be talk about God? And if that is so, should we not conclude that what Aquinas says about the Trinity in the SCG is theologically dubious since it appears to treat the doctrine of the Trinity as a kind of appendage to an otherwise self-contained account of what God is?
In response to this question, I would deny the premises on which it seems to rely. I take these to be (1) “We cannot truly talk about something without taking it to be all that it actually is,” and (2) “Aquinas regards the doctrine of the Trinity as a kind of appendage to an otherwise self-contained account of what God is.”
The first premise here is evidently false. We can speak truly of many things without explicitly alluding to all that they are. We can, for example, truly conclude that John is a thief without paying any attention to the fact that he is six feet two inches tall, or even being aware of this fact. Again, one can deduce that all cats are mammals without knowing, or alluding to, where they were born, what their coloring is, or even the breed of cat to which they belong.
The second premise is false since Aquinas obviously thinks that God is essentially, and not accidentally, Father, Son, and Holy Spirit. If he thinks that, he cannot possibly regard the doctrine of the Trinity as an appendage to a true account of what God is.
The fact that Aquinas is happy to speak about God in the SCG without bringing in the doctrine of the Trinity derives from his distinction between truths of reason and truths of faith. Much of the SCG is concerned with what we can know of God by reason, and as I have shown, Aquinas does not take that to amount to a knowledge or understanding of God’s essence (see chapters 4 and 5 here). Nor does he take it to amount to knowledge concerning a distinction of persons in God. He does not claim that the doctrine of the Trinity is philosophically demonstrable. One should not conclude from this fact, however, that he does not positively believe that God is essentially Father, Son, and Spirit.
Indeed, it is clear from SCG 4 2–26 that Aquinas takes God to be just this while starting from what he believes to be divine revelation. Christian theologians with no interest in what might be established about God without benefit of revelation may, understandably, want to write nothing about God other than a series of books or articles on the Trinity based on the Bible. Aquinas, however, though revering what he took to be the doctrine of the Trinity as revealed in the Bible, also maintains that this doctrine can be discussed separately from the claim that there are creatures who depend from moment to moment on what is not a being among beings.
Why does he think this? Obviously, because he holds that reason tells us something about God without penetrating to the truth of the doctrine of the Trinity. Is he right to think so? He is if he is right to think that we can speak truly of God without having to conclude that God is Father, Son, and Spirit. And, given his claim that reason can only arrive at truths about God based on causal arguments (see chapter 2 here), he is right in thinking that we cannot by reason show that God is three persons. As Peter Geach says:
Since all the propositions of natural theology tell us only what is true of a being by virtue of his being God, they cannot serve to establish any distinction there might be between two Persons both of whom were God and the same God. Thus, so far as natural theology goes, the question whether many distinct Persons can be one and the same God is demonstrably undecidable, on Aquinas’s view.68
Or as Aquinas himself says in Summa Theologiae 1a,32,1:
It is impossible to come to the knowledge of the Trinity of divine persons through natural reason. For … through natural reason we can know God only from creatures; and they lead to the knowledge of God as effects do to their cause. Therefore, by natural reason we can know of God only what characterizes God necessarily as the source of all beings. … Now the creative power of God is shared by the whole Trinity; hence it goes with the unity of nature, not the distinctions of persons. Therefore, through natural reason we can know what has to do with the unity of nature, but not with the distinction of persons.69
However, if God is simple, as Aquinas maintains, how can there be three who are God? As I have said, Aquinas’s answer is that God is three subsistent relations within the divine nature. This nature, he thinks, is not multipliable; so there cannot be three gods as there can be three people or three cats. For Aquinas, the divine essence is God and is not multipliable. Yet, Aquinas argues, this does not mean that there could not be real distinction within God since such distinction could be within the divine essence and based on subsistent relations. But can we make sense of the notion of subsistent relations?
It is, I think, significant that Aquinas does not allude to subsistent relations except in his various discussions of the Trinity, and he does not cite non-Trinitarian examples of subsistent relations. Generally, he takes a real relation, as opposed to a notional one, to be an accident in a creature.70 So, for example, he assumes that it is obvious that if John comes to think about Fred, John comes to be what he was previously not, that is, related to Fred as thinking about him. Yet Aquinas does not take subsistent relations in God to be accidents. So why does he introduce the idea of subsistent relations when talking about the Trinity?
He does so (1) because he thinks that revelation teaches that there is distinction in God, (2) because he does not want to say that there are three Gods, and (3) because he thinks that he has reason to deny that there are accidents in God. If there is distinction in God, Aquinas reasons, this cannot be because of distinguishable accidents that God has, for all that is in God is God, who is ipsum esse (see chapter 4, section 4 here). So Aquinas concludes that distinction in God has to be a matter of there being subsistent relations in God, and in doing so he introduces a notion of real relation that goes beyond the way that he understands this when talking philosophically about created things.
You might say that he should not do so. As you will by now have realized, though, Aquinas frequently employs what he takes to be familiar philosophical terms or words so as to use them in ways that go beyond their usual sense. Take, for example, his use of “agent cause” when talking about God as creator of all things from nothing (see chapter 9, section 5 here). Aquinas knows that the notion of agent cause arose because of reflection on things in the world that modify other things. However, with the notion of God as creator in mind, he speaks of God as an agent cause that makes things exist without thereby changing them. And when it comes to the Trinity, Aquinas uses the term “relation” so as to say that in God there can be relations that are subsistent and not merely accidents. In this context, Aquinas views the word “relation” as justified because of the teaching that God is Father, Son, and Spirit. He takes this teaching to imply that the Father is really distinct from the Son and the Holy Spirit, that the Son is really distinct from the Father and the Holy Spirit, and that the Holy Spirit is really distinct from the Father and the Son. Given his thinking on divine simplicity, he therefore concludes that relations in God cannot be accidents but must subsist in God and be all that God is. This might well be thought of as a natural conclusion for him to arrive at given his view of divine simplicity and given his conviction that orthodox Christian teaching holds to there being three persons in God. If God is entirely simple, as Aquinas holds, then there can be no question of there being three Gods or of there being accidents in God. Yet if there are distinct persons in God, these “persons” cannot be accidents in God. The divine persons have to be thought of only as subsistent relations existing in God. So there is a plausible logical progression that leads Aquinas from belief in God as ipsum esse, and from subscription to what he takes to be orthodox Trinitarian doctrine, to the conclusion that Father, Son, and Spirit can be thought of as real but subsisting relations in God based on relative opposition grounded in proceeding (the Son from the Father, and the Holy Spirit from the Father and the Son).
Some theologians and philosophers have rejected this conclusion while favoring what is commonly referred to as “Social Trinitarianism.” This comes in different forms from different authors, but it basically seems to amount to the view that the Trinity is a group or society of three interacting beings working together as distinct centers of consciousness while relating to each other in something like the way people occasionally do. And some Social Trinitarians have partly defended their position by criticizing Aquinas on the Trinity. Hence, for example, William Lane Craig writes:
It can be safely said that on no reasonable understanding of “person” can a person be equated with a relation. Relations do not cause things, know truths, or love people in the way the Bible says God does. Moreover, to think that the intentional objects of God’s knowing Himself and loving Himself constitute in any sense really distinct persons is wholly implausible. Even if God the Father were a person, and not a mere relation, there is no reason, even in Aquinas’s own metaphysical system, why the Father as understood and loved by Himself would be different persons. The distinction involved here is merely that between oneself as subject (“I”) and as object (“me”). There is no more reason to think that the individual designated by “I,” “me” and “myself” constitute a plurality of persons in God’s case than in a human being’s case.71
Craig here seems to be presupposing some univocal sense of “person” as an individual thinking thing that Aquinas is not employing in SCG 4,2–26. He also seems not to understand how Aquinas’s talk of three persons in the Trinity is presented so as to cohere with his “metaphysical system,” which positively commits him (see SCG 1) to insisting that the existence of God is not different from God’s essence. Be that as it may, though, Craig ends up talking about the persons of the Trinity as if they were parts of some whole, which is why he declares himself to be a Social Trinitarian. God the Father, he says, “is not the whole Godhead,” and “it seems undeniable that there is some sort of part/whole relation obtaining between the persons of the Trinity and the entire Godhead.”72 And, as I have said, other contemporary thinkers share this idea of the Trinity being a collection of things having a common nature that they share, as three human beings share the property of being human.73 By now, though, you will realize why Aquinas would be suspicious of that suggestion. He would take it to be contrary to what God is as simple and lacking composition. He would think that it must somehow erroneously involve a commitment to tritheism, to there being three Gods.
In defense of what Aquinas says about the Trinity, some philosophers have claimed that identity should be understood in relative terms. The doctrine of the Trinity, as Aquinas understands it, says that Father, Son, and Spirit are different persons, each of whom is the one, true God. On the supposition that if X is identical with Y, then all that is true of X is true of Y, one might suppose that the doctrine of the Trinity has to be false since if Father, Son, and Spirit are distinct, they cannot all be the one, true God. Yet might not X and Y be the same even though different things are true of X and Y? It has been argued that they can.
The notion of identity seems to be the same as the notion of sameness. If X is identical with Y, then X is somehow the same as Y. Can we, however, sensibly think of sameness in the abstract? If we say that X is the same as Y, do we not have to provide an answer to the question “Same what as what, and in what respect?” Do we not at least need recourse to a noun when claiming that X and Y are the same? Arguably we do. “They are the same” means nothing unless we know what we are talking about. We can, though, make sense of statements like “The cat that jumped on my lap today is the same cat that jumped on my lap yesterday.” We cannot understand what “X is good” means unless we know what it is we are talking about (see chapter 6, section 6.2 here). Similarly, we cannot understand what “X is Y” or “X is the same as Y” could mean unless we know what X and Y are supposed to be. In other words, we might think that identity is not something absolute but is relative somehow.
That we would be right to think this has been argued with much logical sophistication by Peter Geach. As an analysis of “There is but one God,” he suggests “For some y, y is God, and, for any z, if z is God, z is the same God as y.” Then he adds:
It is important to notice that this would leave open the possibility of there being several Divine Persons; there would still be but one God if we could truly say that any Divine Person was the same God as any other Divine Person. Now different Persons’ being the same God is not manifestly impossible: for, in general, x and y may be the same F although different things are true of x and y.74
I should note, however, that the notion of relative identity has been criticized by a number of philosophers both considered in itself and as employed in order to talk about the Trinity.75 I should also note that Aquinas does not develop a formal defense of relative identity when he talks about the Trinity in SCG 4,2–26. In these chapters he presumes, on the basis of revelation, that there is distinction in God. He does not speak of Father, Son, and Spirit being the same God in a way that might suggest that Father, Son, and Spirit are the same as I might be thought to be the same human being who wrote the sentence you read before the sentence you are now reading. What he says is that in the divine nature, which is “one” only because it is not multipliable, not something shared as, say, humanity is what is shared by different human beings, there can be distinction based on relative opposition.
At the end of the day, Aquinas thinks of the doctrine of the Trinity as a mystery, as revealed by God, as something that we can try to reflect on only so as to make some kind of feeble sense of it. In SCG 4,2–26 he argues that we can make sense enough of the orthodox doctrine of the Trinity so as to declare that it is taught in the Bible and so as to refute the idea that the doctrine is incoherent or nonsensical or unthinkable. But this is pretty much all that he does in the SCG. Some have suggested that the Trinity is something that falls within human experience, or the experience of some people, at least.76 But Aquinas does not argue along these lines. Might he have done well to have considered the Trinity as an object of human experience, one to be understood on that basis? Given his understanding of our sources for truths about God as spelled out in SCG 1, Aquinas’s reply to this question would, of course, be “Certainly not.” There is just no room in the thinking of Aquinas for the idea that people can directly experience God and truly describe God on the basis of “seeing” or “perceiving” God somehow (see chapter 2, section 3.2 here). It is therefore to be expected that his SCG discussion of the Trinity never draws on it. You may think that it should have done so. But its failure to do so leaves Aquinas presenting an account of the Trinity that is at least consistent with what he has previously been saying concerning human knowledge of God. And consistency, after all, is a virtue, even if consistency displayed when lying is, arguably, not.