2.1 Kinds of Natural Theology (SCG 1,10–11)
2.1 Kinds of Natural Theology (SCG 1,10–11)
Aquinas was certainly aware that defenses of natural theology can vary in nature. The natural theology that he favors in the SCG and elsewhere consists of demonstrative arguments grounded on what God might be thought of as producing or bringing about. His basic line is that certain things of which we have knowledge can, on reflection, be thought of as effects of God, who stands to them as a cause.
The word “cause” has a long philosophical history, and Aquinas himself distinguished, as did Aristotle, between causes of four kinds. So, what sense of “cause” (causa) is he working with for the purposes of his discussions of natural theology in the SCG? The answer is “the sense of cause in which a cause is an agent or efficient cause.” But that answer needs some explanation.
Here we might start by noting our familiar word “because.” We say that this or that happened or is happening because of something or other, and in doing so we seem to be seeking to offer explanations of some kind. The word “cause” can be related to the word “explanation.” But there are explanations of different kinds just as there are reasons of different kinds.
I might, for example, wonder why my cat seems to love eating meat while horses seem uninterested in it. The answer, of course, lies in the fact that cats are by nature carnivorous while horses are naturally herbivores.
Again, I might wonder why married friends of mine are getting divorced while other married couples stay together, or why I can slice an apple with a knife but cannot slice a diamond with one. Here the answers might lie (1) in different intentions or aims on the part of my friends who are divorcing and on the part of people who remain married, and (2) on ways in which apples and diamonds differ from each other physically or materially.
So we can distinguish between what Aquinas would have called “formal,” “final,” and “material” causes or explanations. For Aquinas, we appeal to a formal cause when we try to explain how it is that cats like meat and horses do not because of what they are by nature, because of what Aquinas would call their “substantial form.”2 And Aquinas holds that we can appeal to “final” and “material” causes as we (1) note goals that influence people or ends to which even nonhuman things can be drawn, and (2) draw attention to how the physical structure of things can account for what happens to them or what can be done to them. Again, we can make sense of Aquinas’s thinking here by reflecting about contexts in which we use the word “because.” We can make sense of statements like “My cat loves meat because it is a carnivorous animal,” “Jane and Bill split up because Bill’s cheating on Jane led her to want him out of her life,” and “I can cut an apple with a knife but cannot cut a diamond with one because apples have this physical make-up and diamonds have a quite different one.”
Now, however, consider another use of “because.” Suppose that someone stumbles across a human corpse and asks “Why the dead body?” In such a context people could end up settling for an explanation in terms of what are usually referred to as “natural causes.” It might be agreed, for example, that the person whose corpse we are thinking about died of a heart attack. But it might be concluded that the person committed suicide. Or it might be decided that neither “natural causes” nor suicide accounts for what is now in question. For what if it looks as though we are dealing with a case of murder? Should the evidence point in that direction, then, there is an obvious question to raise: “Who did it?”—and this question gives us an entry into what Aquinas means when he talks about agent or efficient causes.
Ludwig Wittgenstein (1889–1951) once observed: “Calling something ‘the cause’ is like pointing and saying: ‘He’s to blame!’”3 We have a sense of “cause” in which a cause is something that acts or operates so as to bring about what we take to be an effect. So one person might be called the cause of another person’s death. Or I might be said to be the cause of a wall becoming painted. Or a particular virus might be taken to be the cause of someone developing certain physical symptoms. And this sense of “cause” is what Aquinas has in mind when he speaks of agent or efficient causes. In his De Principiis Naturae he writes: “Copper is potentially a statue, but can’t make itself into a statue: it needs a workman to draw the statue’s form out of potentiality into actuality.” He adds:
For the form won’t exist unless the thing is made, whereas the maker exists in the coming to be, that is, while the thing is coming to be. So besides matter and form there must be some active principle or origin, which we call the efficient cause or mover or agent, from which the change originates.4
Here, the idea is that something can be thought of as a cause insofar as it brings about an effect in something else, and, according to Aquinas, God is a cause in this sense. In Aquinas’s view, thinking about natural theology can lead us to recognize that God exists as one who accounts for things that we observe in the world. He knows that some natural theologians argue that God can be known to exist without reference to effects. But he rejects what he takes to be their line of argument, to which he turns explicitly in SCG 1,10, in which he discusses “the opinion of those who say that the existence of God, being self-evident, cannot be demonstrated.”5
Aquinas contrasts “being self-evident” with “being able to be causally deduced.” So, he writes:
There are some people to whom the inquiry seeking to demonstrate that God exists may perhaps appear superfluous. These are those who assert that the existence of God is self-evident, in such wise that its contrary cannot be entertained in the mind.6
Here Aquinas is thinking of someone claiming that “God exists” follows immediately from an understanding of what God is. That is clear from the arguments he cites in SCG 1,10 as coming from people saying that “God exists” is self-evident. There are five such arguments.
1. If you know what the word “whole” means, then you immediately know that every whole is greater than its parts. But “God” means “something than which a greater cannot be thought.” From this it follows that God cannot just be a concept we have in our minds. God must be something that exists in reality, not just as thought about by us. From the very definition of “God” as “something than which a greater cannot be thought,” therefore, it follows that God must exist in reality since it is greater to exist in reality rather than only as something in our minds.
2. We can think that there is something that cannot possibly not exist, and such a thing would be greater than something that can be thought not to exist. But God is something than which a greater cannot be thought, in which case God cannot be something that can be thought not to exist. The notion of not being able not to exist is part and parcel of what we mean by the word “God.”
3. Propositions like “Human beings are human beings” or “Human beings are rational animals” are evidently true. But God’s very nature or essence is to exist (his being is his essence). So “God exists” is like “Human beings are human beings” or “Human beings are rational animals.”
4. What we know by nature is self-evident and not based on deduction. But we know by nature that God exists since we naturally desire God as our ultimate end.
5. That by which we know other things is self-evident, not deduced. But by God’s light we know all that we know.
Yet Aquinas rejects these arguments in SCG 1,11.7 But why?
To start with, he indicates that he sympathizes to some extent with people who offer them. It is, he says, understandable that people taught to call on God throughout their lives should just think it obvious that God exists. “What the mind is steeped in from childhood it clings to very firmly, as something known naturally or self-evidently.”8 But he still finds fault with these five arguments. In doing so, he makes one general point and then replies to each of the arguments.
The general point is that while it is true that “God exists” is “self-evident in an absolute sense” (notum per se simpliciter), it is not “self-evident to us” (quoad nos notum). If we understood what God is as, for example, we understand what wholes and parts are, then, Aquinas agrees, we would immediately see that “God exists” has to be true since “what God is is his own being.” Yet, Aquinas adds, “we are not able to conceive in our minds what God is.” Here he means that we lack a comprehensive knowledge of God’s nature and therefore lack the wherewithal to see that God exists in the same way that we can immediately see, from our knowledge of the nature of wholes and parts, that every whole is greater than its parts.
Why does Aquinas take this line about us not understanding what God is? You will get a fuller sense of why he does so as you continue working through this book and through the SCG. For now, however, let me briefly explain what Aquinas seems only to presume in SCG 1,11 while spelling it out in detail later. The main point to note is that, according to Aquinas, we lack what we might call a “scientific” understanding of God. When it comes to God’s nature, thinks Aquinas, we lack scientia.
By “scientific” here I mean “thorough and detailed.” Aquinas would have said that it is, in principle, possible to have a thorough and detailed understanding of what something is; but only insofar as (1) we can pick it out as existing in the physical world, and (2) we can locate the thing in terms of genus or species, thereby understanding how to classify it against a background of other things. If you like, Aquinas means that we have scientia concerning something to the extent that we can define it and thereby capture what is unique about it.
Take cats: the biological family felidae, of which there are a number of species. We all know something about these creatures, some of which are domesticated and some of which are not. Yet few of us are able to elaborate on them as certain biologists or zoologists can. The experts on cats know a great deal about them, even if they do not know everything about them. Such experts will be able to pick out cats of different species and explain how they differ from or resemble other kinds of cat. They will also be able to tell us how cats in general may be distinguished from certain other living animals. Experts on cats will, for example, be able to lecture us at length about how it is that cats are carnivorous, how some of them are solitary while others form colonies, how they tend to have bodies of a certain size and shape, how some of them have distinctive markings, how their eyes work, how their teeth work, what noises some of them characteristically make, how eight “lineages” of cat have been genetically identified, and so on. In this sense, some people have developed a scientific understanding of what cats are based on copious empirical investigation. Yet, so Aquinas thinks, nobody has developed a corresponding understanding of what God is, even though many people will be able to give some account of what the word “God” means.
Why not? Aquinas’s basic answer to this question is: Because God is not something in the universe that we can examine and compare or contrast with other things in the universe so as to come up with anything like the account of what cats are that some people can offer. As I will show, Aquinas holds that God is not a material object, not part of the universe, and not something in time. Aquinas does not even think that God is one of a kind of which there could be more than one member. And all of these points, though developed by Aquinas as he writes the SCG, are there in embryo, as it were, in what he says in SCG 1,11 about us not knowing what God is as we know what wholes and parts are. Yes, he agrees that, if we had a God’s-eye understanding of God, we would understand what God is as some understand what a certain kind of cat is. We would thereby immediately understand that it belongs to God to exist by nature and that there is something amounting to self-contradiction in the claim “God does not exist.” However, says Aquinas, we do not have a God’s-eye understanding of God. Such understanding of God’s nature as is open to us in the present life is going to have to be derived from what we might infer about God on the basis of what God has produced—as we engage in theology “from the bottom up.”
So much for what I am calling Aquinas’s “general” point in SCG 1,11. Now for his more particular responses to the five arguments he cites in SCG 1,10. Here is what he says:
1. Not everyone takes the word “God” to mean “something a greater than which cannot be thought.” Even if one does take “God” to mean “something than which a greater cannot be thought,” it does not follow that God actually exists since a bare understanding of the meaning of the word “God” cannot entail that there is anything in reality to correspond to it.
2. We are not going to be able to show that God cannot be thought not to be unless we have an understanding of what God is, which we lack.
3. In our present life, and unlike the blessed in heaven, who see God, we lack a scientific or adequate understanding of what God is; so our understanding of God is not to be compared to our understanding of what wholes and parts are, and so on. “To those seeing the divine essence in itself [the blessed in heaven] it is supremely self-evident that God exists because his essence is his being. But, because we are not able to see God’s essence, we arrive at the knowledge of his being, not through God himself, but through his effects.”9
4. We naturally desire God by desiring union with God. But the fact that we desire this does not mean that we know, straight off, that God exists. It only means that we yearn for less than what God is.
5. It is true that we know what we know by virtue of God. But to say this is to suppose that God exists and is what somehow helps us to know. It does not imply that we cannot know unless we know what God is as we know the truth of certain self-evident truths.