Natural Theology
Our investigation of the philosophy of religion will consist of three areas: proofs for the existence of God, the religious experience, and the problem of evil. Each of these is a central concern of natural theology. Before proceeding, we need to distinguish natural from revealed theology. The term "natural theology" may be misleading. What it’s not is an attempt to gain knowledge of God through nature. Natural theology is the attempt to gain knowledge of God through the faculties of reason unaided by any supernatural or divine intervention. That is, using our natural abilities to gain philosophical insight into the divine. Revealed theology is the gaining of knowledge about God through direct or indirect communication with the divine. This can be from a religious experience (direct) or through the reading of holy books (indirect). Another way to think of this distinction is to cast it in terms of the difference between reason and faith. How compatible or incompatible these two are we'll perhaps see as our investigation proceeds.
We begin, as Aquinas advises us to do with a consideration of the existence of God. As he points out in the Summa Contra Gentiles, "if we do not demonstrate that God exists, all consideration of divine things is necessarily suppressed." Of course, we have discussed proofs for the existence of God in previous chapters concerning Descartes' philosophy. These proofs were rational in the sense that they did not depend on sense experience. Aquinas' proof is different. Given his admiration for Aristotle, it should come as no surprise that Aquinas is an empiricist. While he concedes, as many did in the Middle Ages, that the notion that God exists is self-evident, humans require some sort of physical evidence to understand this. In other words, our intellect is not sufficient to understand the self-evident nature of the proposition "God exists." We need empirical evidence.
Aquinas' proof is called the cosmological argument for the existence of God because it’s based on the existence of the cosmos; that is the universe. But before we see how the existence of the cosmos can be used as evidence for the existence of God we need to address a fundamental question about the cosmos' existence itself. Question: Was the cosmos created or has it always existed? From Aquinas' viewpoint, this question could not be answered philosophically. Sure, we could offer evidence in favor of one or the other view but the evidence would not be conclusive. So either way, we begin we must begin with an assumption. The question is which assumption should we take? We could, using revelation, take the assumption that the cosmos was created. After all, the Bible tells us this. But then we run into a problem. We are trying to prove that God exists and we're using the Bible as a basis for this proof? Isn't this suspicious? After all, the Bible is only valid if we can show that it’s the inspired word of God which we can only do if we can prove God exists. Using the Bible as evidence for our proof means we're presupposing that God exists. We're begging the question. So despite what revealed theology tells us we should not assume the universe was created.
Besides we run into another problem doing this. If we assume the universe was created and it turns out that it is eternal what happens to our proof based on the assumption of it being created? It’s worthless. After all, our proof will probably attempt to show that God created the universe. But if the universe is eternal it doesn't need a creator. No, the best way to begin is by assuming that the universe is eternal. That way we make no theological assumptions of God's existence to begin with and if it turns out that the universe was created our proof is not ruined. It becomes stronger. By starting with the more difficult of the two assumptions Aquinas is making his proof stronger. If we can prove that God exists and is the cause of the eternal universe it will be easy to adapt this proof to God's existence if the universe was created. So Aquinas is proving that the universe needs a cause and that cause must be God. Even an eternal thing needs a cause (though not a creator; there's a difference).
OK given all of this the structure of the proof contains four premises. Two of them should be self-evident; the other two can be explained and if all four are true then we can conclude that the cosmos must be caused by something outside of space and time, something uncaused and ultimate. This sounds like God! Here are the four premises:
1. The universe exists. (This is self-evident)
2. It could not be the cause of itself. (This will be easy enough to explain)
3. It could not come from anything. (This is self-evident)
4. It could not be an effect in an infinite series of causes and effects (we'll need to explain this in more detail).
The basic idea is that if we can show that these premises are true we can infer that God must exist. What Aquinas is doing is showing that the universe needs a cause and there are only so many options. 1. It could be the cause of itself. But premise two says this is impossible. The reason why is pretty easy. The cause must always precede the effect. But if the universe was the cause of itself it would have to exist before it existed! This, however, is impossible. Something can't exist before it exists. And given that the universe is eternal before doesn't apply anyway. 2. It could come from nothing. But premise three says this is impossible. The reason why should be obvious: you can't get something from anything. As Aquinas put it, ex nihilo, nihil fit. "From nothing, nothing comes." It sounds better in Latin! Anyway, the point is that the universe can’t have arisen from anything.
Given that we're assuming it’s eternal could the universe have been the result of an infinite series of causes and effects? It seems unlikely for the following reason. Suppose I said to you "don't come back to class until you've read an infinite number of books." Are you ever going to return to class? Of course not! You can't read an infinite number of books. The point is it’s impossible to get through an infinite series. So if the universe were the result of an infinite series of causes and effects we would never see the final effect (the existence of the universe). We'd be waiting forever for the universe to exist. Given the fact that the universe exists (premise one), we can infer that the series of causes and effects is finite. In other words, there must be a first cause.
This is likely to seem confusing since we've said that Aquinas assumed the universe was eternal. How can an eternal thing have a first cause? The confusion can be clarified if we remember that cause does not necessarily imply creator. Aquinas is not arguing that God created the universe, but that the universe needs a cause for its existence. And more than this, it needs a cause for its continued existence through time. Another way of putting this is to say that the universe needs a sustaining cause.
There is no objection to the possibility that an infinite series extends backward in time since Aquinas is assuming that the universe is eternal. But, could there be an infinite series of causes and effects in a single moment in time? This is the problem and the answer is no. So what Aquinas is objecting to is not a temporal series but a hierarchical series. The reason this series cannot be infinite should now be clear. But perhaps the reason why the beginning of this series must be God isn't. For Aquinas, this is because the universe is contingent and requires a necessary being to exist to sustain it. Furthermore, as we have seen the cause must also be uncaused and outside of space and time. What other being could this description apply to except for God?
As I said, this derives from Aquinas' supposition that the universe is contingent; meaning it happens to exist but could also not exist. He argues in the following way. Since each thing in the universe is contingent it follows that the universe itself is contingent. Contingent beings come into and go out of existence. So it seems reasonable to suppose that at some point in the past nothing existed in the universe. But, if this were true there would be nothing in existence now; remember you can't get something from anything. So, therefore, there must be a being whose existence is not contingent but necessary and this of course is God.
This point has been the source for considerable criticism of Aquinas' proof. If you remember when we talked about logic we mentioned the fallacy of composition; assigning a trait to the whole because it belongs to the parts. But it doesn't follow that just because something is true of the parts that it must also be true of the whole. It seems that Aquinas is making this inference and it is fallacious. Given that his proof hinges on this point this is a serious problem. Can it be fixed? Perhaps.
In a book titled How To Think About God, twentieth-century philosopher Mortimer Adler addresses this problem and provides a solution. He maintains that once this problem is solved Aquinas' proof is solid and provides us with reasonable evidence for the existence of God. So this bears investigation. Simply put, the notion of contingent seems to be that something could cease to exist. But what would become of the matter once the thing did cease existing? Would the matter also cease to exist? Of course, we would say no given our knowledge of the law of conservation of matter and energy. So, when one contingent being ceased to exist, it’s merely replaced by another contingent being. It is not annihilated. No contingent being can cause the annihilation of another contingent being. It is also worth pointing out that no contingent being can prevent another contingent being from ceasing to exist either.
So is the universe contingent in this way? Adler says no and prefers to say that the universe is "radically contingent." This is not merely semantics. There is a significant difference. The best way to think about it is to ask: What would the universe be replaced with if it ceased to exist? Given that the universe is the total of matter and energy the answer would have to be nothing. So the universe ceasing to exist would be an example of annihilation; that is being reduced to nothingness. What prevents this from occurring? No contingent being can do this even as no contingent being can sustain the existence of another contingent being. In other words, no natural cause could do this. But, there are only two kinds of causes: natural and supernatural. So by deduction, it must be that the universe (being radically contingent) is sustained by a supernatural cause (God).
This has been a fairly complex proof for the existence of God. But you wouldn't expect any less, given the magnitude of the subject. It's ironic to think that such complex proof could be the brainchild of someone nicknamed the Dumb Ox! However, as we've seen Aquinas' proof is not perfect. It requires a small modification to be viable. I should also mention that my synopsis of Aquinas' proof has not represented fully his five ways for proving God that he outlines in the Summa Theologica. In particular, I have not addressed his fifth way; the argument from design. We will look at this argument in its modern form in the next chapter.
We begin, as Aquinas advises us to do with a consideration of the existence of God. As he points out in the Summa Contra Gentiles, "if we do not demonstrate that God exists, all consideration of divine things is necessarily suppressed." Of course, we have discussed proofs for the existence of God in previous chapters concerning Descartes' philosophy. These proofs were rational in the sense that they did not depend on sense experience. Aquinas' proof is different. Given his admiration for Aristotle, it should come as no surprise that Aquinas is an empiricist. While he concedes, as many did in the Middle Ages, that the notion that God exists is self-evident, humans require some sort of physical evidence to understand this. In other words, our intellect is not sufficient to understand the self-evident nature of the proposition "God exists." We need empirical evidence.
Aquinas' proof is called the cosmological argument for the existence of God because it’s based on the existence of the cosmos; that is the universe. But before we see how the existence of the cosmos can be used as evidence for the existence of God we need to address a fundamental question about the cosmos' existence itself. Question: Was the cosmos created or has it always existed? From Aquinas' viewpoint, this question could not be answered philosophically. Sure, we could offer evidence in favor of one or the other view but the evidence would not be conclusive. So either way, we begin we must begin with an assumption. The question is which assumption should we take? We could, using revelation, take the assumption that the cosmos was created. After all, the Bible tells us this. But then we run into a problem. We are trying to prove that God exists and we're using the Bible as a basis for this proof? Isn't this suspicious? After all, the Bible is only valid if we can show that it’s the inspired word of God which we can only do if we can prove God exists. Using the Bible as evidence for our proof means we're presupposing that God exists. We're begging the question. So despite what revealed theology tells us we should not assume the universe was created.
Besides we run into another problem doing this. If we assume the universe was created and it turns out that it is eternal what happens to our proof based on the assumption of it being created? It’s worthless. After all, our proof will probably attempt to show that God created the universe. But if the universe is eternal it doesn't need a creator. No, the best way to begin is by assuming that the universe is eternal. That way we make no theological assumptions of God's existence to begin with and if it turns out that the universe was created our proof is not ruined. It becomes stronger. By starting with the more difficult of the two assumptions Aquinas is making his proof stronger. If we can prove that God exists and is the cause of the eternal universe it will be easy to adapt this proof to God's existence if the universe was created. So Aquinas is proving that the universe needs a cause and that cause must be God. Even an eternal thing needs a cause (though not a creator; there's a difference).
OK given all of this the structure of the proof contains four premises. Two of them should be self-evident; the other two can be explained and if all four are true then we can conclude that the cosmos must be caused by something outside of space and time, something uncaused and ultimate. This sounds like God! Here are the four premises:
1. The universe exists. (This is self-evident)
2. It could not be the cause of itself. (This will be easy enough to explain)
3. It could not come from anything. (This is self-evident)
4. It could not be an effect in an infinite series of causes and effects (we'll need to explain this in more detail).
The basic idea is that if we can show that these premises are true we can infer that God must exist. What Aquinas is doing is showing that the universe needs a cause and there are only so many options. 1. It could be the cause of itself. But premise two says this is impossible. The reason why is pretty easy. The cause must always precede the effect. But if the universe was the cause of itself it would have to exist before it existed! This, however, is impossible. Something can't exist before it exists. And given that the universe is eternal before doesn't apply anyway. 2. It could come from nothing. But premise three says this is impossible. The reason why should be obvious: you can't get something from anything. As Aquinas put it, ex nihilo, nihil fit. "From nothing, nothing comes." It sounds better in Latin! Anyway, the point is that the universe can’t have arisen from anything.
Given that we're assuming it’s eternal could the universe have been the result of an infinite series of causes and effects? It seems unlikely for the following reason. Suppose I said to you "don't come back to class until you've read an infinite number of books." Are you ever going to return to class? Of course not! You can't read an infinite number of books. The point is it’s impossible to get through an infinite series. So if the universe were the result of an infinite series of causes and effects we would never see the final effect (the existence of the universe). We'd be waiting forever for the universe to exist. Given the fact that the universe exists (premise one), we can infer that the series of causes and effects is finite. In other words, there must be a first cause.
This is likely to seem confusing since we've said that Aquinas assumed the universe was eternal. How can an eternal thing have a first cause? The confusion can be clarified if we remember that cause does not necessarily imply creator. Aquinas is not arguing that God created the universe, but that the universe needs a cause for its existence. And more than this, it needs a cause for its continued existence through time. Another way of putting this is to say that the universe needs a sustaining cause.
There is no objection to the possibility that an infinite series extends backward in time since Aquinas is assuming that the universe is eternal. But, could there be an infinite series of causes and effects in a single moment in time? This is the problem and the answer is no. So what Aquinas is objecting to is not a temporal series but a hierarchical series. The reason this series cannot be infinite should now be clear. But perhaps the reason why the beginning of this series must be God isn't. For Aquinas, this is because the universe is contingent and requires a necessary being to exist to sustain it. Furthermore, as we have seen the cause must also be uncaused and outside of space and time. What other being could this description apply to except for God?
As I said, this derives from Aquinas' supposition that the universe is contingent; meaning it happens to exist but could also not exist. He argues in the following way. Since each thing in the universe is contingent it follows that the universe itself is contingent. Contingent beings come into and go out of existence. So it seems reasonable to suppose that at some point in the past nothing existed in the universe. But, if this were true there would be nothing in existence now; remember you can't get something from anything. So, therefore, there must be a being whose existence is not contingent but necessary and this of course is God.
This point has been the source for considerable criticism of Aquinas' proof. If you remember when we talked about logic we mentioned the fallacy of composition; assigning a trait to the whole because it belongs to the parts. But it doesn't follow that just because something is true of the parts that it must also be true of the whole. It seems that Aquinas is making this inference and it is fallacious. Given that his proof hinges on this point this is a serious problem. Can it be fixed? Perhaps.
In a book titled How To Think About God, twentieth-century philosopher Mortimer Adler addresses this problem and provides a solution. He maintains that once this problem is solved Aquinas' proof is solid and provides us with reasonable evidence for the existence of God. So this bears investigation. Simply put, the notion of contingent seems to be that something could cease to exist. But what would become of the matter once the thing did cease existing? Would the matter also cease to exist? Of course, we would say no given our knowledge of the law of conservation of matter and energy. So, when one contingent being ceased to exist, it’s merely replaced by another contingent being. It is not annihilated. No contingent being can cause the annihilation of another contingent being. It is also worth pointing out that no contingent being can prevent another contingent being from ceasing to exist either.
So is the universe contingent in this way? Adler says no and prefers to say that the universe is "radically contingent." This is not merely semantics. There is a significant difference. The best way to think about it is to ask: What would the universe be replaced with if it ceased to exist? Given that the universe is the total of matter and energy the answer would have to be nothing. So the universe ceasing to exist would be an example of annihilation; that is being reduced to nothingness. What prevents this from occurring? No contingent being can do this even as no contingent being can sustain the existence of another contingent being. In other words, no natural cause could do this. But, there are only two kinds of causes: natural and supernatural. So by deduction, it must be that the universe (being radically contingent) is sustained by a supernatural cause (God).
This has been a fairly complex proof for the existence of God. But you wouldn't expect any less, given the magnitude of the subject. It's ironic to think that such complex proof could be the brainchild of someone nicknamed the Dumb Ox! However, as we've seen Aquinas' proof is not perfect. It requires a small modification to be viable. I should also mention that my synopsis of Aquinas' proof has not represented fully his five ways for proving God that he outlines in the Summa Theologica. In particular, I have not addressed his fifth way; the argument from design. We will look at this argument in its modern form in the next chapter.