Though Aquinas [1225-1274] offers five "Ways" to prove God's existence, the first three are the core of the cosmological argument, and those are the ones we will consider here.

These arguments are a posteriori. That is, they rest on factual premises that reason alone could not establish. And in fact, the opening section of the portion of Aquinas that we have in our text clears some ground by trying to establish that it is even worthwhile to pursue such argument. The "First Article" considers the question of whether God's existence is self-evident. If it is, the Five Ways are not necessary. So Aquinas considers three reasons for thinking that God's existence is self-evident.

The first reason comes from an old tradition -- relevant to our reading of Walsh's novel -- that "the knowledge of God is naturally implanted in all." The second reason is in effect Anselm's argument. And the third is based on a point about truth: to say that truth does not exist is in effect to contradict oneself. Because is the statement "Truth does not exist" is true, it is false. So truth must exist. But as the Evangelist John says, God is truth.

Aquinas replies to these points first with a general analysis of self-evidence and then with specific rejoinders. On self-evidence, his point is that we need to distinguish between things that are self-evident "in themslves" and self-evident to us.

The terminology here is a bit unforunate, but we can make the point by way of a couple of examples. It is self-evident that triangles have three sides. It is not just a necessary truth, but it is also evident to anyone who understands the words. This fact, then, is both self-evident in itself -- i.e., necessary -- and self-evident to us. On the other hand, the first derivative of the function x³ -- the rate of change of this function with respect to x itself -- is 3x². This is a necessary truth. But it is hardly self-evident to us. Even readers who have studied calculus might find themselves unable simply to produce a proof of this fact.

So Aquinas's general point is that the existence of God is self-evident in the sense of being a necessary truth, but it is not therefore self-evident to us. It requires proof from things more evident to us.

As for the three specific arguments, his replies are these: (i) It may be that there is implanted in us a general and confused sense of God. But that doesn't mean we know it is God who lies behind this sense. I may here a person approaching, and be aware in a general way that someone or something is coming my way. But I may not recognize that it is Deborah. (ii) Anselm's argument he rejcts (though without mentioning Anslem by name) ont eh gorunds that I can understand the words "that than which none greater can be thought" without thereby understanding that such a thing really exists. As a reply to Anselm, this is not adequate. It ignores Anselm's insistence that a necessary being is one whose non-existence is inconceivable. But we will let this pass. (iii) Finally, Aquinas agrees that the existence of truth is evident. But the existence of one Primal Truth, who is God, is not self-evident to us.

Having established that it is worthwhile giving proofs of God's existence in terms of "better-known" things, Aquinas notes two objections to the conclusion itself. The first is that the existence of evil is incompatible with the existence of an infinite and infinitely good being. The second is that everything in the world can be referred back either to Nature -- to matter and its laws -- or to acts of human will. So there is no need to posit God. He saves his replies to these objections until after the proofs, but we will deal with them briefly here. On the matter of evil, his reply is that God permits evil so that good may come of it. One can wonder if this reply is at all adequate, but we will leave the whole issue of evil until later in the course. On the matter of whether we need posit more than Nature and human will, Aquinas insists that nature works toward an end that goes beyond nature itself to the First Cause Who is God. Similar comments apply to the will, he believes. This reply will be plausible to the extent that Aquinas has made the existence of a First Cause plausible. But that is essentially the issue to which we now turn.

The first two Ways are very similar and similarly puzzling. The first is the argument from motion. "Motion" in this context means change or, better, change of state. Growth would be an example, as would various kinds of ordinary motion. [Parenthetical remark: Aquinas would have thought that any kind of motion through space counted as a change of state. Modern physics disagrees, but agrees that "inertial" motion is not a change of state.] Its basic factual premise is that some things are undergoing change. Then follows a theoretical/philosophical premise: whatever is changed is changed by something else: changes requires an explanation, and the explanation must be in terms of something else that causes the change.

Why does Aquinas think this is so? His reasons are given in the terms of Aristotelian philosophy. (Aristotle [384-322 B.C.E.] Change, he tells us, is the reduction of something from potentiality to actuality. That is, a thing can't undergo a certain sort of change unless it has the potential to enter into the final state in question. An acorn can become an oak; it can't become a beech, let alone a bear. And Aquinas believes that change is caused by something that is already in the state of actuality. An example will help: a thing that is not yet hot, is heated by something that is hot. And furthermore, a thing couldn't be the cause of its own change. For that to happen, it would, for example. have to be both actually hot -- in order to cause the change -- and only potentially hot -- in order to be undergoing change. This can't be. So change must be caused by something external to the thing that is changing.

Now A's change might be caused by B. And B, in turn, might be changing in some way, with this change caused by C. Could this chain of changers stretch back to infinity? Aquinas answer no. What is a little less clear is why he says no. His words are not terribly helpful. He writes:

But this cannot go on to infinity, because then there would be no first mover, and consequently no other mover, seeing that the subsequent movers move only inasmuch as they are moved by the first mover, as the staff moves only because it is moved by the hand.

The second way is concerned with efficient causes. All we need to say by way of explaining "efficient cause" is to say that efficient causes are responsible for a thing's existence. Whether efficient causes are to be understood as originators or as sustaining causes need not concern us here, though some commentators have said that we should understand efficient causes as causes that keep a thing in existence (as the air in this room keeps me in existence) rather than as things that bring a thing into existence in the first place.

Again, we begin with an empirical claim -- i.e., one that is based on experience. In the world, there is an order of efficient causes -- i.e, some things have efficient causes. Furthermore, nothing can be its own efficient cause, since if it were, it would have to be prior to itself, Aquinas tells us, which is impossible. Furthermore, there can't be an infinite series of efficient causes, according to Aquinas. This, he tells us, is because the first cause is responsible for all the intermediate causes, which in turn are responsible for the ultimate cause -- for whatever causes the last thing in the chain. To take away the cause is to take away the effect. But if there is an infinite series of efficient causes, there will be no first cause, and hence the rest of the series won't exist either.

Again, the argument seems to beg the question against the opponent's implicit point. The opponent simply denies that there must be a first cause, as long as everything that requires a cause has one. To say that there is a first cause is not take away anything. It is to say that anything you might have thought to be the first cause is in turn caused by something else. Again, this idea may seem wierd or implausible, but that is a different matter from showing it to be wrong. Our immediate intuitions about abstruse matters are not really likely to be very reliable.

The third way is from "possibility and necessity." Again, we begin with an empirical premise: there are at least some things are capable of existing and of not existing. In fact, ,ost things -- perhaps all -- that we can easily think of are like this. We certainly are. We come into existence at a certain time, and we cease to exist sometime later. But the same is true of my computer, and my desk and my car and the Empire State Building and even Mount Everest. In the Aristotelian vocabulary that Aquinas uses, such things are generated and corrupted.

Now let us suppose that all things are of this sort -- can be, and can not-be. Aquinas insists: any such thing will be non-existent at some time. There is room for a quibble here; a thing might be capable of non-existence but never fail to exist. But leave that aside. Suppose Aquinas is right: all such things -- call them contingent things -- are non-existent at some time or other. Aquinas insists "then at one time there could have been nothing in existence."

Here we need to pause over a matter of translation. The word "could" here is almost certainly a typo in our text or else a mis-translation. The argument won't work with "could"; it requires "would." And other translations near this out. Aquinas is saying, in the words of another translation:

if everything can not-be than at one time there was nothing in existence.

Let's grant for the sake of the argument that nothing can come from nothing. The argument is still depply flawed. Compare: everyone has a mother. Therefore, some one person is everyone's mother. The fallacy is the same. From the fact that each contingent thing is non-existence at some time or other, it simply doesn't follow that there is -- or was -- some one time when each contingent thing was non-existent. The things might exist in an infinite overlapping series.

Aquinas's reasoning seems flawed, but there we have it: he concludes that there must be a being whose existence is necessary -- who is neither generated nor corrupted.

From here the argument continues in the vein of the First and Seocnd Ways. Is this being's necessity caused by another being? Or is it uncaused? Someone might think there could be a chain of necessary beings, "later" members having their necessity caused by "earlier" members, but Aquinas takes himself to have shown already in the second Way that this is not possible.

These are the first three of Aquinas's Five Ways, and as they stand, they seem to me not very plausible as arguments. However, it isn't clear what follows from that. Behind cosmological arguments is the impulse to make sense of the Universe or better, yet, the sense that the Universe does make sense, and that this sense could only come from something other than the ordinary physical stuff from which it is formed.

The idea that the Universe came quite literally from nothing is one that most people find hard to accept. Physics has little if anything to contribute; what it tells us is that, best we can tell, the Universe began about 15 billion years ago. But since the Universe is the space-time continuum and all that is in it, this is taken to mean that time itself came into being 15 billion years ago.

That may make it sound as though the universe has an edge, so to speak -- a temporal edge. and this may seem inconceivable. The physicist would have two replies. The first would be a technical story about the geometry of the universe itself, explaining that we need not posit an edge. We will leave that aside. The second point might well be (depending on the physicist) that our usual notions of what makes sense may not be worth so much anyway; they have been repeatedly and successfully overthrown throughout the history of physics.

We might also note: even though individual things come and go, it seems to be a law of the universe that mass/energy is neither created nor destroyed, though it can change form. This might seem to give to the sum of the Universe's stuff -- thick, wispy or nebulous -- the status of non-contingent being.

Aquinas almost certainly would not agree. And as we saw in our discusison of Anselm, he wouldn't agree either. Anything that has parts, or has a beginning in time, can be coherently conceived of as non-existent. In that case, Anselm would conclude, it cannont be necessary. Aquinas might avail himslef of this reasoning as well. And in any case, the idea that something like brute matter should have the capacity to give rise to all we see and more, and yet have no explanation itself is too much for many people to swallow.

But what is the truth here? The difficulty, such as it is, is that we simply don't know. We don't know whether or to what degree the Universe ultimately makes sense. The cosmological argument bespeaks an attitude that it must make sense, and that the sense must be made in terms of something that is its own explanation. [Whether Aquinas could speak in this way is unclear. Would a self-explaining thing be prior to itself? If so, Aquinas can't allow it. And if God is neither self-explaining nor explained by anything else, is not the positing of God the positing of mere mystery -- august mystery, to be sure but mystery nonetheless?]

I have been very critical of Aquinas's arguments against infinite series. However, the idea is puzzling. If each thing in a series of explainers requires explanation in turn, it may seem that positing an infinite series of such things leaves the whole unexplained. Here is an argument that is supposed to talk us out of this. It is not original to me, though I am not certain who originated it. Suppose that four people are at a bus stop. The first is there to catch a bus. The second is there because he is madly in love with the first, and follows her everywhere. The third is there because the bus stop is on top of a hill with a magnificent view that she wants to admire, and the fourth is there simply resting. Now we know why each person is there. Does it make any sense to ask why the whole group is there? Doesn't explaining why each member of the group is there say all that we could ask? And if this is right, then shouldn't we say the same thing about the members of an infinite chain of movers or efficient causes or necessary beings?

This may be so, but it may feel as though there is a difference. In the case of the people at the bus stop, the logic seems a bit different. The first person is waiting for a bus. As far as it goes, that is reason enough to explain her presence there. The second is there because she is there. If we are satisfied with the explanation of her presence, we need add no more. The third and fourth, in turn, seem to have their presences explained well enough. So indeed, there seems to be nothing left to be explained. But if we have a chain in which each thing depends on the next, our sense it that to leave it with no "anchor" -- with no explanatory fact that needs no explanation -- is to leave the whole explanatory fact that needs no explanation -- is to leave the whole chain's existence a mystery. However, this is a very hard view to sort through. When must we carry explanation further? Notice: there is presumably some reason why our first person is waiting for the bus. Perhaps she wants to go to the Silver Spring metro. Perhaps this is so because that will take her to Union Station. And perhaps she wants to go to Union Station to meet her aged mother, who is coming in from Brooklyn. and perhaps her mother is coming in from Brooklyn because her grandson -- the woman's son -- is having a birthday party. And on it goes. Do we really need to say all this to explain why person number 2 is at the bus stop? If not, our sense that the individual links in an infinite chain are ultimately unexplained ought to waver.

There is a premise that we proposed in the seventeenth century by a philosopher named Samuel Clarke. It is the Principle of Sufficient Reason, and it says that every fact about the universe must have an explanation, either by reference to something else, or of its own nature. The existence of contingent beings or of dependent beings is not accounted for by the nature of the beings themselves. Indeed, that is much of the point of calling them contingent or dependent.

[The two notions "contingent" and "dependent" are actually somehat different. By definition, a dependent being depends on something else for its existence. Whether this is true of contingent beings, however, is not a mere matter of definition. But a contingent being is not self-explanatory. And so if the Principle of Sufficient Reason is correct, it still needs an explanation.]

Now one commentator (William Rowe, in his Philosophy of Religion) re-formulates the argument thus: if the principle of sufficinet reason is accepted, then the very fact that there are dependent beings (or contingent beings, for that matter) requires an explanation. And we can't explain it except by reference to a a necessary being. But Rowe's point is that even if we grant the argument, we are still stuck with the question of whether the premise is true -- of whether there may be things about the universe that are deeply arbitrary and unexplained. The idea is profoundly uncomfortable. Science tends to assume as a working hypothesis that it is false. But even science will appeal to basic laws that are not further explained. And while some scientists have a sort of pious hope that the basic laws will turn out to be somehow self-explaining or self-recommending or what have you, there is no guarantee that this will be so. In other words, reason and science seem unable to guarnantee that the universe must make sense, let alone that its existence and nature must be underwritten by a necessary being.

It seems, then, that the cosmological argument can't be used to force the atheist's hand. The idea that the universe is arbitrary at its core may be one that we choose not to accept. But we should be clear that this is not something forced upon us by logic or philosophy.

© Copyright Allen Stairs, 1998. All Rights Reserved.
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