II. Cosmological Arguments
A. Aquinas' Second Way
Saint Thomas Aquinas (1225-1274)
- Italian philosopher and theologian
- the outstanding representative of "Scholastic Philosophy"
- applied Aristotelian methods to Christian theology; was interested
in reconciling reason and faith, the intellectual life with the
religious life
- His masterwork is Summa Theologica
Aquinas' Second Way
(1) The natural world includes events that occur."In the world of sensible things we find there is an order of efficient causes."
(By the way, when Aquinas says "efficient cause," he just means cause. He inherited this terminology from Aristotle.)
This is undeniable. Here we are. There are these events happening, such as the giving of this lecture, the walking by me across this room, the rain storm yesterday. This is obvious.
(2) In the natural world, every event has a cause, and no event causes itself.
"There is an order of efficient causes." "There is no case ... possible in which a thing is found to be the efficient cause of itself."
Let's take these in turn. If you think about, the claim that every event has a cause seems very plausible. We assume this all the time. If you hear a noise in the hallway, you assume it has a cause-maybe a person, or an animal, or even just something falling over. And that falling over also has a cause-the wind, the loss of adhesive, ... . This is not to say we always know the cause of any event. Very often it is difficult or impossible to know what caused something. But I take it we all agree that every natural event has a cause. Nothing just happens uncaused.
I'd say it is just part of the concept of causation that nothing causes itself. That doesn't make any sense. All events that occur were caused to occur by other events, events that came before. Which bring us to our next premise:
(3) In the natural world, causes must precede their effects.
"There is no case ... possible in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible."
This quotation implies Aquinas' acceptance of P3. This, too, just seems part of the concept of causation. In fact, I would say that (2) and (3) are analytic, or relations of ideas. Just as it follows from the concept of a triangle, that all triangles have three sides, it follows from the concept of causation, that nothing causes itself, and causes always precede their effects.
(4) In the natural world, there are no infinite cause/effect chains.
"Now in efficient causes it is not possible to go on to infinity, ..."
Here we have a premise with some substance. This is something we can sink our teeth into. What is the rational for this premise. Well, Aquinas gives is straight out:
"... because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate be several, or only one. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate, cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false."
I think we might construct a mini-argument for (4):
(4.1) Any infinite cause/effect chain would have no first member (no "first cause").
[by definition]
(4.2) If a causal chain has no first member, then it will have no later members.
[since to take away the cause is to take away the effect]
(4.3) But there exists a causal chain with later members.
[these are the events we witness; see P1]
(4) Therefore, there are no infinite cause/effect chains.
[follows from (4.1)-(4.3)](Sober gives an equally good rendition of Aquinas' argument on p. 41.)
At first blush, this argument seems pretty good. I mean, if there is no first member of the chain, then how could the chain get started. Any existing cause/effect chains certainly had to start somewhere, right?
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(5) Therefore, there is an entity outside of nature (a supernatural being), which causes the first event that occurs in the natural world."Therefore, it is necessary to admit a first efficient cause."
Now, this deduction requires some commentary. How did we get from these four premises to this conclusion? Well, first, let's look at a conclusion we might have reached, that might seem to follow more naturally, and which even seems to be a more accurate rendering of the conclusion Aquinas himself actually draws:
(5´) Therefore, there is a first member of the chain, a first cause.
This seems like the conclusion Aquinas draws, but it is actually inconsistent with other premises in the argument. The argument, with (5´), is thus incoherent. No one, whether you're a theist or an atheist, should accept it.
For it to be the first member, there can't have been any events before it. But since, in order for an event to be caused, it has to have events come before it (to cause it!), it follows that this first event is uncaused. But P2 says this can't happen, that every event has a cause. This is incoherent.
See if we stick the cause in, its no longer the first member. If we don't, it hasn't got a cause.
So, Sober's solution, is to help Aquinas by phrasing the premise as (5). So, this cause of the first natural event is "outside of nature." These principles about causation apply only to events in nature. So we needn't require that this thing outside of nature-this supernatural thing-itself have a cause, or prohibit it from causing itself. These restrictions apply only to natural objects and events.
To repeat: From (1) - (3) we get that there is this chain of causes extending back into the past. From (4) we get that the chain is not infinite -- it has a first member. But in order for this first event to obey the principle contained in (2), it must have a cause. But in order for it to be the first event in nature, it can't have a cause in nature. The only option left seems to be that it has a cause, but this cause is "supernatural." It is caused by an entity that exists somehow not in nature.
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(6) Hence, God exists."Therefore, it is necessary to admit a first efficient cause, to which everyone gives the name God."
Ok. This inference is a bit quick. Why, just because we have established that there is this thing that exists outside of nature, that caused the first event to occur (thereby getting the whole chain started), are we entitled to infer that that thing is God?
We've established the existence of this entity. Maybe it has some of the attributes of God-for instance, it is the creator of the universe (it got the whole thing started); and it's got to be very powerful, since, again, it caused the whole universe to exist. And it's "supernatural," and people often say that about God. But in order for something to be God, it has to have other important divine attributes as well, such as omniscience and omnibenevolence. And it has to be a "person," not just some impersonal "force."
Well, I think we should regard the move from (5) to (6) as some sort of non-deductive inference. The idea is that, while (5) does not entail (6), (5) does make (6) more likely.
Let's draw an analogy. Suppose, on Christmas Eve, you woke up in the middle of the night and heard some trampling on your roof, which sounded like hoofs. You run out into your living room and see some presents under your tree that weren't there before. Then you hear someone struggling in your chimney. You look over and see just his legs and feet dangling-red pants and black boots. Finally, he makes it up your chimney and he's gone.
Now, it seems you've established that there is a thing that gives gifts on Christmas, dresses in red (at least from the waist down), and enters and exists thru the chimney. This seems like evidence that Santa Claus exists.
Someone might protest: but Santa has other attributes, and in order to prove Santa exists, you have to prove that this entity has the other attributes, such a having a long white beard, being jolly, living at the North Pole.
This is something to think about, but you have to admit that we have some good evidence for the fact that Santa exists in this case.
Likewise in the case of God. If we can prove that there is an entity outside of nature (a supernatural being), which causes the first event that occurs in the natural world (is hence created the universe), the atheists aren't gonna be to happy about that. They don't want to have to believe in anything like that either, I don't suppose.
So this is certainly evidence for God. And the cool thing is, we did all from premises that any rational person is supposed to accept -- we didn't appeal to passages in the Bible, or what some priest said, or what you were told in your dream. These are just premises about nature and causation. Pretty cool, huh?
1.
Problems with Aquinas' Second Way
a.
Infinite Causal Chains
I think the most interesting objection to Aquinas' argument is to premise (4), the claim that there are no infinite cause/effect chains -- that claim that the chain of events extending into the past couldn't go back forever -- that is had to start somewhere.
Well, Aquinas gave a little subargument for this premise. So if we don't accept the premise, we need to find something wrong with that subargument. Recall it.
(4.1) Any infinite cause/effect chain
would have no first member (no "first cause").
[by
definition]
(4.2) If a causal chain has no first member, then it will
have no later members.
[since
to take away the cause is to take away the effect]
(4.3) But there exists a causal chain with later members.
[these
are the events we witness; see P1]
(4) Therefore, there are no infinite cause/effect chains.
[follows
from (4.1)-(4.3)]
I think (4.2) is the questionable premise. Aquinas gives it in his slogan that if you remove the cause you remove the effect. But if you "take away" the first member, you're not really removing anything. Rather, you're just adding causes before it. Every event would still have a cause. There would just be infinitely many of them.
It is certainly perfectly coherent to imagine
that the universe last forever (in the future). And it just seems
just as perfectly coherent to imagine that the world goes infinitely
far back into the past. Why not? We can imagine it. It is not
a contradiction to suppose it. Therefore, it is possible. But
Aquinas' argument relies on the claim that it is impossible. So
the argument is unsound because premise (4) (of the main argument)
is not true.
B. Leibniz Argument from
Sufficient Reason
G.W. Leibniz (1646-1716)
- German philosopher, mathematician, and statesman. (Also a physicist, geologist, linguist, historian, and more.)
- Regarded as one of the supreme intellects of the 17th century.
- Invented calculus, independently of Newton.
- Defended the view that all that exists in the universe are conscious, immaterial substances - "monads."
- Maintained that this world is the best of all possible worlds.
1.
The Principle of Sufficient Reason
PSR: For anything that exists, there is a reason why it exists and why it is as it is rather than some other way.
a.
What PSR is Not
PSR is not the claim that everything happens "for a reason," in the sense that every event that occurs has a meaning or grand purpose. Rather, PSR is just saying there is always at least some sort of mundane explanation for everything.
b. Reasons to Think PSR is True
- It has "intrinsic appeal."
- It appears to be free from counterexample.
- It lies at the basis of all science.
- We presuppose it in our ordinary thinking about the world.
2.
The Argument
the world - the aggregate consisting of every contingent thing that ever did exist, does now exist, or ever will exist.
(1). The world exists.
We can know this is true, just from the fact that we know that we exist. If you exist, then there is at least one contingent thing. Even if there is just one contingent thing, then the world exists. Of course, we all know that there is more than that. Whatever it is-however many contingent things there are-the world is the aggregate of all of the contingent things.
(2). If the world exists, then there is a reason why the world exists.
PSR entails this. Since it says for any object that exists, there is a reason why it exists. Leibniz says we have a right to ask, "Why is there something rather than nothing?" (PNG). He is saying that this question must have an answer. Well, this question has an answer only if there is an explanation or reason why the world exists.
(3). If there is a reason why the world exists, then there is something outside the world that the world depends upon for its existence.
This premise rests on two main facts. First, on the idea that the world is contingent. That is, it might not have existed. Just as each thing in it is contingent, so is the whole thing. There might have been nothing. Leibniz thinks this is true, that thiere is a " reason why there is world rather than nothing."
Also:
"for it has been granted and proved that the world does not exist of metaphysical necessity."
This fact is needed to explain P3 because if a thing is a necessary being, then clearly there is not going to be something other than it that explains why it exists and that it depends upon. The explanation of why a necessary being exists is, we might say, "internal" to it. For any necessary being, there is by definition a suff. reason -- the fact that the being is a necessary being. There could hardly be a more satisfying explanation for the existence of a thing than that its non-existence was impossible.
The second idea this premise rests on is the idea that if you want to explain why a contingent thing exists, you must cite facts about things other than it. If you want to explain why a group of contingent things exist, you must appeal to things outside the group. For if you were just say more about the properties of the contingent thing, you would just be presupposing that it exists. But that is precisely the fact you're trying to explain.
The only property of a thing itself that you can appeal to, to explain the thing itself is the property of necessary existence. But that's why we also use the fact that the world does not exist necessarily.
So, back to the rationale. Here's the rationale for P3:
The world is a contingent thing, and for any contingent thing, in order to explain why it exists, you must look to things wholly distinct from it. So, if there really is a reason why the world exists, then since it's contingent, there must be something outside the world (something that is not a part of the world) that is the reason. And since this thing is the reason the world exists, the world is ontologically dependent upon it. So, just from the fact that there is a reason why the world exists, we can infer that there is something outside the world that the world depends upon.
(4). If there is something outside the world that the world depends upon for its existence, then there is a necessarily existing creator of the universe.
This premise is true in virtue of the concepts involved (it's a conceptual truth, or an analytic truth). Since the world is defined as the aggregate of all the contingent things, anything outside the world cannot be contingent-otherwise, it would have already been included in the aggregate of contingent things. Well, if something is not contingent, then it exists necessarily. Also, if the world does depend upon this thing for its existence, that is just it would not have existed were it not for this thing. This just another way of saying that this thing created the universe. So, if this thing is outside the world and the world depends on it, then we can infer that it is necessarily existent and is the creator of the universe.
(5). Therefore, there is a necessarily existing creator of the universe.The follows as a matter of logic from (1)-(4).
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(6). Therefore, God exists.(6) does not following from (5) as a matter of logic. Rather, it is a sort of abductive argument: the best explanation for the fact that there is this necessarily existing creator of the universe is that the thing is just God.
3.
Objections
Note on explaining and objecting to conditionals: Recall that to explain why a conditional is true, you don't have to show why the antecedent is true or why the consequent is true; the conditional doesn't say that either are true. Rather it just says IF the antecedent is true, THEN the consequent is true. So what you need to do is explain the connection between the antecedent and the consequent. The way to do this is assume the antecedent is true, and then explain why, on the assumption, the consequent follows.
To object to a conditional, it will not do to try to say why the antecedent is false or why the consequent is false; the conditional doesn't even say that either is true. What you have to do is show that there is no necessary connection between the antecedent and consequent. The way to do this is assume the antecedent is true, and then show that, even on that assumption, it is possible for the consequent to be false.
1. The world is not contingent (deny P3).
It exists necessarily. There couldn't have been nothing. Just because each thing in the world is contingent and hence has an external cause, a reason why it exists and is that way it is, it doesn't follow that the whole must be contingent. To reason this way is to commit a certain fallacy: to infer that from the fact that members of a collection has a certain property that the collection has it, too. (Heap example: each grain is not-a-heap; but the whole does not have this property: the whole is a heap.)Reply: it does seem intelligible to imagine there might have been nothing. Since each thing is contingent, it could be eliminated. Well, why can't we just keep eliminating until we've eliminate everything. Then there would be nothing. And, more to the point, why couldn't here have been nothing. It certainly seems like a very intelligible question.
2. Deny PSR (and hence deny P2):
Why think this is true for everything? All the examples you gave to support PSR were of smaller things. You didn't show that the principle applied to the aggregate of everything. This is to say there is no reason for the world. It is a brute fact. It's just the way it is, and that's all there is to say about it. There's just no explanation. Why can't there be brute facts?It would be nice if there were independent reasons to deny PSR. There may be: quantum mechanics. According to QM, nature is filled with events whose occurrence has no explanation whatever. If, for example, the nucleus of a radium decays at a certain time, there is no explanation whatever for its decaying at that time rather than some other time.
Granted, this is not conclusive, because there are "hidden variable" interpretations of QM according to which there is an explanation, we just can't find it.
So, if you deny PSR, then presumably you will also claim that there is no explanation for the existence of the universe. There is no answer to the question, Why is there something rather than nothing? There just is something, and there's absolutely no reason for it. It's just here, and that's it. It's a "brute fact."
My impression is that most atheists would take this route. Theists might then charge that atheists are hypocritical -- they say believing in God is to believe in something "spooky," or mysterious. But we can see that atheists also believe in something mysterious -- the existence of the universe.