Existence of God (part 15)
Transcript of William Lane Craig's Defenders 2 class.
Excursus: Natural Theology
§ III. Teleological Argument
Last week we launched into our discussion of the argument for design based upon the fine tuning of the universe. We saw that from its very inception, the universe has been fine tuned for the existence of intelligent life. “Fine tuning” does not mean “design.” Fine tuning, as I explained, means that the range of the fundamental constants and quantities that describe the universe must fall into an extraordinarily narrow life-permitting range if intelligent life is to exist. These constants and quantities can take any of a wide range of values, but, in fact, unless they all fall into this unfathomably narrow life-permitting range, life would be impossible and would not exist anywhere in the universe.
Someone asked last week, “When does something become so improbable that it becomes impossible?” And I answered that question from memory by saying that William Dembski had set a probability bound of 1080, which is the number of subatomic particles in the universe. Checking Dembski’s book, The Design Inference, I see I had a memory lapse and therefore need to correct this. You don’t consider simply the number of particles in the universe; you also need to consider the number of seconds in the universe which he generously places at 1025. So you would consider those states of the universe all through its history. Then he multiplies this by 1045 as the number of events, or reactions, that could take place per second. On this basis, he arrives at a probability bound which is one half times one out of 10150. Anything that falls beyond that probability bound, he says, is not different from impossibility. That would be the answer to that question about when does something become so improbable as to be impossible.
Answer: That is a generally accepted figure – that there are around 1080 [subatomic particles in the universe].That is obviously an approximation. The same with the number of seconds in the history of the universe. That is given by the age of the Big Bang. These are not really controversial figures. He is the only person I know of who addresses the question that was put to me, so I simply give you his answer. I am not a mathematician, so I don’t know whether this is the best answer or not, but this is an answer given by a prominent design theorist to that question. I don’t think anything in the argument depends upon it, because what the argument is, is that design is the best explanation of the fine tuning of the universe. We are not going to argue that it is so improbable that it is impossible. Ours is going to be an argument for the best explanation, and we’ll look at the alternative explanations for the fine tuning, and I’ll argue that the best explanation is that it was due to design.
Some people will object to an argument of this sort by saying, “If the universe had different laws of nature, then maybe a change in the constants and the quantities wouldn’t be so disastrous. If there were different laws of nature, then the universe wouldn’t be fine tuned for life, and we might not have these sort of disastrous results from changing them.” This objection displays a misunderstanding of the argument that is very common. In the fine tuning argument, we are not concerned with universes governed by different laws of nature. We don’t have any idea of what universes would be like that are governed by wholly different laws of nature. That is pure speculation.1 Rather, what we are concerned with in this argument is universes that are governed by the same laws of nature, but with different values of the constants or the fundamental quantities. The laws are the same, but you alter the values of the constants or the quantities of the universe.
John Leslie is a Canadian philosopher who gives an excellent illustration of this point. Leslie says, imagine a solitary fly resting on a large blank area of the wall. He says, suppose a single random shot is fired, and the bullet pierces the fly and kills it. Even if, outside the blank area, the wall were covered with flies, so that a randomly fired bullet would probably strike a fly, nevertheless it still remains highly improbable that within the large blank area, a randomly fired bullet would strike the fly. It is vastly more probable that the bullet would hit someplace else in the blank area. If the shot does strike the fly, then it is probable that that was not the result of chance, but it was in fact aimed, and the fly was targeted by the shooter, and that is why the bullet struck the fly – not by chance, but by design.
In exactly the same way, let our universe be like the fly, and this large blank area would be other possible universes described by the same laws of nature as ours, but with different values of the constants and quantities. What you find is that they are almost all life-prohibiting. Even if there are universes outside [the blank area] which are governed by different laws of nature and in those there is not the sort of fine tuning as existing in our universe, nevertheless the probabilities would still be that a universe governed by our laws of nature ought to be life-prohibiting rather than life-permitting. We only need to be concerned with universes governed by the same laws of nature in this argument. We do not look at, and are unconcerned about, what would take place in universes governed by different laws of nature.
Question: Given sufficient time with sufficient universes out there, wouldn’t life occur somewhere?
Answer: Here we are only talking about there being one universe. These others [outside of the blank area] are just possibilities. It is not that they actually exist. We will see that in order to defend the hypothesis of chance, its defenders have been forced to resort to the Many Universes hypothesis – that there is an infinite number of parallel worlds or other universes – so that by chance alone the constants and quantities would fall into the life-permitting range in some of them. We will deal with that later on. Right now we are talking just about one universe.
Question: The parameters that we are talking about define the laws of the universe. So are you talking similar universes?
Answer: No, they don’t define the laws of the universe. That is the point that I am trying to make. Remember I gave the example of Newton’s gravitational law. You can have universes governed by that same law, but with a different value of the gravitational constant. Governed by different laws would be where you have a different equation – say, instead of multiplying the two masses together you’d subtract them from each other or something of that sort. That would be a different law of nature. What we are talking about here are universes that have the same laws, but the values of these constants and quantities are different.
The question that we are facing is what is the best explanation of this cosmic fine tuning? An increasing number of astronomers and scientists think that the best reason for the fine tuning of the universe for life is that the universe is designed to be life-permitting. But design is not the only alternative. There is also physical necessity and chance.2 On the outline, you have the simple form of the design argument stated in terms of those three alternatives.
It is very simple in its fundamental structure. It goes like this:
1. The fine tuning of the universe is due to either physical necessity, chance, or design.
2. It is not due to physical necessity or chance.
3. Therefore, it is due to design.
This is a logically valid argument. That is to say, if the two premises are true, then the conclusion necessarily follows. The only question is: are those two premises more plausibly true than false?
This is a very simple and easy-to-memorize argument.
Question: What is law? I know what chance and design means, but what is the “law?”
Answer: The idea there is that the universe is physically necessary – that these constants and quantities have the values that they do. It is kind of like what an earlier questioner asked: the laws of nature determine that these constants and quantities have the value that they do, that it is physically necessary for them to exist. It is saying that there is no other kind of physical universe possible – it had to be this way. That is what physical necessity means.
Followup: But the universe does not exist because there is some kind of law floating out there and it generated the creation. Is that what you are saying?
Answer: No, that isn’t what I meant. That is a good clarification. What I meant was simply that the values and the quantities are physically necessary – they could not have been any other way. The universe had to be like this.
Our Choices: Physical Necessity, Chance, or Design
Take the first premise that the fine tuning of the universe is due either to physical necessity, chance, or design. This premise simply lists the three alternatives that are available for explaining the fine tuning, and therefore this is uncontroversial. If somebody has a fourth alternative, he is welcome to add it to the list, and we would have to consider that when we come to premise 2. But I do not know any other alternative than these three: physical necessity, chance, or design. Therefore, the first premise does seem to be true; it simply lists the possible explanations for this extraordinary fine tuning.
Notice that by focusing on the fine tuning, this argument does an end run around the whole emotionally loaded question of biological evolution and Darwin’s theory of biological complexity. The argument from fine tuning, if it goes through, will show that even if life is the product of random mutation and natural selection of a blind evolutionary process, nevertheless, even that still depends upon these finely tuned initial conditions of the universe which cry out for some sort of cosmic Intelligent Designer. You can just do an end run around all of the negative emotions and baggage that are connected with the creation-evolution controversy that exists in biology. Any design arguments that you do want to construct on the basis of things like the origin of life, or the origin of mind, or the development of biological complexity will simply layer more improbability on top of the fine tuning, which will just make the design argument all the stronger and will show that it is all the more improbable that life and consciousness can be explained apart from a cosmic Designer.3
Support for Premise (2)
That means that the really crucial premise of this argument is the second one: the fine tuning is not due to physical necessity or chance. Let’s examine each of these alternatives one at a time.
First, let’s talk about physical necessity. As I just explained, according to this alternative the universe has to be life-permitting. The constants and the quantities had to have the values that they do. It is literally physically impossible for the universe to be life-prohibiting. It is physically necessary that the universe be a life-permitting universe.
On the very face of it, this is an extraordinarily implausible explanation of the fine tuning. It would require us to say that a life-prohibiting universe is physically impossible – such a thing could not exist. And that is an extremely radical view. Why take such a radical position? The constants, as we have seen, are not determined by the laws of nature. Nature’s laws could hold, and the constants could take any of a wide range of values, so there is nothing about the laws of nature that require the constants to have the values that they do.
As for the arbitrary quantities, remember those are completely independent of the laws of nature – they are just put in as initial conditions on which the laws of nature then operate. Nothing seems to make these quantities necessary in the values they have. The opponent of design is taking a very radical line which would require some sort of evidence, some sort of proof. But there isn’t any proof that these constants and quantities are physically necessary. This alternative is just put forth as a bare possibility; and possibilities come cheap. What we are looking for is probabilities or plausibilities, and there just isn’t any evidence that the constants and quantities are physically necessary in the way that this alternative imagines.
Theory of Everything
Sometimes scientists do talk about an undiscovered or yet to be discovered “Theory of Everything” or, as it is abbreviated, a “TOE.” This would supposedly explain everything. But like so many of the colorful names which are often given to scientific theories, this label is very misleading. The purpose of a successful TOE is to unify the basic four forces of nature – which are gravity, electromagnetism, the strong force in the atomic nucleus, and the weak force in the atomic nucleus. These four forces, according to a Theory of Everything, will be unified into one fundamental force which is carried by one fundamental particle. But a Theory of Everything which manages to unify these four forces of physics obviously doesn’t explain everything – the idea that this is a theory of everything is just a misunderstanding. This is just a colorful name, which doesn’t purport to explain everything. It just seeks to unify these four fundamental forces of nature into one force.
Indeed, the most promising candidate for a TOE to date is M-Theory, which is a super-string theory. Instead of thinking of the fundamental bearers of these forces as little particles, it thinks of them as one-dimensional strings of energy. According to M-theory, or super-string theory, there has to exist exactly 11 dimensions: 10 dimensions of space and 1 dimension of time. Otherwise, the theory won’t work. There has to be exactly 11 dimensions. But M-Theory itself doesn’t explain why there are 11 dimensions. That remains just a sort of basic assumption of the theory.4 It doesn’t do anything to explain why that particular number of dimensions should exist. So even M-Theory involves fine tuning of a geometrical sort, namely, there has to be exactly 11 dimensions for the theory to work.
You can see that this so-called Theory of Everything that scientists are on the pursuit of isn’t literally an attempt to explain everything. Indeed the best candidates for it have certain unexplained features of it themselves. Moreover, M-Theory doesn’t predict a life-permitting universe. In fact, it has been shown that M-Theory permits around 10500 different possible universes which are all consistent with the same laws of nature but which would vary in their fundamental constants. Almost all of these possible universes in this range are life-prohibiting. The values of the constants would be such that life could not exist in those worlds. This has come to be called the “cosmic landscape.”
The cosmic landscape has become something of a phenom in its own right in recent years. I think it is important to understand that this cosmic landscape of 10500 different possible universes is not real. These are not real universes; this is just a description of the range of possibilities. It is the range of values that these constants could take allowed by M-Theory. Some people have misinterpreted the cosmic landscape to mean these different universes actually exist, that they are really out there. And they therefore think that the argument for design is undermined by the cosmic landscape because some of these 10500 worlds will be life-permitting and therefore there would have to be life-permitting universes like ours in the cosmic landscape. But you have to keep in mind the cosmic landscape isn’t real; it is just a range of possibilities. It just describes the range of values that M-Theory allows for all of these different constants of nature. It describes the range of possible universes that are consistent with M-Theory.
So, far from undermining the argument of fine tuning, it actually reinforces the argument by showing that a life-permitting universe is not physically necessary. In fact, the range is so huge – 10500 – that some explanation is required for why, out of this vast range of universes, a life-permitting universe should exist. The life-permitting universes are just an infinitesimal part of the landscape, like that solitary fly on the wall that Leslie talks about. A randomly fired shot would probably hit a life- prohibiting universe not a life-permitting universe. So you cannot say that a life-permitting universe like ours is physically necessary because at least according to the best theories of physics that we have today, that is simply not true, but clearly false. The values of the constants are not determined by the fundamental physical theory. The fundamental physical theory is consistent with a vast, vast range of values for those constants, and all but an infinitesimal portion of worlds are life-prohibiting. So there is really no evidence at all to support this first alternative, that the fine tuning is due to physical necessity. The best evidence indicates that it is far from physically necessary that these constants and quantities should have the values that they do.
Question: Does M-Theory predict how many different membranes do exist that are real – not just those that are possibilities?5
Answer: There you are talking about how many actual universes there would be. I don’t know whether or not that theory is consistent with just any number of actual three-dimensional universes.
Followup: Could it then be, theoretically, at or near infinite?
Answer: Yes, and we will talk about this when we get to the Many Worlds hypothesis. Both the earlier question and this one is pushing us ahead to talk about the chance hypothesis. The defenders of chance will say that given the reality of these many, many other worlds – these other universes such as membranes or other bubbles universes – that by chance alone somewhere in this multiverse or World Ensemble there will appear these finely tuned universes. We are going to deal with that question later, when we get to the alternative of chance. But it is important to understand that here we are not talking about chance; we are talking here about physical necessity. Scarcely anyone defends physical necessity. There are certainly lots of theorists who want to because many of them feel uncomfortable with these appeals to the multiverse – it seems to be smuggling in metaphysics. But, on the other hand, the prospects for physical necessity are extremely dim. So hang on to the question about the other universes, we will get to it.
Question: 10500 – is that 1 followed by 500 zeroes? That is a minuscule potential.
Answer: Yes, remember the number of subatomic particles in the universe is only about 1080, so this is a number of which we can form no conception whatsoever.
Followup: The scientists still have to wonder where all these rocks and planets and material came from.
Answer: Absolutely, and that was the argument that we looked at before we looked at the fine tuning argument. Remember, in this series we are looking at a number of different arguments for God’s existence. The first one is the Argument from Contingency. Then the next one we spent several weeks on was the argument based on the origin of the universe.6 But now we are talking about the design argument. So you are right; you can always go back to the cosmological arguments. But we don’t need to go back there, unless there is some reason to. We can let this argument stand on its own merits for a Designer. But you are certainly right to remind us of that.
Answer: It is a cumulative case that one is presenting here. We are presenting a cumulative case in which all of these pieces of evidence come together to build a powerful case for a Creator and Designer of the universe. It is like a lawyer attempting to build a case against the accused where he will interview many witnesses and bring many pieces of independent data. If the data are independent, if the witnesses are independent, that makes his case all the more powerful. That is why I do not want to collapse this argument back on to the cosmological arguments. If we can show independent arguments for God, that would make it stronger than if we would have to fall back on the earlier argument to be sustained. I do not think it does have to fall back.
Question: You have told us that M-Theory still permits at least 10500 possible universes consistent with our given laws of physics. So, clearly, M-Theory isn’t reducing the physical constants to some certain set that they have to be. Does it do anything to even take a step in that direction? Do any of these string theories relate some constants in terms of others or are they all just completely arbitrary?
Answer: It does have a delimited range. This number isn’t infinite – there is a delimited range here: around 10500. But many theorists were hoping that it would enable us to predict these constants, that from the theory the constants would fall out as a prediction. And what happened instead is that the specific values didn’t fall out, but it turned out there is this vast range that are compatible with the theory. That is the focus here. Although it does have a finite range, it is still so large that the question arises, why do we have these life-permitting values, when it is such an infinitesimal part of the cosmic landscape? That is the question.7
Question: It would seem like we could take this further back – if any of these things could be represented mathematically, then that is evidence for design. If everything is random and chaotic, no matter how many universes you want to look at, if it’s possible to represent anything mathematically in these, this is evidence for design.
Answer: This is an independent argument that you are offering here. Some have offered this based on what has been called the “uncanny effectiveness of mathematics.” Eugene Wigner, a very famous physicist, often spoke of how uncanny it is that mathematics works. Why is it that someone sitting at his desk should be able to work out these mathematical equations, and, lo and behold, these experimental physicists go out and find that it really describes the way the world is! The universe is mathematically structured in such a way that makes it possible. Some have argued for the existence of a kind of supreme mathematical Mind which has structured the universe. I do think that that is a very intriguing argument. I haven’t worked on it myself, so I cannot comment any further on that; but it is an independent argument from this one that I think is well worth exploring and thinking about.
As I think about the different possibilities of mathematics existing as separate entities or as being simply creations of the human intellect, it does seem that the most satisfying view of mathematics would be that these are reflective of a supreme Mind which thinks in these categories and has built a universe on the blueprint of the plan that is in the mind of the Cosmic Architect. That is a sort of Platonic idea – that is what Plato believed, that God fashioned the world on the pattern of these mathematical ideas. As Christians, we would say these ideas exist in the mind of God, not independently of God, but as part of the thought of God. He is like an architect who has built a universe that reflects this mathematical blueprint that he has imposed on it. I do think that that is a very intriguing argument. But here we are not concerned with the mathematical structure of reality so much as the fact that out of all the possible universes in this cosmic landscape, what should exist but a life-permitting universe, when the vast probability – inconceivable probability – is that a life-prohibiting universe ought to exist, if it is just by chance.
What we will do next time is turn to the alternative of chance, which several of you have been pressing me on already. That is where the real debate lies today. The real debate lies with this question of whether the fine tuning can be explained away simply as a result of chance, or do we need to infer a transcendent Cosmic Designer for the origin of the world?8
6 The Kalam Cosmological Argument.
8 Total Running Time: 34:07