In his best-selling book The God Delusion (TGD), Richard Dawkins claims that belief in God is not only mistaken but irrational, especially in the light of modern science. He criticises belief in God from many angles, but in what he considers to be the central argument of his book, he claims to have shown that ‘God almost certainly does not exist’ (TGD, p. 158). His argument is based on probability and indeed he refers to it as the argument from improbability, which he thinks ‘demonstrates that God, though not technically disprovable, is very very improbable indeed’ (TGD, p. 109). For those who believe in God, this might be somewhat disconcerting. If such a well-known and high-profile scientist makes such claims, mustn’t there be something to them even if we acknowledge that his rhetoric is a bit overblown at times? What exactly is his argument? And does it stand up to scrutiny? These questions will be the focus of this article.
The Ultimate Boeing 747
The cosmologist Fred Hoyle claimed that the probability of natural processes producing living organisms is no greater than the probability of a hurricane assembling a Boeing 747 in a scrapyard. This illustration is often used to show that just as a Boeing 747 points to a designer so too does the existence of life. Dawkins attempts to turn this argument on its head. According to his ‘argument from improbability’ God is even more complex and so he claims that God’s existence is even more improbable than a Boeing 747 coming about by chance. He puts it like this:
However statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable. God is the Ultimate Boeing 747.
Far from improbability (of living organisms) providing evidence for God, Dawkins claims:
The argument from improbability, properly deployed, comes close to proving that God does not exist.
Let’s get back to the argument itself. Although Dawkins does not state his argument in quite this way, it could be summarized as follows:
1. Complex things are very improbable if there is no explanation for their existence.(That’s why they need an explanation.)
2. God is very complex (if he exists).
(In fact, God would be even more complex than other things we want to explain and so God would be even more in need of explanation.)
3. There could be no explanation of God’s existence.
Therefore, God is very improbable.
Why the Argument Fails
If any one of the three premises (1-3) of the argument is false, the argument fails. Let’s consider the first one:
1. Complex things are very improbable if there is no explanation for their existence.
Is this true? Are complexity and improbability connected in this way? Here is what Dawkins says, ‘The argument from improbability states that complex things could not have come about by chance’. This seems right since, for example, it is very improbable that a Boeing 747 would come about by chance. So there is a link between complexity and improbability for things that come about by chance. But this is very different from premise 1 and it would mean that Dawkins’ argument would establish, at best, that it is very improbable that God came about by chance. But since no believers think God came about by chance anyway, they would hardly be worried by such an argument.
So Dawkins has not given us any reason for thinking that premise 1 is true. And the problem is that if there is no good reason to think that it is true then his argument fails. But let’s suppose that we are generous and grant that Dawkins is right about premise 1. Does that mean that we should accept his argument? The answer to this depends on whether premises 2 and 3 are true. Let’s consider 2:
2. God would be extremely complex.
Is this true? Here is what Dawkins has to say,
A God capable of continuously monitoring and controlling the individual status of every particle in the universe cannot be simple.
Here we must be careful about the words ‘simple’ and ‘complex’. The problem is that it is not enough for Dawkins to say that God would be complex in some sense of the word. Recall that the whole point of the argument is to link complexity with improbability so he would need to show that God is complex in the relevant sense. What kind of complexity is linked with improbability? Dawkins is very clear that it is what he calls organised complexity. Roughly speaking, an entity has organised complexity if it is composed of a variety of parts arranged in a highly specific manner so that it is able to function. So the question is not merely whether God would be complex, but whether God would have organised complexity.
Dawkins seems to think that because the capabilities of humans depend on having a complex brain God would have to have an even more complex structure since his capabilities would far exceed those of humans. He seems to think that human minds function by the interaction of the physical parts of the brain and so, if immaterial minds exist, they must similarly function in terms of the interaction of parts. But this is a mistake. In fact, the very idea of an immaterial mind is that it does not function in terms of the interaction of parts. Now, of course, Dawkins may believe that such immaterial minds do not exist, but it would clearly be begging the question to use that as part of an argument that God does not exist.
So Dawkins has not given us any reason for thinking that premise 2 is true. If God exists, there is no good reason to think that he would have the kind of complexity (i.e. organised complexity) which can be linked with improbability. This is not to say that God is not complex in any sense of the word, just not in the relevant sense required for Dawkins’ argument to work.
Overall then, premises 1 and 2 of Dawkins’ argument are extremely dubious and premise 3 becomes irrelevant since God does not possess the kind of complexity in question. Since this is the case, there is no good reason to accept Dawkins’ conclusion that God’s existence is very improbable.
Problems with Probability
But there is a further problem for Dawkins’ argument. Let’s just pretend for a moment that Dawkins is right in having claimed to show that God’s existence is very improbable. The difficulty is we need to distinguish between the probability before all the evidence has been taken into account and the probability afterwards. If Dawkins’ argument worked, it would only establish that God’s existence is improbable before the evidence has been considered. Yet a belief can be very improbable before relevant evidence has been considered and highly probably afterwards. Consider the following illustration.
Suppose my friend Tom enters the lottery every week and that the winning numbers have just been announced in a particular week. What is the probability that Tom has hit the jackpot? Well, either he has or he hasn’t, but not knowing what numbers he selected it is very reasonable for me to assign an extremely low probability, 1 in 10,000,000 perhaps. However, the next day Tom arrives at my house, driving a new BMW, and he tells me that he hit the jackpot in the lottery the previous night. Initially, I am suspicious because Tom is a bit of a practical joker, but then he shows me a newspaper which has a picture of him receiving the cheque and later I see him on the local news on television which again confirms his story. What is the probability now? Now that all the evidence has been taken into account it is extremely high; in fact, I can be virtually certain that he hit the jackpot.
Could something similar apply in God’s case? Dawkins will claim that there is no evidence for God, but what is his reason for this? It is that God is even more complex and so more improbable than the evidence he is supposed to explain. We have already seen that there are problems with this line of reasoning, but consider Tom’s case again. It would clearly be incorrect to exclude Tom’s winning the lottery as a good explanation of the evidence just because it was very improbable to start with. Similarly, even if God’s existence were improbable to start with as Dawkins claims, this would not be a good reason for excluding God as an explanation for various pieces of evidence.
Arguably there are various features of our world which provide strong evidence for the existence of God. Consider, for example, the fine-tuning of physical constants, the order expressed in the laws of science, evidence for the beginning of the universe, the existence of conscious beings, our awareness of moral obligations and the evidence for the resurrection of Jesus. The idea is that each of these pieces of evidence is not at all the kind of evidence we would expect if God does not exist, but would be much better accounted for if there is a God. Clearly, a detailed discussion of these evidences would take us well beyond the scope of this article.
Richard Dawkins has presented an argument which purports to demonstrate that God almost certainly does not exist. He claims that God, if he existed, would be very complex and as a consequence his existence is very improbable. This argument is seriously flawed on a number of fronts. First, his argument would at best establish that it is very improbable that God came about by chance, which no-one believes anyway. Second, there is no good reason to think that God is complex in the relevant sense. Finally, even if Dawkins were right, it may well be that God’s existence is highly probable once all the evidence is taken into account.
 Richard Dawkins, The God Delusion (London: Bantam Press, 2006).
 Ibid., p. 109.
 Ibid., p. 114.
 Ibid., p. 113.
 For a slightly different formulation of Dawkins’ argument and response to it see Patrick Richmond, ‘Richard Dawkins’ Darwinian Objection to Unexplained Complexity in God’, Science and Christian Belief, 19, (2007), 99-116. See also Keith Ward, Why There Almost Certainly is a God: Doubting Dawkins (Oxford: Lion, 2008).
 Richard Dawkins, The God Delusion, p. 114.
 Ibid., p. 149.
 Even if one denies that there are any immaterial minds, the idea itself doesn’t seem to be particularly mysterious. See, for example, Dallas Willard, ‘On the Texture and Substance of the Human Soul’ (www.dwillard.org/articles/artview.asp?artID=49). An immaterial mind could be understood simply as consciousness coupled with a power to make choice.
 In fact, Richard Swinburne has argued just the opposite, that the intrinsic probability of theism is higher than rival hypotheses because the hypothesis of theism is very simple (The Existence of God, Oxford: Oxford University Press, 2nd ed., 2004, chapter 5). Roughly speaking, he thinks it is very simple because it can be stated in a very simple way in terms of a single entity, namely God, and several properties (such as knowledge and power from which other attributes follow) which are without limit. Indeed, he has claimed that theism can be characterised as ‘limitless, intentional power’.
 And there’s a problem with this premise in any case which presents yet another problem for Dawkins’ argument. Theists often argue that there is an explanation for God in terms of the necessity of his nature. Both theist Gregory Ganssle (‘Dawkins’s Best Argument: The Case Against God in The God Delusion’, Philosophia Christi 10 , pp. 39–56) and non-theist Erik Wielenberg (‘Dawkins’s Gambit, Hume’s Aroma, and God’s Simplicity’, Philosophia Christi 11 , pp. 113–128) think that this is fatal to Dawkins’ argument on its own, although not all theists believe that God’s existence is necessary.
 For such discussion see for example Richard Swinburne, The Existence of God; William Lane Craig, Reasonable Faith: Christian Truth and Apologetics (Wheaton, Illinois: Crossway, 3rd ed., 2008).