In Part 1, we considered the laws of physics as evidence for God. Our focus here is on the so-called fine-tuning of the cosmos. The basic idea is that various features of the universe are ‘just right’ for the existence of stars, galaxies and life itself; had they been slightly different the human race could not exist. For example, according to cosmologist Paul Davies, had the ratio of the electromagnetic and gravitational forces differed by about 1 part in 1040 (1 in ten thousand billion billion billion billion) then stars such as the Sun, which are capable of supporting life, could not exist. As Davies points out ‘the impression of design is overwhelming’.
Other examples relating to the strong nuclear force, weak nuclear forces, the ratio of neutron to proton masses, cosmological constant, low entropy conditions of the early universe and more could be given, but the story is the same: had things been slightly different we wouldn’t be here. The fact that life depends on these features of the universe in a very precise fashion has been established by scientists over the last 40 years or so. Cosmologists Stephen Hawking and Leonard Mlodinow summarize these findings:
The emergence of complex structures capable of supporting intelligent observers seems to be very fragile. The laws of nature form a system that is extremely fi ne-tuned, and very little in physical law can be altered without destroying the possibility of the development of life as we know it. Were it not for a series of startling coincidences in the precise details of physical law, it seems, humans and similar life-forms would never have come into being.
Philosopher Robin Collins illustrates the extent of the fine-tuning by asking us to consider the
values of the initial conditions of the universe and constants of physics as co-ordinates on a dart board that fills the whole galaxy, and the conditions necessary for life to exist as an extremely small target, say less than a trillionth of an inch: unless the dart hits the target, complex life would be impossible.
These are the facts relating to fine-tuning; how are they to be explained? According to the design argument, the best explanation is that the universe is the product of a rational mind. The basic motivation for design can be expressed as follows. We consider a range of possible values for these features of the universe and then ask why they happen to have values lying in the very precise region suitable for life. From an atheistic perspective, there seems to be no reason for this whatsoever. That is, given only atheism and our current scientific knowledge we would have no reason to expect the values of these features to be in the life-permitting range.
By contrast theism provides a very neat explanation. Fine-tuning is a very precise example of the sort of order we’d expect to find in a universe created by God. We pointed out in Part 1 that God would have reason to bring about valuable things, like a community of embodied moral agents. In light of this, we’d have reason to expect God to create a universe that is fine-tuned with values in the life-permitting range. In other words, fine-tuning is the sort of thing we’d expect in a theistic universe, but not at all what we’d expect in an atheistic universe. As such, it provides strong evidence in favour of the existence of God.
There are several common objections to this argument. One is based on the anthropic principle, which is the idea that we shouldn’t be surprised to observe a fine-tuned universe because if it wasn’t fine-tuned we wouldn’t be here to observe it. At one level this seems right – we could only observe a fine-tuned universe – but this doesn’t undermine the design argument. The existence of observers does not explain the fine-tuning of the universe; rather, the existence of intelligent observers is itself a surprising fact in need of explanation (we’ll say more about this in part 3). The design argument provides an explanation why the universe is fine-tuned in the first place and hence why the existence of intelligent life is even possible. From an atheistic perspective, there’s no good explanation for fine-tuning and so no good explanation for the existence of intelligent life. It’s generally agreed that the anthropic objection to the fine-tuning argument fails.
Another objection suggests that future science will provide an explanation for fine-tuning in terms of a more fundamental law, a theory of everything perhaps. Now if such an alternative explanation were available proponents of the fine-tuning argument would certainly have to respond. However, in the absence of such an explanation, the mere possibility that one might turn up in the future is cannot explain away design. In fact, it seems like wishful thinking on the part of opponents of the fine-tuning argument. Indeed, the best current candidate to account for the laws and constants of physics, M-theory, does not predict them uniquely, but allows for numerous possibilities. Finally, even if a new theory did account for the fine-tuning evidence , it would just push design back to the level of the theory because it would raise the question of why this particular theory, i.e. one that describes a universe suitable for life, is the theory that applies to the actual universe.
Yet another objection is to say that our universe is just one of many universes comprising a multiverse. The idea is that all of these universes have different values for the constants and since there are so many of them (perhaps infinitely many) some happen to be suitable for life just by chance. It is not surprising, then, to discover that embodied agents exist in some region of this vast multiverse. However, even if the multiverse hypothesis is to be taken seriously as a scientific hypothesis, the mere possibility of such universes existing in addition to our own universe is not sufficient to explain away design. Second, a multiverse would just push design back to the level of the multiverse itself because it would raise the question of how the multiverse came about in such a way as to generate enough diversity among universes to make life inevitable.
Third, Robin Collins points out that large, non-fine-tuned universes in a multiverse will contain “little islands of order” that assemble purely by chance. Many of these islands will have observers that have assembled by chance. A multiverse will contain many such observers in various non-fine-tuned regions; many more than exist in one finely tuned universe. So the existence of observers is explained on the multiverse theory. However, these “little islands” of order will not exist for very long, and will be surrounded by an ocean of disorder. That’s not what we observe. We live in community of other rational observers (humans) with other embodied beings (animals) in a cosmos of exquisite beauty and order. These are not the observations that the multiverse theory would predict – it is much more likely that we would observe a “little island” of order and an ocean of disorder on the multiverse theory. So our observations confirm design .
Several further objections claim that theism doesn’t provide a good explanation. One reason given for this is that we don’t know what sort of universe God would want to bring about. However, God and humans have certain properties in common. Both are rational, both are agents, and -unless we wish to embrace some form of moral scepticism – we should acknowledge that both would recognise similar values. We know from observation and our own direct experience that rational agents bring about complex states of affairs that are ordered for some purpose (eg. machines) or that bring about some value (eg art). The objective beauty of the cosmos, and the fact it makes biological life possible, cry out for a theistic explanation.
We must compare God’s reasons for creating a fine-tuned universe with the absence of any reason for a finely tuned universe given atheism. The point is that this complex and valuable state of affairs is much, much more likely given theism than chance. So some atheists turn to another objection: theism doesn’t provide a mechanism to explain how fine-tuning came about. However, it is perfectly possible to have good explanations that don’t provide a mechanism. If humans were ever to find a complex artefact on a distant planet, it would be very reasonable to infer intelligent agency even if we had no idea what sort of mechanism was produced the artefact.
It must be stressed that theism provides a personal rather than scientific explanation and personal explanations appeal to beliefs and intentions rather than specifying precise mechanisms (see God and Agent Explanations: a Guide for the Perplexed). And even in a science such as physics, mechanisms are not nearly as important as is often assumed. Isaac Newton’s theory of gravity, for example, provided powerful explanations of planetary motion even though there was much disagreement about the mechanism by which one massive body exerted a force on another. The same applies in quantum theory; no-one really knows what’s going on, but quantum theory certainly explains a lot!
But isn’t God too strange or too remote or too improbable to be considered as a reasonable explanation? We’ve dealt with Richard Dawkins’ argument that God is improbable elsewhere (here, here and here), but it’s worth making a few general points. First, in science, a hypothesis shouldn’t be effectively ruled out just because it doesn’t match our previous experience – the key question is whether the evidence is what we’d expect. If this applies in science, why apply different rules in this context? Second, theism is a very clear and simple hypothesis. The creator is single being who is unlimited in power, knowledge and goodness. The terms used to describe God are pellucid. It might be difficult to imagine an infinite series or a billion sided shape. That does not mean that the terms are difficult to understand!
Third, theism appeals to a kind of explanation we are familiar with – personal explanation. Of course, there are differences between God and human agents, but theism relates to one of the two main kinds of explanation (personal and scientific). Fourth, theism might seem odd to some people, but when we are talking about the fundamental nature of reality some things are going to be odd (just look at modern physics!) Finally, what about atheism? Is it more plausible than theism? Atheism asserts that the universe exists without there being any ultimate explanation for its existence. However, it is more plausible to think that God exists unexplained than that universe does. God is a better starting point for explanation. And if the universe had a beginning it seems theism seems much more plausible than the belief that the universe popped into existence uncaused out of nothing.
In part 1, we argued that the order of the universe as expressed in the laws of science points in the direction of God’s existence. Scientific discoveries made over the last four decades have added considerable weight to this argument. The remarkable precision involved in fine-tuning is much better explained in terms of theism than naturalism. This is due in part to the fact that it is the kind of thing we could reasonable expect if our universe was created by God, but also due to the fact that there are no alternative explanations from an atheistic perspective that are even remotely plausible. For this reason, fine-tuning presents compelling evidence for design.
 Victor Stenger has objected to the scientific consensus on fine-tuning. See, for example, his The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us. Prometheus Books, 2011. For responses, see the article by Robin Collins, ‘Stenger’s Fallacies’ http://home.messiah.edu/~rcollins/Fine-tuning/Stenger-fallacy.pdf and another article by Luke Barnes, ‘The Fine-Tuning of the Universe for Intelligent Life’ http://arxiv.org/PS_cache/arxiv/pdf/1112/1112.4647v1.pdf
 A related objection is that we can’t say anything about how improbable fine-tuning is given atheism because we don’t know the relevant probabilities. According to this objection, we could only talk about probabilities if we knew the mechanisms involved in producing the universe. This objection is misplaced, however. When fine-tuning is described in terms of probability theory, probability refers to rational degrees of belief. So to say that fine-tuning is improbable given atheism is just to say that given atheism there is no reason to expect a fine-tuned universe.
 And it wouldn’t account for it all because it wouldn’t account for initial conditions.
 For more on the fine-tuning argument see chapter 5 of Atheism’s New Clothes. For a more technical and comprehensive treatment, see Robin Collins, ‘The teleological argument: an exploration of the fine-tuning of the universe’, in William Lane Craig and J. P. Moreland (eds.) The Blackwell Companion to Natural Theology, Wiley-Blackwell, 2009.