It is unarguable that life depends sensitively on the physical parameters of our universe. This much Victor Stenger admits, but are these parameters so delicately balanced "that any infinitesimal changes would make life as we know it impossible"? Is the universe fine-tuned for life? In this important and thorough treatment of the subject, Stenger shows that the volume of life-friendly phase space is much bigger than is often claimed, and that fine-tuning is a "dubious conclusion" to draw from the available evidence. To theists, of course, and others disposed to think in teleological terms, the question - "What could possibly be doing the fine-tuning?" - has an obvious answer, one that will often conveniently fit into the believer's particular religious tradition. If they are up for a challenge, and prepared to consider the arguments fairly and squarely, Stenger may well convince some theists "that fine-tuning is a fallacy based on our knowledge of this universe alone" and "that the universe looks just like it should if it were not fine-tuned for humanity". For some atheists, reading about fine-tuning will be a case of move along, nothing to see here, as we file past the latest car-crash folly of religious belief. For others, interested in cosmology and quantum physics, this will be a fascinating guided tour by someone who loves physics and enjoyed a long career as a physicist. For still others, connoisseurs of the machinations of religious apologists, this will provide yet more evidence of the disingenuousness and mendacity of believers.
There is a lucrative and burgeoning market for the kind of book that wallows in this new corner of natural theology. Writers can trade on the reputation of science and have a field day with complex terminology and the latest discoveries in cosmology and particle physics, safe in the knowledge that few of their readers will be either able or motivated to hold the arguments up to rigorous scrutiny. Stenger is more qualified than most of us to pass judgement on these issues, and has "studied a sufficient number of these efforts to have a good grasp of the claims being made" - so that we don't have to. For that service to humanity alone, he deserves a medal. In response to the proponents of fine-tuning, he provides "a plausible explanation consistent with our best knowledge" and suggests it is they who have the burden of proving him wrong.
However, this is tough going in places. Even with two degrees in physics, there are pages of equations and diagrams that I frankly don't understand (Stenger clarifies one point with the gloss - "sort of like a complex conjugate" - which will leave many none the wiser). I don't usually like to draw attention to my ignorance and inability to fully grasp what an author's written, preferring to give the impression of sitting in near-omniscient judgement. But when it comes to fine-tuning, my failure to compute is an important piece of evidence, because I now know just how little the vast majority of theists understand when they trot out "fine-tuning" as if it were some established fact. You may find it hard to credit - religious believers making claims about things they can't possibly know - but there it is.
To defeat the fine-tuning argument, Stenger does not have to give a reason why each parameter has the value it does, he "must only show that life could be plausible under a wide range of parameters". This is important, since fine-tuners make a common mistake: in all the examples of fine-tuning in the theist literature "the authors only vary one parameter while holding all the rest constant" - which inevitably leads to those infinitesimal volumes of phase space. Perhaps theists imagine (mistakenly) that this is a fairer test? Intuitively, you might think that varying one parameter while keeping all the rest fixed is the least restrictive condition, and if that gives a vast improbability, well, you can jump right to the God-what-done-it conclusion. Actually, varying only one parameter is the most restrictive approach and is, according to Stenger, "both dubious and scientifically shoddy". He shows how recognizing that parameters can vary at the same time allows for much a much larger range of habitable universes.
As well as dealing with the more plausible fine-tuning arguments (Stenger concedes that Hugh Ross "has a point about deuterium abundance"), we are still left with the problem of apologists like Dinesh D'Souza claiming that, in "a stunning confirmation of the book of Genesis, modern scientists have discovered that the universe was created in a primordial explosion of energy and light". Stenger patiently enumerates all the rather obvious ways in which "the biblical story of creation bears no resemblance whatsoever to the big bang as described by modern cosmology".
This kind of claim is typical of D'Souza, who is also an expert at mining the Eddington Concession (a rhetorical device identified by Richard Dawkins). Stenger exposes how D'Souza misquotes Hawking to make his case, and provides more evidence that theologians and religious apologists have poor standards of intellectual integrity: inconvenient arguments and facts are ignored, selective quotation is used to make a partisan point, references are not given, irrelevant details are emphasized and out-of-date results are referenced as if still valid.
Being genuinely mistaken is nothing to be ashamed of, so long as you don't just care about truth selectively, whenever it suits you. (See, for example, Lynch's True to Life: Why Truth Matters (Bradford Books)
.) Some Christians believe fine-tuning proves the existence of God. They happen to be mistaken. Many Christians also make a big show of caring about the truth, when time and again it seems that they care more about their faith. It is a pitiful spectacle to see otherwise intelligent theists clutching at straws in this way, wasting so much energy and time and resources trying to salvage natural theology from the beating it has taken from the physical sciences and Darwinism. It gives a new meaning to faith: never knowing when to give up a lost cause.
This is a worthy book in many ways, although badly let down in places by poor maths typesetting and figure work. For me, however, what was missing was the question, why would a believer want fine-tuning to be true? If God could be bothered to fine-tune the universe, why didn't he do a better job fine-tuning away the huge quantities of suffering? On this planet alone, sentient creatures have suffered for millions of years, thanks to evolution by natural selection. Fine-tuning, it seems, is necessarily a morally repugnant concept and one which any right-minded believer should want nothing to do with.