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[jimwalton]

from Mere Apologetics by Alister McGrath, Baker Books, 2012, pp. 98-100

In recent years, increasing attention has been paid to the phenomena of "fine-tuning" in nature. The term "fine-tuning" is often used to refer to the scientific realization that the values of certain fundamental cosmological constants and the character of certain initial conditions of the universe appear to have played a decisive role in bringing about the emergence of a particular kind of universe, one within which intelligent life can develop. Many recent scientific studies have emphasized the significance of certain fundamental cosmological constants, the values of which, if varied even slightly, would have significant implications for the emergence of human existence.

The nature's fundamental constants turn out to have been fine-tuned to reassuringly life-friendly values. The existence of carbon-based life on Earth depends upon a delicate balance of physical and cosmological forces and parameters. Were any one of those quantities slightly altered, balance would've been destroyed and life would not have come into existence. Sir Martin Rees, Britain's Astronomer Royal and President of the Royal Society, has argued that the emergence of human life in the aftermath of the Big Bang is governed by a mere six numbers, each of which is so precisely determined that a minuscule variation in any one of them would have made both our universe and human life, as we know them, impossible.

A recent discussion of this question by Robert J. Spitzer is helpful here. Spitzer suggests that we imagine all the parameters of the universe—such as the speed of light in a vacuum, the gravitations constant, electromagnetic coupling, and the masses of the elementary particles—are represented by the settings of the dials of some kind of "cosmic control panel." The findings of modern cosmology imply that if the settings of these dials were to be nudged even very slightly, we would not be here to discuss the significance. For example, if gravity or the weak force (two of the four known forces of nature) were to be varied in strength by one part in 10 to the 40th power, the expansion of the universe would either be too explosive for galaxies or the universe would have collapsed. If a certain combination of the constants of gravity, electromagnetism, and the ratio of electron to proton mass were varied by about one part in 10 to the 39th power, no main sequence stars such as our own sun would be able to form. If a precise nuclear resonance of the carbon atom did not align with the resonance of beryllium and a colliding helium nucleus (yet without aligning with a corresponding resonance in oxygen and helium(, then there would be almost no carbon—the basis of life as we know it. Most dramatically, leading mathematician Roger Penrose has calculated that the entropy of the universe is such that our universe seems to exist in an absurdly precise state compare to the available range of possible values. (My addition: There are other evidences.) So what are the implications of this remarkable fine-tuning?

The phenomenon of fine-tuning is widely conceded; all debates concern its interpretation. Atheist cosmologist Fred Hoyle was one of those to first appreciate the importance of these observations and their obvious theistic implication. It is, he wrote, as if "a super-intellect has monkeyed with physics, as well as with chemistry and biology, and ... there are no blind forces worth speaking about in nature." Hoyle was an atheist, unsympathetic to the idea that God created the universe. Nevertheless, his comment points to the deep unease contemporary cosmology has created for those not willing to believe in God. ...

One way of trying to avoid the obvious theistic implication of fine-tuning is to postulate a "multiverse." This viewpoint argues that our own universe is only one option among many others. The observable universe is thus to be contextualized within an unseen infinitely larger, and eternal multiverse. Our own universe may be fine-tuned; but none of the others need be. We're just lucky. Someone had to hit the jackpot. ...

But there are obvious problems with the multiverse hypothesis, as Spitzer rightly points out. First, the distinction between universe and multiverse is largely semantic. There is still just one true universe in this hypothesis, if the term "universe" means the entire domain of interconnected physical reality. If the hypothetical multiverse is not connected in any way to the particular universe that we actually observe, it is difficult to see how any laws of physics derived in our domain could possibly apply to the multiverse as a whole. This means we cannot use observations of our own world to draw any conclusions about the multiverse at all. But if the multiverse is structurally interconnected, many problems encountered with the big bang theory are simply displaced, reappear in a modified form, or even become more difficult for atheists.

The observation of fine-tuning is consonant with Christian belief in a creator God. It proves nothing; after all, this might just have been an extremely improbable accident. Nevertheless, it resonates strongly with the Christian way of thinking, fitting easily and naturally into the map of reality that emerges from the Christian faith. The capacity of Christianity to map these phenomena is not conclusive proof of anything. It is, however, highly suggestive. It is one among many clues, accumulating to give an overall "big picture" of reality. It is one among many threads that can be woven together to yield a patterned tapestry. fine-tuning is a clue to the meaning of the universe, insignificant in isolation but richly suggesting when set alongside other such clues.

A comment by Alvin Plantinga, from Where the Conflict Really Lies, pp. 199:

"The basic idea is that such fine-tuning is not at all surprising or improbable on theism: God presumably would want there to be life, and indeed intelligent life with which (whom) to communicate and share love. Of course this life could take many different forms (indeed, perhaps it has taken many forms). But it doesn’t seem at all improbable that God would want to create life, both human life and life of other sorts, and if he wanted to created human life in a universe at all like ours, he would have been obliged to fine-tune the constants. On the other hand, on the atheistic hypothesis according to which these constants have their values by chance (that is, those values are not the result of anyone’s choice or intention) it is exceedingly improbable that they would be fine-tuned for life. This seems to offer support for theism: given theism, fine-tuning is not at all improbable; given atheism, it is; therefore theism is to be preferred to atheism."

And what of the argument that there many be other "universes", with different values that support a different kind of life?

Plantinga says it is true, if there do happen to be many universes displaying different sets of parameters, that the probability that one or another of them will be fine-tuned, display a life-permitting set of parameters, is high. Perhaps it is even as high as the probability that our universe is fine-tuned, given theism. But how does that affect the probability that our universe, this particular universe, is fine-tuned? If I get a set of 4 aces every time I deal, it is indeed possible for that to have randomly happened without cheating. My opponents will most likely not be satisfied with my probability explanation. It is vastly more likely that I am cheating. ... If,in fact, there are other universes, that has no bearing on the probability (as argued by atheism) that this universe is fine-tuned for life. That probability, given what we know of our universe, remains very low.

If I'm playing a game of poker, in a room where at many tables there are many games of poker being played, and I become aware that cheating is taking place at another table, that has absolutely no bearing on what is going on at my table.

In the end, fine-tuning offers more support for theism than for atheism, and therefore theism is the more rational hypothesis of the two.