My last column presented the opening section of the title chapter from John Polkinghorne’s book, Belief in God in an Age of Science, where he presents some evidence for a divine mind behind the universe. This second excerpt presents some evidence for divine purpose in the universe. As you read this, keep in mind that it was originally published in 1998. If he were writing today, Polkinghorne would surely give 13.8 billion years for the age of the universe rather than 15, and he would probably say something about string theory and recent efforts to test it with precise measurements of the microwave background.
My editorial policy for these excerpts is explained at the bottom of this post.
So much for signs of Mind. Where are we to look for signs of Purpose? Before 1859, the answer would have been obvious: in the marvelous adaptation of life to its environment. Charles Darwin, by the publication of The Origin of Species, presented us with natural selection as a patient process by which such marvels of “design” could come about, without the intervening purpose of a Designer being at work to bring them into being. At a stroke, one of the most powerful and seemingly convincing arguments for belief in God had been found to be fatally flawed. Darwin had done what Hume and Kant with their philosophical arguments had failed to achieve, abolishing the time-honored form of the argument from design by exhibiting an apparently adequate alternative explanation.
Since then, two important developments have taken place. One is the realization in the late 1920s that the universe itself has had a history and that notions of evolving complexity apply not only to life on Earth, but to the whole physical cosmos. The other is the acknowledgement that when we take this cosmic history into our reckoning, evolution by itself is not sufficient to account for the fruitfulness of the world. Let me explain.
A convenient slogan-encapsulation of the idea of evolution is to speak of it as resulting from the interplay of chance and necessity. “Chance” stands for the particular contingencies of historical happening. This particular cosmic ripple led to the subsequent condensation of this particular group of galaxies; this particular genetic mutation turned the stream of life in this particular direction rather than another. “Necessity” stands for the lawfully regular environment in which evolution takes place. Without a law of gravity, galaxies would not condense; without reasonably reliable genetic transmission, species would not be established. What we have come to understand is that if this process is to be fruitful on a cosmic scale, then necessity has to take a very specific, carefully prescribed form. Any old world will not do. Most universes that we can imagine would prove boring and sterile in their development, however long their history were to be subjected to the interplay of chance with their specific form of lawful necessity. It is a particular kind of universe which alone is capable of producing systems of the complexity sufficient to sustain conscious life.
This insight, called the Anthropic Principle, has given rise to much discussion. [Polkinghorne cites John D. Barrow and Frank J. Tipler, The Anthropic Cosmological Principle; John Leslie, Universes and his own Polkinghorne, Reason and Reality, chap. 6, and Beyond Science, chap. 6.] Is it no more than a simple tautology, saying that this universe which contains ourselves must be compatible with our having appeared within its history? For sure that must be so, but it is surprising—and many of us think significant—that this requirement places so tight a constraint on the physical fabric of our world. Although we know by direct experience this universe alone, there are many other possible worlds that we can visit with our scientific imaginations, and almost all of them, we believe, would be infertile.
John Leslie, who has given a detailed account of the many processes that depend on the precise character of physical law for their ultimately life-generating effects, has also given a careful discussion of what conclusions we might draw from the Anthropic Principle. [Leslie summarizes his position at here.] We are in a realm of discourse where such conclusions depend on the judgment that we have attained a deeper and more comprehensive understanding, rather than that we have deduced a logically unassailable consequence. Leslie believes that it is no more rational to think that no explanation is required of fine anthropic coincidences than it would be to say that my fishing apparatus can accept a fish only exactly 23.2576 inches long and, on casting the rod into the lake, I find that immediately I have a catch, which is simply my good luck— and that’s all there is to say about it. The end of the matter for Leslie is: “My argument has been that the fine tuning is evidence, genuine evidence, of the following fact:that God is real, and/or there are many and varied universes. And it could be tempting to call the fact an observed one. Observed indirectly, but observed none the less.” [Quoting Leslie, Universes, p. 198. The fishing example is on pp. 9-13 in the same book.] Either there is one world whose fruitful potential is the expression of divine purpose or there are many worlds, one of which just happens to be right for the evolution of life.
Those who wish to avoid any suggestion of a divine purpose manifested in the fruitful fine tuning of physical law will have to opt for the second of Leslie’s alternative explanations. [Here Polkinghorne has a note: “A theist could, of course, combine the two options, but personally I find that unappealing.”] There are a variety of ways in which one might conceive of the existence of such a portfolio of different universes, understood as domains in which different laws of nature are operating. The more plausible accounts will seek to make some appeal to scientific knowledge and will not just rely on the ad hoc assumption that there are a lot of separate worlds that just happen to exist.
Many-worlds quantum theory will not do the trick (even if one believed in it, which I do not), for its parallel worlds are simply ones in which quantum events have different specific outcomes and the basic laws of nature are common to them all. [Polkinghorne cites The Quantum World, pp. 67-68, and Alastair. Rae, Quantum Physics: Illusion or Reality?, chap. 6.] Modern ideas about symmetry breaking offer a little more scope. If there is a Grand Unified Theory of the fundamental forces of the universe, then the particular forces that we actually observe, and which are the concern of the Anthropic Principle, will have crystallized out from this highly symmetric ur-state very early in cosmic history, as expansion cooled the world below the relevant transition temperature. The precise details of this symmetry breaking, and the consequent precise force ratios resulting from it, are spontaneously generated through the amplification of tiny random fluctuations. This process need not be literally universal, and the cosmos may be split into vast domains in which different consequences have been realized. The universe observable by us might be a part of one such huge domain, and, of course, in our particular neck of the woods, the force ratios are “by chance” compatible with our evolution. This account is speculative, but motivated, and I am inclined to consider its possibility as far as it goes. That, however, is not very far. One still needs the right sort of Grand Unified Theory for all this to be feasible, and in that respect our universe is still very special compared to the totality of universes that we can imagine.
Moving up on the scale of bold speculation, one might evoke notions of quantum cosmology which suggest that universes of various kinds are continually appearing as a physical process called inflation blows up microworlds, which have bubbled up as quantum fluctuations in some universal substrate. [Here Polkinghorne has a note: “The quantum vacuum is an active medium owing to fluctuation effects.”] Proponents of this point of view are sometimes moved to describe our anthropic universe as being “a free lunch.” The phrase itself should trigger a cautious evaluation of the offer being made. The cost of this particular cosmic meal is the provision of quantum mechanics itself (a classical Newtonian world would be a perfectly coherent possibility, but a sterile one), and just the right quantum fields to fluctuate in order to produce first inflation and then all the necessary observed forces of nature. This idea is less well established scientifically than the domain option and, in any case, it does not really remove anthropic particularity, for the basic physical laws still have to take certain specific forms which are the necessary foundation of the proposed quantum cosmology.
Beyond this point, speculation becomes rapidly more rash and more desperate. Maybe, the laws of nature themselves fluctuate, so that a vast portfolio of conceivable, or (to us) inconceivable, worlds rise and fall in the relentless exploration of random possibility—occasional patches of transient and varied order in a sea of seething chaos. We have moved far beyond anything that could be called scientific in this exercise of prodigal conjecture. It is time to consider Leslie’s other alternative: that there is a divine purpose behind this fruitful universe, whose fifteen-billion-year history has turned a ball of energy into the home of saints and scientists, and that this purpose has been at work in just one world of consistent physical law (though maybe with domains of different expressions of that law).
Once again the theistic conclusion is not logically coercive, but it can claim serious consideration as an intellectually satisfying understanding of what would otherwise be unintelligible good fortune. It has certainly struck a number of authors in this way, including some who are innocent of any influence from a conventional religious agenda. [Polkinghorne cites two books by Paul Davies, God and the New Physics, and The Mind of God; Hugh Montefiore, The Probability of God; and his own Science and Creation, chaps. 1, 2; and 4.] Such a reading of the physical world as containing rumors of divine purpose, constitutes a new form of natural theology, to which the insight about intelligibility can also be added. This new natural theology differs from the old-style natural theology of Anselm and Aquinas by refraining from talking about “proofs” of God’s existence and by being content with the more modest role of offering theistic belief as an insightful account of what is going on. It differs from the old-style natural theology of William Paley and others by basing its arguments not upon particular occurrences (the coming-to-be of the eye or of life itself), but on the character of the physical fabric of the world, which is the necessary ground for the possibility of any occurrence (it appeals to cosmic rationality and the anthropic form of the laws of nature). [For some historical comments on this approach to natural theology, see here.]
This shift of focus has two important consequences. The first is that the new-style natural theology in no way seeks to be a rival to scientific explanation but rather it aims to complement that explanation by setting it within a wider and more profound context of understanding. Science rejoices in the rational accessibility of the physical world and uses the laws of nature to explain particular occurrences in cosmic and terrestrial history, but it is unable of itself to offer any reason why these laws take the particular (anthropically fruitful) form that they do, or why we can discover them through mathematical insight. The second consequence of this shift from design through making to design built into the rational potentiality of the universe is that it answers a criticism of the old-style natural theology made so trenchantly by David Hume. He had asserted the unsatisfactoriness of treating God’s creative activity as the unseen analogue of visible human craft. The new natural theology is invulnerable to this charge of naive anthropomorphism, for the endowment of matter with anthropic potentiality has no human analogy. It is a creative act of a specially divine character.
In the next excerpt, Polkinghorne turns his attention from physics and teleology to biology and theodicy. Look for it in a couple of weeks.