I want to summarise some lines of argument showing how God might influence the process of evolution (and other natural events), and why that ought to leave visible marks in the world. This matters because, apart from divine action at some stage in the process, theistic evolution is indistinguishable from atheistic evolution and therefore has nothing particular to contribute apart from a fideistic claim that God exists irrelevantly somewhere. I hold that the proposition that God’s involvement is restricted to the creation of the Universe with its laws and initial conditions, and his general sustaining of all things, is inevitably Deistic rather than Theistic, and so falls short of any explanation involving the Christian God, especially any explanation encompassing the Trinitarian truth that the world was created for, by and through Christ.
That said, I don’t want to pursue a particular model of divine action, but its general implications. To begin with, I restate several lines of argument to show that science does not preclude divine action except by unwarranted metaphysical presuppositions.
(1) Reformed philosopher Alvin Plantinga points out that natural laws define (a) what usually happens and (b) what happens if the Universe is a closed system. (a) is simply a statement that law is derived from what we customarily observe: nothing in science explains why there should not be exceptions, and God himself has never told us that he is bound by any such laws. (b) states the obvious truth that conservation of mass, for example, only applies if mass cannot be introduced to the Universe from outside. Since the Christian God is separate from his Universe, it is not closed to him and he can produce effects apart from the laws. In both instances results are produced outside the predictions of natural laws, but do not abolish them. The second doesn’t even bend them.
(2) Atheist philosopher Elliot Sober says that science is incompetent to exclude, include or even be agnostic about divine intervention: any such opinion is a philosophical intrusion into science. For example, random mutations in biology are causally incomplete from science’s perspective, and therefore God cannot be excluded as an underlying cause.
(3) Physicist James Clerk Maxwell, in the nineteenth century, introduced the statistical view of natural law, and specifically contrasted the constraints of laws with the free divinely planned actions performed by individual particles. His inspiration was the statistical handling of the British census results. I would point out here that such statistics don’t entirely mask the actions of free agents. For example, the mass-immigration of Irish families after the potato famine can be clearly seen in the census data. The statistics would have been very different if, say, the government had blocked their entry or they had all chosen to go to America.
(4) Participants in the divine action project have proposed various ways in which God might work without impacting natural law. John Polkinghorne originally proposed God’s acting through chaos theory (though he has, I gather, retreated on this). One assumes he intends us to understand that God acts directively through the complexities of what we see as chaotic systems to produce his desired result. I should point out that a very different kind of divine action would result from proposing that God sets up chaotic systems in order to “play dice” and produce genuinely random outcomes – that doesn’t appear to be what Polkinghorne had in mind. If that be true, then chaotic systems would produce a pattern of outcomes reflecting God’s will. The same is true of Robert J Russell’s proposal that God works freely in quantum events which, since they are undetermined by any physical process, would be completely compliant with natural law. Russell makes it very clear that his proposal leads to divine actions that make a difference – events that would not otherwise have occurred.
Here, then, are four separate approaches that show science to be compatible with the classical Christian God who acts within his creation. In itself, of course, this does not tell us how much, or in what ways, he acts. But what I have said shows that, with the exception of (2), these approaches presuppose that divine action will make a difference. So will it therefore be detectable? That depends on how you look at it, but the overall answer is “Yes”.
Let’s take the least generous admission above, that from Elliot Sober. You can, he says, show the statistical randomness of mutations, but you cannot affirm that they are not produced by God. I take that to mean that if God is tossing a coin to determine the mutation, it will be indistinuishable from a directly random process. But actually, we may suppose the Creator God is actually determining those mutations towards a goal, ie the long-term pattern of evolution of that species, or rather of the whole biological world. It is a means of producing order, by directing highly contingent events that would, if undirected, produce disorder with far greater frequency. That’s a mathematical difference.
Assuming we consider the world to show a high degree of order, which seems axiomatic, the necessity of a pattern of events of low probability to produce that order has only two possibile explanations: (a) the order is the result of divine (or other purposive) action or (b) chance (= no explanation at all). The situation would be completely different, of course, if it were found that the laws of chemistry or physics make life inevitable. That would not preclude God’s activity, but would place it back in time in the fine-tuning of the original laws, a rather Deistic modus operandi from the Christian point of view.
However, what we see so far gives no hint that life is law-like in its evolution. It is very far from high-probability stuff. Wherever chance plays a big hand in producing order – and that appears to be the case in origin of life, mutation patterns, environmental selection, cataclysmic extinctions and the like – then divine action is far more parsimonious an explanation, whether or not the actual mechanisms involved have been delineated.
Chance does not produce order in normal experience. But chance, as information theory shows, is only distinguished from information by its ordered function. So where you see an apparently chance based process producing ordered function, you ought to conclude that information is being input somehow. In this case, you ought to conclude divine action.
You want a mechanism? Just discover what controls the randomness.