This is the second in a series on Alvin Plantinga's latest book. The first post, on the preface, provides bibliographical details and an overview of Plantinga's project. In this post I will merely set forth what Plantinga understands by Christian belief and what he understands by evolution and where he sees real conflict between the two. Things will heat up a bit in my third post wherein I will come to grips with Plantinga's critique of Richard Dawkins. There is a lot of good material that I won't mention, in particular, the discussion on pp. 4-5 on the narrow and broad construals of imago Dei.
A. Plantinga proposes that we take Christian belief "to be defined or circumscribed by the rough intersection of the great Christian creeds: the Apostle's Creed, the Nicene Creed, and the Athanasian Creed . . ." but not in a manner to exclude particular creeds. (p. 8) The "rough intersection" of all of this is ably presented in C. S. Lewis's Mere Christianity.
B. As for evolution, Plantinga distinguishes six theses (pp. 8-10):
1. Ancient Earth Thesis: The earth is "perhaps some 4.5 billion years old."
2. Progress Thesis: "life has progressed from relatively simple to relatively complex forms . . . ."
3. Descent with Modification Thesis: "The enormous diversity of the contemporary living world has come about by way of off-spring differing, ordinarily in small and subtle ways, from their parents."
4. Common Ancestry Thesis: "life originated at only one place on earth, all subsequent life being related by descent to those original living creatures . . . ."
5. Darwinism: "there is a naturalistic mechanism driving this process of descent with modification: the most popular candidate is natural selection operating on random genetic mutation . . . ."
6. Naturalistic Origins Thesis: "life itself developed from non-living matter without any special creative activity of God but just by virtue of processes described by the ordinary laws of physics and chemistry. . . ."
Plantinga uses 'evolution' to refer to the first four theses, and 'Darwinism' to refer to "the mechanism allegedly underlying evolution." He adds that "the sixth thesis thesis "isn't really part of the theory of evolution."
Now where is there real conflict wth Christian belief? That God created man in his image is an absolutely nonnegotiable element of Christian belief. But on Plantinga's account it does not conflict with any of (1)-(4) or with all of them taken together. Nor does it conflict with Darwinism, the fifth thesis, "the view that the diversity of life has come to be by way of natural selection winnowing random genetic mutation. God could have caused the the right mutations to arise at the right time . . . and in this way he could have seen to it that there come to be creatures of the kinds he intends." (p. 11)
This will of course sound crazy to a naturalist. Every naturalist is an atheist (though not conversely), and most atheists consider the notion that there is a purely spiritual, providential being superintending and directing the goings-on of the physical universe to be risible, a childish fantasy on the order ot the Tooth Fairy, and as such simply beneath serious discussion. But in point of strict logic, there is nothing inconsistent in one's maintaining all of (1)-(5) and the proposition that evolution is divinely guided.
But how could random genetic mutations be caused by God? Doesn't 'random' imply 'uncaused'? No. Plantinga quotes biologist Ernst Mayr, and philosopher of biology Elliot Sober. The following is from a credible source I found:
Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not "try" to supply what the organism "needs." Factors in the environment may influence the rate of mutation but are not generally thought to influence the direction of mutation. For example, exposure to harmful chemicals may increase the mutation rate, but will not cause more mutations that make the organism resistant to those chemicals. In this respect, mutations are random — whether a particular mutation happens or not is unrelated to how useful that mutation would be. [Be sure to click on internal link.]
If mutations are random in this precise sense, that does not rule out their being caused.
Real conflict between Christian belief and evolution first arises with respect to the sixth thesis, the Naturalistic Origins Thesis. Here is the source of the incompatibility according to Plantinga. If the sixth thesis is true, then Christian belief is false.
A question. Suppose all six theses are true. Could not one still be a theist who holds that man is made in the divine image? If the sixth thesis is true, then God does not intervene in the workings of nature. He does not cause or prevent genetic mutations; he does not preserve certain populations from perils, etc. He creates the universe ex nihilo and sustains it in existence moment by moment 'vertically' so to speak, but he does not interfere 'horizontally.' He does not insert himself, so to speak, into any unfolding causal chains. As primary cause alone, he has nothing to do with natural, 'secondary,' causation. Accordingly, man as an animal has a purely naturalistic origin. But of course imago Dei has nothing to do with man as an animal . . . . Just a question, to be put on the back burner for now while we continue to examine how Plantinga's overall argument unfolds.