I recently finished reading Alvin Plantinga’s new book Where the Conflict Really Lies: Science, Religion, and Naturalism. The book is written with Plantinga’s usual clarity and wit and is well worth your time. His thesis is that there is superficial conflict but deep concord between science and theistic religion, but superficial concord and deep conflict between science and naturalism. For the purposes of this entry, I want to take a look at Plantinga’s assessment of design arguments, and also what he calls ‘design discourse.’
Naturally, Plantinga addresses evolution, the major competitor to design with respect to a general theory of our existence. Plantinga argues that evolution is compatible with theism; what is incompatible with theism is unguided evolution. He contends, however, that being unguided is no part of evolutionary theory proper, but a philosophical or theological add-on. But isn’t the driving force of evolution random mutations? Yes, but randomness in this context only means that there is no physical mechanism in the organism that detects which mutations would be beneficial and selects them (p. 12). This description is compatible with God, or some other guiding force, selecting mutations that are beneficial for the organism. However, this does add to mutation and natural selection an additional, non-natural, selection mechanism that we arguably cannot detect, i.e. it would be empirically indistinguishable from random mutation and natural selection alone. Thus, even if we grant that the property of being unguided is no part of evolution proper, if simplicity is a virtue of scientific theories, and if the extra hypothesis makes no observable difference, it seems that Ockham’s Razor would apply.
But Plantinga doesn’t see the design hypothesis as superfluous. In fact, he expresses doubts about the efficacy of evolution to produce certain structures, like the mammalian eye. Here he takes up Dawkins argument in the Blind Watchmaker that it is at least possible, i.e not prohibitively improbable, that these structures could have arisen without design. Plantinga appeals to Behe’s irreducible complexity argument which suggests that such structures arising by unguided evolution are prohibitively improbable. He says more about Behe later on and so will I. Note for the moment that Plantinga thinks that the design proponent is in pretty good shape. After all, if one is a naturalist, evolution is the only game in town (p. 24). Complex life simply must have arisen by unguided processes. But the theist has more freedom when faced with these alleged improbabilities; God could have created life in any number of ways, including intelligent design. Yes, but then the main contours of evolutionary theory (which neither Plantinga nor Behe deny) provide some prima facie evidence for naturalism. The probability of evolution on naturalism is 1. It’s probability on theism is at best .5. Special creation is a live option for an omnipotent agent. Thus, if we observe evolution and not special creation, this is more telling in favor of naturalism. Paul Draper has presented an argument to that effect, to which Plantinga responds on p. 51.
Another aspect of Draper’s argument is that evolution exacerbates the problem of evil. Plantinga denies that evolution gives us a novel version of the problem of evil (p. 56). I have to say that I find this counter-intuitive in excelsis. It seems self-evidently true that evolution over billions of years entails far greater suffering than special creation, say, 10,000 years ago. I have no truck with young earth creationism with respect to science, but the theological implications of this position (e.g. no death before the Fall) are arguably what one would expect of a benevolent God’s design. It seems to me that evolution greatly exacerbates the problem of gratuitous evil (Rowe’s fawn times a billion) in a way that special creation, if true, would not. Of course, special creation isn’t true, but again, this seems prima facie to favor naturalism over theism. Plantinga gets around this problem by saying that there are other features of the world (besides evolution and suffering) that, when added to our evidence, swing the probability in favor of theism. Such features include the existence of intelligent, conscious life, the existence of beings with a moral sense, and the existence of beings with the sensus divinitatus. However, if you think that these features are deflationary or can reasonably be explained on naturalistic grounds, then you’re probably going to disagree with Plantinga.
Chapter 7 deals with the fine tuning argument (FTA). Especially interesting is the normalizability objection (pp. 205 — 212) raised by Lydia and Timothy McGrew. The objection, which gets quite technical, goes like this: there are no logical limits to the parameters of the universe. Because the range of values is infinite, there is no way to make the probabilities add up to 1. Contrast this to the odds of rolling a number from 1 to 6 on a six-sided die: 1/6+1/6+1/6+1/6+1/6+1/6=1. Since the odds with respect to the universe do not add up to 1, the FTA cannot be coherently stated. However, Plantinga argues that this objection proves too much. Consider a celestial message that reads “I am the Lord God Almighty, Creator of Heaven and Earth.” This message would have to be in a message permitting range — not too close, not too distant — in order to function as a message. But there are no logical limits on these message permitting values. We have the same problem that we do with respect to the FTA. However, if there were such a message it would certainly be impressive evidence of design. But there is a further objection in the neighborhood: if the range of probabilities is infinite, even if the life permitting range is very large, we would have to say that it is almost certainly designed — the odds against it would be infinite after all. Thus ‘coarse tuning’ is just as improbable as ‘fine tuning.’ Also, we might have to say that coarse tuning arguments are just as good as fine tuning arguments, but this strikes us as counter-intuitive. Plantinga responds by saying that coarse tuning arguments would be good arguments! When dealing with infinite values, our intuitions lead us astray. While this may be so, I find it hard to believe that evidence that the universe is coarsely tuned would be as favorable to theism as evidence that it is finely tuned. But this fits with Plantinga’s modest assessment of the FTA: it provides some mild support for theism. So too, I suppose, would a coarse tuning argument.
I will address some further items of interest from Plantinga’s book in an upcoming post.