We all have to recognize that we have not created our own minds, and must rely on the way they work. Theists and naturalists differ radically over what justifies such reliance. Plantinga is certainly right that if one believes it, the theistic conception explains beautifully why science is possible: the fit between the natural order and our minds is produced intentionally by God. He is also right to maintain that naturalism has a much harder time accounting for that fit. Once the question is raised, atheists have to consider whether their view of how we got here makes it at all probable that our cognitive faculties should enable us to discover the laws of nature.
Plantinga argues that on the naturalist view of evolution, interpreted materialistically, there would be no reason to think that our beliefs have any relation to the truth. On that view beliefs are states of the brain, and natural selection favors brain mechanisms solely on the basis of their contribution, via behavior, to survival and reproduction. The content of our beliefs, and hence their truth or falsehood, is irrelevant to their survival value. “Natural selection is interested, not in truth, but in appropriate behavior.”
Plantinga’s version of this argument suffers from lack of attention to naturalist theories of mental content—i.e., theories about what makes a particular brain state the belief that it is, in virtue of which it can be true or false. Most naturalists would hold that there is an intimate connection between the content of a belief and its role in controlling an organism’s behavioral interaction with the world. To oversimplify: they might hold, for example, that a state of someone’s brain constitutes the belief that there is a dangerous animal in front of him if it is a state generally caused by encounters with bears, rattlesnakes, etc., and that generally causes flight or other defensive behavior. This is the basis for the widespread conviction that evolutionary naturalism makes it probable that our perceptual beliefs, and those formed by basic deductive and inductive inference, are in general reliable.
Still, when our faculties lead us to beliefs vastly removed from those our distant ancestors needed to survive—as in the recent production and assessment of evidence for the existence of the Higgs boson—Plantinga’s skeptical argument remains powerful. Christians, says Plantinga, can “take modern science to be a magnificent display of the image of God in us human beings.” Can naturalists say anything to match this, or must they regard it as an unexplained mystery?
Most of Plantinga’s book is taken up with systematic discussion, deploying his epistemology, of more specific claims about how science conflicts with, or supports, religion. He addresses Richard Dawkins’s claim that evolution reveals a world without design; Michael Behe’s claim that on the contrary it reveals the working of intelligent design; the claim that the laws of physics are incompatible with miracles; the claim of evolutionary and social psychologists that the functional explanation of moral and religious beliefs shows that there are no objective moral or religious truths; the idea that historical biblical criticism makes it unreasonable to regard the Bible as the word of God; and the idea that the fine-tuning of the basic physical constants, whose precise values make life possible, is evidence of a creator. He touches on the problem of evil, and though he offers possible responses, he also remarks, “Suppose God does have a good reason for permitting sin and evil, pain and suffering: why think we would be the first to know what it is?”
About evolution, Plantinga argues persuasively that the most that can be shown (by Dawkins, for example) on the basis of the available evidence together with some highly speculative further assumptions is that we cannot rule out the possibility that the living world was produced by unguided evolution and hence without design. He believes the alternative hypothesis of guided evolution, with God causing appropriate mutations and fostering their survival, would make the actual result much more probable. On the other hand, though he believes Michael Behe offers a serious challenge to the prevailing naturalist picture of evolution, he does not think Behe’s arguments for intelligent design are conclusive, and he notes that in any case they don’t support Christian belief, and perhaps not even theism, because Behe intentionally says so little about the designer.
Plantinga holds that miracles are not incompatible with the laws of physics, because those laws determine only what happens in closed systems, without external intervention, and the proposition that the physical universe is a closed system is not itself a law of physics, but a naturalist assumption. Newton did not believe it: he even believed that God intervened to keep the planets in their orbits. Plantinga has a lengthy discussion of the relation of miracles to quantum theory: its probabilistic character, he believes, may allow not only miracles but human free will. And he considers the different interpretations that have been given to the fine-tuning of the physical constants, concluding that the support it offers for theism is modest, because of the difficulty of assigning probabilities to the alternatives. All these discussions make a serious effort to engage with the data of current science. The arguments are often ingenious and, given Plantinga’s premises, the overall view is thorough and consistent.
The interest of this book, especially for secular readers, is its presentation from the inside of the point of view of a philosophically subtle and scientifically informed theist—an outlook with which many of them will not be familiar. Plantinga writes clearly and accessibly, and sometimes acidly—in response to aggressive critics of religion like Dawkins and Daniel Dennett. His comprehensive stand is a valuable contribution to this debate.
I say this as someone who cannot imagine believing what he believes. But even those who cannot accept the theist alternative should admit that Plantinga’s criticisms of naturalism are directed at the deepest problem with that view—how it can account for the appearance, through the operation of the laws of physics and chemistry, of conscious beings like ourselves, capable of discovering those laws and understanding the universe that they govern. Defenders of naturalism have not ignored this problem, but I believe that so far, even with the aid of evolutionary theory, they have not proposed a credible solution. Perhaps theism and materialist naturalism are not the only alternatives.
Oh God! January 10, 2013
What Can Be Proved About God? December 6, 2012
Can Religious Belief Be Tested? November 8, 2012