I have come up with a new argument for metaphysical naturalism, or perhaps what you might consider an intriguing variation on the argument from religious confusion. The following is a quote from Christian philosopher Alvin Plantinga:
“Perhaps it is not initially implausible to think that unguided natural selection could have produced creatures with cognitive faculties who are reliable about matters relevant to survival and reproduction. But what about metaphysical beliefs, such as theism, or determinism, or materialism, or atheism? Such beliefs have little bearing on behavior related to survival and reproduction, and unguided natural selection couldn’t care less about them or their truth-value. After all, it is only the occasional member of the Young Humanist Society whose reproductive prospects are enhanced by accepting atheism. Given materialist naturalism, the probability that my cognitive faculties are reliable with respect to metaphysical beliefs would be low. So take any metaphysical belief I have: the probability that it is true, given materialist naturalism, cannot be much above .5. But of course materialist naturalism is itself a metaphysical belief. So the materialistic naturalist should think the probability of materialist naturalism is about .5. But that means that she cannot sensibly believe her own doctrine. If she believes it, she shouldn’t believe it. In this way materialist naturalism is self-defeating.”
I agree with all of the bold words. All of them.
Here’s the irony in Plantinga’s remarks: Plantinga is right to suggest that unguided evolution will produce people who rarely have correct metaphysical beliefs. Guided evolution, as in “evolution directed by the hand of God or some supreme teleological force” would be expected to produce reliable cognitive faculties that always (or usually) came to hold correct beliefs. At the very least, reliable philosophical/metaphysical reasoning processes are more plausible under theism than atheism.
The prediction of metaphysical naturalism better describes the world we live in. Think about it, even Alvin Plantinga could not argue that most people’s metaphysical beliefs are true, since two-thirds of the world is not Christian. All throughout history, most people have had false beliefs about metaphysics, and even the staunchest Christian apologist would have to admit this. In man’s early history, most people were animists or polytheists. Only recently has monotheism come to hold sway over many people, and even monotheism can only claim around half of the world’s population today. Moreoever, there have been and still are forms of monotheism that any given Christian would regard as false: Deism, Islam, Orthodox Judaism, Non-religious theism, and a huge swarm of competing Christian sects that hold beliefs contrary to and even heretical to the form of Christianity held by any one particular Christian. Score one point for naturalism.
What about Alvin Plantinga’s contention that naturalism is self-defeating? While I agree that the frequency of true metaphysical beliefs is low, it does not follow from this that naturalism itself has a low probability, if all things are considered. Consider an analogy: it is infrequent for one particular lottery ticket to win. Does that mean you can never be sure that some specific lottery ticket has, in fact, won? No, the initial improbability of the ticket winning can be outweighed if there is strong evidence that the ticket won.
Likewise, it is improbable on the face of it that out of all the belief systems available, naturalism is the winning ticket. So what? Naturalism does a damn good job of predicting and explaining the world we find ourselves living in. It wins the lottery of the worldviews because the numbers on naturalism’s ticket match the numbers of the world around us.
