Religious apologists are known for their ridiculous arguments, especially when venturing into discussions on science, but it is also wise for us to consider the fact that people like Plantinga and Craig are not stupid men; they are well-educated and often have impressive philosophical and logical skills. It is for this reason that when I read this quote:
“There is indeed a science/religion conflict, all right, but it is not between science and theistic religion: it is between science and naturalism. That’s where the conflict really lies”I decided to try to deduce what possible rational line of thinking could give us such a conclusion. For those who are not sure why this would be a particularly strange claim, it might help to look at one of the main assumptions of science: methodological naturalism.
NATURALISM AND SCIENCE
This combination of terms is sometimes rejected as mere "navel-gazing" by people who enjoy the more practical benefits of science rather than analysing the philosophical foundations of science, but when we look at what the concept actually means we find that it isn't very controversial at all. The "naturalism" part refers to the type of things we study; that is, we study things which are observable, measurable, repeatable, and so on. The "methodological" part contrasts it with a metaphysical position, so since metaphysics is the study of what is "real" then a methodological position is one that simply assumes naturalism is true for pragmatic reasons, rather than claiming it is absolutely true. To put it most simply: methodological naturalism is the claim that no matter what is "real" or "true", science should just assume the world is observable and measurable and ignore anything else that doesn't fall within that category because that is what gives us meaningful results.
This is where my first possible explanation for Plantinga's claim came from: maybe Plantinga was conflating methodological naturalism with metaphysical naturalism. It would be a valid argument to claim that science is incompatible with metaphysical naturalism as metaphysical naturalism makes claims beyond what science can demonstrate or support. For example, there is no scientific experiment that could be devised to support the claim that the world is naturalistic rather than dualistic (the idea that reality is composed of two distinct substances; mind and matter) and instead we have to rely on logical arguments to disprove the idea that the brain is simply an antenna rather than being an organ that produces thoughts. Reading through his arguments though, this is not the argument he is making.
This led me to considering a second possible explanation for his claims: maybe Plantinga was conflating the natural/supernatural distinction that is considered in science and philosophy with the distinction that is often used in common language. Unlike the first possibility, this does not constitute a strong argument, however, it would be a reasonable mistake to make given that there is still a fair amount of debate and confusion over what the terms 'natural' and 'supernatural' refer to. As I mention above, what is 'natural' is generally agreed to be that which is observable, measurable, and repeatable, and the supernatural is thus its opposite (the unobservable, immeasurable, and unrepeatable). This is not how the terms are treated in common usage though, as 'supernatural' has come to take on the meaning of 'wacky' or 'magical'. What this means is that sometimes the judgement of what is or is not supernatural is made before considering how the concept is formulated, and instead it is often just claimed that things like ghosts, psychic abilities, gods, and so on are supernatural. This isn't necessarily the case though, as psychic phenomena like the kind that Daryl Bem searches for1 is most certainly "natural". So this would be a reasonable, yet incorrect argument, but again this is not the argument he is making.
THE BAFFLING ASSERTIONS
After racking my brains further I just could not think of any other rational possibilities (none that didn't involve complex conspiracies carried out by the publishers of dictionaries to fool the world anyway), and so after enjoying the mental challenge of coming up with arguments in favour of a position I disagreed with, I researched Plantinga's claims in more detail. It turns out that the possibilities that I had imagined, including both the rational and absurd, were not enough to account for his actual claim:
First, note that naturalists are all (or nearly all) materialists about human persons. A human person is a material object through and through with no immaterial self or soul or subject. For present purposes therefore, I’ll assimilate materialism to naturalism. The central premises of the argument are as follows: where ‘N’ is naturalism, ‘E’ is current evolutionary theory, and ‘R’ is the proposition that our cognitive faculties are reliable. The argument goes like this:
(1) The probability of R/N&E is low
(2) One who accept N&E concedes that 1 is true as a defeater for R
(3) This defeater can’t be itself defeated
(4) One who has a defeater for R, has a defeater for any belief he takes to be produced by her cognitive faculties including N&E itself
(5) Therefore, N&E is self-defeating and hence can’t be rationally accepted
His conflation of materialism (the idea that everything in the world is matter) with naturalism in the prelude does show some resemblance to my first suggestion above, in that materialism is a metaphysical position and adopting materialism is something scientists would need to support with philosophical and logical arguments rather than scientific ones. This is a false claim though, as even if we were to be generous and accept that the majority of scientists were materialists (or even physicalists), it does not follow that there is an assumption of materialism in the scientific method. Unfortunately, that demonstrably incorrect claim appears to be the strongest assertion that Plantinga makes, as the premises of his argument are just ridiculous.
The first premise is really where the argument collapses in on itself but we'll look at the whole argument. He asserts that the probability of our cognitive abilities being reliable (R), given the truth of naturalism and evolution (N&E) is low. That is, since our mental faculties are a product of evolution, and evolution does not necessarily favour "true" beliefs or accurate cognitive processes, it is possible that our beliefs could be wrong. Using some fancy mathematics, where Plantinga assumes that there is a 50/50 chance of a belief being true, he demonstrates that if we held a hundred beliefs, then the probability of three-quarters or more of them being true would be less than one in a million. So what he concludes is that if we accept that naturalism and evolution are true, and naturalism and evolution produce inaccurate beliefs, then the belief in naturalism and evolution could be flawed therefore naturalism and evolution cannot be rationally accepted given the high probability of them being false.
I bring up the mathematical example because it's hilarious and not because it needs debunking, given the nonsensical attribution of a .5 probability to a belief being true. The rest of his argument is not much better though, as we know that the probability of evolution being true is approaching 1 (i.e. practically true). To avoid the issues with naturalism, we adopt the position of methodological naturalism rather than metaphysical naturalism, so we don't assume it's true at all meaning that it can have no probability value of being true. And whilst it's true that our beliefs about the world can be false (in part due to the processes of evolution), this fallibility is not 50/50. The probability that nearly every biologist in the world are all misreading the data, misrecalling facts, fabricating data, and generally acting under a delusion, is near-zero (i.e. practically false), therefore Plantinga's first premise of P(R/N&E) being low becomes false - the probability instead approaches 1; practically true.
For shits and giggles, I'd like to point out that I wasn't too far off with my second suggestion either, in that Plantinga defines naturalism as: "...for any study of the world to qualify as "scientific," it cannot refer to God's creative activity (or any sort of divine activity)"2. This is an incredible definition of naturalism but of course it is not one that is adopted by science. A phenomenon of the world could be studied by science even if it was created by a god, it would simply require that the god was a natural god using naturalistic processes - like the Greek and Roman gods. What Plantinga means to say is that since the Christian god is not natural, and since science only studies the natural, then it must ignore the possibility of a Christian god. This is similar to the Intelligent Design arguments that try to appeal to some vague 'designer' as an explanation for the development of organisms, but rather than accepting the more realistic possibility of aliens creating life on Earth, they prefer to fall back on to a very specifically defined supernatural creator as defined by the holy texts favoured by their parents.
So is the main assumption of science incompatible with science? As you might have guessed, it's not. Any argument that requires us to assume something as clearly true as evolution to be false must be treated with extreme skepticism. The question of whether science and religion are compatible is an immensely interesting one, and I could not do the topic justice by briefly discussing it in my conclusion here so I'll leave the details to another post, but it is one that can't be handwaved away by trying to distract us with nonsensical claims like the ones Plantinga presents. His argument can be summarised as a childish tu quoque, and is really not much better than an educated philosopher's reiteration of "I know you are, you said you are, but what am I?".
1. Bem, D. J., (2011). "Feeling the future: experimental evidence for anomalous retroactive influences on cognition and affect.". Journal of personality and social psychology, 100 (3): 407–25.↩
2. Plantinga, A. (1997). "Methodological Naturalism". Philosophical Analysis: Origins and Design, 18:1.↩