Naturalism's Hard Choices

William J. Murray at Uncommon Descent asks some impertinent questions about the implications of Darwinian materialism. Darwinian materialism claims that we are nothing more than a collection of atoms arranged in a particular configuration over eons of time by the push and pull of natural, physical forces. In other words, everything about us has been determined by those forces as they shaped us, through natural selection, for survival.

If that's true, though, then there are several odd consequences. Here's Murray:

Let’s consider that atheistic, Darwinstic materialism is true. Let’s say that what we believe and think are evolution-generated phenomena, the result of the physics of biology as it interacts with the environment. For instance, if I believe in God and think demons are real and that putting my socks on before I put my pants on brings me good luck, I think those things for no reason other than that I have been compelled by the cumulative interactive physics of billions of years of physical processes to believe such things and think such thoughts.

If this is so, am I responsible for my beliefs and thoughts in any significant manner other than, say, I am responsible for what color my skin is or how tall I happen to be? One might say that because “I” (this particular amalgation of physics/biology at this particular location) “have” or “am” those thoughts, that I am “responsible” for them; but if that is true, then I am equally responsible for the color of skin I have. These qualities of the “I” are just what a long line of interacting molecules happened to generate via evolutionary processes – same as my skin color, height, etc.

Thus, questioning the correctness of someone's opinion, on Darwinian evolution, would be like questioning the "correctness" of their eye color or their height. Murray goes on to ask a couple of questions about this:

If whatever I think and believe is as much an evolutionary product as the color of my skin, how is criticizing what I think/believe any different than criticizing me for my skin color?

Darwinism holds that evolutionary success is measured in terms of the number of progeny one leaves but then If we hold that “success of progeny” is the only significant measure of the success of evolution in any particular species unit, and thoughts and beliefs are evolution-generated features, why argue about whether or not any belief or thought is “true”, when what matters is only if the biological entity with those beliefs produces more successful progeny than those with different beliefs?

and,

If all of the above is true, then isn’t arguing about the “trueness” or “validity” of a thought or a belief the same, categorically, as arguing about which shape of leaf is true, or which pattern of freckles is “true”, or “logically valid”?

In other words, on naturalistic Darwinism (as opposed to God-directed versions of evolution), beliefs are not objectively true or false, they're just successful in producing offspring or they're unsuccessful. If I have a gene that inclines me to hold a belief that I'll be rewarded in the afterlife in proportion to the number of descendents I leave behind, that gene, and thus the belief, would have enormous selective value and would quickly predominate in a population because those who shared it would tend to produce more offspring than those who didn't. The objective truth of the belief is irrelevant to evolutionary mechanisms.

This is why a number of philosophers have come to the conclusion that naturalism leads to a self-defeating paradox, i.e. If naturalism is true we'd have no good reason to believe it, or any other metaphysical belief, is true. If naturalism is true then we're all the products of impersonal evolutionary forces that blindly produce beliefs that give an edge in the struggle for survival. To the extent that such a mindless process might produce beliefs that are objectively true it's just a coincidence. We'd certainly have no reason to think that our belief in naturalism, no matter how fervently held, is anything more than a predilection imposed upon us by genes that are themselves the product of eons of random mutations.

The most a naturalist can say is that his genome has evolved to cause him to believe that naturalism is the best explanation for how things are, just as it has evolved to cause him to have brown eyes. For him to add that naturalism is also objectively true is to talk nonsense.

Thus the naturalist finds himself in an epistemological bind. He can remain a naturalist but then he has to abandon evolution (as Thomas Nagel does in Mind and Cosmos); or he can hold on to his belief in evolution and abandon naturalism; or he can simply accept the implicit irrationality of it all and hold onto both views; or he can do what perhaps most naturalists do which is to simply not think about the problem and hope that it goes away. It's hard being an intellectually fulfilled naturalist these days.