What Is the “Evolutionary Argument Against Naturalism?”

This article is going to seem more technical than most of my posts, especially at first. However, if you persevere to the end, I think you’ll be rewarded. The gist of the argument I describe here is this: many people who believe in naturalism (a form of atheism in which the natural world is all there is) also believe in evolution (the theory that human beings are the result of “lower” life forms changing through an unguided process, by chance and natural selection, over millions of years). Yet if evolution is truly an unguided process, then human brains are not designed to discover truth, and we really have no reason to trust any conclusions our brains come up with–including the conclusion that naturalism is true. So if you believe in naturalism and evolution, then you shouldn’t believe in naturalism. 

Alvin Plantinga’s “Evolutionary Argument Against Naturalism,” or E. A. A. N., is the argument that, given, the conjunction of evolution by natural selection and naturalism, any person has a defeater for his or her belief in naturalism.

It can be described as P(R/N&E), where P = probability, R=the reliability of human cognitive faculties, N=Naturalism and E=Evolution by natural selection.

Naturalism + Evolution = Doubt

If Naturalism is true, then the strongest explanation for how humans came about is evolution by natural selection, either as espoused by Darwin, or else some other, similar version. As noted atheist scientist Richard Dawkins has said, Charles Darwin made it possible to be an intellectually fulfilled atheist.

However, if evolution by natural selection was an unguided, un-designed process, then humans are essentially nothing more than self-aware apes. This leads to the problem of the reliability of any belief which homo sapiens may possess. Indeed, Tom McCall has pointed out that Charles Darwin, Richard Dawkins, and Patricia Churchland have expressed doubt concerning human belief in different ways. The following are McCall’s monikers for each of the three’s expression of that conundrum.

Darwin’s Doubt: humans are merely higher-evolved monkeys, and who would trust the conclusions of a monkey about truth?

Dawkin’s Dilemma: the “watchmaker” of natural selection is a blind watchmaker, and there is no design in the universe.

Churchland’s Charmer: any traits animals may have are only there to help them with what Churchland “charmingly” calls the four Fs: feeding, fighting, fleeing, and reproduction. She says, “Truth, whatever that is, certainly takes the hindmost.”

Plantinga’s argument agrees with these three ideas, and goes like this:

  1. If evolution by natural selection, E, and naturalism, N, are both true, then person S has a defeater for belief
  2. If S has a defeater for belief, then the reliability of S’s cognitive faculties is inscrutable (this is called the Inscrutability Thesis), and S has a defeater for all her beliefs.
  3. N is a belief, therefore S has a defeater for N.
  4. The probability of N being true is therefore inscrutable (unknowable).

What Plantinga’s EAAN Shows

It is notable that Plantinga is not trying to show that the probability of naturalism is low (as some have attempted to do), but rather that on the conjunction of both N and E, there is no way of knowing how probable N is.

Plantinga does not assert that we therefore cannot trust our cognitive faculties. On the contrary, he says that we can—and this is therefore evidence for design and a designer.

Rational But Probably Unconvincing

This argument is rationally sound, though I wish it were more persuasive. It concludes inscrutability, and not low probability, for naturalism with evolution by natural selection.

At the strongest, it seems to lead to cognitive agnosticism for the non-theist. However, I doubt whether any non-theist would follow Plantinga’s line of reasoning to its logical conclusion, that he is therefore faced with the choice between distrusting his cognitive faculties or rejecting naturalism—however rational such a dilemma may be.

Plantinga’s EAAN is a good tool for the Christian to have in his toolbelt. It is a kind of presuppositional argument, in that it uncovers the presuppositions of the unbeliever’s thinking and, through a kind of reductio, demonstrates the absurdity of the unbelieving worldview. However, on its own it does not demonstrate that this particular form of unbelief (naturalism-plus-evolution) is self-contradictory

A necessary followup move, for the presuppositionalist (which Plantinga is not), would be to demonstrate that, now that belief in naturalism-plus-evolution has been shown to undermine itself, there is a better alternative. That alternative, of course, is to presuppose the truth of the Bible–specifically Genesis 1-2, in which God creates the world such that it conveys truth, and the human with a mind corresponding to the world, able to derive truth from it.

In reality, the unbeliever is actually borrowing from the truth of Genesis 1-2 in order to make his argument. In that regard, his belief in naturalism-plus-evolution actually is self-contradictory.

So the EAAN is useful, but it doesn’t quite go far enough. It just needs more #presup.

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10 Comments

  1. This argument is rationally sound, though I wish it were more persuasive.

    While the argument looks to be logically valid, I’m not so certain that it’s rationally sound.

    In particular, the first premise seems dubious. Why should one think that a defeater for belief follows from naturalism and evolution by natural selection?

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  2. Thanks for your comment. The reason for this is that, on naturalism + evolution, our minds (more properly, brains) are merely the result of unguided, natural forces, which, if they are “aimed” at anything, are “aimed” merely at survival and not truth-seeking (any more than any other purported evolutionary adaptation would be aimed at truth-seeking. Is an opposable thumb aimed at truth-seeking? Is fur?). Therefore, as Darwin, Dawkins, and Churchland all point out in their own creative ways, there is no reason to trust the conclusions of a mind formed by such a process, and every reason to doubt them.

    The problem is solved, however, when we presuppose the truth of the Bible, which states that God created humanity in his own image, and gave us dominion over the world, which dominion must necessarily be bound up with both the intelligibility of the world and the intelligence of the human mind (truth-seeking faculties actually designed to seek and know truth).

    The flipside of that, however, is that, upon presupposing the truth of the Bible’s account of humanity’s relationship to the world, we also must presuppose the truth of the Bible’s account of humanity’s relationship to God. And there’s the rub. Anyone who doesn’t like the idea of coming to God as a sinner in need of repentance and faith in the Savior he raised from the dead, is going to have to throw out the baby with the proverbial bathwater.

    How much of that was helpful?

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  3. The reason for this is that, on naturalism + evolution, our minds (more properly, brains) are merely the result of unguided, natural forces, which, if they are “aimed” at anything, are “aimed” merely at survival and not truth-seeking (any more than any other purported evolutionary adaptation would be aimed at truth-seeking. Is an opposable thumb aimed at truth-seeking? Is fur?).

    This is precisely what I don’t understand about the argument. Truth-seeking has fairly clear and obvious advantages for survival. It’s certainly not as if truth-seeking and survival are mutually exclusive concepts.

    I still see no reason to think that a mechanism which selects advantages based on the benefit to a population’s survivability necessarily constitutes a defeater for belief.

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  4. You said, “Truth-seeking has fairly clear and obvious advantages for survival.” Do you see how, on naturalism+evolution, even that statement must necessarily be nothing other than the product of a brain that has evolved to survive and propagate, and nothing else? Obviously I agree that truth-seeking is incredibly advantageous. And I believe our minds have been designed to seek and come to true conclusions. But this is because I believe in God, and that we are not the product of blind forces over millions of years. As a Christian I have a rationale for believing in the possibility of certainty and true thought. On atheism+evolution, there is no such rationale. As Dawkins said, who would trust the conclusions of an ape? Why should anyone think that evolution+natural selection, sans God, would produce creatures with minds (really just brains) that produce thoughts aimed at truth, let alone arriving at truth?

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  5. Do you see how, on naturalism+evolution, even that statement must necessarily be nothing other than the product of a brain that has evolved to survive and propagate, and nothing else?

    On naturalism and evolution, the brain is a product of natural mechanisms in which properties advantageous to the survival and propagation of a population find greater purchase. The phrase “nothing other than” seems unnecessarily condescending, to me, as if one should infer that the process is somehow inferior or incomplete as compared to something else.

    Truth-seeking is quite obviously advantageous to the survival and propagation of a population. Again, I’m not sure why one should think that there is an implicit defeater for belief which arises from the assumption of naturalism and evolution by natural selection.

    As Dawkins said, who would trust the conclusions of an ape?

    We trust the conclusions of apes literally every single day of our lives. Even if we were to only consider non-human apes, they quite often come to conclusions in their decision making which are correct. Again, I see no reason to think that the simple fact that cognition is natural would imply that cognition is therefore unable to be trusted.

    Why should anyone think that evolution+natural selection, sans God, would produce creatures with minds (really just brains) that produce thoughts aimed at truth, let alone arriving at truth?

    The question is just as poignant in reverse. Why should anyone think that God would produce creatures with minds that produce thoughts aimed at truth, let alone arriving at truth? Any answer which a theist could offer– that God is loving, or that God created us in his image, or that God’s Word promises this, or that the person has faith in God, et cetera– is necessarily the product of that person’s mind. It is a conclusion drawn by that mind. Sure, if that mind is aimed at truth and can arrive at truth, it’s possible that these answers are reflective of truth. However, if that mind is not aimed at truth or cannot arrive at truth, it is still entirely possible that the mind could offer these answers. That mistaken mind could sincerely believe these mistaken answers. The mind could quite easily believe that it is correct, despite the fact that it is wrong.

    I think this is exactly what you are claiming about a naturally produced mind. It’s entirely possible that a naturally produced mind could come to incorrect answers to which it sincerely holds. I agree there! I simply don’t think that this is a NECESSARY implication of natural production for the mind, nor do I think that supernatural production of the mind overcomes this problem. We hold to the position that our minds are capable of seeking and arriving at truth axiomatically, whether one holds to a naturalist or a supernaturalist view of the world.

    If we agree on this axiom of cognition of truth, then we cannot simply reject it when considering naturalist positions while upholding it for supernaturalist positions. If we do not agree on this axiom of cognition of truth, then our entire discussion breaks down, as we are utilizing two entirely different sets of criteria to judge the value of the arguments.

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  6. I like how Descartes put it: “The less powerful they make my original cause [if not God, then chance or mindless processes], the more likely it is that I am so imperfect as to be deceived all the time.”

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  7. Hey BP, perhaps we could take this another route to gain some better clarity. Ultimately the issue comes down to one of epistemology, and the related issue of certainty. Could you be wrong about everything you think you know?

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  8. Could you be wrong about everything you think you know?

    I could certainly be wrong about some of the things which I think I know. I do not see any way in which I could be wrong about everything which I think I know, even allowing for the philosophical problem of solipsism.

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