Evolutionary Argument Against Naturalism (EAAN)

The discovery of evolution by natural selection arguably did more to reinforce naturalism than any other single discovery in science. God was out of a job in a serious way because up until that point, most people believed that there was no way to naturalistically explain the diversity and complexity of biological life. The philosopher Immanuel Kant said, “There will never be an Isaac Newton for a blade of grass.” Of course, this isn’t to say that Darwinism logically entails atheism; I’m pointing out that biological life looks like it was designed, so any atheist before 1859 would naturally be bothered by that fact. But Darwinian evolution provides a naturalistic account of biological organisms that has since been empirically confirmed over and over again.

However, not everyone agrees that evolution by natural selection bolsters naturalism. In fact, Alvin Plantinga, a Christian apologist, thinks that you can’t believe both in Darwinian evolution and naturalism simultaneously. He believes that these are incompatible. The argument is that the probability of having reliable cognitive faculties is negligible if evolution isn’t guided by god.

In a letter, Darwin wondered something along the same lines, doubting the trustworthiness of his own capabilities.

“But then with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind . . . ?”

The argument

The bare bones of Plantinga’s argument can be summarized in three points:

1. Our beliefs about the world can only have evolutionary consequences if they affect our behaviors (otherwise they are invisible to natural selection);

2. Natural selection favors advantageous behaviors, not directly the ability to form true beliefs;

3. Natural selection has no way to favor true non-adaptive beliefs over false but adaptive beliefs.

So on naturalism, why would we be able to trust our basic reasoning capacities to any extent? Plantinga argues that naturalism is self-defeating, since naturalistic evolution wouldn’t produce reliable cognition or true beliefs; it would only favor adaptive cognition and adaptive beliefs, regardless of the truth. So if we did evolve naturalistically, we would have no reason to trust our minds or any beliefs they generated, including a belief in naturalism. His conclusion is that the only way that we would be able to trust our own minds is if god was guaranteeing their reliability.

Plantinga writes,

“The traditional theist, [as opposed to the naturalist], has no reason for doubting that it is a purpose of our cognitive systems to produce true beliefs. Nor any reason for thinking the probability of a belief being true, given that it is a product of her cognitive faculties, is low or inscrutable. She may endorse some form of evolution; if she does, it will be a form of evolution guided and orchestrated by god.”

And keep that quote in your mind, because I’ll be coming back to it later. In his book, Warrant and Proper Function, Plantinga makes his point by telling us about a hypothetical ancestor named Paul.

“Paul is a prehistoric hominid; the exigencies of survival call for him to display tiger avoidance behavior. There will be many behaviors that are appropriate: fleeing, for example, or climbing a steep rock face, or crawling into a hole too small to admit the tiger, or leaping into a handy lake. Pick any such appropriately specific behavior B. Paul engages in B, we think, because, sensible fellow that he is, he has an aversion to being eaten and believes that B is a good means of thwarting the tigers intentions. But clearly this avoidance behavior could be a result of a thousand other belief-desire combinations: and definitely many other belief-desire systems fit B equally well. Perhaps Paul very much likes the idea of being eaten, but whenever he sees a tiger, always runs off looking for a better prospect, because he thinks it’s unlikely that the tiger he sees will eat him. This will get his body parts in the right place so far as survival is concerned, without involving much by way of true belief. Or perhaps he thinks the tiger is a large, friendly, cuddly pussy cat and wants to pet it; but he also believes that the best way to pet it is to run away from it. Or perhaps he confuses running toward it with running away from it. . . Or perhaps he thinks the tiger is an illusion, and, hoping to keep his weight down, has formed the resolution to run a mile at top speed whenever presented with such an illusion.”

And again, that was Alvin Plantinga, possibly the world’s most respected living Christian apologist.

Of course, having a mental model of reality that actually corresponds to reality would, in general, be a pretty efficient way to navigate the world and fulfill your interests. On average, in most situations, perceiving reality will lead to adaptive behavior since there is obviously overlap between what is true and what is helpful to know. Cognitive faculties that are generally reliable have survival advantage. The challenges presented to creatures like us are disparate and unpredictable enough that selecting for individual, specified challenges would be an incredibly arduous path in reality. What would be far more efficient would be having reasonably accurate reality detection hardware and software that would allow you to achieve your goals in the face of variant, multifaceted, and often novel challenges. Being delusional in a useful way is not the most direct pathway to success, especially in an environment that is constantly changing and where opportunity and danger are often hard to distinguish. We often need to improvise and deal with new situations.

In response to the example of Paul and the tiger, Doug Shaver has written,

“Plantinga notes that Paul’s survival depends on tiger-avoidance behavior, and so it did, but tigers were not the only predators that our ancestors had to avoid. It would’ve been unnecessary and inefficient for natural selection to have wired our brains with one routine for tiger-avoidance, another for wolf-avoidance, another for leopard-avoidance. A generalized predator-avoidance scheme would’ve been better for several reasons; mainly because only one general routine would’ve been needed if it was flexible enough to respond appropriately to all predators that an early hominid was likely to encounter.”

He goes on to critique Plantinga’s description of our faculties as if they were random belief generators. A belief generator that functioned with no regard for actual truth would effectively always produce a false belief. If Paul is confronting a tiger, the number of false beliefs he could’ve had that would by chance cause adaptive behavior is a minuscule fraction of false beliefs. The overwhelming majority of false beliefs are not going to be adaptive. A ‘random belief generator’ would probably not serve him well. It could, but the odds are long against it. Statistically speaking, he really is better off with a brain that generates beliefs that are likely to be true. Generalized systems would be more efficient and also easier for natural selection to create.

Another serious problem with this argument is that Plantinga doesn’t distinguish between different beliefs. We can’t make blanket statements about our cognitive trustworthiness or our beliefs, since we have beliefs in many unrelated areas that have more or less of an effect on our survival and reproductive success.

The philosopher Massimo Pigliucci has written, “The first thing to do is to break down the category “human beliefs” (which Plantinga conveniently treats as homogeneous) into subgroups. Our beliefs about everyday experience, for instance, are pretty reliable, and the most likely explanation for that fact is indeed the theory of evolution by natural selection. If we held systematically wrong beliefs about things that are dangerous (predators, poisonous fruits) or good for us (animals we can use or hunt, edible stuff) we would have long ago gone extinct.”

Detecting Reality

We also have many ways of checking external reality. We confirm with others, we have instruments that gather data, we build models and make predictions, and so on. We have methods and tools for getting out of our own heads to correct for our errors in subjectivity. We started out with a fairly limited capacity for reason, but we’ve been able to build on what we were given and to some extent, overcome our cognitive biases; or at least find ways to circumvent them, like we have by running our experiments double-blind. In part, we know that these methods we’ve invented work because of the results. Science works, in that it’s incredibly good at predicting future empirical data. We make predictions — specific, risky, non-obvious predictions — and they happen. We can use mathematics and logic and calculate using things like Bayesian reasoning to tremendous effect. We also build incredible technology based on our understanding of the world. So using the humble capacities we began with, we’ve been able to incrementally make progress and gain hard-won knowledge. We definitely don’t have sense organs and mental abilities that are infallible pipelines to reality, which is what you might expect if god were designing us. But we have figured out, little by little, where we have reason to trust our intuitions and where we don’t. Our intuitions have provided a workable foundation and from there, we’ve built on our natural abilities to incredible effect, and we also try to discover ways to teach ourselves to be more rational than we are naturally. The arduous process we’ve engaged in to try to transcend our limitations as best we can is also what you would expect without any design help from a god.

My point is that our beliefs and cognitive faculties are explicable on naturalistic evolution, and our limitations also make perfect sense. But it’s important to note that none of this makes sense on Christianity. If god had any role in intelligently designing us, why would he create so many errors in cognition? Let alone errors that make it look like he didn’t design us?

Plantinga’s whole argument was that we wouldn’t be able to trust our mental faculties on naturalism, but we would have every reason to think they were reliable on god-guided evolution. Plantinga goes out of his way to make the point that on theism, we would have every reason to trust our natural beliefs, apparently not realizing that he’s setting himself up for failure down the line. Let me quote Plantinga on this again:

“The traditional theist, [as opposed to the naturalist], has no reason for doubting that it is a purpose of our cognitive systems to produce true beliefs. Nor any reason for thinking the probability of a belief being true, given that it is a product of her cognitive faculties, is low or inscrutable. She may endorse some form of evolution; if she does, it will be a form of evolution guided and orchestrated by god.”

He’s saying that with god-guided evolution, we would have no reason for thinking the probability of our beliefs being true to be low, since they are a product of our cognitive faculties, which were designed by god. The assumption being that our minds are totally reliable, and that’s hard to explain on naturalistic evolution. But of course, our faculties are not totally reliable, and as I’ve tried to explain, the contexts where they are reliable and where they aren’t is what you would predict on naturalistic evolution.

cognitive flaws

We’re plagued by numerous cognitive biases, like confirmation bias, where we remember and focus on information that confirms our preconceptions and forget information that challenges them. Or anchoring bias, where we rely too heavily on one piece of information when making decisions, and it’s usually the first piece of information we got. If two events are correlated in time, we tend to believe that they’re causally related and have to be trained to distrust this instinct. Our understanding of probability doesn’t come intuitively. Our affinity for anecdote far outweighs our comprehension of statistics.

On Christian theism, our cognitive biases and flaws are bewildering. Why would god make our perception unreliable? Why wouldn’t we simply be able to accurately detect objective reality in fullness and always know when the correlation meant causation and when it didn’t? Why would god give us any cognitive biases, or problems in our sensory hardware, like our visual blind spot? The fact that we have systematic cognitive biases is well explained by evolution and it’s byproducts. But our cognitive flaws and limitations don’t make any sense on Christian theism. Why on earth would god go to all the trouble of intelligently designing us but also build us in such a way that we’re prone to confirmation bias or seeing nonexistent patterns?

Some young-earth creationist types might invoke the Fall at this point, but that effectively makes their ideas unfalsifiable. Everything good is because of god’s intelligent designing; everything bad is because of the Fall. This means that literally anything we see would be compatible with that idea. If you see something good, that’s because god did it. If you see something mediocre or bad, that’s because of the Fall.

On the other hand, with Darwinian evolution, the places where we’re reliable and unreliable actually make sense when you consider the environments of our ancestors and the likely byproducts of our adaptive traits. Many of our cognitive biases are byproducts of advantageous abilities. I mentioned mistaking all correlation with causation. Being able to relate events in time is extremely useful (eg, I ate those berries and I got sick). The cost of the misfiring of that ability is acceptable so long as on the whole, being able to relate events to each other is adaptive.

Plantinga, however, needs to explain why god guided the process of evolution to give us some types of thinking that would be reliable but also all of our cognitive shortcomings.

In summary

It might sound weird that someone like Alvin Plantinga can spend decades working on an argument that can be seriously undermined with a couple simple thoughts like “Wouldn’t perceiving reality be adaptive in a lot of situations? Wouldn’t that also be the path of least resistance, by like, a lot?”

I think that this argument has the life it has because there is a grain of truth in it. Our reality-detecting hardware and software has flaws; we can’t uncritically trust them in every area. But the areas where they are reliable and unreliable make sense on naturalistic evolution. However, the flaws we do know about are inexplicable on Christian theism. There’s no reason god would intelligently design us with so many errors in cognition, especially errors that happen to make perfect sense on naturalistic evolution.

So this argument continues on in it’s existence because the answer requires nuance. Explaining that our minds are reliable in some contexts but not others and why that is can’t be summarized in five seconds with a pity reply. Trusting our minds is not an all-or-nothing thing. There’s no reason to think that because we are naturally subject to cognitive errors, we can’t trust a single thing we think. I don’t think it’s that hard to understand that we can rely on our cognitive faculties in their specific domains while recognizing that we’re not infallible or omniscient. You can’t just make blanket statements about our beliefs or mental functions either all being reliable or all being unreliable with no context. On the one hand, it would take a superficial understanding of evolution to believe that we’re evolving to have ever-more accurate pictures of reality; but it would also take a superficial understanding of evolution to make Plantinga’s argument.

And he does appear to have a superficial understanding of evolution, but one of his initial observations is accurate. “Adaptive” belief doesn’t necessarily mean “true”. Of course, much of the time, it does; and it’s often the most direct path to get adaptive behavior. But natural selection will favor human cognition that is adaptive, not cognition that is an infallible pipeline to reality. That’s true. However, understanding what is real is often adaptive. It would be absurdly costly and inefficient and convoluted and difficult for natural selection to do anything other than create faculties that have a generalized purpose. It’s simply the path of least resistance for a creature that has to be flexible and navigate an ever-changing environment. Opportunity and danger both present themselves in ambiguous and novel ways and our minds have to be versatile to deal with the complexity we’re faced with.

The philosopher Massimo Pigliucci said, “I do not have much sympathy for philosophers like Alvin Plantinga. . . . [he] still strides what should by now be an impossibly uncomfortable divide and ever widening gap between serious philosophy and theology. Not to put too fine a point on it, Plantinga is engaging in . . . the sort of philosophy that was perfectly acceptable at the time of Thomas Aquinas, but that should have by now securely been consigned to the dustbin of intellectual dead ends.”



CA33 Evolutionary Argument Against Naturalism (EAAN)

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Listen to Magic Tricks by Whalers

Evolutionary Argument Against Naturalism [wiki]

Alvin Plantinga on EAAN [YouTube]

Warrant and Proper Function – Alvin Plantinga (Excerpt) [Google Books]

rd23 Plantinga Schmantinga [Reasonable Doubts Podcast]

Massimo Pigliucci on EAAN [Rationally Speaking Blog]

List of Cognitive Biases [wiki]

A Critique of Plantinga’s Probabilities in EAAN [PDF]

(I didn’t cover this part of the argument, but I would’ve pointed out that in Plantinga’s Bayesian reasoning, he sets his priors absurdly low.)

Richard Dawkins on Evolution [YouTube]


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