A final word on Plantinga's EAAN (Part 4)

I’ve been blogging about Alvin Plantinga’s Evolutionary Argument Against Naturalism (EAAN) over the past few weeks. The original plan was to (1) explain the argument, (2) suggest that it wasn’t that devastating to naturalists if a humble idea of ‘truth’ was adopted, (3) show that Plantinga’s theistic beliefs don’t give him any better epistemic foundation than a naturalistic one, and finally, (4) to refute the first premise, without which, the argument fails. Steps 1-3 have been accomplished, and while I’ve been trying hard to accomplish step 4, I'm not confident that I or anybody else has been able to clearly and convincingly succeed. Philosopher, Stephen Law, believes he has, but I must admit that I don't understand his response to the EAAN well enough to explain it here. I'm waiting for him to provide a dumbed-down version for lay people like me to understand. In the meantime, though, I'm forced to consider that Plantinga may well be right about premise 1: on naturalism and evolution, the probability that our cognitive faculties are reliable probably is low. I actually want to thank Plantinga for reminding me of this prediction for it seems to me that things turn out looking very much as Plantinga would expect. This, I believe, provides even more evidence for naturalism and evolution and makes Christian theism even harder to accept. But before I get to that, there is one way that the first premise could very well turn out to be false.

If beliefs don’t affect behavior (epiphenomenalism), or they affect behavior but not by virtue of their content (semantic epiphenomenalism), then it is hard to see how evolution could select for mechanisms that produce True* beliefs, for evolution would seem to be blind to belief content just as Plantinga has suggested. However, if beliefs do affect behavior by virtue of their contents, then Plantinga’s crucial first premise is very likely false. As Plantinga himself has said:


"Now if content of belief did enter the causal chain that leads to behavior--and if true belief caused adaptive behavior (and false belief maladaptive behavior)--then natural selection, by rewarding and punishing adaptive and maladaptive behavior respectively, could shape the mechanisms that produce belief in the direction of greater reliability. There could then be selection pressure for true belief and for reliable belief-producing mechanisms." (Naturalism Defeated? p. 257)

It is probably the case that the naturalist lacks a robust explanation for how immaterial beliefs could cause behaviour, but that doesn't mean that there isn't one and it's not at all clear to me that the naturalist must be wedded to the idea that it's impossible. There is a long history attesting to the outstanding success of methodological naturalism (ie. science) in filling gaps in our knowledge and imagination - gaps previously filled by God or gods - with natural explanations. Plantinga likes to fill this particular explanatory gap with his God but there are problems with doing so that I have explained here, and I see no reason for the naturalist to also have to do so. If Plantinga disagrees, then I’d have to ask why he isn't correspondingly required to explain how it is that God himself tracks Truth*? I mean, how does he know, and even deeper, how does He know?

Ok. let's move on and see if the EAAN actually places a burden on Plantinga himself. Paraphrasing Plantinga: on naturalism and (therefore, unguided) evolution, the probability that a given belief will be true is 0.5. Accordingly, if someone has 100 independent beliefs, the probability that most of them, say, 75% of them, are true is going to be less than one in a million.

Now consider Harry the homo sapien living on the African Savannah 150,000 years ago. I suspect that Plantinga is correct in suggesting that the chance that the vast majority of his beliefs are going to be true is << 1/1,000,000.

Plantinga does think that our sensory organs could evolve naturally to reliably indicate certain environmental states of affairs, so some of Harry’s beliefs could also be true in some ways. For instance, Harry may believe that a green tree is in front of him and that he had better run around it or risk serious injury. Is his belief that the tree is green True? The tree merely absorbs all wavelengths of light except green. It reflects green wavelengths which are then detected by the indicators in his retina, leading to a belief that the tree is green, but the only thing that is green is his mental representation of the tree. Nevertheless, his idea that there is something in front of him and that colliding with it will cause injury surely is true. Does it matter that the tree isn’t really green but that his mental representation of it is? Evolution doesn’t seem to care about it so long as Harry sees the tree and avoids injury. Should we really care? That’s just how we experience certain truths about our environment. As I argued in part 2 of this series, that’s just truth to us.

So while most of Harry’s beliefs surely are false in a variety of possible ways, some are likely to be True and those that are likely to be True are the ones most likely to be derived from reliable indicators as Plantinga likes to call them, otherwise known as our senses. Now imagine what can happen when Harry and his colleagues can communicate and share their beliefs with tens, hundreds, thousands, and eventually billions of other people. And imagine what can happen when we realize, as a species, that the beliefs most likely to be True (or the ones with the most True content associated with them) are the ones that we can test against our environment. Imagine what can happen when that process shows us how poor many of our cognitive capabilities actually are and that we can begin to correct for those inadequacies. Plantinga is probably correct that the majority of Harry’s beliefs will be false, but thanks to science our species has developed ways of obtaining and sharing ideas that go far beyond anything evolution could have cooked up for Harry. As Sam Harris has pointed out, we’ve flown the perch built for us by evolution, and it’s far from clear to me that a modern day person, well educated in science and skepticism needs to worry too much more about her beliefs being false because of the EAAN. Anybody with a modicum of epistemic sophistication is already a humble fallibilist. She already looks to the best sources for justification that we can hope for: those delivered by science. A reliance on science is really an admission that our cognitive faculties suck and that to find Truth we have to follow a rigorous methodology that’s about correcting for sources of error and bias both within and outside of us and even then, we'll very often end up with adaptive models of Truth that we call truth.

So really, it is not naturalism that has troubles explaining the reliability of our faculties: it's theism. Cognitively, we seem to be pretty good at the kinds of things that require us to survive and successfully reproduce like avoiding predators, caring for our offspring, obtaining food, etc. However, as a species, our members are horrible at understanding physics, advanced mathematics, statistics, probability, chaotic (but fully deterministic) systems, etc. Getting good requires many years of advanced education and hard work; it certainly doesn’t come naturally. This would seem to be precisely the case expected on unguided evolution. So it seems to me that there is a burden on Plantinga to explain how our lousy cognitive processes are reflective of the notion that an allegedly perfect being created us in his image. Are we to believe that God is also subject to a plethora of deeply problematic cognitive biases and perceptual and memory errors? Could Satan plant false memories into the mind of God as certain psychologists have done to people, for example? Does God also condemn people to (eternal) punishment on the basis of shoddy eye-witness testimony?

The question of the conditional probability of reliable cognitive faculties is just too blunt for such a complicated topic. If none of our cognitive faculties are reliable, then I will admit that our search for Truth is hopeless. But if some of our faculties are reliable some of the time, then by cooperating and communicating and finding ways to avoid our cognitive weaknesses, I don’t see why we can’t build up from a humble foundation creating models of truth that get closer and closer to the Truth, and that, it seems, is precisely the situation I think we find ourselves in. Plantinga’s EAAN is interesting but at the end of the day, it changes little, if not nothing for me. I’m still very much a naturalist who firmly believes in the truth of evolution, and I’ll keep following the deliverances of empiricism over pure rationality. This, it seems to me, is an epistemically challenging and responsible stance, while making the whole matter go away by simply asserting that “Goddidit” ... well, you can decide for yourself what you think of that.

* In this 4 part series, I use lower case t 'truth' to denote what seems true to us and capital T 'Truth" for what's actually or ultimately true. More on this here.

Do I even know anything? Alvin Plantinga's EAAN (Part 1)

"The greatest trick the Devil ever pulled was convincing the world he didn't exist."
-Verbil Kint, The Usual Suspects

Can we have the wool pulled over eyes in an extremely powerful way without having any idea of it? How correct are our ideas, if at all? Can we rely on our brains to provide us with the truth? It sure seems that way to us, but haven’t we been mistaken in important ways before? I believe, for instance, that billions of people alive today and throughout history have been wrong about their theistic beliefs ... but what ground do I have for believing that my world view is right? It seems that I must rely on the products of my cognitive faculties in reaching that conclusion, but what if they aren't reliable?!

Alvin Plantinga, arguably the most important Christian philosopher of our time, believes that naturalists are in no position to know that their beliefs are true, including the belief that naturalism itself is true. I’ll be describing his clever and interesting Evolutonary Argument Against Naturalism (EAAN) in this post and I'll be discussing my responses in the next few weeks. If you are a naturalist, you owe it to yourself to at least think about Plantinga’s argument and spend some time making sure that you have a response that you can sleep well with. If you are a theist, you’ll love how the EAAN can appear to turn the tables on us naturalists.

Naturalism (N) is notoriously difficult to define, but Plantinga defines it as the belief that there is no God, nor any being like him. Fair enough.

Naturalists tend to believe that we have arrived here according to the unguided random processes described by the Theory of Evolution (E) over billions of years. Accordingly, a question that the naturalist must ask is how E could account for faculties that deliver true beliefs.

On naturalism, a belief will be an event or structure in the brain. Here’s how Plantinga puts it:

“[A belief] will be a structure involving many neurons connected in various ways. This structure will respond to input from other structures, from sense organs, and the like; it may also send signals along effector nerves to muscles and glands, thereby causing behavior. Such a structure will have at least 2 kinds of properties: On the one hand, it will have neurophysiologic properties (NP properties) specifying, for example, the number of neurons involved in the structure, the rate of fire in various parts of it, the change of rate of fire in one part in response to a change in rate of fire in another, the way in which it is connected with other structures and with muscles, and so on. But if it is a belief, it will also have a property of a quite different sort, a mental property: It will have a content.”

Evolution will have ensured that our behavior is adaptive; if a tiger is around, it will have selected for NP properties that lead us to run away or hide. That protective behaviour increases one's chance of living another day and passing one's genes (that code for adaptive behaviour producing mechanisms, among other things) on to the next generation. But notice that it's the behaviour that is adaptive, not necessarily the belief that motivates the behaviour. If the belief content associated with adaptive NP properties is true, great, but if it’s false, that’s equally fine, so long as it leads to adaptive behaviour.

For example, Norm the Neanderthal sees a sabre tooth tiger and it occurs to him that he may be the tiger’s next meal, so he runs away and lives to tell the tale. On the other hand, Harry the Homo sapien sees a tiger and thinks that the tiger wants to scratch his back and the best way to do that is to run away. That seemingly bizarre belief content still gets him in the right place to survive; it just doesn’t matter whether it's true or false, or so argues Plantinga.

If that’s true, then the probability that a given belief is true or false is going to be roughly 0.5 at best (because truth just doesn’t matter). If someone has 100 independent beliefs, the probability that most of them, say, 75% of them, are true is going to be less than one in a million.

On naturalism and unguided evolution, therefore, the probability that our faculties will be reliable is low. It follows that we no longer have any reason to think that our faculties are reliable. If we cannot trust our faculties or the beliefs they produce, we can’t trust the belief that naturalism is true. It would be irrational for anybody who accepts Plantinga's reasoning here to continue to believe in the truth of naturalism itself; that belief, combined with E, is self-defeating.

Please note, the conclusion of the EAAN is not that naturalism is false (a de facto objection), but rather that it’s irrational to continue to believe it (a de jure objection) or anything else for that matter. Naturalism could be true, or it could be false, but since our faculties are unreliable, we just have no way of knowing either way. The EAAN concludes that we have no way of knowing anything, plunging us into the quagmire of extreme skepticism.

Here's how Plantinga clearly spells it out:

(1) On unguided evolution, the probability that our cognitive faculties will be reliable is low
(2) One who accepts unguided evolution and agrees that (1) is true, must conclude that one's cognitive faculties are unreliable.
(3) If one's cognitive faculties are unreliable, then one is in no position to believe any product of one's cognitive faculties, including the belief in unguided evolution
(4) Therefore, the belief in unguided evolution is self-defeating, and can't be rationally accepted.

Plantinga rejects naturalism: he’s a Christian theist. From his perspective, God has guided E by creating environments that select for genetic mutations that he has caused and which have made us in his image. Since God has reliable faculties, he has given us reliable faculties as well. Like magic, the skepticism that results from the combination of naturalism with E is wiped away by combining E with supernaturalism.

The greatest trick evolution ever pulled was convincing naturalists that their beliefs are true 
-Alvin Plantinga

"Keaton once said: "I don't believe in God, but I'm afraid of him" -Verbil Kint, TUS

I don't believe in God either. Maybe I should be afraid of Alvin Plantinga.