Tuesday, June 24, 2014

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 falseAs 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.


  1. I'll have to go back through and read your series, but my thought is that the simplest response to Plantinga's argument is that we do not have to operate on the bare assumption that our experience is reliable; we can put our assumptions to the test of scientific scrutiny to determine whether we can accurately and reliably predict observation. In other words, the reliability of our phenomenological experience — and the degree to which it's fallible — is an observation, not an assumption.

  2. Thanks for your comments, Mike.

    I think that Planting might respond that our cognitive faculties - the very cognitive faculties whose reliability is in question - are required to, as you say, put our assumptions to the test, so the process itself begs the question.

    But I think that the question is just too blunt. If even some of our faculties - if even some of the beliefs that we can derive from reliable senses, say - are reliable, then I think that we have a basis for building models of reality that are adaptive, for sure, and with effort, time, and rigorous methodology, ultimately deliver some capital-T 'Truth's. We've managed to get beyond the capabilities that evolution alone could provide us and that, too, has to be taken into consideration.

    The thing about the EAAN is that it has received a far bit of critical attention over the decades that Plantinga has considered and responded to and he clearly thinks that it survives. If you're interested, Beilby's collection of critical essays - "Naturalism Defeated?" - is a pretty good read. I’m keen to get to a better understanding of Law's refutation. I think that adaptiveness will share conceptual constraints with true beliefs, so I can kind of understand how it might. In the meantime, though, I suspect that the naturalist may be reminded by the EAAN to remain epistemically humble, but I'm not sure that the EAAN survives as an undefeatable defeater for all of our beliefs because I think that the question it addresses is just not sophisticated enough.

    And at the end of the day, classical theism entails a God that we can’t trust to deliver capital-T ‘Truth’, anyways, so Plantinga isn’t any better off …

  3. It seems like he's positing a false dichotomy — either we believe that God exists and created us with True Experience™, or we embrace Radical Skepticism. But if that's the case, then he can't trust his own faculties which he used to reason God's existence.

    I think Plantinga also overlooks the fact that we view knowledge, and our understanding of "truth", as provisional and amenable to evidence. We don't have to unequivocally accept that what we think is true is necessarily true — which I think you're touching on nicely in your second paragraph there.

    Finally, there's a skeptical theism problem. An omnipotent and omniscient God could have morally sufficient reasons for giving us false beliefs as well.

  4. "True Experience™": I love it!

    Agreed. A false dichotomy seems to be a good way to put one of the criticisms of the EAAN.

  5. I've been reading and thinking about the EAAN for at least 3 months and in that time, I'm sure I read PZ Meyers' blog entry about it from 2009. It must have had quite an impression on me because I found, when re-reading it again tonight, that it shared many similarities with what I have been writing in the last few weeks.

    To be sure, I didn't consciously plagiarize what I've written here. In the interest of transparency and full disclosure, here's the link to PZ Meyers' blog about the EAAN:


  6. Yorgo,
    Great series and a wonderful blog in general. You said:

    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.

    Why would the naturalist agree that beliefs are immaterial? It seems very likely that beliefs, as neural patterns, cause behavior. When I looked at the EAAN this was what jumped out at me. It looked to me like Plantinga tried to sneak dualism into the argument. Why do you think that is a valid move? I couldn't figure it out.

  7. Travis R,

    Thanks for your interest and kind words. I had a look at your blog and it is very impressive. Please keep up the great work - I am a new follower.

    It’s been a few months since I blogged about the EAAN, and the issues are not particularly fresh to me at the moment, so I will direct you to Paul Draper’s excellent interaction with Plantinga on the EAAN, here:


    I agree that beliefs, as neural patterns cause behavior, but the problem that Plantinga raises is that if the belief content is epiphenomenal, there’s no reason to think that it ought to be true. Adaptive, yes. But why true? Why not false, and adaptive?

  8. Yorgo,
    Thanks for the compliments. Regarding the question at hand, the argument you linked to is exactly what I was familiar with from Plantinga's book. He resorts to separating belief content from physical composition, which I take to be a type of dualism. I really don't think this is representative of naturalism, but in this post you seemed to accept it.

    It looks like Draper opened the door to do this with his definition of "sensible naturalism". Draper allowed that non-reductive materialism was vulnerable to Plantinga's argument but did so on the premise that it isn't sensible to equate belief content with a physical pattern. I presume his reasons for this come from the strong intuition that our objective perspective on neural patterns is non-informative. That is, there is no content to be found in a series of electrical and chemical reactions. But I say that context is king. Those same neural patterns, when existing within a brain, become subjective and then can be translated by that subjective party into a description that draws upon language and experience to describe the pattern to other brains. This is what we take to be its content. In this case, there is no assignment of immaterial content properties to the pattern, as Plantinga assumes.

    So it seems that this really comes down to the "hard problem" of translating between the objective and the subjective. If we assume that this is not an impossible problem but is rather just a difficult problem, as I take naturalism to assume, then Draper's original response (which I find very sensible) still holds up under this refined definition of naturalism.


  9. "Those same neural patterns, when existing within a brain, become subjective and then can be translated by that subjective party into a description that draws upon language and experience to describe the pattern to other brains. This is what we take to be its content."

    You seem to be describing semantic epiphenomenalism. That content will be adaptive (and maybe that's good enough), but what reason is there to think that that content will be *true*?

  10. Draper defines semantic epiphenominalism as "beliefs exist and they affect behavior but not by virtue of their content". I don't find that to be a proper definition of the position I am proposing. Rather, I am proposing that what Plantinga and Draper call "content" is just a type of representation of the actual makeup of the belief. I guess you could distinguish between neural content and semantic content and then I would say that semantic content is the comprehensible representation of the neural content; the translation of neural content into language.

    Now, why would it the content be true? Because both the neural content and its semantic relations are outputs of the same mechanism which processes sensory input (and neural feedback). The inputs are representations of the external world. Survival and reproduction is absolutely dependent on proper interaction with the external world, so evolution would select for continued improvements in the processing functions ability to accurately represent the external world. Selection is predicated on the organism's response as a function of the content, where responses which demonstrate a proper representation of the world are favored. In short, brains are constantly creating representations and associations between representations and the more this is an accurate reflection of reality, the more likely we are to survive.

    I can't help but feel again like I'm missing something. This explanation seems incredibly obvious to me, yet even when I read philosophical responses to the EAAN I don't see this articulated. What am I missing? How does content become disconnected with reality?

  11. Plantinga uses the example of a frog on a lily pad shooting it's tongue out and catching a fly. That frog needs to have a way to detect when a fly is around and a way to actually intersect the fly's path with the projection of it's tongue, but the frog needn't have any thoughts about the matter at all and if it does, there are innumerable things it could be thinking. Whatever it's thinking is irrelevant, so long as it's tongue gets the fly. The content need only be related to reality very loosely. Evolution doesn't care about the content, so long as the behaviour is adaptive.

    I've suggested that the content represents "truth to us" and that it may very well not represent the real "Truth". The latter would seem to be even in principle unavailable to us, so why should we care if our "truth" is adaptive. I've also suggested that with humility, empiricism, and care, we ought to be able to refine our "truth" so that it better and better approximates "Truth" and that this appears to in fact be the situation we find ourselves in. So perhaps the EAAN isn't that devastating to the naturalist and contains epiphanies that are at least somewhat damaging to the theist.

  12. Yorgo,
    The example you cite from Plantinga looks like a variation of the "philosophical zombie" argument from Chalmers. Massimo Pigliucci has a good critique, which summarizes Marvin Minsky's objection as:
    "Chalmers’ argument begs the question: in order to work, it has to assume that some characteristics of human beings, namely consciousness, are not produced by physical processes, which is precisely what the argument allegedly sets out to prove."

    I completely agree and think something similar is happening here. In Plantinga's example, the unspoken assumption is that the thoughts about the external world are independent of the neurological patterns which dictate interaction with the outside world. I doubt that is an assumption that the naturalist will grant, particularly from the evolutionary perspective in which consciousness is a more recent development from "less conscious" organisms. If the consciousness function is a gradually evolved descendent of a more simplistic reactive function, then it will only be selected if it is an adaptive benefit; implying that it improves the organism's interaction with reality, implying that its representations of reality are generally accurate.

    I agree with your pragmatic approach to truth and with your assertion that the degree to which our faculties actually are unreliable presents a problem for theism. It is certainly true that adaptation does not guarantee reliable faculties and so we should not be surprised to find that we are sometimes wrong. The theist has to add a new doctrine, corruption, to explain this. I have argued in a manner similar to your argument here that the theistic perspective has this problem; see the comments of my post on Plantinga's book and the subsequent extension of the discussion at the blog of my interlocutor. So though you and I agree that the state of affairs in which we find ourselves is better explained by the evolutionary account of the reliability of our beliefs, we disagree as to how unreliable those beliefs are in the absence of corroboration and scientific method; which undoubtedly improve them - but there has to be a decent foundation for them to first build upon. Do you think that a feral child would have vastly incorrect beliefs about the world? I do not grant that our foundation is vastly unreliable because I think that Plantinga is sneaking assumptions into his argument (probably not deliberately) that don't actually fit with the naturalist account.

    Thank you for engaging on this topic. I'm fascinated by the argument and haven't yet found anything that has even hinted to me that my objection to the argument is in some sense invalid. It was interesting to see you, from a naturalist perspective, accepting the conclusions you did and I appreciate your willingness to discuss it further.