Something seems to have somehow been programmed into our brains that delights in crushing, easy victories. The New Atheists have a dozen sure-fire, slam-dunk arguments against Christianity that they regularly use, and John Loftus is inventing new ones every month or so. When I was a boy, I thought Noah's Ark had been found on Mount Ararat. Wouldn't that be wonderful if it had been? See! There's the elephant's stall! What's an elephant doing at 15,000 feet?
Slam dunk! Christianity is utter foolishness. The Bible is proven beyond all doubt.
In Annie Hall, Woody Allen is standing in the line for a movie by Marshall McCluhan, and gets into an argument with a Columbia professor who is also in line. Just then, McCluhan himself wanders by, and jumps in on Allen's side, telling the prof, "You know nothing about my work!" Allen turns to the camera and says, "Don't you wish life was like that?"
Yet I think what Plantinga calls the Evolutionary Argument Against Naturalism is, in fact, mistaken.
I am neither an evolutionary (nor any other kind of) scientist, nor a professional philosopher. It may be that my own arguments against the EAAN themselves fail, and fail badly. I would be happy for Plantinga's argument to be proven successful, and welcome supporters of that argument to defeat my defeaters, and rout the naturalistic opposition, along with me.
I am currently debating the EAAN with half a dozen or more fellow apologists elsewhere, all of whom so far appear to take the opposite viewpoint from me. One of my reasons for posting this argument here, is so people can find my disputed arguments in a readable form easily, instead of searching for them through a long and shifting thread. (About twenty new posts have appeared, since I started writing this post.) So to save time, let me simply quote Wikipedia's description of the EAAN (I will not read criticisms of the EAAN on that page -- for better or for worse, what follows will be my own thoughts about the argument):
- N as naturalism, which he defined as "the idea that there is no such person as God or anything like God; we might think of it as high-octane atheism or perhaps atheism-plus."
- E as the belief that human beings have evolved in conformity with current evolutionary theory
- R as the proposition that our faculties are "reliable", where, roughly, a cognitive faculty is "reliable" if the great bulk of its deliverances are true. He specifically cited the example of a thermometer stuck at 72 °F (22 °C) degrees placed in an environment which happened to be at 72 °F as an example of something that is not "reliable" in this sense.
and suggested that the conditional probability of R given N and E, or P(R|N&E), is low or inscrutable.
Plantinga's argument began with the observation that our beliefs can only have evolutionary consequences if they affect behaviour. To put this another way, natural selection does not directly select for true beliefs, but rather for advantageous behaviours. Plantinga distinguished the various theories of mind-body interaction into four jointly exhaustive categories:
- epiphenomenalism, where behaviour is not caused by beliefs. "if this way of thinking is right, beliefs would be invisible to evolution" so P(R/N&E) would be low or inscrutable.
- Semantic epiphenomenalism, where beliefs have a causative link to behaviour but not by virtue of their semantic content. Under this theory, a belief would be some form of long-term neuronal event. However, on this view P(R|N&E) would be low because the semantic content of beliefs would be invisible to natural selection, and it is semantic content that determines truth-value.
- Beliefs are causally efficacious with respect to behaviour, but maladaptive, in which case P(R|N&E) would be low, as R would be selected against.
- Beliefs are causally efficacious with respect to behaviour and also adaptive, but they may still be false. Since behaviour is caused by both belief and desire, and desire can lead to false belief, natural selection would have no reason for selecting true but non-adaptive beliefs over false but adaptive beliefs. Thus P(R|N&E) in this case would also be low. Plantinga pointed out that innumerable belief-desire pairs could account for a given behaviour; for example, that of a prehistoric hominid fleeing a tiger:
Thus, Plantinga argued, the probability that our minds are reliable under a conjunction of philosophical naturalism and naturalistic evolution is low or inscrutable. Therefore, to assert that naturalistic evolution is true also asserts that one has a low or unknown probability of being right. This, Plantinga argued, epistemically defeats the belief that naturalistic evolution is true and that ascribing truth to naturalism and evolution is internally dubious or inconsistent.
Editing note: The first two arguments here are to Plantinga's argument itself, the second two, more to objections that came up to them in the discussion.
1. Argument from simplicity. The simplest solution would be for evolution to produce a brain that perceived reality fairly accurately, as the simplest solution would be to produce eyes that see reality somewhat accurately. These Byzantine alternatives, like wanting to pet a tiger and thinking the best way to do so is to run away from it, would never work in practice. Clever, but highly improbable, what a philosopher would think up, but I doubt an engineer.
And suppose that weird belief about petting tigers did save you once. How if you were Pi, on a boat with a tiger for weeks? Or suppose next time it was a snake, or a cliff, or a tribe of cannibalistic pygmies, or a flood, or an oncoming semi with a drunk driver and black ice on the road? In each case you are just so lucky as to hold a belief that is totally wrong, but that inspires you to take just the right actions to rescue yourself? All your life long?
This is what I mean by the need for simplicity. A brain that tells us things that really are, is much simpler than the endless chain of fortuitious chances that would be required for false beliefs to lead to adaptive behavior.
A brain that created beliefs that were utterly tangential to reality, all things equal would get us killed quickly. Plantinga's proffered example of the tiger is ludicrous, I think, because the brain would have to come up with false reasons for doing the right things each and every time one's surival was at stake. That might happen once, but consistently? Simplicity here is absolutely essential: the skin protects the body because it has a set of characteristics that ward off nettles, insects, radiation, bacteria, and also allow evaporation, flexibility, and other important functions. If it were a computer software that fed in random traits at every encounter with objects in its environment, we would quickly be toast.
2. Analogy to the eye. The simplest way to construct an eye that helps us survive, is to make the eye see what really is. The simplest way to construct a brain that helps us survive, should by analogy also be to make it perceive what really is. Plato recognized the correlation between these two:
It was the sun, then, that I meant when I spoke of that offspring which the Good has created in the visible world, to stand there in the same relation to vision and visible things as that which the Good itself bears in the intelligible world to intelligence and to intelligle objects . . . Apply this comparison, then, to the soul. When its gaze is fixed upon an object irradiated by truth and reality, the soul gains understanding and knowledge . . . (Republic, vi. 508)
A "sight" here is analogous to an "insight:" neither is a body part, both might be thought to arise from the action of body parts.
By this analogy, why should our eyes accurately see objects that don't directly affect our survival? It does not often aid survival to see the dots on a monarch butterfly's wings. Nor did it much help, before the Voyages of Discovery, to count stars. But the ability to see objects like tigers, snakes, mosquitos, and clouds, could also be applied to stars or, with mechanical aids, distant galaxies or tiny bacteria.
Suppose you want to construct a machine that represents a three-dimensional scene in two dimensions. There may be many ways of doing this, but the simplest are a mirror or a camera, that "reflect" or "fix" light as it actually comes in, rather than building up an image from scratch with some complex machine. It's the same way with "seeing" reality mentally. It would seem that the simplest way of navigating life cognitively, would be with a brain that "perceives" objects as they really are, rather than creating some complex mental machinery that happens to react to diverse situations successfully, while misperceiving actual states of affairs, as Plantinga suggests.
3. Teleology? Some object to my argument, saying unguided evolution is not teleological. It has no aim or purpose. So how could it succeed in creating a brain that perceives the truth about things?
Well, maybe it can't. I'm not committed to the theory that unguided evolution can produce much of anything that is very complex.
But by hypothesis, evolution IS a blind engineer looking for simple solutions, in as much as it is posited to have formed all of life. If evolution created the eye, then the purpose of the eye -- to see things clearly -- is built into the function which the "blind watchmaker" is struggling to create, mechanisms that work to enhance survival and allow fecund reproduction. Of course this anthropomorphic and rather misleading language, but not on the key point: that if evolution works at all, one must be able to see apparent, if not real, planning in retrospect.
4. Why don't our brains work any better? Some of my critics claim that I simply failed to understand the EAAN, and therefore my arguments were hardly worth answering. It seems to me that when someone misunderstands, a good thing to do is explain what they got wrong, and how to put it right. But also, if the critics are right, and I am wrong, why is that so? The brains of both Marshall and his critics were, by hypothesis, divinely designed by an omniscient being to find truth.
But one side or the other, maybe both, has failed to find truth.
So perhaps this is (a) a consequence of the Fall or (b) of sin on their part or mine, (c) evidence that the human brain was not directly designed by an omnipotent God, or that (d) for some reason, a perfect God created brains prone to error.
In any case, it seems empirically obvious that our minds are far from completely reliable. It is not self-evident that that state of affairs, or say Alzheimer's Disease, is easier to explain under theism than under naturalism. (Though being somewhat skeptical of naturalistic arguments for evolution -- as Plantinga also is -- we for the sake of the argument ignore general objections to purely materialistic neo-Darwinian theories).
Conclusions: I haven't really come to any definite ones, yet. I am still willing to be corrected about the EAAN. I certainly see some of Plantinga's points as interesting, and some of the distinctions he makes about neurology and belief useful. But I don't think the "slam dunk" goes through. This is not so unusual: even in the NBA, one can occasionally witness an All-Star center "slam dunk" the ball, and the ball come flying off the rim, the laws of physics doing their honest work even in the face of occasionally misfiring basketball genius.