An Evolutionary Argument for Naturalism

Let's take our intuition, our faculty of memory, our powers of perception and introspection, our powers of deduction and inference, and put them all in a box. This box can be seen, maybe a bit too simplistically, as a machine that produces belief. Somewhere within us, no doubt in our brains, this box receives input from our senses and outputs a representation of the external world. To keep things simple, let's call this amalgamation of neurology our faculties. And, without worrying about how it works, let's worry about whether it works at all. There are different senses in which our faculties can 'work'. We are able to navigate our environment without dying, and that's a sort of success. But it's possible to navigate effectively while being completely wrong about what one is navigating. Our faculties could very reliable for keeping us alive, but be very unreliable for delivering truth. The psychologist might be very interested in the first sense that our faculties are reliable, and want to study it more (maybe with the hopes of replicating them; AI technology is much sought after). But the philosopher is interested in the second, he wants to know whether there is a serious threat of skepticism. It is this latter sense we will be concerned with.

Many think there is an argument against Naturalism and for Theism from the reliability of our faculties. After all, whether or not God was directly responsible for human origins, we can expect he would intervene in some respects. Maybe God doesn't care if we're bipedal or quadrupedal, or whether or not we have a tail or are covered in fur. But God does care about our intellect, and our ability to discover truth. God cares, then, about our brains. And so, on Theism, there is an available explanation for how our faculties might be reliable, in that they were designed to be reliable by God. But on Naturalism, how can this issue be addressed?

The standard scientific explanation is that our brains, along with the rest of us, evolved by natural selection over millions of years from a long extinct ancestral species. And that species likewise evolved from something even older, and so on and so on. Our faculties, then, were produced somewhere along this line of animal evolution. But herein lies the problem. There doesn't seem to be any selective pressure for having reliable rather than unreliable faculties. One might think an animal must know where the water is, know who the predators are, and know what to mate with, to successfully pass on its genes. But this isn't quite right. What matters is that the animal goes towards water when it's dehydrated, hides from predators when threatened, and pursues a mate of its own species. In other words, what matters is the animals behaviour, and not his beliefs. If the animal moves in all the right ways, then his mind can be on vacation and he will survive just as well. As a result, it seems the truth of an animal's belief does not factor into his evolutionary fitness.

Given an alternate evolutionary history, humans might have had a very different understanding of the world. Imagine, in this alternate reality, someone sees a tiger and, thinking it is friendly, tries to befriend it. But, they think, playing tag with it and running away as fast as they can is the best way to befriend it. In their mind, tigers respect fast runners. When they run away, it doesn't matter what was going on inside their head. Their belief about the tiger still motivated the right action, even though it was false. And, if you think about it, there are many ways a network of beliefs could be beneficial but false, but only one way in which they could be true. Maybe instead of thinking the tiger is friendly, this fellow thinks the tiger is lucky. And that seeing a tiger means you will be blessed with finding riches if you run away immediately. I'm sure there are an endless many silly little stories we could tell about why a false belief would cause someone to perform the right action.

But if there are many more ways in which our faculties could get it wrong than right, and if natural selection has no way to differentiate between the two, then we would expect our faculties to become very finely tuned to keep us alive, but not at all reliable for discerning truth. And so the probability of our faculties being reliable (R) on evolutionary naturalism (E&N) must be very low.

This is where the argument gets interesting, for if we must accept that Pr(R|E&N) is very low, then we must accept that E&N is a defeater for R. But if E&N is a defeater for R, then it is likewise a defeater for all the beliefs we know were produced by our faculties. In a strange twist, we recognize that E&N is beliefs of ours—having been produced by our faculties—and, as such, is self defeating. Since the evolution of man is an established fact, Naturalism must be rejected. Ironically, one of the perceived pillars of naturalistic thought defeats our warrant for believing Naturalism.

Or so some think, but there's more to the matter. However beneficial it is to have the right beliefs, it's even more beneficial to be able to draw the right conclusions. An animal who is able to infer truths about his environment can acquire knowledge of things he has never before experienced, which allows for planning and forethought to guide the animal's behavior. Suppose a species is plucked from their home environment and dropped into one they've never before encountered. Evolution couldn't have possibly equipped them for this new environment, since they only ever evolved to suit their old one. And yet, they might already have crucial knowledge of this new environment simply by making inferences. Clearly this species will survive at a greater frequency than one who doesn't have any such inferential power.

But inference is a garbage in, garbage out process; only true premises guarantee true conclusions. This provides selective pressure for evolution to maximize the number of truths an animal possess, offering him a large pool of premises to safely draw conclusions from. On the other hand, a false belief allows the animal to draw false conclusions (even if the reasoning is flawless). And so to minimize the chance of error, evolution is pressured to weed out falsehoods. Furthermore, false beliefs can have a sort of domino effect: one might allow many in, which in turn might allow many more. And so the pressure to not have false belief is fairly strong.

Looking back, the stories of the fellow and the tiger all involved him having more beliefs than necessary to motivate the right behaviour. If he merely understood that the tiger was dangerous, that would surely be enough. But in thinking the tiger was friendly, he had to have other false ideas of how to befriend it. In thinking it was lucky, he had to have other false ideas about how to pursue riches. Since there is evolutionary pressure to minimize an animal's false beliefs, these over-complicated, false belief structures are actually less likely to be beneficial, and thus less likely to evolve, than the simple truth. And so, given an evolutionary origin, we would actually expect our faculties to be more or less reliable.

That being said, many parts of our faculties (particular intuitions, or other belief-forming mechanisms) are actually quite unreliable. On evolutionary naturalism, scattered cases of unreliability here and there are not at all surprising; evolution by natural selection is a messy, imperfect process. But this isn't a problem because over time we've developed methodologies to help us along. We don’t just blindly follow our gut anymore, but instead put more weight behind the scientific method than behind any single metaphysical intuition. For example, the results of quantum physics are mindbogglingly odd, but we accept them anyway. And even for fields like ethics where intuition still plays a significant role, we have learned to filter out intuitions through thought experiments, and thus aiming at generalized theories.

Over time we have refined the process by which we acquire belief. But if our faculties were designed by someone who cared about our epistemic situation, why would this refinement be necessary? If God exists, why would he leave so many people in the dark for so long? Why would he have left us to pursue false religions, false ethical theories, false medical practices and so on, especially since these areas actually matter? And so, if anything, it seems our epistemic situation strongly supports Naturalism over Theism. Not only can Naturalism explain the reliability of our faculties but, unlike Theism, it can explain the extent to which our faculties are reliable.

Conspiracy of Creationism

This post is a bit of fun, all of which is being poked at young earth creationists. A powerful case for evolution can be made all without ever touching the science itself, but rather by making an appeal to theistic authority.

The Pew Research Center did a study of public and scientific opinions on a number of controversial topics, some of which were evolution and religion. From the study we get a number of unsurprising, but telling statistics:

• 97% of scientists believe in evolution (that living things, including humans, evolved over time)
• 48% of scientists have some religious affiliation
• 33% of scientists believe in God

These numbers shouldn't be a shock to anyone, the widespread acceptance of evolution within the scientific community is common knowledge. And it's likewise generally understood that scientists are less likely to be religious or theistic. But now that we have these numbers, we can play with them a bit. Assuming the best case scenario (that only the religious would reject evolution) we get that, at the very least, 93% of religious scientists affirm the theory of evolution. With a similar assumption we can see that, at the very least, 90% of theistic scientists affirm the theory of evolution.

These numbers dispel the myths you hear floating around about evolution in academia, like that scientists believe evolution just to save their naturalistic biases, or because those who doubt it are bullied into silence by their non-religious superiors. Sure naturalism is the majority view within the scientific community, but not by much!

The question I'd pose to creationists, then, is why do so many theistic scientists accept the theory of evolution? It seems that creationists are faced with a daunting trilemma. Are the vast majority of theistic scientists incompetent with science, in that they are rational and honest enough to follow the evidence wherever it might lead, but are simply not well enough informed to see the folly of evolutionary theory? Or are the vast majority of theistic scientists incompetent with reason, in that they are well informed and honest enough, but cannot keep this all straight in their heads and somehow succumb to fallacious reasoning? Or, finally, are the vast majority of theistic scientists well informed and rational, but simply dishonest? Do they know the truth, having made the right observations and having drawn the right conclusions from it, but for some reason or other are lying to the public about their findings? I can't think of any explanation that doesn't paint theistic scientists in an embarrassingly bad light.

The first horn is bold and foolish; surely the vast majority of scientists, people who have devoted their careers and lives to studying nature, are more informed than lay-people. The second horn is almost as rash; surely having undergone many years of education would make someone sufficiently rational. To get to where most scientists are, one must be extremely intelligent and well-versed in critical thinking. The final horn, then, is the least absurd, and yet it's still too much to accept. To think that the vast majority of scientists are lying to the public is crazy enough, but to think that such a large portion those perpetuating this deception are themselves theists is some next level conspiracy theory. I don't see how this is any better than thinking the government is hiding extraterrestrials, or that 9/11 was an inside job.

Then again, maybe the problem is that most lay-man creationists have never set foot in academia, and as such are simply unaware of the frequencies of different opinions of academics. After all, over half of them reported that there was no consensus on evolution within the scientific community.

On a final note, I'd like to put the creationists skepticism in perspective. In defending the historicity of Jesus' resurrection, the popular Christian apologist William Lane Craig wrote "In a survey of over 2,200 publications on the resurrection in English, French, and German since 1975, Habermas found that 75% of the scholars surveyed accepted the historicity of the discovery of Jesus' empty tomb."

Only 75% of scholars accept the historicity of Jesus' empty tomb. The intellectual arbitrariness required to hold to the standard creationist world view is jarring. There is not only a greater percentage of scientists, not only religious scientists, but even theistic scientists who accept evolution, than there is historians who accept such a meager claim that Jesus' tomb was empty on Easter morning. No wonder they're so skeptical of achedemia, they just can't win.

The Problem of Freewill (an extension of the Problem of Evil)

A common response when faced with the problem of evil is to offer a freewill theodicy. Many believe that libertarian freedom is necessary for very great goods, such as moral agency, spontaneity, or a genuinely loving relationship with God. And, it is thought, unless God violates our freedom, he cannot prevent us from doing evil. God would thus have good reason to permit the bulk of evils that populate our world.

While both premises are often contested, it's sometimes argued that the very patterns and magnitudes of human freedom are themselves evidence against God. As such, the theological problem simply resurfaces. After all, with freedom comes power; power over the well-being of oneself and others. And sometimes it can be quite inappropriate, or even harmful, to give someone this sort of power.

First it's important to notice that freedom isn't an all or nothing deal. Everyone has certain powers and limitations. No human, for example, has the freedom to fly about like Superman (at least not yet). And very few humans have the freedom to bring about war, genocide or famine. Most people don't have nearly that much influence on the world, so clearly these sorts of freedoms are not so important that God should always preserve them.

The question, then, is which actions should we be free to perform? This largely depends on the individual. God himself is a perfect being, and as such it's good for him to have unrestricted freedom, for he will only ever do good with it. God does not struggle with temptation, he fully understands the moral consequences of his actions and, more importantly, he cares. But humans are, for whatever reason, not so impeccable.

Anyone who gives their young child a loaded gun and the freedom to use it at his own discretion is doing something quite evil. Not only is the child ignorant of the potential harm he could cause himself and others, but he isn't even capable of understanding. There is a certain level of maturity one must reach, before one can fully grasp the evil consequences of their actions. Furthermore, even if the child was fully aware of how dangerous a loaded gun is, we still shouldn't expect him to choose wisely. There's a certain level of maturity one has to reach before they're capable of caring about the consequences of their actions. You might think this is silly, of course people care about their best interests. But then, what were you doing as a teenager? Right. Many adults, even, live for the moment and throw caution to the wind, racking up debt they know they wont be able to pay back because they are so focused on the immediate satisfaction.

Of course there comes a time when it would be very appropriate to place a gun in your child's hands, after all you can't learn to use a gun if you're never permitted to touch one. But even then, you still wouldn't give him completely unrestricted freedom. You would teach him gun safety, and appraise his maturity level every step of the way. You personally make sure he's not going to hurt himself or anyone else. And this is how people should acquire freedom: slowly and gradually, as they learn to be responsible with it.

Then again, there are some people whose freedom should be restricted, not because they're ignorant or immature, but simply because they are evil. This is precisely why we jail criminals; if someone proves themselves irresponsible with their freedoms, we take those freedoms away. If someone has a tendency for violence, cruelty, or has a general apathy towards human well-being, then it would be very wrong to place him in any sort of power over others. It would be wrong to allow him to hold a job as a child educator, or a nurse, and it would be especially wrong to let him be a politician.

On theism, one would expect God to give us only as much freedom as we deserve. And yet sometimes children get their hands on guns, and sometimes genocidal maniacs are elected to public office. Many of the most horrific evils brought about by human freedom are the result of undeserved freedom, and as such are doubly problematic to theistic belief. Not only is the evil act itself surprising, but the freedom it was performed in is highly unexpected on classical theism.

The patterns and magnitudes of human freedom do not very well match the patterns and magnitudes of human responsibility, and as such actually constitute evidence against the existence of God just as much as any other seemingly gratuitous evil.

ECREE and the Argument from Miracles

When faced with miraculous testimonies, skeptics often cite the mantra 'extraordinary claims require extraordinary evidence'. In turn believers charge skeptics of being overly skeptical, and arbitrarily setting a higher bar for claims to the supernatural. And, often times, they are right. If you ask most skeptics why extraordinary claims require extraordinary evidence, or what it is to be an extraordinary claim, they usually aren't able to explain themselves very well. But, I think, there is some truth to this mantra, and it can be fleshed out in a mathematically rigorous way. Enter Baye's theorem, which states:

Pr(A|B) = Pr(B|A) * Pr(A) / Pr(B)

Once you're aware of it, all the pieces fall into place. An extraordinary claim is simply one with a very low prior probability. Extraordinary evidence is simply evidence that is very strong, having a very high conditional probability. It's almost self-evident that very improbable events require very strong evidence before we can reasonably accept them, but Baye's theorem shows us why. Suppose A is an extraordinary claim (having very low prior probability), and B is an established fact which isn't incredibly probable or improbable. The ratio Pr(A) / Pr(B) is going to be very close to zero, which will cause Pr(A|B) to be a very small fraction of Pr(B|A). If Pr(B|A) isn't incredibly large to begin with, the fact that B is evidence for A is going to be practically insignificant.

Now let's turn our attention to a particular miracle—probably being the most influential—the resurrection of Jesus of Nazareth. I'll admit, there is interesting evidence for this miracle. It's enough, at least, to catch ones attention. But rationalize belief? I'm not so sure. The problem is precisely that extraordinary claims require extraordinary evidence; while the evidence of Jesus' resurrection seems fairly strong (if similarly strong evidence was presented for a more mundane claim, you would surely be convinced), it doesn't seem strong enough to overwhelm the initial implausibility of the claim.

Think about the sort of claim being made, that someone rose from the dead after three days of rot and decay. In all of our experience with death, people tend to stay dead. Even under ideal conditions where the body has been frozen and there is a team of doctors standing by, resurrection is still incredibly difficult. But in all of our experience with death, never have we observed someone coming back from the dead after three days (excluding this one case). In fact, over a hundred thousand people die every day, and we never see anyone raised as Jesus is said to have been. It then seems we must think that resurrection after three days is really really really improbable.

Apologists will agree to an extent, but say drawing conclusions about Jesus' resurrection isn't fair. This is, after all, supposed to be a miracle, which suggests it occurred by supernatural means. But even here still, one can assume God exists (and has the power to raise the dead), and still point out that it happens (if at all) at a frequency of near zero. Even under the assumption of classical theism, a resurrection of this sort seems incredibly improbable. Apologists will retort that Jesus was a special case; he was, after all, the son of God. But herein lies the problem. If one must assume the existence of a god that wants to raise Jesus in particular, but not anyone else, then they're practically assuming the Christian god. There isn't any other god we know of that would have special reason to bring back this one particular Palestinian, two thousand years ago.

And this is fine for them to assume, given that Christianity itself is a fair assumption. But what isn't permissible is them using the supposed fact that Jesus rose from the dead as evidence for Christianity as apologists typically do. They are committing a sort of question begging fallacy. They want to argue that Jesus' resurrection is evidence for the Christian god, when they must presuppose something very much like the Christian god exists to even establish that Jesus rose from the dead in the first place. But if that's the case, then the fact that Jesus rose from the dead offers nearly nothing in favour of Christianity. It can't raise the probability of Christianity significantly more than what is already granted.

All this is to say that there is still a wide chasm between establishing classical theism, and establishing Christian theism. And, it can only be crossed by showing that the god of classical theism would probably have motive to raise Jesus, in particular, from the dead. But this in of itself seems just as difficult to defend as anything else and, as such, it seems the prospect of defending Christian theism by use of an argument from miracles is bleak.