Creationists often accuse evolutionists of having a 'naturalistic bias' that supposedly rules out the possibility of the supernatural. More generally, atheists are also sometimes called to account for their so-called belief that nothing beyond the natural realm exists. The famed apologist Josh McDowell has expressed this notion in denouncing "[c]ritics who doggedly hold to a purely naturalistic worldview that excludes all possibility of miracles" [1]. Does evolution truly presuppose naturalism, though, and are atheists committed to denying the supernatural? This article will lay out the case for naturalism with three points of primary focus: the relationship of mind and brain, the existence of unnecessary suffering, and the persistent failure of supernatural explanations. But first of all, we need to define just what is meant by naturalism.

I. Belief and Method

In the anti-science crowds of creationism and religious fundamentalism, science is frequently criticized for excluding miraculous explanations by fiat. Yet there is no preconceived conclusion among scientists that only the natural world exists. In fact, there are noteworthy biologists like Kenneth Miller and geneticists like Francis Collins who believe in the supernatural and are still able to fulfill their duties as scientists. However, science does involve a kind of naturalism, but it is not what Josh McDowell and his ilk suppose, and this is where the confusion often enters.

Science is a discipline that operates on methodological naturalism, which is to be distinguished from metaphysical naturalism. Metaphysical naturalism is the belief that the natural world is all that exists - that the truths we encounter are truths of nature, not of another world beyond this one. Methodological naturalism, then, is the practice of studying the world with reference to natural causes and natural events. Because science seeks to understand and explain nature, it's only reasonable that it maintains a preference for a naturalistic method. If all non-natural theories were to be entertained with equal vigor when we know that natural explanations work, then the progress of science would diminish greatly.

Thus, the difference between these types of naturalism may be thought of as a difference of belief and method. The methodological naturalist can believe in a world beyond our own while recognizing his practice as one that is limited to our current world. Obviously, this does not rule out the possibility of the supernatural at all. Metaphysical naturalism, on the other hand, does reject the notion of a supernatural realm, and it is this kind of naturalism that will be argued for in this article.

II. Physical Minds Support Naturalism

Religious believers have claimed for centuries that the mind is separate from the brain. The part of us that does the thinking and houses our personality, typically referred to as the mind, is associated with concepts like the soul and the afterlife in many religions. According to this dualistic view, the brain is merely an organ that temporarily contains the mind. Some believe that 'out-of-body' and 'near-death' experiences are proof of the mind's separation from the brain. A mind that somehow sustains itself with no need of a brain would certainly be cause for further investigation, and perhaps raise suspicions about a non-physical realm of existence. However, there is more evidence that the mind is inextricably bound to the brain than there is for a separation.

Everything that has been attributed to the mind has a physical correlation with the brain. Neurologists can stimulate the brain in ways that evoke various experiences, even those of a religious nature [2]. Traumatic brain injury can produce drastic changes in personality, and can also impair language, memory, thought processing, and other functions some have assigned to the mind [3]. If brain injury is serious enough, mental capability may be lost altogether, resulting in a permanent vegetative state. These physical correlations are not just present in human beings, but in other animal species too. Animals with more complex brains (complex in the development of neurons) show signs of more complex behavior [4].

But what about the dualistic side of the debate? Do things like out-of-body experiences provide evidence that the mind is separate from the brain? As I discuss in my article on The Elusive Afterlife, a series of experiments in the 1970s seem to indicate otherwise. Out-of-body and near-death experiences appear to be triggered by traumatic events, likely due to the release of serotonin and endorphins when the brain loses blood or oxygen. These experiences can be explained as the body's way of calming us down and inducing a euphoric sensation to help us cope with significant injuries or 'equipment' failures. With the variety of different visions from such experiences, as well as the absence of any substantial verification, there is greater reason to think minds are physical rather than non-physical.

How does the mind's reliance on the brain support naturalism? If minds are made up of matter, then souls - typically understood as the mind within religion - do not survive death. God is also usually thought of as a disembodied mind by many theists, which would have to be the case if he exists outside of physical reality. Yet when minds are physical constructs, god's mind becomes a meaningless idea. If naturalism is correct, we can expect that minds are dependent upon the physical world, since the physical world is taken to be all that exists. But if theism is correct, it seems unlikely that minds would be physical phenomena, as such a state of affairs creates some very confusing and complicated problems theologically.

III. Unnecessary Suffering Supports Naturalism

Why do the righteous suffer while the wicked prosper? For over a thousand years, theistic thinkers have struggled with this question. Perhaps we suffer so that god may impart a moral lesson to us, as some have surmised. Though for what reason should we suppose that every suffering we endure is intended to teach us something? Scripture doesn't endorse such a view; sometimes we suffer because god wanted to brag to Satan, as the Book of Job tells us. And what about the degree to which certain people suffer? In 2007, a 35-year old mother and her 12-year old son were brutalized in terror that lasted three hours [5]. The mother was forced to perform oral sex on her child, she was raped and sodomized by up to ten teenage boys, and then the two were left on the floor after being doused with chemicals. What lesson was god trying to impart here? Could he perhaps - being all-powerful - have chosen a different way to teach an effective lesson, one that would not involve so much unspeakably horrible suffering?

Most theists believe their god is a moral god, whose goodness far surpasses the goodness of fallible human beings. But at the same time we are asked to believe that god has a purpose or plan behind tremendous suffering and terrible evils that any decent person would put a stop to if they could. If god is morally better than the average human, there is no excuse for his tolerance of unnecessary suffering. Free will did not stop god from interfering in the lives of people like Job, nor is it relevant to natural disasters and other causes of suffering that are well within god's control. The existence of unnecessary evil and suffering is a problem that theologians are still wrestling with today, and it certainly seems an unlikely thing if theism is true.

Once again, though, naturalism can account for this quite easily. We experience unnecessary suffering because life is a continuous struggle for survival, and there is no supernatural being who is purportedly all-powerful, all-knowing, and perfectly moral to regulate good and evil in our universe. This issue has been so pervasive in religious thought that countless believers have abandoned ancient notions of angry gods causing earthquakes and volcanic eruptions in favor of blind naturalistic processes. Not all suffering is necessary, nor is it divinely-caused, and this is much more in line with naturalism than with theistic conceptions of a personal, interventionist deity.

IV. The Failure of Supernatural Explanations Supports Naturalism

As I have pointed out in some of my previous work, the track record of naturalistic explanations is staggering. Supernatural theories have been supplanted numerous times, yet no naturalistic proposal has been overturned in favor of supernatural claims. Would this be something we would expect if theism is true? Hardly! The creationist idea of irreducible complexity would be a clever way of recognizing god's handiwork, but there is, so far as we've discovered, nothing in our universe that can serve as a real example. Everything in nature appears to have arranged itself from pre-existing materials. With the Big Bang now commonly realized as the origin of time, it becomes paradoxical to talk of a "cause" before time, or causality, existed.

Through history, god has lost dozens of jobs, from manufacturing lightning and making it rain to sustaining the planets and creating human life. Although the inability to comprehend the cause of something does not mean the supernatural is involved, it leaves at least a little room for that possibility, whereas the dominance of naturalistic explanations has forced out the possibility of supernatural ones for many phenomena. The theist may still contend that god is the man behind the curtain, quietly controlling it all, but this curtain has been reduced to a washcloth by the advancement of naturalistic science. The persistent failure of supernatural explanations to withstand critical inquiry makes superfluous the prospect of a supernatural god directing the natural functions of the universe.

Some might object that these explanations have failed because humans have put them forward. We are known to make mistakes, they may argue, but these mistakes are merely a reflection of our fallible nature, and they don't cast doubt on the supernatural itself. Unfortunately, until it is demonstrated otherwise, explanations given by humans are all we have to go by. Being a firm believer in truth that stands on its own weight, I find it preposterous to think that no supernatural explanations should be valid if the supernatural exists. If the supernatural realm has never once crossed into our realm or intervened in any way, perhaps this might be plausible, but such a view is already flimsy speculation to begin with. Certainly a god who wants to make itself, or its message, known would do its best to provide persuasive evidence of the supernatural.

Rational beliefs are those accepted on good evidence and strong reason. When we believe in spite of evidence and reason, that belief is irrational. In many cases, a tendency toward rational skepticism is the default position. We will not believe in an alien invasion unless we feel that we've found supporting facts, as well as a convincing explanation of those facts. Religious believers latch onto their own facts and explanations, leading them to feel that the supernatural is accounted for. Obviously, I disagree with their conclusion, because the best explanation will account for the most facts, and as we've seen in the two previous examples, supernatural explanations leave much to be desired, both internal and external to religion.

And what about naturalism? Are there facts for which naturalistic explanations don't suffice? Indeed, but this goes back to the point I've been making, that the track record of successful naturalistic explanations far exceeds that of supernatural explanations. Naturalism may not currently explain everything, but it is at present the best explanation of the most facts.

V. Naturalism Prevails

These are only a small sampling of the arguments that could be made in the case for naturalism, but they serve as a better foundation than anything put forward by theism. At the heart of naturalism is a very non-controversial idea: the natural world exists. Only stubborn solipsists will object to this simple truth. Since the majority of theists concede the reality of the natural world, the burden of proof is with them to establish the existence of another realm beyond our own, a supernatural world. The same is true of astrophysicists who propose multiple universes and similar theories. Until good arguments are made or persuasive evidence is introduced, suggestions of worlds beyond our own are simply speculative, and speculation does not hold a candle to an explanation supported by empirical evidence and consistent reason.

1. McDowell, J. (2009) Evidence for the Resurrection. p. 125. Gospel Light: California.
2. Hitt, J. (1999) This Is Your Brain on God. Wired. Retrieved Aug. 11, 2011.
3. (2010) What are the Potential Long-term Outcomes of TBI? Centers for Disease Control. Retrieved Aug. 11, 2011.
4. Banguet, L. & Marlowe Hood. (2011) Chimps Are Self-Aware. Discovery News. Retrieved Aug. 11, 2011.
5. (2007) Florida mother and son are attacked. USA Today. Retrieved Aug. 11, 2011.