As I argue in Sense and Goodness without God (pp. 29-35), philosophy is wasting its time if its definitions of words do not track what people really mean when they use them. And when we look at the real world, we find the supernatural is universally meant and understood to mean something metaphysically different from the natural. I could adduce many examples of the bad fit between real language and this ill-advised attempt at an "official" definition, but here are just two:
- The underlying mechanics of quantum phenomena might be physically beyond all observation and therefore untestable, but no one would then conclude that quantum mechanics is supernatural. Just because I can't look inside a box does not make its contents supernatural.
- Conversely, if I suddenly acquired the Force of the Jedi and could predict the future, control minds, move objects and defy the laws of physics, all merely by an act of will, ordinary people everywhere would call this a supernatural power, yet it would be entirely testable. Scientists could record and measure the nature and extent of my powers and confirm them well within the requirements of peer review.
I define "nature" in Sense and Goodness without God (on pp. 211-12, with a little help from pp. 67-69). But I explain this in elaborate detail, with considerable supporting evidence, in my Secular Web article Defending Naturalism as a Worldview (2003), to which I referred readers in my book. After this, and the publication of Sense and Goodness, I defined the natural-supernatural distinction even more rigorously in the joint statement of the Carrier-Wanchick Debate (2006). Anyone who wishes to interact with my definitions of natural and supernatural must read these two articles.
In short, I argue "naturalism" means, in the simplest terms, that every mental thing is entirely caused by fundamentally nonmental things, and is entirely dependent on nonmental things for its existence. Therefore, "supernaturalism" means that at least some mental things cannot be reduced to nonmental things. As I summarized in the Carrier-Wanchick debate (and please pardon the dry, technical wording):
If [naturalism] is true, then all minds, and all the contents and powers and effects of minds, are entirely caused by natural [i.e. fundamentally nonmental] phenomena. But if naturalism is false, then some minds, or some of the contents or powers or effects of minds, are causally independent of nature. In other words, such things would then be partly or wholly caused by themselves, or exist or operate directly or fundamentally on their own.Despite all I have written on this, several people have had difficulties understanding how to apply my construction of these terms, so I thought I'd have some extended fun. Analogies and concrete examples always do a better job getting across to people what we're talking about, so that's what I'm going to do today. With a bit of fantasy, I'll show how my natural-supernatural distinction can be used to tell the difference between a natural and a supernatural explanation (a metaphysical question), and how we can know when one or the other actually is true (an epistemological question). I take a look at supernatural beings, substances, powers, properties, and effects, and we'll get to see what natural explanations of similar observations would look like, and how they would be different.
Before we can get to that, we need to get past one other important distinction: the meaning of paranormal.
Defining the Paranormal
I don't know if there has been any consistency in common practice, but I have always maintained a distinction between the paranormal and the supernatural. In my parlance, a paranormal phenomenon or explanation can be either natural or supernatural. What makes something paranormal is the fact that it exists outside the domain of currently plausible science. As such, it could just be a natural phenomenon we don't yet understand or haven't yet seen. But it could also be something supernatural. Or an entirely bogus claim. We won't know until we have enough evidence to make a determination. But either way, the category of "paranormal" can be applied to phenomena (hence the mere claim that something happens or exists can be paranormal) as well as explanations of that phenomena, i.e. paranormal hypotheses.
Typical example: alien abductions. There is no scientific evidence this happens, nor any scientific evidence that it's even plausible to suppose it happens. There is even, now, scientific and historical evidence that the phenomena offered as evidence of alien abductions are actually nothing of the kind. Back in the middle ages it was faerie and demon abductions. The monsters abducting us curiously change appearance, equipment, and tactics with the times. But even if we didn't have evidence confirming, for example, hypnagogic and hypnopompic hallucination, the claim that aliens abduct people remains outside the realm of scientific plausibility.
That alone doesn't mean it's scientifically impossible or inexplicable or even false. It's just paranormal. If we gathered enough scientific evidence to confirm it was true that aliens really were snatching people, then it would cease to be paranormal. It would then enter the realm of normal scientific fact. Moreover, the fact that extraterrestrials were abducting people, using ordinary, though highly advanced technologies, would not be supernatural. It would be an entirely natural phenomenon, as natural as the CIA abducting people off the street and whisking them off in helicopters to secret medical labs in Detroit (ooooh, scary!).
On the other hand, some Christians have proposed that these abductions really do happen, but the abductors are not really aliens but demons from Hell flying magic Satanic saucers, working their evil mischief on earth by snagging and buggering the locals (see Close Encounters: A Better Explanation). This would be a supernatural explanation of the same phenomena. Thus, a paranormal explanation can amount to a natural or a supernatural claim, depending on what kind of metaphysical entities are evoked. That something is paranormal is a separate distinction from whether it is natural or supernatural.
Another example: David Hume listed "fire burning under water" among the things he regarded as impossible and therefore unbelievable, owing to vast human testimony to the contrary. If someone told Hume, "Hey, I saw some wizards in Spain carrying torches to light their way in underwater caverns!" Hume would say, "Poppycock!" For this would be, for him, a paranormal claim, beyond the bounds of what was then scientifically plausible.
But Hume wasn't entirely dogmatic about this. Hume himself used the example of water turning into a white powder when cold: someone from a region where temperatures were always high would rightly regard "snow" to be a paranormal phenomenon. Until, that is, they were presented with adequate evidence to warrant believing it really does happen: water really does turn to white powder when sufficiently cold (at least, if you whisk a lot of air into it as it freezes, otherwise it turns into a glassy rock, which would sound even weirder to someone who'd never seen this). Hence Hume granted that, with sufficient evidence, the once-paranormal can become a normal fact: a desert native can come to a reasonable belief in snow and ice.
The same would then follow for the Spanish wizards. It turns out fire does burn under water. You just need the right chemicals or equipment. Napalm burns under water because it chemically contains its own oxygen. Magnesium flares burn under water by actually breaking the molecular bonds of water and consuming the oxygen released. The Olympic Torch was carried under water by using a welding apparatus that supplied fuel and oxygen under high pressures. And, of course, there are always flashlights, arc welders, glowsticks, volcanic magmas, and so on.
Regardless of what Hume may have written, if Hume saw these wizards himself, or heard reports from several eye-witnesses whom he trusted, whose trustworthiness in every relevant respect was abundantly supported by evidence available to Hume, then the phenomenon of underwater fire would no longer be paranormal. But any proposed explanation would still be paranormal, if it wasn't based on plausible science.
"Some unknown chemical reaction is occurring" would not be a paranormal hypothesis, because even in Hume's day there was a good grounding in established science to make that kind of hypothesis plausible. But "the wizards impregnate the wood with the element of fire" would be a paranormal hypothesis even in Hume's day, because there is and was no properly scientific basis for such a claim. However, if it turned out to be true, and fire really was an irreducible element that could be absorbed into a stick, that would be a paranormal but still natural explanation, until scientifically proved, or grounded in supported science, the way "chemical reaction" explanations now are. Then even this bizarre claim would become natural and normal. On the other hand, "the wizards cast a spell on the sticks" would be a hypothesis both paranormal and supernatural, and if this theory were scientifically proved, though it would cease to be paranormal, it would remain supernatural.
The same thing could be said about ESP or crystal healing or Big Foot and so on. These are definitely paranormal claims, at least at present (there is no scientific reason to consider them plausible). But each could still be explained either naturally or supernaturally. For example, ESP could be a natural phenomenon of human brains producing and transceiving radio waves, or it could be a supernatural power that doesn't involve any such mechanism. Crystal healing could be the operation of unknown physics or chemistry, or it could be a supernatural power. Big Foot could just be a rare but perfectly natural species of hominid, or the supernatural victim of an evil sorcerer's spell. Confirming the existence of any of these phenomena would remove it from the category of the paranormal ("ESP exists," "crystal healing works," "there is a Big Foot"), but how one still chose to explain it would still be paranormal if you appealed to concepts that are currently groundless or scientifically implausible. But even a supernatural explanation would cease to be paranormal if it was scientifically confirmed.
So the question is: What really is the underlying difference between a natural and a supernatural explanation? What follows now presupposes all I've said above.
Let's start with supernatural beings. You know, like God. Or gods. Or demons, angels, faeries, or ghosts. Or invisible pink unicorns or flying spaghetti monsters. You get the picture. These are all supernatural if they have any mental property or power that is not reducible to a nonmental mechanism. If, however, all of their powers and properties can be reduced to nonmental mechanisms, then they are not supernatural beings after all, but natural ones.
In the most obvious case, the God of traditional theism is a pure mind, composed of nothing else but mental powers and concepts. That is indisputably supernatural. So is the ability to cause things to happen in the universe merely by willing them to happen, since that means there is no nonmental mechanism (like arms and nervous systems or graviton rays) mediating between the act of will and its realization. Such direct mental causation is certainly supernatural. And so on. Of course, just because you see God does not entail the God you are seeing is disembodied, or omniscient, or omnipresent, or omnipotent, or anything else supernatural. You would need additional evidence to confirm each of those attributes. Hence it's possible to find evidence that the God you just saw is not supernatural after all, but some sort of natural being.
The Stoic and Epicurean Gods
How would a natural God be different from a supernatural God? Well, he would have a body of some kind, and all his thoughts would be the product of a machine of some sort, like a brain, and he would only be able to realize his will by initiating a chain of causes-and-effects that is entirely reducible to nonmental events. A hypothetical analogy would be the God proposed by various Stoic theologians of the Roman era. The Stoics were not always clear or in agreement on every detail, but I shall describe here the most naturalistic conception imaginable on Stoic principles.
For convenience I'll call this naturalistic Stoic God "Theostoa." Theostoa is composed of a superfine material called pneuma, which is indestructible, invisible, and indivisible but elastic, which permeates the entire universe, like gravity or dark matter. So this God is the same size as the universe and located in every part of it, and thus "naturally" omnipresent, and because of his material composition he is "naturally" invincible and immortal. His pneumatic body interacts physically with all other matter and space, like a gigantic machine, and thereby produces all physical laws and effects, and this conversely operates as God's sensory apparatus. Since he is in contact with every piece of the universe, he is "naturally" omniscient and "naturally" omnipotent (obviously both in a certain qualified sense). This pneuma also physically stores and generates the thoughts and memories and ideas of God, and thus serves as his brain.
If Theostoa's entire mind (every thought, every memory, etc.) is entirely reducible to a system of nonmental pneumatic particles interacting together, and Theostoa's ability to perceive and affect the universe is entirely reducible to a system of nonmental interactions between these pnuematic particles and everything else, then Theostoa is not a supernatural God. But if any part of Theostoa's mind or activity is irreducibly mental, then despite everything else, he is still supernatural. I would then call him Supertheostoa.
But though entirely natural, the existence of Theostoa would still not be compatible with naturalism unless Theostoa's origin was also completely reducible to natural causes. If Theostoa evolved through some nonmental cosmological process, entirely without intelligent design or any mental causation at all, or was intelligently engineered by entirely natural beings, then Theostoa would be compatible with naturalism. In fact, we can vaguely imagine the possibility of mankind technologically creating a deity somewhat like this at some point in our distant future. On the other hand, if Theostoa had no origin but existed eternally, fully-formed, the issue would no longer be his temporal origin, but his ontological foundation, i.e. why he exists. This could have a natural or a supernatural answer, depending on whether this foundation were fully explicable without appealing to anything irreducibly mental about the nature of existence.
Therefore, only an evolved or accidental or naturally inevitable Theostoa would be compatible with naturalism, and this is the only sense in which naturalism could ever include something near to a traditional God. Of course, no one on earth believes in a God like this, and for good reason: there is no evidence of it, and it's highly implausible. So we have no reason to believe it. But if he did exist, we could (in principle) demonstrate his existence scientifically in the same way we can demonstrate the existence of any other embodied person: we could develop instruments capable of detecting, documenting, and measuring the existence and properties of his pneuma, and then use these instruments to communicate with his mind, learning things about him in the exact same way we learn things about people, through sciences like psychology and biodynamics.
The rival philosophy of Epicureanism offers another example. In Epicurean theology, there were many gods, but all were naturally evolved aliens of naturally superior substance and abilities, who resided far away from earth without any concern for us. We only know they exist because very fine atoms coursing through the universe bounce off their bodies, fly through space in the same pattern that they struck, and collide with our brains, causing us to "see" them in our dreams and sometimes in waking visions. Like Theostoa, these gods have no supernatural cause, no supernatural powers, and no supernatural properties. Their origin is a series of unguided, unintelligent, mechanical collisions of atoms. Their composition is a mindless substance, just atoms in space. Even their ability to appear to us in dreams and visions is entirely explained by the causal interactions of a mindless mechanism, just atoms bouncing around.
Obviously, these gods are not supernatural. They are just very odd, very lucky extraterrestrials. But notice how they are very different from what most people mean by "gods," so much so that most people today would not even call them gods. Nor would any Christian acknowledge Theostoa as a proper God. Hence there is a clear difference here between a "natural" god and a properly supernatural god. That difference is meaningful, metaphysical, and substantial.
Demons, Angels, Faeries, and Ghosts, Oh My!
The same things could be said of demons and angels and faeries, for example. They could be just like Epicurean gods, maybe even living in alternate spatial dimensions and using natural physics to travel to and from (thus "Heaven," "Hell," and "Faerie" in naturalistic terms), in which case they would be entirely natural beings. Or they could have some irreducibly mental property or power (like the ability to transport from one dimension to another by a mere act of will), which would make them supernatural. And even if they were entirely natural, if they had a supernatural origin (e.g. "God willed them into existence" rather than "they evolved by mindless processes"), then naturalism would still be false.
Note again how this differs from the epistemological question. If you dink around with a freaky puzzle box and Pinhead steps out of your wall and you beat the shit out of him and haul ass out of there, you probably won't have any reason to doubt you just beat the shit out of a demon. The characters in Hellraiser had plenty of evidence they were involved with demons. But were these just twisted, interdimensional aliens, or real supernatural demons? That's another question altogether. But regardless of whether you can know the difference, there is still a difference.
Likewise, if ghosts exist, they could be explained supernaturally, or by some Epicureanesque physics. Since ghosts are usually regarded as human souls divested of their mortal bodies, if these ghosts did exist and were supernaturally created or composed, then this would mean even humans are supernatural beings. Our flesh-and-blood bodies would not be supernatural, but our souls would be. Which brings us to our next category...
A supernatural substance is any substance (or any comparably definable point or volume of space) imbued with mental properties or powers. For example, is our "mind" the product of a brain or a soul? If the mind is entirely caused by a mindless mechanism like the brain, which is just a system of mindless cells causally interacting with each other, then our mind is just a brain, which is a natural substance, since no part of it is irreducibly mental. It only produces mental properties as a causal consequence of a system of interacting nonmental parts. But if our mind could depart our brain, and survive and think without any material to sustain it, then just like a disembodied God, our mind would be supernatural, since it would then be irreducibly mental.
But even if our soul was a substance, it could still be a supernatural substance. Most Christians, Jews, and pagans in antiquity understood the human soul as a body composed of pneuma, an ultra-fine, indestructible substance, which inhabits our body of flesh until we die, and then leaves, and physically flies up to heaven, or descends into hell, or rests inside the corpse until the resurrection, or hovers around the graveyard, or whatever. In some accounts, this soul-body departs the corpse-body and takes on a shape more like a ball of light, though still bearing a vague stamp of a person's physical features, but all invisible to ordinary people. In our terms, we could say soul-bodies radiate and reflect light only in frequencies, or only of a sort, that normal human eyes can't detect.
Suppose this were true, and we found a way to detect these soul-bodies with instruments and track them as they left the corpse, even ascertaining their physical properties, like their mass and volume and elasticity and so on. If these soul-bodies retained mental function through some naturalistic mechanism, so that all mental powers and properties were still completely reducible to the mindless interaction of particles (like another brain made of soul-stuff, comprising, let’s say, a system of mutually interacting particles of dark matter), then as strange as this soul-body would be, it would be a natural body. It might yet have a supernatural origin, but that's a separate question. The body itself, the substance, would not be supernatural.
However, if this soul-body turned out to have no relevant sub-structure, if in fact it simply carried a person's "mind" with all its functions and powers and properties, all as an irreducible "property" of that soul-body, and not as the product of any system of interacting parts within it, then this soul-body would be a supernatural substance. What distinguishes this supernatural soul-body from a natural soul-body is the same thing that distinguishes mind-brain physicalism from traditional notions of a soul: just as mind-brain physicalism entails that all mental powers and properties are fully caused by a functioning collection of neurons called a brain, so a natural soul-body entails that all mental powers and properties are fully caused by an analogously-organized soul-brain made of ethereal substances that can float free of the flesh-and-blood brain. But in a supernatural soul, there are no interacting parts that fully explain how the soul produces mental powers and properties. It simply possesses them, as innate properties of the substance. That makes it supernatural.
We can imagine other supernatural substances. A typical example would be a magic love potion. A drink that causes someone to fall in love could be a natural substance, if the potion contained chemicals that got into the blood, and from there into the brain, and were of just the right construction as to have all the right causal effects in all the right places there. In other words, it could, for example, be an incredibly advanced nanorobotic saline solution designed by clever futuristic brain scientists.
But if the love potion contained no such chemicals, but was simply imbued with the property of "causing love" and had this effect directly, by possessing no other structure or properties except that innate power, then the potion would be a supernatural substance. This is because the idea of love is a mental property, which in this case would not be reducible to any nonmental system. That a potion would just "know" it was in a human body and "know" where their brain was and "know" precisely how to affect and reorganize that brain so as to cause the person to fall in love (much less with a specific person), is all impossible without a causal mechanism. So if the causal mechanism in the potion consists solely of the mental property of just "knowing" all these things and then directly causing them on contact, with no underlying or intervening mechanism, we're talking about a supernatural potion.
Surely you can see by now that metaphysically there is a huge difference between a natural substance (whether a soul or a love potion) and a supernatural one. That difference derives from whether an irreducible mental property or power is possessed by that substance, or whether, instead, everything that substance does (mental or not) is entirely the product of nonmental mechanisms operating in a causal system. This still leaves open the epistemological question of how we could tell the difference between a natural soul and a supernatural one, or between a natural love potion and a supernatural one. But already you may be starting to see how that might be done.
Supernatural Powers or Properties
Supernatural beings and substances are basically just beings and substances with supernatural powers or properties. However, we could make a further distinction between an ordinary substance that is imbued with a supernatural property, and a substance that always has a supernatural property by its very nature. The latter would be a proper case of a supernatural substance, while the former would be a substance that can have a supernatural property added to it and taken away. For example, temporarily imbuing someone with the supernatural power of flight or giving a broom the supernatural power to chase down Jehovah’s Witnesses and thwack them on the head until sunset.
A popular example is the Ark of the Covenant. There is nothing inherently supernatural about its construction or composition. It's made of ordinary wood and gold, in an ordinary way. But it was then imbued by the will of God with supernatural powers: it inflicts boils and mice upon anyone who steals it, instantly kills anyone who touches it, dries up or burns away any obstacles to those who carry it, gives advice to those who consult it, and various other things, generally nasty.
For all these powers to be natural, they would have to be fully caused by some mechanism. Some machine, some interacting system of nonmental parts, would have to be able to detect and calculate when it's touching a person or facing an obstacle or in the hands of a thief or being asked a question, and then activate its powers appropriately. Then some other mechanism would have to be able to cause mice to reproduce or boils to appear on human skin or rivers to dry up or brambles to burn away or snakes to die, and so on. But no such machine would be needed if these powers were supernatural.
We can certainly imagine a super-advanced technology that could accomplish all this in a compact portable form that would look deceptively like an ordinary Ark, but it would still have all that internal structure (computers, sensory systems, particle emitters, etc.), which would in principle be detectable. Likewise if all these powers were effected from, say, a spaceship in orbit, and only made to appear as though they were coming from the Ark, even then, all the same technology would exist and could in principle be found, as happened, for instance, when the crew of Picard's Enterprise discovered how Ardra was pretending to be Satan with supernatural powers. If she needed no spaceship and thus no mechanism or technology to work her miracles, then her powers would have been supernatural. Thus Clarke's Third Law ("any sufficiently advanced technology is indistinguishable from magic") is only, at best, an epistemological principle, not a metaphysical one. Metaphysically, magic and technology are very definitely always distinguishable.
Thus if the Ark of the Covenant had no internal structure at all, just ordinary wood and gold arranged as the bible describes, yet could do all these things on its own, actually knowing when and how, then these would be supernatural powers. For then there would be something fundamentally and irreducibly mental about its ability to know when to perform certain miracles (like knowing when it was stolen and who the thieves were), and to know what miracles to perform, and where. So, too, for its ability to cause intelligent effects without any underlying mechanism. Like a love potion, for the Ark to "cause death" to anyone who touches it, the Ark would have to be imbued with the idea of death, and the idea of a person and of touching and of causing and so on. If these concepts are not realized by an underlying mechanism in which no single part knows anything about death or persons and so on, then these concepts can only be realized supernaturally. In other words, they would have to be irreducibly innate to the object.
Another way to convey this distinction is to contrast the underlying metaphysics implied in Forbidden Planet and Harry Potter. In Harry Potter's world, a wizard speaks a word and something happens. A single word causes a wand to generate light, another word causes objects to move wherever the wand points, and so on. Suppose this really happened. There is no doubt we could document the hell out of it scientifically and thus confirm beyond any reasonable doubt that the effect exists. That’s why in Harry Potter's world entire agencies are vexed with the task of trying to prevent this evidence from getting to the public (like, say, photographs of flying cars over London). So we can scientifically test for its existence. But would the phenomenon be natural or supernatural? That depends on what really is happening.
In the film Forbidden Planet (and similarly in other books and movies since) whatever a man dreamed, happened. Of course, this meant his nightmares caused monsters to appear and ravage and kill. It was subsequently discovered that the entire planet had been hollowed out by an ultra-advanced alien civilization and filled with a gigantic machine that used futuristic technologies to scan his mind and then mechanically generate (with particle beams and so forth) what his mind was thinking. The effects were therefore entirely natural. But in the Harry Potter world, there is no gigantic machine inside the earth scanning the air for spoken words and sending out particle beams to construct what is requested. There is no comparable or analogous mechanism behind what happens at all. The universe itself simply responds to spoken words.
In a similar fashion, in the novel Jonathan Strange & Mr. Norrell, the rocks and trees and winds respond to verbal commands, despite having no brains or ears or nervous systems, or anything structurally analogous to these. Therefore, magic in the Harry Potter and Jonathan Strange universes is genuinely supernatural. It relies on irreducibly mental powers and properties of the universe. Words directly cause what they request, without any mindless mechanism connecting the spoken word to the realized effect. Such a universe would have to be fundamentally supernatural, because it would be fundamentally mental to some extent.
Similarly, the Force in the Star Wars universe would be supernatural, unless it was entirely caused by nonmental mechanisms of some kind (whether natural or technological), which mediate between what one willed and its effect. Likewise, an innate force of love in the universe would be supernatural, if it actually had causal effects and was not solely the product of a nonmental mechanism like a brain. For example, if the mere act of loving someone directly healed their wounds or illnesses, or the amount of love in a community caused crops to grow, or the power of love in the cosmos caused cruel animals to go sterile and kind animals fertile, so evolution proceeded according to survival of the kindest instead of merely the strongest. And so on. You get the picture.
Last but not least are supernatural effects. Anything that is the effect of a supernatural cause is a supernatural effect, even if the effect itself is not supernatural. Thus, in the Belgariad when Garion created a new species of flower by simply willing it into existence, the flower itself was entirely natural, but its existence was a supernatural effect. Indeed, given everything Garion observed in the Belgariad saga, he would have no reasonable doubt that naturalism was false and that the universe contained supernatural powers. Even his wife Ce'Nedra could talk to trees and make them move. If these trees had no brains or muscles or nervous systems, or anything causally analogous, then trees in Garion's world must also have supernatural powers. So when these trees supernaturally bend their limbs, though a bent tree limb in and of itself is not supernatural, this particular bending would be a supernatural effect. The same distinction can be made between the effects of Harry Potter magic and the phenomena of the Forbidden Planet.
I shall end my examples with the mother of all purportedly supernatural effects: the claim that Jesus was raised from the dead. Contrary to what some have inferred, I have never said naturalism, if true, entails that Jesus did not rise from the dead. Aliens, for example, using advanced but perfectly natural technology could have done it, like Gort in The Day the Earth Stood Still. Heck, we could do it now, with a defib kit and modern drugs (and I've said this before: see The Event is Not Proportionate to the Theory, part of my old Secular Web article Why I Don't Buy the Resurrection Story).
If you accept the probable truth of naturalism, this only leads to ruling out supernatural causes of resurrections, not resurrections themselves. Hence in The Empty Tomb I argued that the inference to naturalism only supports arguments against a supernatural resurrection (p. 370, referenced on pp. 196-97, 364). Moreover, not only are natural resurrections possible (thus an inference to naturalism is not alone sufficient to warrant disbelieving in the resurrection of Jesus), it is also possible to have enough evidence of a supernatural resurrection to actually refute naturalism. I have never claimed otherwise.
So, applying to this all I've surveyed above, it follows that if "God" were actually an organism like Theostoa, entirely produced by the interaction of mindless building blocks much like we are, and if he needed chemicals or machines of any sort to raise Jesus from the dead, then he is not a god in any traditionally accepted sense, and certainly not any kind of supernatural being. Moreover, even if this being retained some supernatural properties (if he was a faerie, say, or a wizard), but still needed natural mechanisms to raise Jesus, then the resurrection would still not be supernatural even if it occurred. Therefore, when I say naturalism rules out supernatural explanations of what happened in Jerusalem two thousand years ago, I am obviously not including mechanical pseudo-gods. Such entities would fall closer to the "aliens did it" category of explanations, which naturalism does not address, nor does it need to. Good old fashioned inductive logic already does away with them.
Ultimately, since The Empty Tomb was not written to address such fringe hypotheses (after all, Christian apologists are not claiming aliens or a mechanical God raised Jesus), it would be rather silly to expect a chapter or even a paragraph in The Empty Tomb debunking such theories. This would be as silly, in fact, as devoting even so much as a sentence to debunking the theory that Simon Magus supernaturally raised Jesus by casting a spell. Obviously, when "resurrection" is the theory we are responding to, everyone knows we're not talking about aliens, mecha-gods, or spellcasting, but an immaterial God directly willing a man back to life. And that is most definitely a supernatural claim.
Is the Supernatural Knowable?
Clearly there is a metaphysical difference between the natural and the supernatural, and it tracks the reducibility of phenomena to the nonmental. This must not be mistaken as requiring any particular form of physicalism or reductionism. Naturalism does entail causal physicalism and reductionism, but only in the very broadest sense of these terms (see what I say about this in Sense and Goodness without God, pp. 130-34, with pp. 143-44 & 224-25). But whatever the essential metaphysics of naturalism and supernaturalism may be, the epistemological question remains: even supposing the supernatural is possible, as something metaphysically distinct from the natural, does this distinction entail that the supernatural is untestable and therefore unknowable?
I don't see how. There is nothing inherent in either my definition of the supernatural or in the definition of scientific method (see Sense and Goodness, pp. 214-26) that leads to any such entailment. And all of the examples I have given are clearly capable of scientific test and empirical demonstration. The claim that supernatural hypotheses can never be verified or falsified, are untestable, and therefore unknowable, is therefore not tenable. With sufficient evidence I am certain any reasonable scientist would be persuaded to believe any of the supernatural scenarios I have described above. In fact, with sufficient standards and documentation I am certain I could get them into any peer reviewed scientific journal.
Hence I reject radical methodological naturalism, which holds that science can only investigate natural phenomena. Nonsense. Science would have no special problem investigating the supernatural. If there were any. But I do embrace pragmatic methodological naturalism, which holds that supernatural phenomena have been shown to be so scarce (in fact, as far as we can tell, non-existent), and therefore so improbable, that it is a waste of time and money to investigate supernatural hypotheses, or any uncorroborated paranormal claims. Science should only investigate the paranormal when there is sufficient reason to believe there is really something that needs explaining, and even then should only bother testing natural explanations first. This is a pragmatic position, not an epistemological one. If someone wants to spend his own time and money testing supernatural hypotheses and claims, then all the power to him. If they exist, he should be able to find them, and confirm them scientifically. Good luck.
The objection I usually hear is that though science could prove, for example, the existence and efficacy of Harry Potter magic, and even analyze in scientific detail its properties and limitations, science can never really establish that there wasn't some natural explanation underlying it all. For instance, there could be a gigantic machine inside the earth making it all happen with particle beams, and we just haven't found it yet, nor detected any of its scanning or constructing beams or anything else. But I can say exactly the same in reverse: no matter how much evidence we get that aerodynamics causes airplanes to fly, there could still be supernatural sky faeries keeping planes in the air and we’ve just not detected this yet.
Hence this "could be" argument is an unreasonable demand that no scientist would accept in any other context. Obviously we can always not know something that would change our conclusions. Science actually embraces this fact, and gets past it, by concluding that we can arrive at confident conclusions anyway, so long as we remain open to new evidence that could prove us wrong. Scientists rightly accept that there comes a point when it is unreasonable to hold out for alternative hypotheses, until new evidence arrives.
In the case of Harry Potter's magic, for example, it would be absurdly unreasonable to claim there is an undiscovered machine behind it all. Yes, there could be. But we would have no reason to believe there was. When we've conducted a detailed investigation and all we have left that actually carries substantial predictive success is a supernatural hypothesis, then science has established the latter as well as it could any other theory. Science can therefore prove the supernatural. It just needs damned good evidence. And yet like all science, even this conclusion would be revisable, if we discovered new evidence of a natural cause after all. But it would be irrational to hold out for that evidence. This would be as irrational as holding out for evidence of sky faeries rather than accepting the conclusions of aerodynamics.
By analogy, it is always possible that there is a gigantic machine inside the earth that is changing the course of photons approaching the earth, fooling us into thinking the earth revolves around the sun. In this way the heliocentric theory could actually be false. But no scientist would claim we have not proven heliocentrism merely because of possibilities like this. Yet if a scientist will not tolerate such objections to heliocentrism, he cannot tolerate methodologically identical objections to any supernatural hypothesis that is as well established as heliocentrism. Therefore, this is not a valid objection to allowing supernatural hypotheses into science.
If the supernatural existed, we should be able to accumulate evidence in support of it just as we have accumulated evidence of heliocentrism. Indeed, if the universe were as blatantly and pervasively supernatural as we have found it, instead, to be natural, then naturalism would be as untenable as supernaturalism is now. Supernaturalism would then be the default worldview. But even if the evidence was not that overwhelming, just as for heliocentrism, at some point the evidence could accumulate so high that you will have to admit a supernatural explanation is the best explanation there is. In fact, eventually the evidence could stack so high you will concede it's the best explanation by far. It's not reasonable to say "possibly, therefore probably" something else is going on. This is as irrational for a creationist to maintain against evidence for evolution as for a naturalist to maintain against the same quality of evidence for supernatural creation. If there were such evidence. It just so happens there isn't. But no one should confuse an actual lack of evidence for the theoretical impossibility of having it.
Thus, for example, if Biblical Creationism were true, by now we should have accumulated tons of scientific evidence that the entire universe is less than six light days across and the earth is at the center of it, all fossils and rocks radiologically and stratigraphically date no older than six thousand years, the fossil and DNA records confirm that all species appeared simultaneously six thousand years ago and have not substantially changed since, and much more. For further examples of how the evidence should have turned out if creationism were true, see The Original Christian Cosmos, the last part of my Secular Web article Why I Am Not a Christian (2006). But alas, the data didn't come out that way. But if it had, supernaturalism would have been as scientifically established as naturalism is now.
Many naturalists have a poor conception of how to define naturalism or the supernatural. They might know it when they see it, but when they try to capture in words what exactly it is they are talking about, they often come up with a badly worded travesty. I've done what little I can to remedy this by developing and testing a precise definition of naturalism and the supernatural, providing a sensible and usable natural-supernatural distinction, which also happens to align adequately well with how people use these words in practice (as I believe our terminology ought to do as much as possible). And now I have amplified my past work on this by surveying numerous hypothetical examples of how my proposed distinctions can be applied.
In defining the words "natural" and "supernatural" as I do, I differ from the legal and science community, as exemplified most recently in the Kitzmiller v. Dover case. There, Judge Jones was bound by legal principles to follow case precedent and the professional standards of established industries. Following the 1982 McLean decision he found the courts had defined "supernatural intervention" as intervention that "cannot be explained by natural causes, or be proven through empirical investigation, and is therefore neither testable nor falsifiable." Jones further cited the official statement of the National Academy of Sciences, which declares "claims of supernatural intervention...are not science because they are not testable by the methods of science." Thus we see the same trend in both the legal and scientific communities, to veer away from metaphysical distinctions and in favor of purely epistemological ones, but as my articles, and now examples, have shown, this does not track the real-world use of the word at all, which can tend to no good.
I think the legal and scientific communities are on a bad track with this (hence the barely coherent discussion of the supernatural in Wikipedia), especially since the same point can be made without abusing the word "supernatural." It is enough to say, for example, that creationism isn't science, not because it is supernatural, but simply because it is untestable (assuming you can prove it is). There is no need to conflate the two.
Though I understand their reasons for wanting to keep metaphysics out of it (since both enterprises are more fundamentally epistemological), I disagree with their attempted solution of coopting and changing the meaning of a popular word. That's the wrong way to go about it. Hence I believe a paradigm shift is needed in those communities regarding how the word "supernatural" is defined and applied. Both law and science must get back in line with ordinary English and real-world language, ideas, and concerns.
My discussion of this issue has been continued on this blog and in print. See Defining Naturalism and Defining Naturalism II.