Normally, I wouldn't care a whit about this, but the people bent on talking about it, mostly religious apologists and their followers, insist on wasting the time of the rest of us with this unendable debate. I present this unnecessary and useless defense of naturalism about this unendable debate, then, mostly because I'm told it is problematic that I haven't (and, indeed, that I don't do it every time I talk about something, apparently). I certainly don't present it to give into the intellectual hostage-taking game these apologists play, by which they simply seek to keep talking about their nonsense without having to support it.
Disclaimer: I'm not a philosopher. In fact, while I have a great deal of respect for the field of philosophy, for the part of it that insists on pissing on naturalism, I wouldn't want to be. I'd be embarrassed to be that, in fact, beyond making a simple honest note that we can't know with impossible-to-obtain certainty on this matter.
To be perfectly clear for the purposes of this unnecessary and useless essay, let me put a direct definition down for the philosophical position known as naturalism.
Naturalism: A philosophical viewpoint according to which everything arises from natural properties and causes, and supernatural or spiritual explanations are excluded or discounted.The only reason that I can figure that this topic even can be bandied about is the universal quantifier "everything," along with the corollary complete exclusion of supernatural and especially "spiritual" (non)-explanations. Technically, as already noted, we can't know that with impossible-to-obtain certainty, but it really doesn't matter.
Of course, there's a very narrow epistemic gap, and it's philosophically fair and mature to note its existence. It is neither philosophical, nor fair, nor mature, however to desperately want to shove into that gap any supernatural non-explanation for any unknown something (or everything). People who want to do this are opportunists who conflate philosophical possibility with "my claim gets a fair shake because it's possible." On those grounds, so does the Force, so does Hogwarts, so does a cheesey center of the moon, and so do dragons.
Mere possibility and a robust defense of the natural
This "catch," philosophical demand on leaving open mere possibilities, is part of why this essay is useless. It is well-known to be impossible to prove the non-existence of anything that is not logically impossible, so it's useless to try to "prove" naturalism. It can't be done. It's a childish game to demand it.
Rather importantly, that lack of proof that naturalism is true is not proof that naturalism is false. Naturalism could conceivably be falsified. We'll talk about how that could be achieved a bit later, and hopefully it will be clear why the onus here is on disproving naturalism, and not by appeals to the unknown, unknowable, or possibility.
First, we should talk about evidence. There is evidence for nature. In fact, given what we're calling nature is all we ever see, all we have is evidence for the natural. Of course, we are annoyingly required in these conversations to say "off all hypothetical situations where we live in some kind of simulation." I'd say we have to say that out of philosophical honesty, but I think we really have to say it because of philosophical dishonesty, which is something slightly different.
So if we go into hypothesis evaluation mode, perhaps by appealing to the Bayesian method--whether or not we can produce an argument for some prior probability that nature is all that exists--we can see which direction our evidence is pushing us in terms of updating the posterior probability. All we ever see is natural. Everything. All of it. Always. Every supernatural hypothesis we've been able to examine closely enough has been replaced with natural explanations, and none have gone the other way. Our updated plausibility over all of this evidence is that natural explanations are all we have and all we need, whatever knot one wants to twist himself up upon about "first principles" (i.e. abstract axioms--not things that actually exist).
If we were to think in a Bayesian way about the question of naturalism, we've seen the evidence pointing unilaterally in one direction, something that was true even when the default position was taken to be that supernatural forces were everywhere. In such an analysis, then, we have so much evidence mounted for naturalism that the subjective posterior plausibility of naturalism being false is so low as to be hardly worth mentioning--and yet here we find people shoving their "infinite" God. Heretics.
Thus, we see why this essay is unnecessary. The evidence for naturalism is that all we ever see and ever have seen is natural. What's my proof of naturalism? Surely you jest!
A special note for the religious
Now, let's make a special note for believers in particular belief structures, like Christianity: a philosophical defeater of impossible-to-have certainty regarding naturalism does not prove supernaturalism, nor does it lend support to your religion. All it does is suggest merest possibility. It's possible that I'm going to win the lottery every week for the next eleven years too, but it doesn't imply that I need to take that chance seriously or that it will happen.
More importantly, though, a lack of impossible-to-have certainty for naturalism cannot be used to get to specific religious beliefs. There is a long way to go to get to those. First, it must be demonstrated that there is something supernatural, which we'll discuss more momentarily, then the claims under the religious beliefs must be demonstrated beyond that. By demonstrate, I mean prove, although I won't be as ridiculous as challengers to naturalism are and insist upon certainty (which every philosopher, including them, know isn't a possible standard to meet). I will only insist upon the accepted (non-certain) standards of "proof" of any existence claim. Give me evidence for God that is as suggestive as the evidence for the Higgs particle, and then we'll talk. As I've said before, good. luck. with. that.
"Unfalsifiable" should be a word that shuts them up. It doesn't.
To start this on the opposite foot, there's a problem that seems to be able to render naturalism unfalsifiable, but it is kind of a contrived problem, as I will point out. The matter is different for the supernatural. By one definition, the supernatural is outside of nature. Thus, this supernatural cannot be evaluated and is unfalsifiable. That means it can't be proved that this supernatural exists no matter what is done. Of course, this problem is created by the definition of the word "supernatural" as being something outside nature.
It's not really a problem, though, by the dictionary definition of supernatural: "attributed to some force beyond potential scientific understanding or the laws of nature." An extant God could actually easily satisfy this definition by bending the laws of nature whenever it chooses, perhaps in response to intercessory prayers. Why do we get the other definition of "supernatural"? No evidence for the potentially falsifiable kind--evidence that should exist given the claims of those who believe in it.
What's important to point out about the unfalsifiable nature of claims to the supernatural is that because we never see them, they've been punted out of the realm of possibility. If that's how anti-naturalists want it, so be it. In that case if anyone tries to argue that some supernatural must exist because of some claim at a philosophical defeater of absolute naturalism, no one possesses the necessary tools to distinguish one supernatural claim from another. So, someone might want to call the supernatural by the word "God," and I might call it the Pink Invisible Unicorn, and we literally have no way to tell each other we're wrong.
That means when we talk about the supernatural we're all absolutely and completely equally right/wrong (meaningless terms here) in anything anyone wants to claim about it, automatically and always. If God is supernatural in this way, every claim about God is equally right and equally wrong. In that case, I think that God never interacted with the world at all, Jesus was just a superstitious lunatic, all the religions are wrong, no one will be judged at death, there is no heaven, and God is really a dill pickle with a beard. Prove me wrong.
Mind the gap
What we need to remember is that all this supernatural twaddle rests on the vanishingly unlikely case and unsubstantiated claim that there is a supernatural, which currently resides in the infinitesimal gap between the natural and philosophical meditations on first principles. Why is that gap so small? No evidence for anything supernatural. Not now, not then, not ever.
This problem, then, lets us look at the apparently unfalsifiable nature of the kind of supernatural anti-naturalists defend, which amounts to saying even more on why this essay is useless. If someone is motivated to simply make shit up that can't be falsified to satisfy some set of intellectual or emotional needs, apparently he will, so this essay, like all others, is useless in deterring him from doing it. People engaging in this behavior don't understand the importance and utility of falsifiable hypotheses, and so it's useless to keep pointing at them.
To tie this to some other things I've written in the past, a vanishing possibility does not imply anything. That's why I have called it "probability/plausibility zero, almost surely," implying that the set upon which supernaturalism lives is entirely dismissible. Even if the math on that can be shown to be erroneous--not yet, it hasn't, with some other mathematicians helping me explore this possibly bold claim--all the anti-naturalist is left with is an astoundingly small and rapidly shrinking degree of plausibility for the existence of supernatural.
Giving the burden back
I want to use this unnecessary, useless essay to put the burden back where it goes, though. If someone wants to assert naturalism is false, there is a way. Evidence. All he has to do is show us anything supernatural. We have all the evidence in the universe, literally, for the natural. If someone wants to overturn that, let him show us something supernatural.
Simply, since we're not nearly so superstitious now, the claim that naturalism is false is not a negative position. No one has to prove "naturalism is true (off a negligible set of philosophical possibility)" because all of the evidence we have points us to holding it as the default. Therefore, the burden is on people seeking to establish the supernatural. Show something supernatural and defeat naturalism. Until it is done, all the calls to "prove naturalism" are simply yammering.
Of course, no one can produce anything supernatural. Not only can no one do it, by definition it cannot be produced. The only hope an anti-naturalist could conceivably have is for a deity that isn't epistemically hidden, but they have, of course, outlawed that possibility because it would immediately disprove the existence of their God. No wonder religious apologists make so many weird philosophical arguments and appeals to gaps in knowledge, epistemology, and ontology, gaps which I've argued must exist in essentially all philosophies because of the Incompleteness Theorems. Except theistic philosophies, of course, but those don't have this problem because they just baldly assert that they don't, which by the Incompleteness Theorems implies that their philosophies are probably incoherent. (They don't care.)
And, even after this, apologists will still make these kinds of arguments. As I said, this essay is useless.
Here's some honest questions: Why do apologists really waste their time on this? More pressingly, why do they waste our time with them, given the points about "useless" and "unnecessary"? Maybe they want to talk about this stuff endlessly, but no one else does.