The supernatural exists.

Con begins his rebuttal by claiming that "Proving a negative is not demonstrating your claim." I think he means that disproving naturalism does not prove supernaturalism. So he's claiming that my attack on naturalism, even if sound, would not prove supernaturalism.But Con is mistaken. By the law of excluded middle, either the natural world is all that exists or the natural world is not all that exists. If the natural world is not all that exists, then something exists beyond the natural world. And that is how I defined the supernatural--something existing beyond the natural world. So it follows inescapably by the laws of logic that if naturalism is false, then supernaturalism is true.Con goes on to insinuate that I did not say what the necessary preconditions for rational thought and justified belief were. But I did so quite plainly. One of the necessary preconditions is that our beliefs are the result of good grounds rather than blind mechanistic causes. I explained already why these are distinct and how one leads to justified belief and the other doesn't.I also explained why, given naturalism and evolution, the probability that our belief-producing cognitive faculties are reliable is low. It follows that one of the necessary preconditions for rational thought is that supernaturalism is true.There's one more thing I want to address before I refute Con's arguments. He claims that I misrepresented naturalism. That is an illigitimate claim given that he stipulted at the beginning of the debate that "I will argue any version of the supernatural you wish." He gave me permission to define supernaturalism, which entails a definition for naturalism. By Supernatural, I mean anything beyond the natural, and by "natural," I mean what is describable by the laws of physics and chemistry. It follows from my definition of "supernatural," that naturalism is the belief that only what is describable by the laws of physics and chemistry exist. If I am allowed to define "supernatural" any way I wish, and if my definition of "natural" follows from my definition of "supernatural," then Con can't fault me for misrepresenting naturalism.I went on to argue that given naturalism, beliefs and desires must somehow be by-products of the material brain, and I made my arguments on that assumption. In reality, I don't think it's even possible for beliefs and desires to be merely the by-products of the brain, but I let that slide in the interest of space. Even given that they are, that does not salvage our rationality since under naturalism, (1) the beliefs are not arrived at through grounds, (2) it is impossible for the beliefs and desires to influence our behavior, and (3) even if they did influence our behavior it is still unlikely that our belief-producing cognitive faculties would be reliable.Now, let's see how Con responded to each of these arguments.My first argument relied on the premise that since the brain is a physical object that it behaves deterministically according to the laws of nature. Con attacked this premise on the basis that brain reacts to stimuli, like light and sound, which are non-deterministic since the "brain can not pre-determine what the input will be." But clearly it doesn't follow that because the brain gets no say in what input it receives that it therefore does not behave deterministically according to the laws of nature. A pool ball gets not say in how hard it is hit by the cue ball and at what angle, but it nevertheless behaves deterministically according to the laws of collision. Once sound hits the ear drum, a cascade of determinitic causes follows.Con claims that "beliefs are products of information input," but he fails to recognize that on naturalism, nothing about the "information" has any bearing on the final belief. When a parent tells a kid about Santa Clause, all that happens is that sound waves interact with the ear, which send an electric signal to the brain, which results in a certain physical brain state. The belief is arrived at, not by virtue of the semantic content of the original statement, but by the blind mechanistic causes that happen in the air, the ear, and the brain. So it isn't by virtue of any semantic content in propositions the kid becomes aware of that results in his belief, but merely the syntactic structure of the underlying physical processes. And as I argued earlier, unless our beliefs are the result of good grounds, rather than blind mechanistic causes, they are not justified or rational.Con seems to be under the impression that as long as the input comes from outside the brain, that brain chemistry alone is not what contributes to belief. But on naturalism, outside input can only contribute to belief by affecting brain chemistry! So even given outside input, the belief is still arrived at purely by brain chemistry, given naturalism.Con reacts to the phrase, "blind mechanistic causes" by saying, "Can something blind react to light? Ok, then brain mechanisms that react to light are not blind. We observe things by using light, and our observations develop our beliefs." Honestly, I'm not sure if this is a joke or not, but I think the safer bet for me is to go ahead and respond to it as if it's not a joke. By "blind," I did not mean "inability to have visual perception." I was using "blind" as a metaphor representing non-sentience. There are laws that describe how physical entities interact with each other, and those laws operate wholly apart from those entities thinking about it, making decisions about it, etc. When gravity pulls an acorn to the ground, the acorn doesn't choose to fall, and gravity doesn't choose to pull it. The same is true of atoms, molecules, and electrons. An electron that moves through a magnetic field will undergo a force perpendicular to its motion, causing it to accelerate in that direction. There's no thinking that goes on in the process. The electron is just behaving deterministically according to the laws of nature. That is true of everything in the natural world, including the brain.I argued in the previous round that given naturalism, our beliefs and desires cannot contribute to our behavior. Pro's response essentially boiled down to, "Yes they can." He gave the example of a kid who goes to look for Santa Clause because of his belief. The problem is that Con didn't explain how that's possible on naturalism. Responding to an argument by simply denying the conclusion does not amount to a refutation.Con goes on to explain how justiied beliefs can be arrived at through observation and experimentation, but this all assumes that the semantic content of brain input has some bearing on belief, which I argued against. Con hasn't responded to my arguments. He's simply asserted various negations. On naturalism, all of this input can only contribute to belief by virtue of it sentactic content, not its semantic content. It is only by affecting brain chemistry that any input can influence our beliefs, and it does so deterministically according to the laws of nature. So Con's claim that "It's [Our beliefs are] definitely not pre-determined by the brain" is false under naturalism.After agreeing with me that for any true belief that results in adaptive behavior, there is a false belief that would result in the same behavior, he went on to claim that "vastly more true beliefs yield adaptability than do false beliefs." But that negates his agreement. Besides that, the question isn't whether there are, in fact, more true beliefs that are beneficial than there are false beliefs that are beneficial. The question, rather, is whether in any situation where there is a true belief that would result in adaptive behavior, there is a false belief that would accomplish the same thing. And Con has agreed that there is. It follows that since evolution selects for adaptive behavior regardless of whether the unlying belief is true or false, that it's improbably our belief-producing cognitive faculties would be reliable.