Carrier's Opening Statement (2006)
Naturalism Is True, Theism is Not
If we want all our beliefs to be more likely true than false, then we must proportion our beliefs to the evidence. So if our reasons to believe are few and unreliable, our confidence should be low, and if our reasons to believe are many and reliable, our confidence should be high, with an appropriate continuum between. That means if we have no reason to believe something, then we should not believe it, and if we have much better reasons to believe something than we have not to, then we should believe it.
Basic Argument for Naturalism (BAN)
The cause of lightning was once thought to be God's wrath, but turned out to be the unintelligent outcome of mindless natural forces. We once thought an intelligent being must have arranged and maintained the amazingly ordered motions of the solar system, but now we know it's all the inevitable outcome of mindless natural forces. Disease was once thought to be the mischief of supernatural demons, but now we know that tiny, unintelligent organisms are the cause, which reproduce and infect us according to mindless natural forces. In case after case, without exception, the trend has been to find that purely natural causes underlie any phenomena. Not once has the cause of anything turned out to really be God's wrath or intelligent meddling, or demonic mischief, or anything supernatural at all. The collective weight of these observations is enormous: supernaturalism has been tested at least a million times and has always lost; naturalism has been tested at least a million times and has always won. A horse that runs a million races and never loses is about to run yet another race with a horse that has lost every single one of the million races it has run. Which horse should we bet on? The answer is obvious.
That's the basic argument for naturalism. Naturalism (N) is the belief that there is nothing supernatural. Carrier Naturalism (CN) is a variety of N. Other varieties of N either add to or subtract from the elements of CN, so we shall label these NMore and NLess. If N is true and all observed phenomena are explained by CN, then there is no reason to believe anything in addition to what is countenanced by CN, and therefore no reason to believe in any NMore. If N is true and every kind of phenomenon entailed by CN is observed, then there is no reason to believe anything less than CN, and therefore no reason to believe any NLess. I assert that N is true and that all observed phenomena are explained by CN, and every kind of phenomenon entailed by CN is observed. For the purposes of this debate, any elements of this assertion that remain unchallenged should stand.
We should believe CN unless we find a very compelling reason not to, since we should not believe any proposition established on less reliable methods that contradicts a proposition established on more reliable methods. Moreover, CN is currently the only worldview implied by all the findings of the most reliable methods of science, history, and critical investigation. Formally:
P1: We should believe any proposition that follows from the findings of more reliable methods over any proposition that follows from the findings of less reliable methods.
P2: CN is the only worldview that follows from the findings of the most reliable methods.
C1: Therefore, we should believe CN.
I shall assume only P2 will be challenged. That P2 is true follows from the fact that all claims and phenomena that have been thoroughly investigated, using the best methods available to us for ascertaining the truth, have verified and conformed to CN, without any confirmed exception despite hundreds of years of searching, involving countless observations by countless qualified experts. Yet things did not have to turn out that way. If these most reliable methods had turned up abundant, or indeed any confirmed evidence of the supernatural, then we would have to believe supernaturalism unless we found very compelling evidence to the contrary. And had that happened, then N would have a much greater burden of proof before it would ever be reasonable to believe it. However, things turned out quite the opposite, so it is any supernatural worldview that bears a greater burden of proof than CN, enough to refute P2. So if P2 is not successfully refuted in this debate, BAN stands.
Basic Argument to Naturalism as the Best Explanation (BANBE)
If E constitutes a small collection of things we know to be true, and B constitutes all other things we know to be true, such that the sum of E and B constitutes everything we know to be true, then I assert that CN explains E better than any known alternative, and that no known alternative explains B better than CN. And if that is true, then we have more reason to believe CN than any alternative. By "better" here I mean in the formal sense explained below. So:
P3: If any worldview W explains E better than any other known worldview, and we know of no other worldview that explains B better than W, then we have more reason to believe W than any other known worldview.
P4: CN explains E better than any other known worldview, and we know of no other worldview that explains B better than CN.
C2: Therefore, we have more reason to believe CN than any other known worldview.
P5: BT (basic theism) is another known worldview.
C3: Therefore, we have more reason to believe CN than we have to believe BT.
I shall assume only P4 will be challenged, so the truth of P4 requires further empirical defense, which shall consume most of the remainder of my opening argument. But if no observation is presented in this debate that is better explained by a worldview other than CN, and at least one observation is presented that is better explained by CN than any other view presented here, then BANBE stands. Since I am under a strict word limit, I can only present a case for a few members of E. For the purposes of this debate, I assert that everything else lies in B until any evidence is offered to the contrary.
For this debate, the use of the adverb "better" in P3 and P4 is meant solely in a formal Bayesian sense. This entails (among other things) that, given all our accepted background knowledge, if any explanation H of a set of observations O is initially as or more probable than any other explanation, and is more likely to have produced the entire contents of O than any other explanation, then H is a better explanation of O. But if H is not initially more probable, nor more likely to have produced the entire contents of O, then H is not a better explanation. CN explanations are no less initially probable than BT explanations, so the following arguments independently establish P4 for elements of E.
Argument from Divine Inaction (ADI)
The moral code accepted by most Christians entails it is a duty upon every moral person to protect the innocent from harm, heal the sick, provide means to the impoverished, feed the hungry, build safe and healthy homes and workplaces, and tell everyone who asks what they need to know to achieve a happy life here and hereafter (which set of duties we shall label D). There is no evidence that God does any of these things, yet according to BT he has the means to do them and always obeys the same moral duty that most Christians accept. In contrast, that the natural world is brutal, dangerous, harmful, indifferent, and unsafe is the only way the natural world could be if CN is true. Therefore, the evidence refutes BT and confirms CN. For people starving to death is expected on CN but not on BT; innocent people frequently coming to harm is expected on CN but not on BT; sick people who never recover is expected on CN but not on BT; and so on. CN explains all these things and makes them highly probable. But BT doesn't explain any of them, leaving a lot of what we observe highly improbable. Formally:
P6: The moral code accepted by most Christians entails a set of duties D.
P7: A BT God only acts in ways consistent with the moral code most Christians accept.
C3: A BT God only acts in ways consistent with D.
P8: There is no evidence that any God acts in ways consistent with D.
C4: Therefore, there is no evidence that a BT God exists.
P9: If CN is true, the actual state of misery, ignorance and injustice that we observe is exactly what we would expect.
P10: If BT is true, the actual state of misery, ignorance and injustice that we observe is not what we would expect.
C5: Therefore, CN explains what we observe better than BT.
The Argument from Mind-Brain Dysteleology (AMBD)
The scientific evidence confirming the necessity of a functioning human brain for human consciousness to exist is vast and secure. We have identified where in a brain different kinds of memories are stored, where emotions and reason operate, where each kind of sensory experience is processed, and so on. We have observed that if we physically remove or deactivate any one of these parts, the memories or abilities it contains then cease. It follows that if we take away all the parts, everything that we are will cease. Naturalism predicts this must be the case, since on N there is no other way to have consciousness except as the product of a large, delicate and complex physical system (lying at the end of an extremely long, meandering, faulty process of trial and error over billions of years). But this is not what we'd expect if BT were true, since BT entails that consciousness can exist and function without a brain, and there is no known reason a BT God would imbue us with any other kind of mind, and good reason to expect he wouldn't. CN thus predicts exactly what we observe, while BT predicts the opposite: that we would instead be made "in God's image," which is not what we observe.
If BT is true, then (a) a brainless mind is possible, (b) God could have imbued humans with one, (c) no mind exists that was not deliberately created or allowed by God, and (d) in choosing what to do or allow, God would have obeyed the same moral code that a majority of Christians obey. From this it follows that:
P11: Instead of the embodied mind we actually have (EM), God could have provided every human being with a brainless mind (BM) that (a) always operates correctly without need of food or oxygen, (b) is incapable of being damaged by any wounds or disease, (c) always perceives and reasons correctly, (d) doesn't pose a physical threat to a mother's life or health during delivery (as human brains do, in contrast with all other mammalian brains), and (e) is otherwise in every respect the same as our current mind.
I am certain a clear majority of Christians, given the choice between bestowing a child in the womb with a BM or an EM, would choose the BM. And rightly so, since regardless of what drawbacks a BM might have, an EM will always have more. And surely the Golden Rule (GR), "love thy neighbor as thyself," is the most universal moral dictate in the whole of Christendom. So if God adheres to "the moral code most Christians accept," then he must adhere to GR. Most people would want a BM rather than an EM and would thus choose one for themselves if they could. Therefore, anyone who adheres to GR must want their neighbor to have a BM instead of an EM, too. Therefore:
P12: Any moral person adhering to GR would, if able, bestow a BM upon all children and an EM on none.
P13: By definition, a BT God is a moral person adhering to GR and is able to bestow a BM upon all children and an EM on none.
C6: Therefore, a BT God would have bestowed a BM upon all children and an EM on none.
P14: If C6, then we would observe everyone to have a BM, and no one an EM.
P15: We observe no one to have a BM and everyone to have an EM.
P16: If we observe exactly the opposite of what we expect on BT (or CN), then BT (or CN) does not explain very well what we observe.
P17: If P15, then we observe exactly the opposite of what we expect on BT.
C7: Therefore, BT does not explain very well what we observe.
P18: If CN is true, then we would observe no one to have a BM and everyone to have an EM.
P19: We observe no one to have a BM and everyone to have an EM.
P20: If we observe exactly what we expect on CN (or BT), then CN (or BT) explains well what we observe.
C8: Therefore, CN explains well what we observe.
C9: If C7 and C8, per logicum, CN explains what we observe better than BT.
Atheistic Cosmological Argument (ACA)
The universe is almost entirely lethal to life. By far, most of existence is a radiation-filled vacuum, and there are easily a trillion times more dead worlds than life-bearing planets. Life is clearly an extremely rare and unusual product of the universe. We also know it took the universe billions of years to finally produce any life anywhere, and then only an extremely simple single-celled life form. Then it took billions more years of a long, meandering and often catastrophically failing process of evolutionary trial-and-error to finally produce human beings. CN explains this state of affairs better than BT, since this state of affairs is highly probable on CN but not particularly probable on BT.
Even if a God might have some reason to build a universe this way, he had many other ways he could have chosen (like the way the Bible literally depicts and early Christians believed), and some make more sense on BT (a God has no need of a universe so old or big, for example). But we know of only one way CN could produce human beings: pretty much the way they were, with vast ages of unguided trial-and-error spanning across vast stretches of life-killing space. For example, if CN, then (a) life could only be an accidental byproduct of the organization of the universe, but (b) the only way life could then exist is if the universe were so incredibly old and big that something as improbable as the origin of life would be possible, yet (c) that is exactly the universe we find ourselves in. We have no comparably good explanation for why the universe would be so old and big on BT, or for many other peculiar features of our universe. Therefore, CN is a good explanation for why we observe what we do, while BT is not. Formally:
P21: If CN is true, the nature and scale of the universe, and the history of life that we actually observe, is the only possible way we could exist that we know of, and is therefore what we would expect to observe.
P22: If BT is true, the nature and scale of the universe, and the history of life that we actually observe, is one of countless possible ways we could exist that we know of, including some that make more sense, and is therefore not what we would expect.
C10: Therefore, per logicum, CN explains what we observe better than BT.
Many more arguments could be added to support P4 if room were available. Instead, I must close with two special arguments against BT.
Argument from Nonlocality (ANL)
According to Wanchick, God in BT has no spatial location. But if God has no location, then by definition there is no location at which God exists. And if there is no location at which God exists, then God exists nowhere, which entails that God does not exist. For the proposition "there is nowhere that God exists" is literally synonymous with "God does not exist." From any intelligible definition of being, in order for anything to exist, it must exist somewhere--even if that somewhere is everywhere, or some location other than space. So God in BT must have some location other than space. But there is no place we know of except space, so we have no reason to believe any other place exists (even if one does). Therefore, if God does not exist in any location in space, we have no reason to believe God exists.
Argument from Physical Minds (APM)
According to Wanchick, God is nonmaterial (not consisting of matter), but has a conscious intelligence and the power to act. We have confirmed no instance of any C (consciousness, intelligence, or conscious or intelligent action) occurring in the absence of a required material, and all observed instances of C have occurred in the presence of a required material. These observations must number beyond the millions, including countless observations made under the best conditions, subject to the most reliable means and methods of inquiry. Therefore, regardless of what may be possible, we have no reason to believe that any elements of C ever do occur without a required material. Since a BT God by definition cannot have the required material, we therefore have no reason to believe that any BT God exists.
Given the argument from nonlocality (ANL) and the argument from physical minds (APM), we should not believe basic theism (BT). But given the basic argument for naturalism (BAN) and the basic argument to naturalism as the best explanation (BANBE), we should believe Carrier naturalism (CN). Q.E.D.
 See this debate's joint statement.
 See Richard Carrier, Sense and Goodness without God: A Defense of Metaphysical Naturalism (2005) and its companion website Naturalism as a Worldview.
 See Wanchick's definition of BT in this debate's joint statement.
 See this debate's rule number 4.
 In addition to the brief summary provided in Richard Carrier, Sense and Goodness without God: A Defense of Metaphysical Naturalism (2005), pp. 135-57, see: V. S. Ramachandran, A Brief Tour of Human Consciousness: From Impostor Poodles to Purple Numbers (2004); Encyclopedia of the Human Brain (2002); Phantoms in the Brain: Probing the Mysteries of the Human Mind (1999); Gerald Edelman, Wider than the Sky: The Phenomenal Gift of Consciousness (2004); Steven Johnson, Mind Wide Open: Your Brain and the Neuroscience of Everyday Life (2004); Christof Koch, The Quest for Consciousness: A Neurobiological Approach (2004); Susan Blackmore, Consciousness: An Introduction (2003); Joseph Ledoux, Synaptic Self: How Our Brains Become Who We Are (2002); John Ratey, A User's Guide to the Brain: Perception, Attention and the Four Theaters of the Brain (2001); Bernard Baars and James Newman, eds., Essential Sources in the Scientific Study of Consciousness (2001); Gerald Woerlee, Mortal Minds: A Biology of the Soul and the Dying Experience (2003); Oliver Sacks, The Man Who Mistook His Wife for a Hat, and Other Clinical Tales (1998); Frederick Schiffer, Of Two Minds: The Revolutionary Science of Dual-Brain Psychology (1998).