In Three Hours I'm Debating One Of The Most Influential Living Atheists About God's Existence. Here's My Opening Statement

Later today, I'm debating atheist Matt Dillahunty about whether God exists. Here's my opening statement

At 2 EST, 7 UK time today, I’ll be debating Matt Dillahunty about God’s existence. This debate has been in the works for a long time—should be lots of fun. Hope you tune in! I’ll probably be vastly outnumbered in the live chat, so if you turn in, make sure to talk endlessly in the live chat about how clever—and handsome—I am. It will be livestreamed on Matt’s YouTube channel!

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First let me thank Arden for moderating and Matt for agreeing to do this. Matt and I agree about the importance of considering evidence and avoiding irrational dogmatism and pseudoscience like denial of vaccine efficacy or belief in Young Earth creationism. If you at home would like to follow along with my opening statement, on my blog Bentham’s Bulldog—which you can find by googling—you can find a written transcript of it, with sources included, as well as links to where you can find out more about the arguments I’m giving.

One brief comment before I get into the arguments: I think a lot of atheists can have a tendency not to give theistic arguments a fair shake—to assume from the outset they must be stupid, like belief in Santa Claus. This isn’t rational. Many smart philosophers and scientists believe in God unlike Santa Claus. While this doesn’t make the view true, it does mean that it’s pretty unlikely that all the arguments for it are obviously fallacious. Many atheists like Alex O’Connor have come to see theistic arguments as more formidable than they previously believed after studying philosophy.

I think many of my disagreements with Matt will come down to epistemology—how one comes to know things. So let me describe how I think one should evaluate hypotheses about the world. First, one should look at the prior probability of the hypothesis—how likely it is before gathering any data. Even though the theory that I’m cheating in poker and the theory that fairies rigged the deck so that I’d get ten royal flushes both explain the data of me getting ten royal flushes, it’s likelier that I’m cheating because it has a higher prior probability.

Next, one should look at the evidence. Evidence for a hypothesis is simply something that’s likelier if the hypothesis is true than if it’s false. This isn’t my conjecture—mathematicians have shown that if some event is likelier given that a hypothesis is true than given that it’s false, then that event makes the hypothesis more likely. This became formalized through something called Bayes theorem.

For example, suppose that you want to figure out if I’m cheating in poker. Suppose you think that the odds I’d cheat are low—maybe 1/10,000. Thus, in order for the evidence to establish that I’m cheating with more than 50% probability, it must be that my stream of luck is so unlikely that it’s more than 10,000 times likelier it would happen by cheating than by chance.

This is the method applied in science and history.

Consider the discovery of dark matter. Scientists believe it exists because light from faraway galaxies seemed to be bent as if affected by gravity, but the places giving off the gravitational field didn’t release any light. In addition, the speed of galactic rotation seemed to indicate more mass than we could observe. Scientists came to believe that there was dark matter—a kind of invisible matter that exerted gravity—because it explained these otherwise puzzling facts about the world.

It wasn’t first demonstrated that it was possible nor was there any kind of direct experimental verification—scientists instead believed it because the supposition that there was invisible matter wasn’t wildly unlikely in terms of its prior probability and it explained the evidence very well.

Similar things apply to the discovery that Hannibal used elephants to cross the alps. This wasn’t first demonstrated to be possible, but was believed because it was the best explanation of written records of Hannibal crossing the alps and soil samples containing large feces deposits.

People criticize this method by saying that we have no way of precisely deciding upon the priors and the degree of update. But to apply this method you don’t need highly precise priors, only rough approximations. I don’t know the exact prior of evolution, but there’s clearly enough evidence to believe it.

So now let’s apply this methodology to God.

First, consider the prior probability of God. The prior probability, how likely a view is before considering the evidence, is influenced by various factors—two major ones are simplicity and non-arbitrariness. The theory that the world is infinite has a higher prior than the theory that the world is exactly 10 quadrillion light-years across because infinity is a less arbitrary size. Similarly, as Ockham’s razor tells us: we should not multiply entities without necessity. That’s why absent a good reason, you shouldn’t think that there’s an uncaused teapot between here and Mars.

Note that as the atheist philosopher Jonathan Schaffer argues, Ockham’s razor should be about the number of unexplained or fundamental entities rather than the total number of entities that exist. Otherwise, solipsism would be the simplest theory, because it just posits your mind, rather than a big universe.

On this metric, theism—which I use to mean that there’s a perfect God—does very well. It posits only one fundamental entity—a mind totally without limit. Because this mind is unlimited, nothing restricts its power or awareness, so it can do anything and knows everything. Once it’s omnipotent and omniscient, it will act to do the right thing, because a perfectly rational person would come to see the irrationality of immorality. Just as if you’re rational you won’t be racist, as racism is irrational, and you won’t arbitrarily privilege your present self over your future self, a perfectly rational limitless mind wouldn’t arbitrarily privilege anyone over anyone else, and thus would be morally perfect.

This also shows the error of the claim that belief in God is like belief in fairies or unicorns. Fairies and unicorns are very complicated things—they have many distinct properties with no core explanation—and there’s no real evidence for them. In contrast, God is the simplest possible kind of mind—simply one without limits.

The world has three kinds of things: abstract objects, like numbers; the material world; and minds.

Minds can’t reduce to the physical world, because no amount of matter alone is enough by itself to produce a mind. As the philosopher Frank Jackson famously argued, while reading textbooks could allow you to learn every physical fact about the world—for instance, you could learn the laws of physics from a book—it wouldn’t allow you to learn everything about minds, like what it’s like to see red if you’ve never seen red. Thus, minds must not be purely physical, because textbooks can teach you every physical fact but not every mental fact. But if minds are non-physical fundamental entities, a limitless mind is a very simple kind of thing—one category of fundamental reality instantiated without limit. It also is distinctly non-arbitrary because it’s totally without limit.

You don’t have to think all of this is obviously true. It only needs to be plausible enough for theism to start with a somewhat reasonable prior probability. Dark matter didn’t start with a very high prior, but it’s reasonable to believe in because it had lots of evidence and its prior wasn’t super low.

Now let’s turn to the evidence. In my view, there’s a lot of evidence—more than I can list here—but let me just discuss a few lines.

First is the fine-tuning of the constants in physics, meaning the values that go into the equations of physics. Around 1980, physicists discovered that many of the constants are finely-tuned, in the sense that they fall in an infinitesimal range that happens to be the only kind that can form complex structures. If the cosmological constant were a bit weaker, the universe would have collapsed in on itself right after the big bang, and if it were a bit stronger, every atom would have been ripped apart so that no two particles ever interacted. Luke Barnes, an influential physicist, calculated that the odds of getting finely-tuned constants by chance are only one part in ten to the power of 136. That’s about as unlikely as throwing a dart across the known universe and hitting a particular atom (actually, that’s about 40 orders of magnitude less likely, but who’s counting).

If there is a God of the sort I described, this fine-tuning is probable or at the very least, not astronomically improbable: God being good wants valuable stuff to exist so he’d set the constants to whatever value is needed to give rise to life. In contrast, on atheism, the odds of life are astronomically tiny. Thus, this is one line of evidence for theism—it’s a fact that’s likelier if there’s a God than if there’s no God. Atheists have lots of ways of trying to explain this and I can’t hope to discuss them in detail, but if you want a lengthier rebuttal to the objections, check out my article “the fine-tuning argument simply works.”

A second bit of evidence is consciousness itself. If there’s a perfect God, he’d want to create conscious agents, because conscious agents are good things. However, if there is no God, then it’s a surprise that consciousness exists at all—why would particles moving about give rise to subjectivity? This is especially so if you agree with the arguments I gave before, showing that the material world alone isn’t enough to produce consciousness by itself. Thus, to get consciousness on atheism, you need extra special consciousness laws, which are improbable.

A third line of evidence is the fact that the laws give rise to any life and anything of value. It would be much simpler for there to simply be a single particle that never does anything, or for there to be two particles circling around each other for eternity. Those studying cellular automata—dots moving about—have discovered that with a random set of laws, you’re much likelier to either get total chaos or simple patterns that don’t produce any structure than to get the kind of stable order needed for life.

This even leads the mathematician Euan Squires in a published paper to propose that we may live in the simplest possible interesting world—interesting in the technical sense of producing complex structure. If there is a God, it makes sense that our world would have the balance of simplicity and complexity to give rise to an interesting world—in contrast, in a godless world, either a world that never produces any conscious life at all, and just has particles moving around in highly simple repetitive patterns, or one that’s random chaos is far, far more likely than this world.

The fourth bit of evidence is the fact that you exist. This one’s a bit complicated—so strap in!

Your existence can give you evidence for many things—for example, your existence gives you evidence that your parents didn’t use effective contraception. But can it give you evidence for God’s existence?

As I’ve argued in a published philosophy paper, your existence is likelier if more people exist, just like it’s likelier that your card would be drawn from a deck if all the cards are drawn than if just one card is drawn. Now, here’s where things get weird: because the number of possible people is a very large infinite, as David Lewis showed, for your existence to be likely, it must be that a very large infinity worth of people get created, which is likelier given a God than atheism. So your existence gives you infinitely strong evidence that the number of people that got created is the most people that could have been created, which is likelier if there’s a God than if there’s no God.

To see this, consider an analogy. Suppose a coin is tossed. If it comes up heads, one person gets created. If it comes up tails, ten people get created. After getting created, you should think that it’s ten times likelier it came up tails, because that made it ten times likelier you’d get created.

But now suppose that if it came up tails instead infinity people would get created. Well now, by the same logic, you should think tails is infinitely likelier than heads. If ten people existing makes your existence ten times likelier, then infinity people existing makes it infinity times likelier.

I have one final case, but first I need to explain something about infinity. As mathematicians have firmly established, there are bigger and smaller infinities. The smallest infinity is called aleph null and it’s the maximum number of people you could fit into one universe. But the number of possible people is a much bigger infinity. An infinite multiverse could have a number of people that could never fit in a single universe, even one infinite in size.

Now consider the last case: a coin gets flipped. If it comes up heads, aleph null, the smallest infinity, people get created. If it comes up tails, a much bigger infinity worth of people get created. Upon being created, you should think the coin came up tails: it’s infinitely likelier that you’d get created if the coin came up tails than heads, because infinitely more people get created by tails than heads.

You might doubt that your existence is likelier if more people exist. But this must be wrong. To see this, imagine one person is created and then a coin is flipped and if it comes up tails nine other people get created. Suppose that you learn you get created but you don’t know your birth rank. Then you’re told that you’re the first person. Because the odds you’d be the first person are only one in ten if there are ten people, while they’re 100% if there’s only one person, unless you start out thinking ten people existing makes your existence ten times likelier, you get the result that the odds of the coin coming up heads before it’s been flipped are 10/11ths rather than 50%.

But this is absurd—fair coins only come up heads half the time. If there’s a fair coin that hasn’t been flipped yet, you should think there’s a 50% chance it will come up heads. Worse, we can get even more absurd results by changing around the numbers so that you end up arbitrarily certain of improbable chancy events, like that you’ll get many royal flushes in poker, so long as if you don’t get many royal flushes many people will be created. In short, it’s been conclusively demonstrated that so long as before flipping a fair coin, you should think there’s a 1/2 chance it will come up heads, it must be that your existence is X times likelier if there are X times as many candidates for being your present self.

(Note: there are many more arguments for the idea that your existence gives you evidence that there are more people—I’ve compiled a list of 27, in fact! I’m happy to discuss many of the others if Matt is doubtful of this principle).

But if you think your existence is likelier if more people exist, and infinitely more likely if infinity people exist, then from the fact that you exist, you should think with certainty that there are infinite people. But this logic doesn’t stop at infinity—as we saw in the above example, you’re likelier to exist if a bigger infinity of people exist than a smaller infinity. Thus, you should think that the number of people that exists is the very most that there could be—whatever the maximum infinity worth of people there could be is, that’s how many people exist. Otherwise only 0% of possible people exist and your existence is infinitely unlikely.

So far we’ve shown that there is a giant infinity worth of people. Once again, this fits well with theism. A limitless perfect God would want to create a giant infinity worth of people, to give a good life to as many people as possible. Thus, he’d be expected to make a huge multiverse containing an enormous infinity worth of people. In contrast, if there is no God, even if there’s a multiverse, it’s highly unlikely to be big enough to contain the most people that there could be—which is, remember, an infinity of people too large to fit in a single universe and more than the number of numbers. None of the existing multiverse models have enough people to make your existence anything but infinitely unlikely. Such views also have other problems in that they undermine induction, but I unfortunately don’t have time to discuss that in any detail.

This was all a bit technical so let me give the two sentence synopsis: if anything other than the most people that there could be exists, because each infinity is infinitely bigger than smaller infinities, then only 0% of possible people exist, and thus your existence is infinitely unlikely. Therefore, from the fact that you exist, you should conclude that the number of people that exists is the most that it could be, but given that there could be a giant infinity worth of people—too many to fit in one infinite universe or in any but the most gerrymandered of atheist multiverses—that gives you strong evidence for the existence of a good God who wants to create with no limits on how much he can create.

Laid out more succinctly, the three steps are:

1. Your existence is X times likelier if there are X times as many people.

2. If that’s right, you should think the maximum number of people there could be exists.

3. The maximum number of people there could be existing is likelier given theism than atheism.

This is a complicated argument, so I’d encourage you to read more about it—I have an article called the ultimate guide to the anthropic argument that explains it in considerable detail. It’s convinced some very competent philosophers, and at least one atheist mathematician takes it seriously, so if you’re thinking it’s dumb for a very simple reason, probably you’re misunderstanding it.

Here I’ve presented four bits of evidence that point to God’s existence: the fine-tuning of the constants, the existence of consciousness, the fact that the universe has laws capable of giving rise to complex structures without devolving to random chaos, and the fact that you exist out of the infinite number of possible beings, which is only likely if a God of limitless creative power exists. I’ve additionally argued that theism has a high likelihood even before looking at the evidence, so because it explains so much so well, it’s likely to be true. Thank you!