Debating Richard Yetter Chappell About God

In written form

Richard Y Chappell is one of my favorite philosophers. He and I had a written debate a while ago about theism that was going to be published elsewhere, but that didn’t end up going through. Thus, we just decided to release it—hope you enjoy!

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Matthew: My general view on the God question is that I think there are quite a few different individual bits of evidence for God’s existence, each persuasive individually, and decisive in combination. Take, for instance, the fine-tuning argument, which proceeds from the fact that we have both constants and law structures that are conducive to life. The cosmological constant, for instance, falls in a tiny range that gives rise to life roughly one googolth of the possible values it could have taken on. That strikes me as quite surprising and good evidence for God. If there is a God, life permitting laws and constants are expected—if not, they’re quite striking.

This is just one of the many lines of evidence. You combine that with psychophysical harmony, the anthropic data, and a bunch of other considerations and it seems pretty decisive. What would you make of that, Richard?

Richard: I worry that those arguments may ultimately prove to be sophistry, and am more drawn to a kind of flat-footed empiricism: Does the world look more like it contains or lacks a God? Seems lacking to me. The problems of evil and divine hiddenness loom especially large from this perspective.

Here’s one way to put the contrast: There are any number of ways the universe could be, given atheism. Some look like ours. Many don’t (and aren’t even capable of supporting life). It’s not at all obvious why there’d be something like this rather than something different or nothing at all. Maybe it’s just brute. So the fine-tuning and psychophysical harmony arguments are on to something when they point out that the atheist has to take our (mentally coherent) existence to be a striking piece of good luck. It’s surprising!

Theism puts more “selection pressure” on expected outcomes. The problem is that the universe we’d expect from a perfect God is one very different from ours—we’d expect much less wild animal suffering, for starters, and more divine chit-chat. So whereas atheism doesn’t steer us towards any particular style of universe, theism would seem to steer definitively away from ours.

Matthew: I agree that the world is, in many ways, not the one we’d expect if there were to be a God. But crucially, I think that this is also not one we’d expect on atheism. So one has to compare relative probabilities. As an analogy, on the hypothesis that I’m cheating, it’s very unlikely that I would be so stupid as to deal myself ten royal flushes in a row. But if I do get ten royal flushes in a row, that is obviously very strong evidence that I’m cheating.

The way of going about this, in my judgment, is straightforward: be a Bayesian. Look at how likely you’d guess the facts of the world to be if given atheism vs if given theism. If you were an atheist disembodied mind floating freely, you would not expect the universe to contain fine-tuning, laws capable of producing any structure, or psychophysical harmony. Nor would you expect the shocking anthropic fact that you, Richard Chappell, happen to exist out of the infinite possible agents that could exist.

Now you say that it could just be brute. But declaring a fact brute does not do anything to raise the probability that the fact would obtain on bare atheism. What matters is how likely you’d expect the fact to be given atheism vs given theism.

Why accept this methodology? Why be a Bayesian even when applied to the earliest bits of the universe? This is the right methodology to apply to other kinds of things (for instance, it is quite a serious probabilistic hit if hypothesis A merely must declare fact B brute, when B is not expected given A but B is expected given views other than A). But why should theism and atheism be any different? Epistemology doesn’t work differently just because you’re working with God! (And note, there are various betting arguments for Bayesianism applied in other contexts).

Now, if that’s the methodology then I think that atheism will likely lose. There are a great many features of the world that are quite shocking given atheism and only one that is really surprising given theism. That feature is that the world is filled with pointless evil. Fortunately, I think that while this fact is surprising, the theist can explain it without taking too much of a probabilistic hit—both because there’s a not totally crazy theodicy and there’s the possibility of a great many unknown reasons.

But compare that to fine-tuning. On atheism fine-tuning is extremely unexpected (on the order of having a probability of one in googol, provided you either use the indifference principle or some other natural procedure. (Clarificatory note added later: I am not quite sure why I said this! I obviously don’t think the odds of fine-tuning given atheism are one in googol. I think those are the odds assuming fine-tuning has no explanation, but obviously the odds of a multiverse are way, way, way more than that. Probabilities are never one in googol.) Additionally, I don’t think there are any plausible naturalistic explanations of fine-tuning that really take away the sting much.

I think probably evil and fine-tuning basically crash into each other and cancel out—then on the theist side we’re left with the anthropic argument, psychophysical harmony, the fact that there are laws at all, nomological harmony, the fact we’re not in a skeptical scenario, moral knowledge, and far more. On the atheistic side we’re left with little. So I guess I’d ask you Richard: what do you think of my support for the broadly Bayesian methodology? And do you think there’s some not-super-implausible way to explain fine-tuning?

Richard: I think you really just have two arguments: anthropics and fine-tuning. The various harmony arguments are thematic variations on fine-tuning, and seem likely to stand or fall together.

I’m not sure how to assess the anthropic argument; it’s interesting, for sure. But I disagree that evil and fine-tuning “cancel out”: I think the former is orders of magnitude stronger. Some might take the problem of evil to establish that God’s existence is strictly incompatible with the world we observe, whereas there’s no question that atheism is at least compatible with our observations. So a lot hangs on whether one finds any theodicies to be remotely plausible. (Not a debate we can settle today!)¹

Neither atheism nor theism especially predicts the particular world we find ourselves in. Theism concentrates probability on the best possible world, not ours. The fine-tuning argument cherry-picks general features of the best possible world that happen to be shared by ours—it contains life!—and pretends that this means that theism predicts our situation. But that’s a trick, like p-hackers testing 20 variables and only reporting back on the one that suits their narrative. What theism really predicts is a very different life-supporting world than the one we observe.

Picture a probability distribution layered over a space of possible worlds. Theism sucks up probability from outlier worlds and pipes it all to the best possible world. Theodicies poke holes in the pipes, in the hopes that some probability might leak back into our world. The contest between our rival arguments then comes down to whether we should expect our world to gain more probability from inbound leaky pipes than we lose to the “best possible” pump. My money is on the pump.

One last point I want to stress in response to your arguments is that we have very little idea what the “natural” probability distribution over possible universes should look like. You suggest that fine-tuning has “a probability of one in googol, provided you either use the indifference principle or some other natural procedure.” But this neglects higher-order or model uncertainty. The likelihood that your background assumptions are wrong is much higher than one in a googol!² It’s genuinely obscure to me what priors we should have across the space of possible universes, and I think we should give some weight to priors on which a world like ours is much more likely than you suggest.³

Let’s shift angles. Up till now, we’ve assumed a particular conception of God: one on which he is all good, and hence actualizes better worlds (containing life) over worse (empty) ones. But isn’t that cheating? Why not expect God to love paperclips rather than people? Isn’t it a striking coincidence that, out of all the possible gods in logical mind-space, we got the one-in-a-googol whose motivations are fine-tuned for life?

Matthew: You’re right that evil might be incompatible with theism while fine-tuning is definitely not incompatible with atheism. But that doesn’t tell us much about the relative force of the arguments. Compare: me getting ten royal flushes is not incompatible with me playing fair poker. In contrast, it might be that various facts in physics are incompatible with the standard model—and you wouldn’t have expected them on the bare standard model. Nevertheless, obviously me getting ten royal flushes is better evidence that I’m cheating than anomalies in physics are against the standard model. What matters is probabilities not whether some hypothesis has a chance of being incompatible with the other hypothesis.

I also agree theism doesn’t predict our world. My claim is merely that it predicts it better than atheism. Compare: if I see a piece of paper in front of you that contains some crude drawing, it would be evidence that you drew it rather than that you randomly spilled ink that was in that pattern. This is so even though my prior in you making a crude drawing is rather low.

Now, regarding why I think God is good—I’ve sketched this out in a bit more detail here, but let me give the brief outline. I’m a dualist (I know you are too Richard, but a lot of the audience won’t be—so I’ll link Richard’s powerful arguments for dualism). I think that mind and matter are, therefore, distinct and don’t reduce to each other. The world is, therefore, filled with three kinds of things: minds, physical stuff, and abstract objects.

Now, I think of theism—of the sort I advocate—as the hypothesis that simply one of these things (mind) exists totally without limit. God is a mind without limit. Being unlimited, nothing restricts his power or knowledge. Because he has no rational constraints, following Parfit, he’d be motivated to always do the right thing.

Now, it’s true that a limitless mind is just one of infinite conceivable designers. But crucially it’s a much simpler and more modest hypothesis than the other designers with random built in desires, powers, and bits of knowledge. It posits one of the fundamental things exists without limit. Just as the theory that space has uniform laws all throughout is much better than any of the infinite theories on which the laws of physics break down in a random patch, I think the theory that there’s a totally unlimited mind has a higher prior than the limited god hypotheses. Then, when we observe that it fits the data way better than alternatives, it’s worth believing. (Note: I think even if you think there’s a low but non-trivial chance that theism is very simple, it will still start with a big share of the prior space for reasons I lay out here).

One final point about P-hacking: I think almost all atheistic worlds wouldn’t be expected to have any conscious agents at all. So it’s not like I’m just picking random good things that are a bit unlikely. I think the fact the world has even a tiny sliver of value is very much more expected given theism than atheism—especially because most conceivable laws produce nothing of value, plus we need finely-tuned constants, and there’s no reason for any physical arrangements to give rise to consciousness.

Richard: So it all comes down to whether “mind without limit” entails moral perfection. I don’t see why it would. Wanting things other than what one objectively ought to want doesn’t strike me as a metaphysical “limitation” on a mind. A paperclip God has just as much Mind as a beneficent God; it’s just directed towards different ends. We happen to have a simple-sounding concept that unpacks into some specific set of (potentially very diverse) ideal desires. But I don’t think the simple tag we apply to it makes the ideal desire set any “simpler” or more metaphysically “modest” than a singular desire for nothing but paperclips. Perfect virtue may be an extremely complex psychological property, and not one we have any reasons of parsimony to especially expect to see realized.

Perhaps we can wrap up with a look at the practical implications of theism. People often move rather quickly from a philosophical belief in theism to acceptance of some particular world religion (such as Christianity) that memetically evolved to demand proselytizing. If you think the fate of others’ immortal souls depends on their converting to your religion, missionary work could start to look a lot more important than literally anything else.

But a truly good God couldn’t possibly be so petty as to punish honest non-believers who are trying their best to make sense of the world in which they find themselves. So I can’t imagine why God would want us to do anything other than what would be independently good and worth doing whether he exists or not. If I’m right about this, then—intellectually stimulating as this debate may be—the outcome probably shouldn’t make any difference to how we live our lives. What do you think?

Matthew: I didn’t mean to suggest that being evil is inherently a limit. I don’t think it is intrinsically, at least not qua mind. What I suggested was that being ignorant of some facts is a limit on a mind. It means its awareness is restricted. So therefore if a mind is totally without limit, it would know every fact and lack any rational constraints so always pursue the good. Just as a rational agent would, as you’ve noted, care about their own interests on a future Tuesday, they’d also care about the interests of others.

Note: you don’t have to think this is very probable. All it needs to start out is not astronomically improbable. Then when you update on all the surprising things about our world, you get a high likelihood of theism.

I agree with you that a good God would not send people to an eternal hell. I suppose I think the practical implications of theism are:

1. You should, after learning there’s an afterlife, prioritize how things go throughout eternity over trivial pleasures. So you should prioritize building relationships over short term pleasures.

2. You should seriously investigate various religions to see if any are correct.

3. You should pray and attempt psychologically to cultivate a relationship with God.

But I would grant that most of the normal EA causes are just as good as they’d otherwise have been even if we’re theists. In fact, they’re likely better!

1. Though I also have a favorite.

2. Analogous reasoning suggests that no-one should be certain that the logical problem of evil succeeds, either. On such abstract matters, it’s very hard to be sure what one should think, alas.

3. In support of this, I find it independently plausible that our priors should strongly disfavor various wacky “skeptical” scenarios, such as that the world just popped into existence fully-formed (fake memories and all) one minute ago. Some worlds are intrinsically less credible than others (though it’s an interesting question why that should be so). Now, it’s far less obvious that inhospitable universes should be considered similarly incredible. That’s why the fine-tuning argument gets more of a grip on us than radical skepticism does. But I’d think there’s at least a 0.1% chance (certainly more than 1 in a googol!) that some generalization along these lines could turn out to explain why we shouldn’t be so baffled by fine-tuning after all.