Stephen Casper, thestephencasper@gmail.com

Euconoclastic blog series

When I was a child, I was taught the biblical story of Abraham: God commanded Abraham to sacrifice his only son, Isaac. He followed God’s instructions and bound Isaac on an altar atop a mountain. But right before Abraham killed him, an angel came from heaven and explained that Abraham had passed God’s test of faith and that instead of killing his son, he should sacrifice a ram instead. For Abraham’s obedience, God told him, “I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore. Your descendants will take possession of the cities of their enemies, and through your offspring, all nations on earth will be blessed, because you have obeyed me” (Genesis 22: 17–18).

The Beginning of the Beginning of a Discussion

Nature dealt humans an interesting hand. We’re capable of some really impressive cognition, but we’re still animals who evolved in small tribes in Africa’s Great Rift valley. Life there was “nasty, brutish, and short.” In an evolutionary sense, each of us is a bag of molecules arranged to replicate and propagate genes. Evolution shaped us to survive in an unforgiving world. Form follows function, and consequently, our natural instincts are tribal, heuristical, and selfish.

But now we now live in a world very different from the plains where we evolved: globalization, science, and social progress give us many more opportunities and obligations than savanna. Because of this, I think it’s time we shed parochialisms that may have helped our tribes cohere and survive long ago but that only hold us back today. For the sake of truth and progress it’s time we tapped into the “better angels of our nature.”

Here, I’d like to discuss what I think are some key arguments in the debate over religion that are usually ignored or poorly presented. I have an audience in mind. Most everything that I say will apply broadly to today’s organized religions, dogma, and superstitions in general, but I have Christianity at the front of my mind.

I’ll be making two main points. First, that probabilistically, core religious ideas and world religions are almost certainly false. And second, that ignorance, regressiveness, and tribalism make religion overwhelmingly net-negative and a principle barrier to moral, political, scientific, and intellectual progress.

I used to be very religious, but since leaving, it’s been difficult for me to understand the mindset of religious people. So to any religious reader, If you indulge me, read this, and still believe in your religion, feel free to explain to me why I’m wrong. Email me at thestephencasper@gmail.com.

Section 1: Bayes’ Theorem

1.1 Derivation

Before getting into specific arguments, I need to talk about Bayes’ Theorem. If you’re familiar with the theorem already, feel free to skip to subsection 1.2. You won’t miss anything if you know what posterior, prior, likelihood, and normalization refer to.

Let A and B simply be overlapping events in the space of all possibilities.

Let’s say that we have a space of all possibilities for something unknown (an example could be the set of all types of weather we might see tomorrow). Let’s also say that we have two events A and B within that possibility space (which could, for example, refer to the events that it’s rainy and that it’s cold). Also suppose that A and B overlap.

Probability is a function of an event and can be written as:

A conditional probability is the probability of an event if we know that some info that another event is the case. The probability of an event given some other information can be written using bar notation:

Conditionals are useful in statistics. For example, if we know that tomorrow will be cloudy, we can assign a higher probability to it being rainy than if we had no information about whether it was cloudy.

And we now have all of the tools we need to derive Bayes’ theorem. First, we can write an expression for the probability of A and B as the probability of B given A times the probability of A. If it’s not immediately clear that this is true, refer to the diagram above.

We can then do the same thing with the letters switched. After all, there’s nothing special about the labels A and B.

We can then write an expression with these two expressions as equal.

And then we can simply divide both sides by P(A).

This is Bayes’ theorem. Now, let’s ascribe some meaning to A and B. I’ll replace A with D which stands for data. We can think of it as some set of observations. I’ll replace B with H for hypothesis. We can think of it as some theory of what is true.

Our expression now reads: “The probability of a particular hypothesis given some data we have observed is equal to the probability of observing that data if the hypothesis is true, times the prior probability of the hypothesis before we observed the data, divided by the probability of observing that data without regard to a particular hypothesis.” This is probably confusing, but things roughly make sense if we consider each term individually. In fact, each of these terms has a name.

If you aren’t familiar with Bayes’ theorem, I recommend grabbing a pen and copying down this diagram for reference as you read.

The posterior probability refers to the probability of H after (post) we observe D. The prior probability refers to how likely H was prior to observing D. The likelihood is how likely D is given H. And the overall probability of D is called the normalization because it doesn’t change when you use a different H, and this term normalizes the probability distribution around 1. Sometimes this term is also called the marginal likelihood, marginal evidence, model evidence, evidence, or significance.

What is where in the equation should intuit nicely.

The more likely that D is given H, the more consistent H is with observing D, so the likelihood is in the numerator of the fraction.

The more probable H is prior to observing D, the more probable the posterior, so the prior is also in the numerator.

The normalization term is in the denominator because the more likely D is in general, the less strong it can be as evidence for or against an H.

Here’s an example. Let’s say you have two opaque jars full of marbles. One has 9 black and 1 white marble, and the other has 5 black and 5 white ones. You don’t know which is which. You pick a jar and pull out a black marble. What is the probability that this jar is the 90% black one? In other words, what is P(H|D) — the probability that the jar is the 90% black one given the D of having chosen a black marble? We can find our terms and write our equation.

P(D|H) is 0.9 because if this is the 90% black jar, there is a 90% chance of pulling out a black marble. P(H) is 0.5 because there is a 50% chance that choosing a random jar will result in the majority-black jar. P(D) is 0.7 because out of all 20 marbles, 14 (70%) of them are black.

This evaluates to about 0.64, meaning that there is about a 64% chance that this is the 90% black jar given the data of having pulled a black marble from it. Hopefully, Bayes’ theorem makes sense now, but I won’t pretend that I’m the best teacher. I recommend looking up alternate explanations to strengthen your understanding. From now on, I’ll assume a comfortable understanding of the theorem.

1.2 Why Bayes’ Theorem?

Bayes’ theorem is part of the answer to any question of the form, “How likely is this hypothesis?” for any hypothesis that pertains to an empirical fact about the world [1]. In comparing the probability of different hypotheses, we need to take both likelihood and the prior into account (remember that normalization isn’t usually too important when comparing different hypotheses because it’s just a constant that depends on the data). Priors, likelihoods, and Bayes’ theorem in general are concepts that religious cultures tend to conveniently ignore — and for good reason. They show why religion is almost certainly false.

A certain type of radical frequentist might philosophically disagree with the concept of a prior probability entirely because ascribing priors to events is inherently arbitrary. To this person, I say:

You’ll see that most of my number-crunching here will not involve very arbitrary priors. It will mostly involve qualitatively assessing events as “very likely” or “very unlikely.” We should spend our time conditioning on what’s unknown instead of what’s known. We have to have some notion of priors. Consider two events: that I am wearing shoes and that I am wearing brown shoes. Without any evidence at all (and given the fact that non-brown shoes exist), we can say, a priori, that the first is strictly more likely than the second. A frequentist had better be an agnostic instead of a religious person. If we don’t discriminate by priors, then we can’t say that even the most ridiculous, ad hoc set of explanations for the world are of any less merit than any others.

1.3 My Terms

There are legitimate, high-level discussions in epistemology to be had about the validity of bayesian reasoning and empiricism, but If you’d like to start a discussion about these questions, please save it for another context. To keep things topical and relevant, I would like any discussions that follow from this to assume an empirical and bayesian epistemic framework. And really, this isn’t asking much.

1.4 There’s a dragon in my garage!

What if I told you that there was a dragon in my garage? That seems far-fetched — you’ve never seen a dragon before and wonder why one would be in my particular garage, but there is a straightforward way to verify whether or not I’m telling the truth — just look in my garage. Let’s say that you open my garage and see no dragon inside. But then I tell you that the dragon is there, but it’s invisible. You raise your eyebrow, but there is no reason to get too frustrated. If there is indeed an invisible dragon in the garage, there are other ways of detecting it. For example, you could throw flour at it, and if the flour hits some invisible surface, there might be something to this dragon hypothesis after all. When you throw a handful of flour into the garage, it falls to the ground. I then tell you that it’s an invisible dragon that’s permeable to flour.

After seeing no dragon and watching flour fall to the flour, how does your degree of belief change about whether or not there is a dragon in the garage? It goes down, of course. But why? Let’s refer to Bayes’ theorem:

At first, before you made any observations, the probability of there being a dragon in the garage would just be the prior probability (whatever that is — probably a somewhat low value):

But then you see no dragon when opening the garage, so you update your belief with the equation.

Your posterior probability of there being a dragon has clearly gone down. It’s not because of the prior probability — it’s the same as the prior for the last equation. And it’s not because of the normalization — it’s actually less than 1. It’s the likelihood. Presumably, it’s not very likely that if there’s a dragon, we would be unable to see it, so the probability of seeing no dragon when there really is one is low.

Your degree of belief in the dragon (though not zero) in my garage is decimated again with the second observation for the same reason. If there’s a dragon, it’s not so likely that we’d see the flour fall to the floor of an empty garage.

But wait! We’re writing the wrong equations! After each observation, I update my hypothesis. The hypothesis changed from just “dragon” to “invisible dragon” to “invisible, permeable dragon.” The likelihood term isn’t going down. Our new observations are perfectly consistent with my updated hypotheses!

Well, let’s update our final equation.

Sorry for the long expression, but let’s look at what’s going on. Once again, the normalization term isn’t interesting. It doesn’t change when we change hypotheses. But look at the likelihood term! If I am right about my dragon being invisible and flour-permeable, then P(not seen, flour falls | invisible permeable dragon) is very close to 1 — the observation is completely consistent with the hypothesis!

But surely enough, I run into a problem. There is a probabilistic price to pay for making excuses. Invisible, flour-permeable dragons are presumably a very, very small subset of all possible dragons. The prior probabilities of my new, increasingly-specific hypotheses are lower than the original, more general hypothesis. It doesn’t matter what excuses I make. The more specific I get, the lower my prior gets. In fact, the prior probability always decreases by a factor greater than or equal to how much the likelihood increases when we make our hypothesis more specific. Coming up with ad hoc (a good phrase to Google) hypotheses has done nothing to defend my claims against our observations.

If you are anticipating the type of argument that I’m about to make, you’re probably correct, but bear with me. I’m going to explain my arguments in a somewhat unique way.

Now let’s begin our hunt for dragons!

Section 2: Probability

2.1 The Empirical Test

The hypothesis that this test applies to is “there is a god or gods”. By “god,” I mean something along the lines of a being with supernatural powers who exercises some significant dominion over the world.

We already have a lot of information about the world, but I’d like us to begin our test imagining that we are in a very agnostic position. Let’s say that we knew almost nothing about the universe or how anything worked, and we had nothing to reference in answering this question. So we might assign our hypothesis some modest prior, whatever that might be (we could even be so bold as to say that it’s 0.5 — but the exact value doesn’t matter).

Now let’s imagine that we come across some data in the form of the total body of today’s scientific knowledge. We certainly have more to discover, but it’s quite an impressive collection of knowledge. We notice that there is no scientific evidence (at least none that remotely meets the standards of today’s scientific community) of a god or anything supernatural. Let’s see what we get when we plug this into the equation.

Our posterior probability is low, and the reason is the likelihood. If there truly is a god, then from an agnostic standpoint, it really does seem pretty weird that there is no evidence of them at all.

But absence of evidence isn’t evidence of absence, right? Actually, not at all — that’s literally, completely, abjectly false. It is evidence of absence. If I am looking for a dragon to find out if it’s real, and I check everywhere I can possibly think to look, yet find none, Bayes’ theorem tells me that I must be less confident that dragons are real post-checking than I was pre-checking.

But this hypothesis that we’ve been working with is very vague and not the kind of hypothesis that most religious people have. That one more closely resembles, “There is a god who doesn’t want to be detected.” But this is awfully convenient — a lot like saying that my dragon is invisible. This ad hoc hypothesis might save the likelihood, but it doesn’t save the posterior. It’s a really arbitrary thing to believe. Why would some god who exists conveniently make itself completely unobservable? Surely, of all possible gods that could exist, one who cares so strangely much about making themselves hidden would be an anomaly among them. We have to penalize the prior probability, and the resulting equation leaves us with a posterior that’s less than or equal to before.

Some may object to my assertion above. They might say that it’s not arbitrary to think that a god would want themselves to be undetectable in order to test people’s faith. Put a pin in this. I’ll discuss it in subsection 2.8.

Finally, concerning the counterargument that there are supposedly figures in religious history who have directly observed god or the supernatural, this meets no standard whatsoever of scientific scrutiny. Noting this, the likelihood suffers. Also, virtually every religion believes in these events, so it would be awfully convenient to see one’s own religion as being special, and the prior suffers as well.

And there we have it: that fact that there is zero credible, empirical evidence of a god or supernatural phenomena is itself a strong reason to doubt their existence.

2.2 The Historical Test

The hypothesis that this test applies to is “[religion X] is true.”

Every major world religion, to my understanding, has its own mythology about the creation of the world and certain events that have happened since: Christianity, Islam, Judaism, Hinduism, etc. This applies less to Buddhism, but the somewhat mainstream Buddhist idea that there was “no beginning” is itself a dogma, and there’s a plethora of mythology surrounding the Buddha nonetheless. It’s plain to see that these religious histories tend to conflict with scientific consensus on concepts like evolution, the geological history of the Earth, and the Big Bang.

Consider Christianity. The Bible explains that the universe is several thousand years old, that the world was populated by an incestuous family from a single location twice, and that Earth underwent a global flood. It almost seems as though these historical accounts were made up before science was there to disprove them, but let’s not get ahead of ourselves. It’s also noteworthy that religious histories usually have stories of times when a god revealed itself, spoke directly to people, or something of the sort. For example, Yahweh supposedly spoke to old-testament figures like Abraham directly and often. Almost invariably, these occurrences are believed to have happened a long time ago. Convenient right? I can’t think of a good reason why a god would regularly reveal themselves for a while and then conveniently stop directly communicating with people once civilization became more advanced and scientific.

Let’s turn to Bayes’ theorem. Recall our hypothesis that religion X is true. Once again, we can assign it some modest prior. Let’s have our data be the scientific observations that have led to the consensuses about the history of the world plus the event that a god does not seem to reveal itself anymore.

What does the posterior probability look like? Well the prior is modest, and the normalization is just the normalization, but look at the likelihood term. What is the probability that we’d have our scientific consensus about history and the observation that no god reveals themselves given that religion X is true? This is very low, and because of it, so is our posterior probability. For this hypothesis and these data to be compatible, either our scientific understanding must be completely wrong or the religious history must somehow be excusably false despite the religion being true in general!

This could be treated, prima facie, as a demonstration that religion X is false. But there are three tactics that religious believers tend to use. But considering the likelihoods and priors, none improve the posterior. They are:

“I don’t know, but I still know religion X is true on other grounds. “Religion X is true, and the science is false.” “Religion X is true, and the science is true. The religious history is an analogy for a more scientifically-compatible account of creation.”

The first viewpoint doesn’t propose a new hypothesis. It confronts the likelihood head on. But we know that likelihood to be very low. If we ever find ourselves defending a belief by saying “I don’t know how it could be possible for [X] to be true, I just know it is.” then we need to stop believing this [2]. If our hypothesis is that something absurd is true, it’s a very bad hypothesis. [3] For more thoughts on this, see the other tests in the following subsections as well as subsections 2.8 and 2.9.

Concerning the second viewpoint, I don’t think it’s worthy of much consideration. There are real philosophical discussions we can have about induction, empiricism, and the scientific method, but rejecting them outright isn’t really something that’s practically justifiable. We should feel fine dismissing this viewpoint for what it is: flagrant ignorance. Needless to say, this viewpoint doesn’t beat Bayes’ theorem. It’s safe to say that that the science being completely wrong is not likely, so the prior probability for this new hypothesis is presumably very, very low.

The third response is the most egregiously ad hoc of the three, and it brings up far more questions than it answers, and the prior suffers. Why would this be any god’s plan? Why would such a god give people a false account of the world? What would be the harm in telling the truth? If the purpose of mortal life is to be morally tested, why would this lie have anything to do with that? This may fix the low likelihood, but the prior probability of a god who behaves so strangely is low. I can’t imagine a plausible reason why this would be the case (but that doesn’t seem to stop some people from doing backflips to justify it).

2.3 The Consistency Test

The hypothesis that this test applies to is “[religion X] is true.”

For any major religion, you can easily find some sort of doctrinal contradiction compilation with Google. If you think it’s worth your time, and if you’re interested in the specifics of contradictions, feel free to delve into them for a religion of your choice. But for now, I’ll frame this around Christianity.

There is no reasonable debate to be had over whether Christian doctrine is contradictory. Have a look at one compilation of contradictions here, and watch some of the incisive videos from this YouTube channel (If I can’t convince you that Christianity is false, this channel might be able to.) And none of this goes to mention how commandments somehow change over time periods. This poses an obvious problem for Christianity (or any other established religion). Why would religion X’s deity(ies), an ostensibly good and powerful god, do such a terrible job of disseminating doctrine. It almost seems as if book so contradictory as the Bible is a messy compilation of ancient texts instead of the literal inspired word of an impeccably-wise god, but I digress. Let’s turn to the theorem, and, as before, assume some qualitatively-modest prior to religion X.

As with previous tests, the posterior is very low, and it’s not because of the prior or the normalization. It’s the likelihood. If a central tenet of religion X (like christianity)is that god is all-good and all-wise, then it’s clear that the probability of there being egregious contradictions in that religion’s doctrine given its truth is very low — so low that a straightforward, rational explanation for it does not exist. Three common responses are:

“What contradictions? Oh, those? You’re just misunderstanding the context.” “These aren’t contradictions. There’s a higher meaning to them that just isn’t clear to our meager mortal minds.” “People are imperfect, and god chooses to work through them. It was them who messed up the doctrine — not god” (note that some, such as Muslims who believe that Allah literally dictated the Qur’an, can’t make this argument).

This first viewpoint is intentionally general. It’s a cheap attempt to blanket hundreds of documented contradictions in the case of the Bible. The proper response would be to go through these contradictions and see what can and can’t be chalked up to context. And when it comes to matters of simple fact (like whether Aaron died at Mt. Hor or Mosera) or basic law (like whether God forbids or ever commands killing), no reasonable “context” excuse exists. The posterior is still low because of the likelihood.

For the second viewpoint, the likelihood remains low when we recall that our deity is supposed to be all-wise and powerful. Simple ambiguities — let alone flagrant contradictions — aren’t compatible with the hypothesis. There is no coherent explanation for why an all-wise and powerful god would compile a set of doctrine so messy and confusing with portions that are for some reason so complex, they make no sense. If the purpose of doctrine is to instruct people, we’d probably expect it to not be so confusing. We can also notice that this argument is circular. It aims to defend contradictions by assuming that the hypothesis is true, asserting that god is super-sophisticated and profound, and then using that belief to explain away the problem.

This third argument is a textbook example of an ad hoc hypothesis. It asserts that an all-powerful god both limits themselves to working through people and lets these people make glaring mistakes. We have problems all-around when we put it to the test. The point from the last paragraph about how an all-wise and powerful god would probably not let egregious mistakes into highly important doctrine keeps the likelihood low. And the fact that this argument asserts that an all-powerful god, for some mysterious reason, limits itself to working through people, allowing them to do a terrible job, keeps the prior low as well. Some may insist that it’s justifiable that a god would work through people in order to test them, but objectively, this is as arbitrary as the original assumption, and the prior suffers because of it.

By now, our posterior probability of religion X isn’t doing so well (as in it’s so low, multiple absurdities are required for it to be true) from the hits it’s taken in the past three sections, but the final tests that I’d like to explain next are, I believe, the most potent.

2.4 The Designer Test

The hypothesis that this test applies to is “there is a basically ‘good,’ powerful, and rational god who exercises significant dominion over the world.”

If I were more cautious, instead of this hypothesis, I would say that I’m applying this test to the hypothesis that there is an omnipotent, omniscient, and omnibenevolent god. My point would cleanly come through, but I think there’s a stronger point to be made with this hypothesis. It’s not just that the world is inconsistent with the existence an omnipotent, omniscient, and omnibenevolent god. It’s inconsistent with the hypothesis that there is any god who isn’t weak, illogical, or monstrous. Once again, let’s pretend to start from an agnostic position, ascribe some modest prior to our hypothesis, and then make some observations about the world. I think there are 5 key things to notice and update on. When we treat each as data, the likelihood of our hypothesis suffers greatly.

There is a lot of evil and suffering in the world. Children starve and die of horrible diseases. People are born with terrible conditions. Others suffer from tormenting mental health problems. And people — including children — and animals are brutally killed, tortured, and raped. We could go on — the world gives us countless examples of horrific suffering. What kind of person would allow this to happen? If a god knew about this and could prevent it, what type of horrific mind must they have to see this suffering, know they have the power to prevent it with the wave of a hand, and then not do it? This would not be wise, kind, or loving behavior— especially if this god supposedly wants us to prevent suffering when it does not. There are massive inequalities in the world. Some people are wealthy enough to hire personal chefs, chauffeurs, butlers, and maids, while others are too poor to afford rice. Moreover, inequalities correlate strongly with family, neighborhood, region, country, ethnicity, and race. And what about inequality in religious truth? If we assume that some religion is true — whatever that religion is — we can observe that its truth is concentrated in specific places with people of specific races and cultures. What kind of god would allow this to happen, let alone, as most religions believe, intentionally make the world like this? What kind of god would be so callously classist, nationalist, and racist? As discussed in the last section, certainly no major world religion, and probably no organic religion at all is without blatantly inconsistent doctrine. Also, religious texts (perhaps most of all the Bible) tend to be bizarre and hard to read. When we look into them, we tend to find countless examples of god-sanctioned crusades, cruelty, violence, persecution, and the like (have a look at this video on the Bible). What kind of god who is anything better than terrible, ignorant, or impotent would give priceless doctrinal instructions to the world (filled with people they presumably care about) in such a sloppy and confusing way? And why would it sanction so much evil? There are some things of moral importance that major religions’ gods don’t seem to command people to do. For example, the consumption of meat is responsible for the inhumane treatment and/or killing of hundreds of billions animals each year (if we include fish, ~50 billion if we don’t), extraordinary land degradation, pollution, and climate change. This is a problem that causes suffering on a massive scale while posing a principal threat to global civilization itself. What kind of good and powerful god would not tell their followers to abstain from meat and environmentally destructive lives? Yet few major world religions treat this as an obligation. (It almost seems as if religion is something that’s culturally and anthropocentrically self-serving.) Moreover, we tend to see many morally neutral and arbitrary practices that religions do treat as commandments. For example, some Christians see church attendance, sacraments, baptisms, countless other rituals, avoiding caffeine, not eating fish — but only on certain days, specific clothing, non-masturbation, heterosexuality, and abstinence as morally required. And what about tithes and missions? Isn’t that convenient? The world is full of organic complexities. It’s often said that the world has an interesting complexity, such as that of a watch, and that its very existence must imply a watchmaker-like god. This is naïve. We can observe many organic complexities in the world that imply a blind, messy process of evolutionary organization and certainly not rational engineering. Anyone who likens the world to a watch should study biology (or anthropology). For example, why are there different languages (with very arbitrary grammars) and races? Why do we have appendices? Why does menstruation happen? Why genders at all? Why do we have so much biodiversity? Why are 25% of all animal species beetles? Why do vestigial structures exist? Why do infectious bacteria, viruses, and pryons exist? Why are there pseudogenes? Why do cancer and so many other diseases exist? Why is RuBisCO so catalytically inefficient? Why all of the complexities of gene regulation? What kind of rational engineer would design a world like this? None of these organic complexities that we see in society and biology make any sense at all given the plans that major religions profess that their gods have for humanity.

Let’s now turn to the theorem. We now have a set of five types of observations: suffering, inequality, bad doctrine, not-good doctrine, and complexities. We will just call these observations, and we’ll refer to our hypothesis that there is a good, powerful, and rational god simply as “god”.

Once again, the posterior is low, and it’s because of the likelihood — not the prior or the normalization. And the likelihood is low — extremely so because of absurdities on top of absurdities. How could it be possible that a good, powerful, and rational god would make a world with so much unneeded suffering, so much unneeded inequality, immoral and inconsistent doctrine, morally inadequate doctrine, and organic complexities?

There are some alternate hypotheses that religious people will take up to boost the likelihood in the equation. Here are a few.

One is the assertion that suffering is a price of agency, but not only does this do what we’ve seen before — lowering the prior proportionally or more to how much it increases the likelihood — but it does so very poorly. This could only be anything more than completely ad hoc if somehow the ability to cause each other pain was an essential part of a god’s goals of judgement, but this would itself not be consistent with the idea of a good, powerful, and rational god.

People will also sometimes say that suffering is needed for happiness. I think this is highly doubtful [4], but regardless, this doesn’t explain the distributions or amounts of suffering that we can see. It runs into the same problems as the last excuse — it decimates the prior, and it fails to increase the likelihood much.

Another strategy is to say that inconsistencies in doctrine or bad doctrine are really just high-level complexities that meager mortal minds can’t understand. See the previous section on the consistency test for my thoughts on this.

Another is to say that moral good is defined by god, so something like farming and eating meat — which is factually causing massive suffering and damage to the planet — is not bad simply because god says it’s not bad. It should be clear that this is circular which makes the prior very low. It’s also inconsistent with humanistic morality. Why would a god make us have such an incorrect sense of their morality when we reason about ethics?

And it could be argued that organic complexities in the world are just signs of a god whose intelligence is far superior to ours. But as discussed last section, this is circular, and the prior suffers.

Maybe there are other new hypotheses that religious rationalizers have ventured, but what always seems to happen is them taking a stand in one last corner: the cliché that “God works in mysterious ways.” This idea translates to a hypothesis that there is a mysterious god whose actions, for no conceivable reasons, yet because of consistency with a sort of mysterious good, explain exactly the type of world we live in. Needless to say, this prior probability is ridiculously, ridiculously low. Remember: if our hypothesis says that something incomprehensible is true, it’s a very bad hypothesis. And I proffer that given our aforementioned observations about the world, the idea that a good, powerful, and rational god exists is absurd. Goalpost-moving — especially dropping out and regurgitating the idea that “God works in mysterious ways,” — can’t save a virtually hopeless posterior when we put it to the Bayesian test.

Isn’t it funny how willing some religious people are to admit they don’t understand the nature of god compared to how unwilling they are to consider that their god doesn’t exist?

2.5 The Second-Order Designer Test

The hypothesis that this test applies to is “there is a basically ‘good,’ powerful, and rational god who exercises significant dominion over the world.”

The posterior goes even lower. Once again, let’s start from an agnostic position and ascribe some modest prior to our hypothesis. Now let’s observe that in the last section, we concluded that our hypothesis was so unlikely that its truth would require multiple absurdities. As reasonable Bayesians, we can safely say that the hypothesis is a very bad belief.

Interestingly, observing our previous conclusion has further bearing on our posterior probability for the hypothesis that there is a good, powerful, and rational god who controls the world. The key consideration is that if this type of god created the world and wanted us to believe in them, then they would probably make their existence something that could be rationally concluded — or at least not absurd. What kind of arbitrary and bizarre god would give people the ability to reason, yet expect them to have faith despite an abundance of evidence to the contrary? Once again, an answer would be absurd. Our equation is as follows.

The posterior is yet another degree of absurdity lower. But what is the religious response? That “faith is important.” As I’ve discussed in subsection 2.1, the lower prior of this new hypothesis pulls down the posterior. And for more of my thoughts on this faith argument, see subsection 2.8.

This second-order test extrapolates to third, fourth, fifth…ad infinitum tests, though the amount by which each successive test reduces our prior approaches zero with higher-order tests because successive absurd events are positively correlated.

2.6 Alternate Hypotheses

So if the religious hypotheses we’ve considered are bad ones, what hypothesis should we adopt instead? Well, when we observe the world’s religions, zero evidence of a god, false religious histories, inconsistencies, the lack of modern appearances of a god, contradictory doctrine, immense suffering, arbitrary inequalities, immoral doctrine, insufficient doctrine, arbitrary doctrine, and organic complexities in the world, there are a few reasonable conclusions to reach:

There is no powerful god who intelligently and virtuously designed the world and who wants to be believed in. The world as we know it a product of physical laws and evolution. Religions are self-serving, tribal belief systems based on messy, contradictory doctrine and arbitrary culturalisms instead of direct instructions from a good, powerful, and rational god.

I think that unlike any religious hypotheses, this three-part hypothesis has a compelling posterior probability to specificity ratio.

But where did the universe come from? How did it all begin without some particular god? This is a great question with a fantastic answer. I don’t know — something I admit instead of defining an imaginary god to be the answer. In my experience, religious people seem to think they’ve scored a point when they have a belief system that explains the world when atheists don’t. But I could contrive some completely made up hypothesis that a non-benevolent spaghetti monster created the world, and I would probably still have a higher posterior than religion because mine doesn’t involve any flagrant contradictions or absurdities! I’ll discuss this more in section 2.9.

Three more quick points: First, the same question can and should be turned back onto religious people about the origin of god. Second, in reality, we do have some good hypotheses about the origin of the universe, and solipsistic theories are also interesting. And third, it’s perfectly conceivable that there is something deity-like out there, but it is not plausible that world religions’ are true.

2.7 Biases

If religions are so unlikely, why do so many people believe in them? There are a lot of biases and fallacies that help to explain this.

Bandwagoning: Mark Twain wrote, “Whenever you find yourself on the side of the majority, it’s time to pause and reflect.” It’s well-understood that people are biased toward views that a majority holds. Social deviance isn’t typically rewarded, and many people believing something tends to lend credence to that idea. Unfortunately, not enough credence when the idea is contradictory and absurd.

Tribalism: If you look at religion in the world, the extremely strong association between communities, regions, countries, and ethnicities with religion is immediately clear. This obviously isn’t a coincidence — religion is part of culture. Almost everyone who is religious is religious for the same single reason: geography. Humans have strong tribal tendencies that cause them to cohere within ingroups and maintain distinctness from outgroups, and religion is a tribal flag to rally around. If you’re religious, and you have the same religion as the majority of people in your society, you ought to have a lot of skepticism of your beliefs based on that fact alone.

Confirmation Bias: It’s all too well-known that people, once they adopt a particular belief, are very resistant to change it. In this sense, religion traps people into bad belief— especially children. Most parents teach their children to believe in a certain religion (which I think would be criminal in an ideal world). Children have no choice but to believe what they’re taught. As they grow older, they find themselves trapped into rationalizing a view they never had the chance to view from the outside. If you’re religious and were taught that way as a child, it’s probably time for some introspection.

Sunk Cost Fallacy: Imagine two people: the first bought tickets to a sports game, and the second got the same tickets for free. They like watching the sport equally. On the day of the game, it’s raining. Who is more likely to go to the game despite the bad weather? Of course, it’s the first person who has made an investment in the game. But to this person, that cost is already sunk, and the choice that they face versus the one that the second person faces isn’t actually different from a rational, forward-looking perspective. Being part of a religion typically takes an investment of time, money, and social capital. Given the urge to save sunk costs and confirmation biases, it’s no wonder why many people feel such a barrier to leaving religion.

Optimism Bias: People are prone to be overly optimistic. Religion is a perfect example. Isn’t it interesting that everyone seems to believe an omnipotent, omniscient, and omnibenevolent god who will send them to heaven while nobody believes in a god who is lame, dumb, or a jerk? But this type of belief isn’t rational — it’s more like a drug of the imagination. Just because a belief system is nice-sounding doesn’t mean it’s at all reasonable. Also see my related discussion in section 2.10 about Pascal’s Wager.

Anthropomorphic Bias (and projection): Isn’t it interesting that all religions seem to believe in human-like deities? Why not lizard or noodle gods? Certainly, of all the possible deities that could exist, the prior probability that god or the gods are humanoid can’t be that high, yet we see this common denominator across most religions (that, and human-like animals). Moreover, gods seem to embody very human ideals, but why doesn’t anyone ever seem to believe in a god who has different morals than them?

If you fit the mold for any of these pitfalls, I think it’s time to take a long, hard look at your beliefs. I’ll leave it to you to work out a version of Bayes’ theorem for debiasing.

2.8 The Fallacy of Faith

I suspect that my religious readers have at some point while reading this thought of the objection that their god wouldn’t be obvious because they want us to exercise faith in them. But as I’ve mentioned before, this is an ad hoc hypothesis that increases the likelihood but at the cost of the prior (I’ll spare you the equation). Of all possible gods, presumably ones which ascribe some mysterious value to belief are a small subset.

I sometimes hear people talk about faith in some unobservable god as if it were a virtue. But why would a god expect this of us? What is admirable about belief for belief’s sake? Why would it ever be a good thing to suspend our criticality and trust in something whose existence is illogical? It’s no coincidence that we see religions prop up faith as good. Yet interestingly, they only seem to value faith in their religion while condemning faith in other ones. The only way we could have a “justified” belief in some sort of inherent virtue to faith is if we already had faith in a god who wants us to have faith in them. Do you see the circularity? If we have to assume a claim is already true in order to justify it, it’s probably a very bad belief.

And isn’t it also interesting that religion used to be something to be believed and not believed in? It used to be that gods would make their existence obvious. Only as our ability to disprove the disprovable has increased, has religion’s emphasis on faith emerged.

2.9 Other Counterarguments

So far, I’ve been only considering evidence against religion. Certainly though, there must be things we can observe that would increase the posterior probability. And yes, there are! But none are very potent. Let’s visit some. If you think I’m missing something important, let me know.

The Universe: Sure, from an objective viewpoint, the existence of a universe is more consistent with some notion of a creator than the notion of no creator. But this doesn’t get us far. It’s just an observation that it’s a mystery how things all began, a definition of “god” as the explanation for all that, and the assumption that some particular god is the one true explanation.

Needless to say, this doesn’t justify any particular religion. Assuming that a “god” created the universe, we still can’t infer anything about its nature other than that it is something which creates. Anyone can make up some origin of the universe story, but they must pay the price of the prior. I might as well say that an apathetic noodle-god made the universe, and my posterior would be higher than any contradictory real religion because of how many contradictions it avoids.

Also, we have to be careful about applying Bayes’ theorem here because of the Anthropic Principle — it’s not remarkable to observe anything that is a prerequisite to observation. We could never see no universe because were it not for the universe, we wouldn’t be around to make that observation. When we translate this to Bayes’ theorem, we need to be extra careful. The prior of observing anything that is a prerequisite to observation is effectively 1 because we have to implicitly condition on the ability to observe, and given that the hypothesis takes up all probability mass, conditioning on the hypothesis doesn’t tell us anything about the probability of the data, so the likelihood and normalization are the same and cancel. We’re left with a posterior probability of effectively 1.

Consciousness: When it comes to consciousness, first, we have to consider the anthropic principle again. It’s not remarkable to observe consciousness because it would be impossible to genuinely observe non-consciousness. Second, we need to recognize that nothing uniquely equips religion as a hypothesis to explain consciousness. Consciousness may be mysterious, but mongering another mystery to explain it doesn’t get us anywhere. The prior remains low in this case because of how many explanations for consciousness could exist. And again — I could have a higher posterior for the claim that an apathetic noodle god is responsible for consciousness because it wouldn’t create direct contradictions like the world’s religions.

The Existence of Religion: The existence of religion definitely makes us more confident that there might be a god, but there is even more important context to consider in this case. If there were one world religion, the existence of religion might be a somewhat compelling bit of evidence that there’s a god. But have a look at the hundreds of religions in the world past and present. Is it a coincidence that these religions correlate so impeccably with race, ethnicity, and culture? Is it just a chance occurrence that they are each so similar in the social and political role they play in solidifying tribes, enforcing norms, and creating social power structures? When we observe both that there exist religions and that religions are so similar, we are led further away from the religious hypothesis than toward it. The likelihood of all religions being so similar yet only one of them being true is bad news for the religious hypothesis.

“I have felt the spirit of god:” This is the crux of countless people’s belief, so let’s unpack the idea. First, people of all religions and beliefs seem to have similar feelings of spiritual euphoria. How likely is it that only one religion’s people’s spiritual experiences are legitimate while everyone else’s are some degree of nonsense? Second, the likelihood is not high when we make this observation and informedly put it into Bayesian form. Let’s note that that humans are extremely prone to tribal and cultural delusions. As evidence, look at false religions, other cults, nationalism, etc. People tend to toe their tribal lines on a deep, emotional level. So what hypothesis is more likely? That a god expects people to believe in them because of completely unfalsifiable and unscientific belief-induced euphoria while they make their existence logically absurd? Or the hypothesis that belief-induced euphoria is a glitch of human emotion?

2.10 Pascal’s Wager

While the probability of any of the world’s religions being true may be absurdly low, it’s not zero. Absurdities are a possibility, and we shouldn’t be crunching literal 0’s and 1’s in the real world. So why would we need to care about truth? Why not care about utility? Pascal’s wager is an argument which goes as so: if I don’t believe in a religion and I’m right, nothing happens, but if I’m wrong I go to hell. If I do believe in a religion and I’m right, I go to heaven, but if I’m wrong nothing happens. So religion must be a better bet, right?

There are two problems with this argument. First, when we consider utility, we can’t ignore the costs of participating in religion. It takes time, energy, and usually money. Also, as I’ll discuss in section 3 of this essay, it’s a principal force for bad in the world. These very probable drawbacks might outweigh an extremely small probability of going to hell.

Second, I frankly think a moral atheist’s lifestyle is more likely to send someone to heaven than a religious one — seriously. We can’t just consider religions as the only hypotheses that involve postmortal rewards or punishments. We need to consider others too. And if we’re going to bet on something with no evidence, we should bet on something plausible and with no contradictions instead of absurd with many contradictions. Like I’ve said before, the completely arbitrary hypothesis that an apathetic noodle monster created the universe probably has a higher posterior than the world’s religions do. Instead of something like the world’s religions, something closer to the best hypothesis (assuming there exists some rewarding/punishing deity) would probably be that there is a god or gods who don’t reveal themselves to us, but will reward or punish us for how we embody rationally-derived virtues like morality and reason in a broken world full of evil and uncertainties. Pascal’s wager, properly applied, should compel us to reason and humanistic virtues that make sense, not religious dogma and parochialisms.

Section 3: Progress

3.1 The Wrong Debate to be Having

Religious readers might be anticipating what I’m going to say: that religion makes people intolerant, belligerent, and closed minded. They may have the response in mind that religion, in fact, makes people kinder and more charitable while believing that my criticisms are (A) not a feature of real religion or their religion, and (B) outweighed by the good.

But slow down a bit.

This debate has been had countless times before, and it doesn’t seem to get us far. Religious people point out good things religion does, and anti-religious people emphasize the bad things religion does. For example, for every anecdote about a religious act of service, we can point out one of hate, and for every instance of paternalism, we can point out one of hope. And for all of these, we can question whether religion’s association with an event was causal. And I subjectively suspect that the bad outweighs the good. But ultimately, I’m not optimistic about how productive this type of debate is, and I’m even less optimistic about this convincing anyone to change their mind about whether or not religion is actually good or bad.

Instead, I think we need to focus on big-picture issues and common denominators of religion to find that in general, it’s very net bad for the world and that rejecting it is necessary (though not itself sufficient) for a more enlightened, flourishing world.

3.2 Philosophical Progress

Religious moralities are invariably manifestations of a culture’s or individual’s belief. It’s not surprising that religions and cultures are so inseparable. In the early days of human civilization, it makes sense that religions existed because they helped to establish social coherence and order. Now though, they are a burdensome vestige that gets in the way of critical thinking. Worse yet, most people in the world believe in religions that are thousands of years old and who carry with them conservative moral norms antithetical to human progress. Above almost all else, religions don’t encourage free thinking. They promote — even enforce — adherence to dogmatic beliefs. Remember the story of Abraham and Isaac? Only if someone has broken the cultish bonds of religious indoctrination can they begin to think freely, consider values rationally, and develop moral ideas soberly.

3.3 Tribalism

This subsection should almost go without saying. Religion is another cultural line in the sand between an us and a them. And if there’s a single lesson to be learned from the panoply of tragedies throughout human history, it’s that tribalism is bad.

3.4 Science and Intellectual Progress

There are a lot of important questions out there, and a lot of answers that we need but don’t have. Religion pretends it has answers, closes minds, and often breeds outright hostility to science that conflicts with it. It’s no wonder that scientists are much less religious than the rest of the population. But if there’s a single lesson to be learned from the progress of human civilization over the past several thousand years, it’s that science and technology make life better through medicine, infrastructure, electronics, automation, etc. A world that fully embraces science, the scientific method, critical review, and rationality must reject religion.

3.5 X-Risk

Believing that “god has a plan for the world” is almost universal among religious people. But this leads to dangerous attitudes toward existential (civilization-destroying) risks, also known as X-risks. After all — if god has a plan for us all to die, then we’re all going to die, and if god wants us to live, they wouldn’t let us all die, and there’s nothing we can do about it either way. This is wrong — dead wrong.

Are you worried about X-risk? You should be. There are numerous threats that could take us out in short or medium timescales, and you should probably be taking them more seriously than you do. The greatest tragedy of destroying our entire civilization though, may not be the immense death and suffering up front. It would be the blown chance of humanity taking advantage of its immense potential cosmic endowment in the future and creating very many more happy lives. Nick Bostrom has done a back of the envelope calculation that reducing the chances of human extinction by just one billionth of a billionth of a percentage point is equivalent to saving 100 billion billion human lives. X risk is serious, and we need to face the overwhelming likelihood that no god is going to save us.

Addendum

There I was, staring at the wall — I loved that wall. At the time, it was everything that I knew, and the story flickering across it was simple and beautiful. I’m sure that I would have been happy only knowing that wall, but then I saw something new. I didn’t know it at the time, but I was involuntarily loosening my restraints and leaving my cave. And it was terrifying.

I don’t quite remember my state of mind while in flux, but asking those questions planted a seed of skepticism in me. My entire life, I’d never seriously doubted what I had been learning since I was little, but when I did, I was suddenly unbound like the protagonist of Plato’s Allegory of the Cave, seeing a whole new world that I never could have comprehended before. I spent hours just thinking, cautiously pondering metaphysics from a completely new perspective. My questions turned into objections as I decided that key things about my religion were contradictory.

I’d opened a Pandora’s Box — I felt like I was self-destructing, watching helplessly as my identity and worldview crumbled at the assault of my own involuntary thoughts. For a while, I would have wanted nothing more than to find a way to doubt my doubts, but I couldn’t. I talked to some of my religious leaders. I tried to pray. I cried.

Then I let go and began the slow, messy process of building a new set of beliefs — much less a castle in the sky this time. I began to follow my own conscience, see different perspectives, and look at them more critically and curiously. I now know that I’m now a smarter and more moral person for having left religion. And even though the outside of the cave is intimidating, the newfound sense clarity, freedom, and morality are not only sobering, but empowering and meaningful.

Footnotes

[1] Notably, Bayes’ theorem does not apply to the validity of meaningless semantic structures with no empirical antecedent. For example, we can’t use it to see how probably tautologies or the liar’s paradox are. But we need not care much about the truth of such statements because they don’t pertain to a real fact about the world.

[2] If you’re tempted to respond by saying something like, “That also applies to science-look at stuff like dark matter and dark energy,” recall that science is not a dogma, it suspends belief where there is uncertainty, and all scientific knowledge is tentative. And the reason we even know that dark matter and energy exist is from scientific observations.

[3] Unless all other hypotheses are equally absurd, in which case, we can only remain agnostic.

[4] I’m highly skeptical of the idea that suffering is needed for happiness. I think it’s perfectly reasonable to understand quality of experience completely in terms of hedonic valence of computations. In stemming questions, we should account for uncertainty, but I don’t think we can do much better than this unless we were able to somehow answer seemingly-impossible phenomenological questions.