Saturday, August 27, 2016

The Plant Model of Morality

Several years ago, I tried to determine whether the status of Oklahoma's winter wheat crop impacts near-surface air pressure during the afternoon. I found that it indeed does, but it's practically unnoticeable because it's almost entirely masked by numerous other factors that have a bigger impact on air pressure. When those other factors are subtracted out and we look at the resulting anomaly, the impact of the wheat is unmistakable.

An anomaly is a difference between reality and some predetermined standard or baseline. That baseline doesn't have to be perfect and doesn't have to explain everything, but if it accounts for a lot of what you're not looking for, it makes it that much easier to see what you are looking for. I chose the winter wheat example because plant life is an excellent baseline for comparing human morality. Plants are, by all accounts, morally neutral. Yet, they do many of the same things humans do. They eat, sleep, adapt to their environments, respond to stimuli, defend against threats, compete and cooperate with others, and much more.

The "decisions" plants make can be explained by a cost-benefit analysis, where both the cost and benefit are closely related to survival. In other words, plants do whatever has the most net benefit to their survival. A similar cost-benefit analysis also explains much of human decision-making and behavior. Humans have a strong desire to survive, and we usually act accordingly.

Starting only with the reasonable assumptions that (1) plants are always morally neutral, (2) there is such a thing as moral good and bad, and (3) humans are not always morally neutral, it follows that moral choices are part of the anomaly -- i.e., what's left over after we subtract out morally-neutral plant-like choices & behavior. Thus, moral good is somehow related to the extent to which someone deviates from their optimal cost-benefit solution. In other words, moral good involves going against what's apparently in one's own best interests. But why would anyone do that?

The other major difference between humans and plants is that humans are aware of other people's needs and can consider or neglect to consider the cost-benefit analysis from the perspectives of others. Thus, moral good can be defined as the extent to which one chooses to sacrifice self-interests for the benefit of others. Moral bad, then, would include anything that isn't either morally good or morally neutral (i.e., an anomaly in the opposite direction). In fact, the majority of the world's problems can be attributed to one thing -- people acting according to their own cost-benefit analysis while ignoring or going against that of others.

According to this model of morality, a lot of what seems morally good may in fact be morally neutral at best. There are many social, emotional, and even financial benefits to being a good, generous, "selfless" person. We all want to be thought of by others, by ourselves, and by God (if we believe in him) as morally good, which requires doing morally "good" things and avoiding the "bad". When we act altruistically in order to maintain our "good person" status, feel good about ourselves, or score points with God, it's really a form of self-preservation and self-advancement that isn't much different from what a plant would do. And if we do it to get undeserved attention or praise, or to deceive people into thinking we're morally better than we really are, we've gone beyond what a plant would do; and that anomaly, I would argue, is on the wrong side of moral neutrality.

Some of the other interesting implications of this morality model include:
  1. Morality is both relative and absolute. The morality of specific actions depends very much on the context (i.e., is relative), but the fundamental principle of morality is absolute, objective, and universal.
  2. Intent matters a lot. The same action can be moral, immoral, or neutral, depending on the intent. And intentful thoughts can still be moral or immoral even if not acted on.
  3. "Good" actions are much more likely to be truly good if done in secret and/or with no apparent benefit to oneself. [Note: Moral good doesn't necessarily require complete lack of benefit to oneself. It just requires that a different choice would've had more apparent net benefit to oneself.]
  4. Morality is a full spectrum, not binary or black & white. There are different degrees of anomalies relative to plant "morality", so there are different degrees of moral good and bad.
  5. Following the "golden rule" (to treat others the way you would want to be treated) probably is, in most cases, morally neutral. The "platinum rule" (to treat others the way they would want to be treated) is better but still inadequate as a moral guide.
  6. Refraining from immoral behavior doesn't necessarily mean you're being morally good, particularly in situations where the personal cost of that immoral behavior (e.g., going to jail, friends thinking worse of you, etc.) outweighs the apparent benefit.
  7. Refraining from immoral behavior is more likely to be morally good if it's personally difficult to refrain from and/or easy to get away with.
  8. Doing what's morally good is never "worth it" from a personal cost-benefit perspective. If it truly seems "worth it", it might be morally neutral at best.
  9. Doing true moral good is very difficult and doesn't come naturally. If it seems easy or comes naturally, there's a good chance it's morally neutral at best.
It also follows that true moral goodness requires one of two things: irrationality or faith -- not necessarily religious faith, but faith in some reason to do something that doesn't make logical sense from one's own cost-benefit perspective. Most religions are pretty similar on specific moral teachings like the "golden rule", but when compared with the plant-based model of morality, their differences are magnified. Next time, I'll explore how various religions and moral philosophies interact with personal cost-benefit analyses and dramatically change the terms of the morality equation.

Sunday, August 9, 2015

Are Beliefs About God Genetic?

As a believer in both God and Evolution, I often wonder about the role God might've had in evolution. But as one with a strong interest in psychology, I think an even more interesting question pertains to the role evolution might've had in human perceptions and beliefs about God. Is there a strong genetic component to belief (or non-belief) in God? And if so, what are the theological implications?

I believe the evidence is pretty conclusive that, like most human conditions, belief in God probably has a strong genetic component [in addition to a strong environmental component]. The following are what I consider the strongest evidence:

  •  Autism, which has been shown to have a strong genetic component, is an excellent predictor of atheism, even after controlling for other variables such as gender, IQ, education, religious attendance, and interest in math/science/engineering
  •  Women are much more likely than men to believe in God, even after controlling for many other variables including lower rate of autism
  • Personality tests, such as MBTI and the Empathizing-systematizing scale, are good predictors of belief in God, and such personality characteristics have been shown to have a genetic component
  • Scientific studies, especially those of twins (comparing identical vs. fraternal, adopted and non-adopted), have concluded that 30-55% (depending on the study) of the variation in belief about God was heritable.

Because there is a right and a wrong answer to the God question (i.e., God either exists or he doesn't), it follows that some people, although we don't know who, must have genetic advantages and disadvantages when it comes to correctly answering it. That has some interesting and unnerving implications.

For atheists/agnostics...
You might be fooling yourself if you think your lack of belief in God is rational. There's a distinct possibility that you're like a blind person who doesn't believe the moon exists because you can't see it, hear it, or feel it. Maybe you have an innate advantage of not sensing things that aren't there, or maybe you have an innate disadvantage in detecting certain things that are. Maybe you naturally have a difficult time processing evidence that isn't concrete. Or maybe your genetics make you naturally inclined toward theism, which might help explain why you sometimes feel like you're fighting against a natural urge to embrace the spiritual.

For theists...
You might be fooling yourself if you think your belief in God is rational. There's a distinct possibility that you're like a person with schizophrenia believing [non-existent] people are spying on you, because your hallucinations seem totally real. Maybe you have an innate advantage in detecting things that other people can't, or maybe you're wired to sense things that aren't actually there. Maybe you're naturally more gullible than others. Or maybe your genetics make you naturally inclined toward atheism, which might help explain why believing in God is an especially difficult struggle for you.

For everyone...
Regardless of one's beliefs about God, recognizing a strong genetic component should humble us and make us even more careful not to be dismissive of theological views we don't share. Everyone experiences the world differently, and what may seem obvious to some might be nearly impossible for others to grasp.

How do you know that, if you had someone else's genetic makeup, you wouldn't believe (or lack belief in) the same things as them? And how do you know that your genetic makeup isn't one that inhibits your ability to discern the truth about God? Those are difficult questions that I think all of us should consider very seriously.

Fortunately, the other side of the coin is that the evidence reveals a similarly strong non-genetic component. Thus, everyone possesses the ability to believe or not believe in God, examine the evidence and arguments for themselves, and hopefully come to the right conclusion -- even if it might seem more difficult and unnatural for some of us.

Whatever weakness we might have, it's probably also someone else's strength. We can take full advantage of that, whether it's by applying the Ensemble Model of Religion or just by humbly and receptively listening to other people, keeping in mind that the truth isn't necessarily in the same direction as our inclinations lead us.

"The way of a fool is right in his own eyes, but a wise man listens to advice." (Proverbs 12:15)

Sunday, March 8, 2015

The Flying Spaghetti Monster

"We are all atheists about most of the gods that humanity has ever believed in. Some of us just go one god further.” That's the difference between atheists and theists, according to Richard Dawkins. The implication is that theists have a double-standard. They apply critical thinking and skepticism to the gods of other religions, but not to their own. If only they were consistent, they'd be atheists like him.

Here's a video of Dawkins making a similar argument in response to an audience question:

The premise of his response is that there's no reason to believe in one god over another. Belief in a particular God is just an accident of upbringing. If one grew up in Classical Greece, they'd believe in Zeus. Viking-era Denmark, they'd believe in Thor, and so on. Believing in the God of the Torah is just as arbitrary as believing in the Flying Spaghetti Monster. Is he right?

To answer that question, I'll go back through some of my previous posts and apply the same standards to the Flying Spaghetti Monster.

1. Defining God viaPrincipal Component Analysis

Compared to the God of the Torah, the Flying Spaghetti Monster has very specific, knowable, observable characteristics. Thus, it'd have a relatively low “Prior Believability” score. If these two were the only options, the Spaghetti Monster would have a slightly lower prior probability, but more evidence would be needed in order to make a definitive choice.

2. Extraordinary Claims and the Principle of Indifference

Some might disagree with my conclusions in #1, and I doubt I could prove them here. So instead of relying on that for a prior probability, I'll start with the Principle of Indifference. Until evidence is evaluated, I'll start by regarding the God of Abraham and the Flying Spaghetti Monster as equally probable.

3. Verifying Torah Model Predictions

I'm not aware of any predictions made by written accounts about the Flying Spaghetti Monster. No evidence means no change from prior probability unless there is evidence for another mutually exclusive possibility. The verified Torah predictions move it slightly in favor of its God, which reduces the probability of the Spaghetti Monster. Maybe something like 60% for the God of the Torah and 40% for the Spaghetti Monster, if those are the only two options.

4. The Religiosity of Bigfoot Believers

I suspect that Bigfoot-believers might be more likely to believe in the Flying Spaghetti Monster than non-Bigfoot-believers are, but that probably isn't relevant here.

5. The Gospel According to a Map

The prophets of Israel made correct predictions that are more probable if their God exists than if he doesn't. The prophetic predictions are independent of the Torah's predictions used above, so they count as additional evidence. No such evidence exists for the Spaghetti Monster, at least not that I'm aware of. Now I'm closer to 70% for Israel's God and 30% for the Spaghetti Monster.

There is a lot more data to consider, but it's futile. My above attempts at evaluating evidence also are futile, because the probabilities I assigned are [arguably] arbitrary and the strength of the evidence surely would be questioned by people who disagree. Thus, it'd be pointless to present evidence and give my evaluation of it. Fortunately, my most recent post provided a way to use everyone's evaluation of the evidence, giving mine no more weight than anyone else's.

6. The EnsembleModel of Religion

The ensemble model provides a very clear answer. In the absence of unambiguous evidence or relevant insight that others don't have, if humans have any skill at all in discerning such things, the most rational default position is that the God of Abraham probably is the true God and any other, including the Flying Spaghetti Monster, probably isn't. Virtually nobody who has evaluated the evidence believes in the Spaghetti Monster, which suggests that the evidence for it is very weak at best. That doesn't mean it doesn't exist. It's possible that everyone is wrong about it. But believing that would require very strong evidence, and we don't have it.

If writings about the Spaghetti Monster gave accurate predictions of world-changing future events, I'd spend a lot more time studying them. And if millions of people examined the available data and concluded that it's real, I wouldn't necessarily believe in it, but I'd take it very seriously and would be very, very careful about calling it a "delusion" or saying there's "no evidence" for it. Until that happens, or I discover compelling new evidence for it, I probably won't be joining the Church of the Flying Spaghetti Monster, although I wouldn't mind visiting it some time.

Monday, February 23, 2015

The Ensemble Model of Religion

Religious beliefs are a lot like medium-range weather forecasts. They're our best educated guesses about things about which we don't know for sure and don't have much direct, indisputable evidence. The evidence we do have can be interpreted in a variety of ways. Rather than expecting to get everything perfectly right, the main goal of medium-range forecasts is to minimize the error. I think that's a good goal for religious beliefs too. And I think a similar method can help.

The human mind is hopelessly biased, especially when it comes to religious beliefs. We have all kinds of [often subconscious] motivations that lead us believe what we want to believe. We think our beliefs are based on evidence and the beliefs we reject lack evidence. But our interpretations of the evidence are so infected by confirmation bias and other biases that we often come to opposite conclusions when evaluating the same evidence.

Weather forecast models also have errors and biases. One of the best ways to minimize them is to use ensembles. Ensembles are collections of different forecasts based on slightly different initial conditions and/or model physics. They rely on the principle that the ensemble mean (i.e., the average of all forecast solutions) has, over a sufficiently long period of time, less error than any single ensemble member (i.e., an individual forecast). Biases of individual members tend to cancel each other out and their unique errors tend to be somewhat corrected by other members with different solutions. On any given day, a few of the members might be more accurate than the ensemble mean, but we seldom know which one will be the best until it's too late.

So it is with religion. There's a wide variety of flawed, biased beliefs, many of which contradict each other. Some believe there is one God, some believe there are many Gods, and some believe there is no God. They can't all be right, but they all might have some insight that others don't have. Attempts to determine which beliefs are most accurate are inevitably contaminated by a plethora of cognitive biases. But we don't have to give up and adopt total agnosticism. Fortunately, in situations where the evidence is ambiguous and there are multiple conflicting answers, science gives us a reliable default solution: the ensemble mean.

The most straightforward way to define an ensemble model of religion is to consider the beliefs of each person on Earth as an ensemble member. Everyone gets one equal vote. The ensemble mean would be the “average” of everyone's beliefs. This generally would be similar to the world's most common beliefs, with moderate/centrist positions in areas of disagreement. Using this definition, here are a few beliefs that I think would represent the worldwide ensemble mean:
  • There probably is a God.
  • There probably is only one God.
  • That God probably is the God of Abraham, as originally described in the Torah.
  • God probably created animals and humans via the process of Evolution.
  • There probably is some kind of life after death.
  • There probably is something uniquely special about Jesus of Nazareth.
  • Unique doctrines taught only by particular sects within Christianity, Islam, etc. probably aren't true.
  • Extreme fundamentalism and extreme theological liberalism probably aren't the best interpretations of holy texts.
This “ensemble mean”, based on global religious statistics, is consistent with beliefs that are largely based on biblical Judaism, influenced by Christianity, Islam, and (to a lesser extent) smaller religions, and contain a relatively small but still significant dose of secularism and atheist skepticism.

To be clear, I'm NOT saying the majority is always right or that truth should be determined by popular vote. The majority has been wrong many times throughout history. The centrist position also has a long history of being wrong. As with ensemble forecast models, the mean tends to smooth out important details and minimize extremes that some members might be correct about. The point simply is that in the absence of compelling evidence, the ensemble mean is the best starting point.

It's natural for humans to think there's strong evidence when there isn't, or vice-versa. It's also natural to think we have insight that other people with different beliefs don't have, perhaps because we're more intelligent, had more-relevant life experiences, or are more educated in science, philosophy, or religion. Though these may indeed be useful in evaluating certain verifiable beliefs, they don't provide consistent non-circular answers to fundamental questions such as “Is there a God?”. Much smarter, more experienced, more educated people than you or I have come to opposite conclusions about such questions.

Another natural inclination is to believe other people's biases are stronger than our own – which itself is an especially pernicious bias known as the “bias blind spot”. It's easy to think of reasons why others' religious beliefs are biased – e.g., growing up in a particular religious environment, indoctrination, bad experiences with religious people, not wanting to accept that one's behavior is sinful, fear of death, etc. It's much harder to recognize biases in ourselves, some of which we're not even consciously aware of.

Though I believe the “ensemble mean” of religious beliefs is the best starting point in the absence of compelling evidence, I don't think we're stuck there. As I think I've shown in previous posts, evidence does exist, and it should shift our position away from the mean. My beliefs deviate quite a bit from the mean sometimes [as anyone who knows me can attest]. But it's something that I think we should be very careful about. Deviating far from the ensemble mean requires strong evidence. It also requires a lot of faith in one's own ability to overcome cognitive biases. That ability, at least in my case, is inconsistent at best.

Saturday, January 24, 2015

If God is so good, why is the world so bad?

Why do bad things to happen to good people? How could a loving God allow so much sadness and suffering? Why didn't God give us a better world? I've heard many "answers" to these questions. None of them are very compelling. They generally don't address what I believe to be the core issue: human perception.

When it comes to human circumstances, our perception of "good" and "bad" is largely relative (note: this doesn't mean morality is relative). For example, rain is considered "good" during a drought but "bad" during a flood. An American at the poverty line would be considered "rich" in Liberia. Even universally bad things, such as the death of children, which truly is a tragedy, is only considered tragic because humans generally live longer and develop more. If humans lived as long as bristlecone pine trees, even 200 years would seem tragically short. If our average life span was that of mayflies, a few years would be a very long life.

We also tend to perceive the present relative to the recent past [or at least our distorted perception of it]. We are happy when our situation improves and unhappy when it worsens. Otherwise, we perceive the present relative to [a somewhat idealized version of] what we think our lives could or should be like. Thus, we often are not content when our situation isn't improving. In mathematical terms, human happiness is closely associated with the first derivative (i.e., rate of change with time) of the "goodness" of our circumstances. We're happy when the derivative is positive (i.e., improving with time), sad or unhappy when it's negative, and discontented when it's near-zero. The Bible includes numerous examples of this concept, especially in the books of Exodus and Numbers.

The Israelites were slaves in Egypt for many years. After being miraculously freed (Exodus 14), they were elated and sang praises to God (Ex. 15). But eventually, after they started getting short on food, many started wishing they had never left Egypt. Then God gave them an endless supply of food (manna; Ex. 16). That satisfied them for a while, but they eventually grew tired of eating it. Again they started wishing they had never left Egypt, remembering the diverse food they had there (Numbers 11). The absolute "goodness" of their circumstances (C) is plotted on the time series graph below:

Though their circumstances were objectively better than when they were slaves in Egypt, it wasn't reflected in their levels of happiness and complaining. Those more closely followed dC/dt:

The derivative aspect of happiness explains a lot about life. It explains why drugs and other forms of instant gratification don't ultimately make us happy. It explains why people always try to acquire more money and more things despite having more than they'll ever need. It explains why it's so much more painful to have something and lose it than to have never had it. It might also explain the Bible's moral teachings, which generally encourage selfless and healthy behavior that isn't quite as enjoyable in the short-term as the things it discourages or forbids. And I believe it helps us better understand why a loving God would create a harsh, imperfect, broken world and ask us to fix it.

It's natural to think a loving God should've made the world a happy, pain-free place where everyone lives at least 80 years. But such a utopia only seems good relative to our world. If the utopic world was the only one we ever experienced, it wouldn't necessarily seem any better because we'd perceive "good" and "bad" relative to that world. In mathematical terms, the value of C would be higher but dC/dt wouldn't be any different. We'd be like the Israelites after the Exodus, finding new [and more petty] things to be unhappy about.

So why do bad things happen? If "bad" is indeed relative, bad things happen simply because good things happen. The only way to eliminate the "bad" is to eliminate the "good", which implies a constant C(t) that is the same for everyone. That would make dC/dt = 0, which, as the ancient Israelites can attest, seems quite attractive when dC/dt < 0 but not so much after you have it for a while.

To be clear, I'm not saying God created the world to maximize human happiness in it. If that was his goal, he didn't do a very good job with it. But I think the nature of human happiness points us to something deeper. It suggests that a truly good world is one that is always improving. That's the kind of world the Bible promises, and I believe history shows that it's the kind of world we have. An improving world means there are things that need improving, which can be uncomfortable, painful, even horrific at times.  It's also the kind of world that enables innovation, compassion, justice, forgiveness, mercy, hope, and perhaps even purpose. What is your purpose in life? And what would your purpose be if the world had no room to improve?

Sunday, October 26, 2014

Is God Supernatural?

Christian apologists often criticize atheists for presupposing a naturalistic worldview, thereby making the supernatural (and specifically, God) a virtual impossibility. I disagree with this argument for one of two reasons: A) because God is not necessarily supernatural, or B) atheists do believe in the supernatural. Whether it's A or B depends on the meaning of "supernatural".

I'm not interested in semantic arguments, but I think Merriam-Webster's definitions of "supernatural" helpfully describe ways that people think about God. In reverse order, I'll apply them to the question: "Is God Supernatural?"

Definition #3: "of, relating to, or being God"

God certainly is supernatural by this definition, but I don't think it's a useful one. It says nothing about the key issue, which is the nature of God and his interactions with the world.

Definition #2: "being so extraordinary or abnormal as to suggest powers which violate the laws of nature"

I think this is what many people, especially atheists and fundamentalist Christians, think of when they hear "supernatural". God "miraculously" intervenes in the world such that the laws of nature are violated. After all, God is omnipotent, so he's not bound by such laws. Naturalistic explanations of miracles are seen as denying God's power or avoiding the "plain meaning" of the Bible.

It's problematic if not impossible to find any evidence that the laws of nature have ever been violated. Even if it existed, the prior probability would be so low that the evidence would have to be extraordinarily strong. We don't have such evidence. And if we did, we'd simply modify our understanding of the natural laws. Then the supernatural would still be impossible.

Furthermore, I don't see anything in the Bible that necessarily would've violated natural laws. Wherever God's means are mentioned, it's always something that can be explained within the bounds of natural laws. The flood? Genesis says it rained. Parting of the Red Sea? Exodus says strong east wind. God speaking to prophets? They say visions and dreams. Where the means aren't mentioned (as is usually the case), there's no reason to assume violation of natural laws. Rather, in the absence of very strong evidence to the contrary, we should assume that natural laws weren't violated. To not do so would be to commit the base rate fallacy.

Using Definition #2 and considering the available evidence, I conclude that God (as described in the Bible) probably isn't supernatural. Can't rule it out, but the base rate and evidence suggest a low probability.

Definition #1: "of or relating to an order of existence beyond the visible observable universe"
I think this one is by far the most useful. According to this definition, God is indeed "supernatural". And so are other unobserved things like dark matter, strings (as in string theory), strangelets, preons, photinos, gravitons, life on other planets, other dimensions and universes, etc. These generally are not "gods of the gaps". They are reasonable hypotheses that explain what we can observe and aren't inconsistent with what we know about the laws of nature. I think the same is true of God.

Some things that once were "supernatural" (by Definition #1; e.g., viruses, atoms, distant planets) are no longer supernatural now that we have ways to observe them. Until we find a way to observe God or disprove the God hypothesis, we should carefully and scientifically consider the possibilities. We shouldn't allow our definition of "supernatural" to dictate our understanding of God or deny his existence. Rather, we should strive to have a view of God that best explains the data and is consistent with what we discover about the natural world.
“It is evident that an acquaintance with natural laws means no less than an acquaintance with the mind of God therein expressed.”
- James Prescott Joule, father of thermodynamics

Monday, October 13, 2014

Why So Many Scientists Are Atheists

According to Pew Research, 17% of scientists identify as atheist, compared to only 2% of the general population. 41% of scientists say they don't believe in God or a higher power, compared to only 4% of the general population. Why are so many scientists atheists?

Some say it's because science disproves God or that science and religion are somehow incompatible. Others point out that most were atheists before they ever became scientists, suggesting they pursue science because of their atheism. Both explanations assume a false dichotomy. The true answer probably is very complex, but two factors might explain a lot of it: demographics and personality.

Atheists are predominantly white men. According to Pew, 70% of American atheists are men and 90% are white or Asian, compared to 48% and 74% of the general population, respectively. Scientists [according to NSF] are 72% male and 87% white or Asian, almost identical to atheists. Thus, any random sample of people with the racial and gender makeup of scientists, for that reason alone, should have a higher percentage of atheists than the general population. Among sciences, chemistry and biology employ a relatively high percentage of women -- and, perhaps consequently, a relatively low percentage of atheists.

Personality may explain even more. The Myers-Briggs Type Indicator (MBTI) is probably the most common measure of personality. Though it has several major flaws, it has been used and studied enough to provide useful statistics.

The MBTI type typically associated with scientists is INTJ, whose description closely resembles the stereotypical scientist. Hence, it often is called the "Scientist" type. INTJs generally are analytical, opinionated, and don't believe things without "cold hard facts" -- a common description of atheists as well. In a survey of 10,627 American atheists, 13.7% were classified as INTJ, compared to only 2.6% of the general population.

A few other personality types are typically associated with scientists. By far the most common of these is ISTJ, which tend to prefer more practical, applied science than their INTJ cousins. For example, ISTJ has been found to be the most common type among National Weather Service employees. It's also the most common type among atheists. 41.2% of atheists are ISTJ, but only 13.8% of the general population are ISTJ. Thus, a majority (54.9%) of atheists are either ISTJ or INTJ, compared to only 16.5% of the general population.

Personality type can explain the high male-to-female ratio among atheists [and perhaps scientists as well]. Male and female atheists have similar proportions of ISTJ and INTJ (40.8% and 11.7% for female atheists, 41.4% and 14.4% for male atheists). But in the general population these two types are approximately 70% male -- just like atheists and scientists!

Combining demographic and personality data, we can calculate the probability that a random person is an atheist, given basic demographics. For example, starting with a prior probability of 2.0% (the % of atheists in the general population), the probability that a random white male would be an atheist is 3.5%. If the random white male is an INTJ, that probability increases to 14.5%. If we consider random college graduates, it becomes 21.1%.

Extending the calculations to a random group of college graduates (and post-graduates, in parentheses) with the same race and gender makeup as scientists [72% male, 69% white, 18% Asian, etc.], the following percentages are expected to identify as atheist:

  • INTJ: 20.2% (23.7%)
  • ISTJ: 11.4% (13.7%)
  • INTP: 7.4% (9.0%)
  • ENTJ: 6.0% (7.3%)
  • INFJ: 5.5% (6.7%)
  • ISTP: 4.6% (5.6%)
  • ESTJ: 3.6% (4.4%)
  • ENTP: 2.8% (3.4%)
  • ESTP: 2.0% (2.5%)
  • INFP: 1.7% (2.1%)
  • ENFJ: 1.5% (1.9%)
  • ISFJ: 1.5% (1.8%)
  • ISFP: 0.6% (0.8%)
  • ENFP: 0.6% (0.7%)
  • ESFJ: 0.4% (0.5%)
  • ESFP: 0.3% (0.4%)

Thus, if scientists are predominantly INTJ and ISTJ, the 17% who are atheists is similar to that what would be expected from a random sample of people with those personality types and similar basic demographics.

Of course, there are much deeper factors than what these crude statistics represent. Scientists are quite diverse in ways that aren't accounted for here. Not all are INTJ or ISTJ, including myself (an INFJ), and I couldn't find any statistics about that. Correlation doesn't imply causation, and these variables probably aren't completely independent as the equations assume. However, unlike the "science and religion are incompatible" explanation, this one at least has some science to support it.