In 2012, a paper co-authored by Will Gervais and Ara Norenzayan in the journal Science claimed that confronting religious beliefs with rationality tends to lead people toward atheism. But when more rigorous subsequent studies found zero effect of rationality on religious beliefs, he and Norenzayan publicly disavowed their findings.

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“Can we actually win a war of ideas with people? Judging from my email, we can. I’m constantly getting email from people who have lost their faith and were, in effect, argued out of it. And the straw that broke the camel’s back was either one of our books, or some other process of reasoning.”

~ Sam Harris, committing the fallacy of selective attention in The Four Horsemen

Is atheism ultimately rooted in rationality? To public atheists like Sam Harris, the answer is undoubtedly yes. Harris, along with other prominent New Atheist voices, has long argued that people become atheists because they use their faculties as rational beings to think their way out of religious indoctrination.

The notion that atheism is ultimately rational is strategically central to New Atheist thinking. After all, using science and rationality as wedges to drive people from faith only works if there’s a tight relationship between atheism and rationality.

Even outside the New Atheists, the notion that atheism is about rationality proves incredibly popular. I sometimes give talks to atheist groups and chat with people about how they became atheists. The most common narrative by far involves people applying their rational faculties to escape a religious upbringing. Time after time, people tell me that they got out of religion by thinking clearly and rationally about religious claims that just don’t comport with science.

But is it rationality that ultimately undercuts faith? 

Those who make this claim tend to be firm advocates of science. So let’s see what science has to say on the matter. 

The notion that atheism is ultimately rational is strategically central to New Atheist thinking. But is it rationality that ultimately undercuts faith? 

I’m a scientist who’s been studying the psychology of atheism for more than 15 years, and I think that New Atheists and others who suggest a strong and direct causal connection between rationality and atheism have gotten the science wrong. Rationality is not generally corrosive to faith, and the sparse scientific evidence trumpeted by those who link atheism and rationality is itself quite uncertain. As we scientists have come to better understand atheism over the years, we’ve learned that the relationship between rationality and atheism is far more complex than we’d once assumed. 

Buckle up while we unpack a twisting scientific story.

Intuitive religion and rational atheism?

The notion that rationality lies at the heart of atheism isn’t entirely farfetched. The lived experience of many atheists suggests a link between rationality and atheism, and the idea has some theoretical plausibility as well. Since the late 1990s, there’s been a consistent interdisciplinary effort to understand religion with scientific tools. This movement, often called the cognitive science of religion, has tried to situate the human religious impulse in a broader evolutionary and cognitive context. What in evolutionary history led our species, and our species alone, to have religions? 

Central to this effort has been the notion that we didn’t evolve to have religion as an adaptation in its own right, but that religions might emerge as cognitive byproducts. We have cognitive adaptations that helped our ancestors solve a lot of recurring challenges. These mental adaptations often work below our conscious awareness. And maybe, say the cognitive scientists of religion, these mental adaptations all work together in such a way that some religious concepts are just “sticky.” 

All else equal, our brains work in such a way that religious concepts are intuitively compelling, even though we didn’t specifically evolve to be religious.

Within this framework, religions rely on our intuitions. As a species, we seem to find it quite intuitive to think about minds existing apart from bodies; we find it intuitive to think that objects and animals exist for some functional reason; we don’t at all have a hard time imagining gods, ghosts, djinn, and other supernatural agents. This isn’t to say that our brains have “God centers,” but instead our brains just work in a way that makes religious concepts easy to think.

But human psychology isn’t all about intuition. Since at least William James, psychologists have recognized that we have different ways to process information. Nobel laureate Daniel Kahnemann’s book Thinking, Fast and Slow summarizes decades of work finding that people shift back and forth between relying on gut intuitions and relying on more effortful rational thought. These two systems – a fast intuitive one and a slower rational one – often run in parallel, but sometimes come into conflict. So if religions are supported by our natural intuitions, maybe atheism results from the rational system taking charge. As Pascal Boyer, a leading figure in the cognitive science of religion, put it in a prominent summary, “Some form of religious thinking seems to be the path of least resistance for our cognitive systems. By contrast, disbelief is generally the result of deliberate, effortful work against our natural cognitive dispositions—hardly the easiest ideology to propagate.”

Putting rational atheism to the test

Around 2010, towards the tail end of my graduate school career, Ara Norenzayan and I decided to scientifically test whether rational thinking was a pillar of atheism. Specifically, we wanted to test two possibilities: first, that individual differences in rational thinking would predict atheism, and second, that experimental nudges to think more rationally would promote atheism. We published a paper in Science that seemed to show support for both possibilities. One study revealed a correlation whereby people scoring higher on a standard test of rationality-over-intuition also rated themselves as less religious than did more intuitive thinkers. Four follow-up studies found that various experimental nudges to engage the rational system led people to report less religious belief. Our results were joined by similar results published by two independent teams.

Our work attracted a lot of attention, both popularly and within the ivory tower. Popularly, our paper was seen as a key piece of evidence linking rationality to atheism. What was this, after all, if not scientific vindication for the idea that rationality was a key to atheism?

What was this, after all, if not scientific vindication for the idea that rationality was a key to atheism?

To take one unfortunate and poignant example of this rhetoric, in A Manual for Creating Atheists, Peter Boghossian exhorts his fledgling followers (termed Street Epistemologists) to seek believers out in public and try to disabuse them of faith. He advises atheists to rationally confront the faithful at work, at school, in grocery stores, and even on airline flights (he recommends booking a middle seat, so you have more neighbors to confront). He even claims that the science backs up his proposed strategy, citing our 2012 paper as proof positive that rationality undercuts faith: “in other words, if one gains a proficiency in certain methods of critical reasoning there is an increased likelihood that one will not hold religious beliefs.”

While popular attention on our paper was largely celebratory (at least among public atheists), scholarly attention quickly turned critical. In 2017, Clinton Sanchez and Bob Calin-Jageman, (along with their colleagues) published a solid good-faith effort to replicate our 2012 finding. Their project was much more methodologically rigorous than our initial effort: the samples were larger, the techniques more finely tuned. And their results were negative—contrary to our initial claims, experimental nudges to think rationally had precisely zero effect on self-reported religious beliefs. A 2018 paper attempted replications of all social science papers published in Science and Nature over a span of time, and this paper too was unable to replicate our 2012 results (along with a large number of other prominent findings). 

Norenzayan and I faced the music and publicly disavowed our findings. It looks increasingly like our results were a false positive, noise that we’d mistakenly assumed was an exciting signal. Experimental prods to think rationally do not seem to have any discernible impact on people’s reports of religiosity. Compounding matters, a team led by Miguel Farias tried experiments pushing in the other direction—asking whether nudges to go with the gut and trust intuitions would increase belief—also turned up a whole lot of nothing.

Whatever the links between rationality and religion, it wasn’t something we could easily push around in the lab.

It looks increasingly like our results were a false positive, noise that we’d mistakenly assumed was an exciting signal.

So experiments linking rationality to atheism (and intuition to faith) didn’t hold scientific water. But what about individual differences? After all, our paper and two independent teams had all nearly simultaneously found that rational thinking was at least correlated with atheism. This pattern, with the gift of hindsight and now a decade’s worth of research, does appear to be legit. Gord Pennycook conducted a meta-analysis to synthesize all available evidence on the correlation between rational thinking and atheism and reported that, overall, the correlation was robust. 

Doesn’t this partially salvage the idea of rational atheism? After all, here’s large-scale evidence that in sample after sample, rational thinkers tend to be a bit less religious than folks who rely on their gut intuitions more heavily.

Rationality and atheism: a weak and fickle correlation

Pennycook’s meta-analysis found a correlation of only about r = .2 between rational thinking[1] and irreligion. That means if we know people’s scores on a test of rational thinking, we can only account for about 4% of the variability in belief in god(s). Not nothing, but also not that impressive. The correlation between rationality and atheism also looks to be quite fickle across cultural contexts. I led a team to look for rational atheism in 13 countries spanning a pretty full portion of the global secular-to-sacred spectrum, from the Netherlands and Finland to India and the United Arab Emirates. In places like the USA, the correlation is reliable without being strong, but it disappears entirely in other parts of the world. We found that the modest correlation between rationality and atheism disappeared pretty much entirely in more secular European samples, and was weaker in most places than it appears in the USA. Averaging across all 13 countries, we found a measly correlation of r = .1 between rationality and atheism, meaning that in this global analysis rationality is only accounting for about 1% of the observed variability in religious beliefs. 

Clearly other factors are a lot more important here.

Another research project enabled us to test a very specific dynamic hinted at by the New Atheists: the possibility that rationality might be especially impactful for prying people away from strongly religious upbringings. Maybe rationality isn’t generally corrosive to religion (as the previously mentioned analyses suggest), but might it be a key factor in atheism among people who were strongly raised to be religious? Maxine Najle, Nava Caluori, and I recently published a study in which we tested various predictors of atheism against each other in a nationally representative sample of US Americans. We were able to conduct a statistical analysis to specifically pinpoint the relationship between rationality and atheism among those who were most strongly exposed to religion while they were growing up. And among these people most culturally brought up to be religious, the correlation between rationality and religious disbelief dropped to zero. 

That’s right: among those folks with the most exposure to religion, there’s no reliable correlation between rationality and atheism. This means that among those with strong religious upbringings, the ones who are most rational are no more likely to end up as atheists than are those who are most inclined to trust their intuitions. Far from rationality being a key factor that leads people away from strongly religious upbringings and towards atheism, it turns out that rationality isn’t even modestly correlated with atheism among this subset of people. There is no relation whatsoever.

What then of the popular narrative linking atheism and rationality? Are all the people at atheist meetups who tell me their rational journey to atheism simply self-deluded? 

Not at all. To an individual person who left religion, rationality can seem like the most important factor. But in aggregate – looking across the entire population of everyone who was raised in a religious home and who tries to apply rationality in their life – there’s no general trend whereby rationality leads people to atheism. People’s individual narratives aren’t invalid, they just can’t speak to broader trends. The atheist groups I talk to might genuinely be made up of people who used rationality to go atheist; it’s just that these groups won’t include all the people with similar upbringings who use rationality to explore and strengthen their faith.

New Atheists trumpet rationality as the antidote to faith. Yet they’ve failed to engage with a now-substantial body of scientific evidence that flatly contradicts their core premise. Experiments causally linking atheism and rationality have failed to replicate and been denounced by their authors (including me!). The correlation between rational thinking and atheism appears robust, if somewhat unimpressive in magnitude. Sure, folks who score a bit higher on a task measuring rationality also tend to rate themselves as a bit less religious. But this correlation is small in magnitude, fickle across cultural contexts, and disappears entirely among people strongly exposed to religion while growing up. On each of these points, scientific evidence stubbornly fails to align with the world New Atheists describe, a world in which rationality leads even kids raised in fundamentalist families to atheism.

Atheists, freethinkers, and skeptics typically embrace science. We trust science in part because we trust scientists to stay up-to-date on the relevant evidence. In The Four Horsemen, Christopher Hitchens pithily summarizes this deference to scientific authorities: “I’ll take things that [Dennett and Dawkins] say on the natural sciences … knowing that [Dennett and Dawkins] are the sort of gentlemen who would have checked.” Yet for more than a decade, public atheists have failed to engage with the science on one of their most treasured assumptions: that rationality can lead people away from religion and towards atheism. The evidence has never been strongly supportive of rationality as a key underpinning of atheism. And now, after we’ve had more than a decade of direct study, it looks like rationality is at best a minor thread in the tapestry of atheism, rather than a central theme. 

Rational atheism is (more or less) a myth.

What does it mean that rational atheism is largely a myth? Should freethinkers stop promoting rationality? Hardly! The promotion of rationality may intrinsically bring its own rewards and should be pursued on its own merits without any pseudoscientific pretensions that it will convert believers to atheism. I also firmly believe that abandoning the rational atheist myth may pay secondary dividends if it leads New Atheist allied thinkers to stop trying to use science and rationality to undermine religious faith. These efforts are incredibly unlikely to succeed. Worse still, they have substantial potential to backfire. Dawkins and others have long tried to use science and rationality to pry people away from religion, but they’ve misdiagnosed the source of atheism in the first place. Their efforts in all likelihood do more to drive believers away from science than they do to attract anyone to atheism. 

Our world currently faces a number of overlapping existential threats: climate change, racial and wealth inequity, war. To solve these problems, we need all scientific hands on deck. These challenges are too important to risk alienating people from science, all over faulty assumptions that rationality will lead people away from religious beliefs.

[1] One important caveat to all this: Most of these studies relied on the same measure of rational thinking. It’s a useful measure, but far from perfect. Other measures—those that ask people to subjectively rate how much they like to evaluate evidence and change their minds accordingly, for example—tend to be more strongly correlated with atheism. But asking people how rational they think they are is quite different from actually determining how rational they are.

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Dr. Will M. Gervais is a global leader in the scientific study of atheism and a Senior Lecturer of psychology at the Centre for Culture and Evolution at Brunel University London. Dr. Gervais’s research...