Disbelief is a strong attempt to explain how atheism originates and why it seems to be on the rise in some parts of the world. The book is broken into two main parts: the puzzle of faith and the puzzle of atheism, with two short chapters wrapping it all up and making (some rather insane) predictions of the future.

In part one, he examines various theories about why we are a religious species and rejects them one by one before introducing and explaining his version of dual inheritance theory(DIT). This theory claims that religious belief is the product of both our genetic and cultural inheritance. Generally, we are genetically predisposed to try to create order and explanations for the world around us (even for things that might seem unexplainable) and our beliefs are also the product of our cultural milieu. This is why someone in India is more likely to be Hindu, someone in Kuwait is likely to be Muslim, someone from Kentucky is likely wearing a MAGA hat, and someone in LA is likely throwing rocks at Police cars as I type (mid June, 2025).

In part two, Gervais turns that gaze from belief to disbelief. If this is why people tend to be religious, then why disbelief? What makes some people become atheists? Again, using the DIT, on the cognitive side, Gervais says that some people are genetically predisposed to be more trusting and others to be more skeptical. On the cultural side, Gervais mentions CREDs (credibility signalling). Basically, people tend to believe the culturally dominant belief when they: 1. See others acting in support of those beliefs, 2. see others make sacrifices on behalf of those beliefs, and 3. see behavior that aligns with those beliefs. So in other words, Gervais claims that atheism is actually the default position for people who are more cognitively reflective, socially secure, and have lower exposure to practising believers.

As the proverb says, "A witness sounds reasonable only until he reaches the point of cross-examination." The book makes sense... as long as you don't really think about it. I've got a hundred and one arguments against this garbage (give or take, I haven't actually counted them all out) but here are just a few from various disciplines:

History
Gervais describes atheism arising organically when a society becomes more affluent. This might explain Europe (not really, but let's pretend), but it certainly doesn't come close to explaining the largest concentrations of atheism in the last century. The former USSR, China, and North Korea have all had a top-down imposition of atheism. You've got two choices: become an atheist or enjoy an all-expense-paid vacation to this gulag in Siberia for a couple of decades. And actually, in China, we are seeing the reverse play out. As social standards have been rising, so has the number of both Christians and Buddhists.

Evolution
Gervais is placing an overemphasis on the neutrality of evolutionary development. He claims that atheism is actually the default position when there aren't enough CREDs to prop up any particular religious belief. But most evo devos (of which I am not one) would say that religious credulity is the default position, and to be atheist requires a cognitive override of this position.

Epistemology
Gervais completely sidesteps probably the single most important question that should be addressed in a book titled Disbelief. Is the belief true? Both atheists and believers should have strong opinions on this point. Whether a person believes in a god or in the nonexistence of gods, the most important question to be addressed is whether this belief is rational, justified, and true.

Sociology
The author is both strongly shaped by and speaking towards a very particular worldview and much of what he says bears little relevance or applicability to anyone outside of that social setting. He has a WEIRD worldview: White, Educated, Industrialized, Rich, and Democratic. Everything laid out in this book is dependent on this culturally contingent and not globally universal.

Morality
Some would say that Gervais is removing agency from the equation. Nobody truly chooses to be an atheist or a believer, but rather they are stuck with what they are based on their genetic predisposition and their cultural placement. This might be true, but it is also true that he is removing the consequences of the choice. There is no moral value in converting or deconverting since they are both merely "outputs" of cognitive/cultural inputs. Although he shows a clear bias towards atheism, his framework requires one assume no moral difference between believing and atheism. Instead of authenticy, conviction, and sacrifice, our beliefs are merely psychological inevitabilities.

Philosophy
The entire concept of DIT is actually one of circular reasoning. In order to understand why some people become atheists, we must a priori assume that God does not exist. The entire worldview in which the theory is built assumes philisophical materialism and therefore cannot adequately or fairly asses whether belief or its lack is reasonable and true. DIT is built on three faulty premises: 1. It treats both religious belief and disbelief as products of evolved cognitive mechanisms and cultural transmission, not as possible responses to a metaphysical reality. 2. It explains belief in God as a byproduct of evolution and cultural reinforcement and rules out the possibility that belief in God is grounded in actual divine encounter or truth. 3. Most importantly, it implicitly assumes that there is no God to reveal Himself, no metaphysical or ontological referent for belief, and no transcendent source of meaning.

And now I need to cut myself off. I have so much I would like to say. But I am supposed to be doing a review, not writing a book of my own.

Disbelief: The Origins of Atheism in a Religious Species by Will M. Gervais is a thought-provoking exploration of the psychological and evolutionary underpinnings of atheism. Gervais, a researcher in psychology, examines the origins of disbelief within the broader context of human evolution, suggesting that atheism is not merely a philosophical stance but is rooted in cognitive processes shaped by our species’ religious tendencies.

The book is well-researched and offers a unique perspective on atheism by framing it as a natural outcome of human cognition. Gervais draws on empirical studies, psychological theories, and evolutionary psychology to argue that atheism can be understood as an adaptive response to the human brain’s propensity for religion. This approach provides readers with a deeper, science-backed understanding of why some individuals reject religious beliefs, making the book a valuable resource for those interested in the intersection of psychology, evolution, and religion.

While the book presents a fascinating and comprehensive analysis, it occasionally delves into technical language and academic jargon that may be challenging for general readers without a background in psychology or evolutionary theory. Some of the arguments might feel repetitive at times, as Gervais reaffirms points throughout the book without offering many new insights as the chapters progress.

Despite these minor drawbacks, Disbelief is an enlightening and intellectually stimulating read that challenges conventional ideas about religion and belief. Gervais successfully combines scientific inquiry with philosophical questions, offering a compelling narrative that provides readers with a fresh perspective on the origins of atheism. This book will appeal to anyone interested in understanding the psychological and evolutionary factors behind belief systems, making it an informative and valuable addition to the conversation on faith and reason.

As a general (research) fan of Dr. Gervais' work, I appreciated the opportunity to read this book before it officially hit the presses. While I am usually more interested academically in people who are religious and how that impacts their behaviors in current days, I do appreciate learning more about the perspective of why religion came to be evolutionarily and why people may or may not believe. I am not sure if it was just my ARC copy or everyone's but some random parts of my text were red rather than the normal color (white for me since my kindle is in dark mode) and that was a bit distracting but I am guessing this was just an ARC issue and not really a full release issue.

Despite my personal struggle with finishing non-fiction reads, I appreciate how Disbelief encourages readers to rethink their views on religion and atheism. Gervais' casual prose and engaging examples make complex theories accessible and thought-provoking. For those interested in the intersection of psychology and religion, this book offers a profound exploration of how we came to be a religious species and why some are moving away from faith.

👏👏👏

Riveting, insightful, and skeptical. Atheists and theists alike will turn their heads at this one.

Few people understand disbelief as well as Gervais, a truly radical thinker in any circle. Down with the subtle pseudoscience of the New Atheists ... even heavyweights like Dawkins ...! Finally, someone who calls them on their BS and can back it up with rigorous, peer-reviewed research. I can only imagine how high Dawkins's brows will raise if he deigns to read this text ... putting aside my schadenfreudean glee, this is an excellent and easy-to-understand text on the science of disbelief that I do believe anyone can grasp. Of course, this is coming from a self-identifying agnostic atheist who's already thunk a bunch on this particular people puzzle. I really appreciate how atheism is framed: "a human quirk demanding serious scientific explanation." I appreciated even more the author's ability to criticize his own work and admit to academic failure ("small samples, unvalidated methods, flashy and counterintuitive findings: a recipe for irreproducible science" ... this one published in Science itself, as I recall). The tear-down of modern atheist philosophy on religion hand-in-hand with clearly reasoned and described empirical research ... mwah. After recent events in my own discipline, I took heart that I'm not alone in bemoaning the childish antics of certain professionals. At the same time, this work and Gervais's down-to-earth prose left me feeling hope.

I'm not without my confusions and criticisms. I do feel that Gervais was out of depth when it came to social identity theory. Group categorization is as much about the categories we define and place ourselves /without/ as within. Revisiting the theory and especially subtheories with this perspective could be enlightening for understanding atheism and disbelief. I'm also surprised that he wasn't wise to another very obvious problem with the "mindblind atheism" label: it's ableist (as well as inaccurate). I also felt like some details were glossed over (even in the many footnotes).

But this is quibbling. I highly recommend this book to anyone. After all, belief and its lack are fundamentally human modes of being. We're the only species on the planet, as far as we know, that has religion ... as well as people who decline belief. As Gervais summarizes, "cultural learning is a better predictor of atheism than is rational sophistication, science knowledge, or any other cognitive proclivity we've tried." To have faith or be faithless? Well, "we've evolved cultures that naturally sustain either," so I guess it's another kind of lottery by circumstance.

Fascinatingly, this book was about belief and disbelief studied in a scientific context. I found the tone very conversational and Dr. Gervais demonstrates a good sense of humour. His personal journey was also very interesting and I found the footnotes were definitely worth reading. Although not the point of the book, the book also did a great job of talking about how science works, with some information on study design and reproducibility, all written at a very basic level. Thank you to Netgalley and Prometheus for the advance reader copy.

This is a well-structured and detailed non-fiction book about the origins for atheism. The book is divided into chapters that gradually build up.
The second part of the book title goes “in a religious species”, and this marks the central question of this book: why do members of a religious species choose disbelief? Or do they not choose it, perhaps?

To answer these question, the writer talks about religion and belief.

I will not spoil the conclusion. It surprised me a little, based on my own experiences.
Overall, this is a nicely organised history and a comprehensive summary of belief and disbelief. The argument is supported with research, statistics and examples. It was nice to read about Ireland.

I need to reread parts of this to fully make up my mind about what I will read next about atheism and absorb the discussions in this book, however, I kept wondering, who is the target audience? As an academic, I value and enjoy scientifically written books but those who do not like to see numbers, graphs, statistics, research summaries can benefit from this book. I hope the publisher and the writer consider a more popular science style book about the same topic.

A well-researched and informative account of how and why atheism occurs.

To understand atheism, we must first understand religion. The book informs us that there are essentially four factors which promote and explain religiousness. They are summed up as ‘imagine, motivate, learn and maintain’ (Chp.11). What that means is that people need certain cognitive powers of imagination (which are found more in women, than men, and that may be why more women are religious than men). People need to be motivated by a degree of hardship. They need to learn religion by seeing displays of behaviour which make it seem credible. And they need to maintain that belief when confronted by challenges.

Atheism occurs when those four factors are reduced, or absent. Lack of motivation is a particularly interesting factor which is at work in countries like Denmark and Sweden. Life is so stable in those countries that there is not the hardship to ‘motivate’ religious commitment. That means that in those kinds of contexts there is also a lack of ‘credibility enhancing displays’ of religious behaviour, and so there is no incentive to maintain a belief in theism. Instead, people tend to drift into atheism through a kind of apathy towards religion.

That may seem an initially controversial view, as it flies in the face of the New Atheism polemic, which essentially argues that atheism is the product of superior reasoning. That New Atheism view is examined and dismissed, as simply lacking evidence. There is a certain irony in the fact that some of the polemical atheists who make the loudest calls for rationality, are actually not being rational enough in their own commitments to evidence.

Across the 427 pages of this book, there is a wealth of detail and significant referencing of sources and evidence bases. With a commendable honesty the author is clear about where he has personally changed his mind on issues, and he also flags up conclusions which rest on less secure research or evidence.

Although I enjoyed the overall thrust of the book, I wished in places that the editing had been a little tighter. There were digressions to describe the Natural History Museum (Chp 1) and St Bartholomew’s Church (Chp 15). And it wasn’t clear how some of the notes were relevant when they described the working of elementary schools (18%) or the author’s difficulties in coming up with ideas when he is sitting in his office (55%).

Overall, this is an interesting book which provides an excellent summary of research and leading theories about the developments of religion and atheism. The level of detail means that it is a book to be savoured, rather than skimmed quickly. But inveterate skimmers will be pleased to find that there is a helpful summary of key ideas at the end of each chapter.

(These are honest comments based on a digital advanced review version of the text).