In Samuel Perry's new book, he argues that most people in the West view religion incorrectly. We think religion is about theology, about a marketplace of ideas that rewards the best ideas and perhaps the more "correct" ideas. Yet Perry argues that religion is in fact more of a social phenomenon that is more about social groups, or political tribes, than it is about the substance of the beliefs. People do not form beliefs based on rational thinking but rather an affective understanding of who one's people are, and societal structures like the (de)coupling of church and state, as well as birth rates, can all affect the spread of religion. Perry gives the example of Islam in Western Europe, where it is growing simply because of immigration and birth rates rather than any sort of attempt to convert people rationally. Perry also spends a lot of time talking about Christianity in America, especially in the ways evangelicals have managed to defeat mainline Protestantism mostly due to birth rates and parallel networks. David Hollinger's book on American Christianity also touches on this.
Perry's big insight is that the Western view of religion is mostly an Anglo-Protestant view. As he is a sociologist and not a philosopher, he doesn't get into the nitty-gritty of this topic, especially regarding the way Protestantism shaped the metaphysical understanding of the western world by centering the self, rather than God, as the site of rational thought. While Perry mentions Joseph Henrich's concept of WEIRDness, Perry never discusses Henrich's claim that the Catholic church's ban on cousin marriage created a genetic effect that caused a breakdown in kinship structures among Western people that led to the creation of what he calls Anglo-Protestantism: that such an ideology comes down to genetics rather than rational attempts at conversion. Such a claim would bolster Perry's own claims about the tribal nature of religious belief, but the genetic element is probably too controversial to gain much traction in the secular academy.
Perry also ignores the fact that his emphasis on a scientific study of religion, which he argues for throughout the entire book, itself comes from an Anglo-Protestant way of thinking. Nietzsche, for one, argued that the faith in science is metaphysically similar to faith in Christianity or other religions. "Science is real" is still an appeal to an objective or empirical truth, and thus is arguably metaphysically no different from "God is real." And as thinkers like Charles Taylor and Tom Holland have pointed out, it was this post-Enlightenment emphasis on science within Protestant traditions that led to our "secular age" to begin with. Perhaps Perry does not take up these critiques because he is a sociologist and not a philosopher or theologian, but I was disappointed to not even see these critiques being mentioned. Perry also does not engage with postliberal forms of philosophy or theology, despite the obvious relevance his project has with dismantling the liberal (and thus secularized Protestant) view of the world, as thinkers like Leo Strauss and Carl Schmitt have already done.
Also, this book could have been a lot shorter, as Perry's central thesis can probably be summarized in just an essay. So some of the content ends up getting repeated and ends up sounding like filler. The last two chapters also aren't even about his central thesis but rather talks about the ways religious studies as a field is marginalized in academia, and about the ways religious studies is marginalized in contemporary society, and how to fix this issue. This subject alone could form a different book, but it appears that Perry doesn't have enough for just one book if he didn't address those subjects as well.
So while the first four chapters are really good in talking about the way that our understanding of religion is a WEIRD one that doesn't account for how religion actually works in real life, Perry misses a lot of material that would have further challenged our conceptions of religion, of the secular, and of the metaphysical.