There are two great questions that occur to most people when thinking about religion: (1) Why are there so many religions? and (2) Why is religious belief immune to data? It turns out, only evolution can answer these questions.
Adherents.com lists 22 religions with over 500,000 adherents or more: Everything from Christianity, with the most adherents (over two billion) to Scientology (right around 500,000). But these numbers don’t get to the heart of the matter. According to the World Christian Encyclopedia, there are at least 30,000 different varieties of Christianity alone. Of course, it is hard to be precise about what counts as a Christian denomination. Still, even if this number is only in the ballpark, there are thousands of Christianities. And some of these differ from each other more than Christianity differs from Buddhism. What could possibly explain why there are so many religions?
Consider an analogy — language. All people speak a language — no matter how isolated. Indeed, speaking a language is considered a hallmark of being human. Language evolved from animal communication. There are and have been thousands of languages on planet Earth. But evolution only produced an African ape that could speak, not one that could specifically speak, say, Spanish. The details of the language spoken are up to the relevant group of speakers to “decide.” Humans can make a lot of sounds. All that matters are that the sounds have meanings and structure of some sort. The constraints on languages are loose, so languages vary wildly in their sounds, structures and meanings. This explains the large variation in languages.
I would argue that the same is true of religion. Religions are an evolutionary adaptation primarily for keeping groups together. Religions positively bind groups together by giving everyone in the group the same special belief system, and they negatively bind groups together by elevating distrust and rejection of competing, outlying groups. Since binding groups together is most of what religions have to do, their details can vary wildly. Wicca is very different from Islam. But they both do exactly what they were evolved to do: Keep the groups together so the groups can survive and their members reproduce.
In the same way, evolution also explains why religion is immune to data. Suppose a medical researcher claims that she has discovered a cure for a deadly virus. She bases this conclusion on the lab tests she has run where, after treatment with the cure, her informed patients show no sign of the disease and are otherwise healthy. Now other scientists try to replicate her results. Suppose no one can replicate her results. What happens? The researcher’s claims are considered false. Empiricism is in stark contrast to religion’s treatment of disaster. For example, a Washington Post poll found that Hurricane Katrina overwhelmingly strengthened survivors’ religious faith! That’s right, after Hurricane Katrina, belief in God went up! This sort of phenomenon happens routinely.
How could a disaster make people’s religious faith go up, while the failure of a drug kills it as a treatment option? How can we be so data-driven by drugs and so data-immune when it comes to religion? Again, only evolution can explain what’s going on.
Religions affect our sense of well-being. Specifically, our sense of hope and order which comes from living in a well-ordered universe. This is partly how they implement group binding. During a disaster, our sense of well-being is harmed, and we come to doubt that we live in a well-ordered universe. To restore that sense, especially to restore our hope, we appeal to our deity. This alters our feelings for the better and perhaps gives us much needed hope to keep going. So, simply in virtue of this feeling — a purely psychological state — we feel closer to our deity and hence our belief in It (or Her or Him or Them) goes up.
Research on religion’s role in our evolution and the formation and development of religion is vibrant and growing quickly. Evolution is a robust and powerful process and we are only now really beginning to understand its sweep and influence. Clearly, evolution will stand us in good stead as it helps us understand the diversity of religion and the single-mindedness of our hope in it. That humans evolved answers many questions about what it means to be human.
– Eric is a professor of philosophy and faculty member of the evolutionary studies (EvoS) department