An article in a recent issue of The Economist discusses the evolutionary basis for religious belief. The hypothesis being evaluated is that being religious confers some kind of advantage upon those with the trait, explaining the degree to which the trait is widespread. The hypothesis is not an entirely implausible one, and several studies suggesting some degree of validity are listed.
The thing the studies made me wonder was: “If you believed both that being religious would make you more healthy or successful, but you also believed that the religion had no basis in fact, would you practice nonetheless?” This would be akin to adopting Islamic dietary restrictions and fasting requirements because scientists had shown they conferred benefits for cardiovascular health. Such behaviour might achieve the aims that these scientists claim are embedded beneath religious behaviours, but they would clearly deviate from the stated principles of most faiths.
Another possibility acknowledged is that religiosity doesn’t confer direct benefits on individuals. Rather, it just makes them more fertile. There certainly seems to be an inverse correlation between the degree of secularism in a society and birth rates. Genes that promote religious faith may thus be doing so in order to increase the number of offspring who later carry them. The beliefs themselves may lack a basis in fact, but, if they contribute meaningfully to the propagation of selfish genes, part of the near-ubiquity of faith might be explained.