The first scientist to propose testable hypotheses concerning the biocultural evolution of religiosity (biological predisposition to behave towards superempirical agents) and religions (cultural traditions relating to superempirical agents) has been Charles Darwin. But although some classic scholars of religion such as Emile Durkheim fruitfully worked in that field, it finally succumbed to heated polemics of religious vs. antitheists as well as the natural vs. social sciences. Until some years ago, when it was finally brought up again by evolutionary biologists for the sake of their own field...
For example, you might have heard about Richard Dawkin's theoretical framework of the "Selfish Gene", whereas genetic "selfishness" pitted phenotypes of all kinds against each other - including women and men (in the "battle of sexes"), siblings (for access to the families resources) and mothers and children (struggling for more or less parental investment). According to this framework, cooperation could only evolve in the strict conditions of genetic competition, kin selection and (seldom) reciprocal altruism. Therefore, cultural phenomena such as celibacy served Dawkins as the very epitome of "Memetics" - the belief that cultural traditions would evolve into genetically parasitic forms such as "religions".
David Sloan Wilson and the Jain Ascets
Welcome the evolutionary biologist David Sloan Wilson - one of the increasing number of evolutionary biologists first wondering and then doubting whether the "Selfish Gene"-metaphor turned out to be scientifically viable. In more and more cases, the amount of cooperation and altruistic behavior among animals and Homo sapiens turned out to be far beyond those levels that Dawkins and his followers would have thought possible. And what about these celibates, who obviously did not (or seldom) reproduce?
David Sloan Wilson explored the case of the Jain Ascets, whose Digambar branch expected them to forfeit family and sexual relations as well as almost any possesions including clothing.
Didn't they constitute a case of "memetic" evolution? No. David discovered that the Jain Ascets served their communities as a kind of religious & trust-building police. By inspecting Jain lifes and families and accepting or rejecting food as a result, the ascets did not only symbolize and reinforce the religious values of the tradition. They also fostered trust and acceptance among the devout, contributing to the success and survival of Jain live throughout India - constituting a cooperative potential far above anything "Selfish Gene"-theoreticians would have thought possible!
To David and a growing number of colleagues, religious traditions, networks and communities turned out to be a rich field of cultural group selection, reshaping and enhancing the chances for prosocial behaviors and traits. "Darwin's Cathedral. Evolution, Religion and the Nature of Society" constituted an early breakthrough to this new perspective.
The Importance of Evolutionary Studies of Religion for Evolutionary Biology
Here is a new lecture opting for an evolutionary perspective on understanding human nature and culture - as the intertwined magisteria they have always been.
Therefore, evolutionary studies of religiosity and religions turn out to be not only of specific importance to scholars in social or cultural sciences, in theologies or philosophies. They are also on the center stage concerning our understanding of evolutionary processes in general, of building variation and cooperation, of understanding evolutionary success even beyond reproductive advantages (which are bestowed by successful religious traditions as well!). And it is quite ironic to see very unlikely alliances emerging i.e. among religious fundamentalists such as answersingenesis and some antitheist scholars such as Richard Dawkins or Tom Rees jointly (and increasingly desperately) ranting against evolutionary studies of religion in order to protect their respective worldviews. But others such as Susan Blackmore showed the integrity and courage to accept the empirical evidence. It seems that this time, the scientific field cannot be muzzled again as it has been during the first half of the 20th century. Or as Razhib Khan from Gene Expression has put it:
As you can see, the big picture is this: religion wins! Assuming…. And what are the assumptions?
1) Religious people have higher fertility. This is true!
2) Religiosity exhibits heritability. This is true!
Combine these two, and you have an excellent ingredient for natural selection to drive a trait and its underlying alleles to fixation. The question is not if, but when.
Or, as David Sloan Wilson put it once: Let's bring on more of the (empirical) legwork!