I thought about posting this on the science forum. It's here because a lot of discussion centers on the factuality of claims. Also, I have argued for the idea that societies enshrine their moral code in religions. This explains some of that.
Here is the crux of it, from
Quote, from partway through:
Gods, as full-access strategic agents, occupy a unique role that allows them to detect and punish cheaters and reward cooperators. In moral religions, such gods are conceived of as “interested parties in moral choices.” They are concerned with social interactions and fully cognizant of the behavior and motives of those involved. Communal belief in such beings lowers the risk of cooperating and raises the cost of cheating by making detection more probable and punishment more certain. Promoting the belief that one will be caught and punished if they cheat isn’t sufficient, though, because there are always people who won’t accept that belief (or who will cheat anyway). Thus, religion also offers another advantage: it provides a means by which people can more quickly identify likely cooperators and likely defectors.
Religious rituals and rules function as ... hard-to-fake signals, and indeed, Irons has characterized religion as a “hard-to-fake sign of commitment.” He points out that religions are learned over a long span of time, their traditions are often sufficiently complex to be hard for an outsider to imitate, and their rituals provide opportunities for members to monitor each other for signs of sincerity. This is a costly and time-consuming process.
Showing oneself to be a member of a religion signals that one has already made a significant contribution of time and energy to the group. That is, it signals that one is a reliable partner in social interactions and can be trusted to reciprocate.
From an evolutionary perspective, religious morality provides a vehicle for extending the evolutionary mechanisms for morality, kin selection, and reciprocal altruism. Also, by serving as a hard-to-fake sign of commitment, religions function to discriminate between in-group members (those who have invested in the religion and so can be trusted) and out-group members (those who have not invested in the religion and so cannot be trusted).
If this is true, and it certainly sounds plausible, it may provide some insight on the question of why liberal religious groups in America have been declining while conservative ones have been growing. Perhaps the more liberal the church, the less commitment is required by the members — in that case, though, the church and religious community do not serve to help people predict whether someone is trustworthy because the signals are too easy to fake. Conservative churches which require more commitment, however, may be more appealing because people unconsciously recognize the higher value of the hard-to-fake signals that such churches develop.
One this forum, we see skirmishes between self-styled Christians over subtleties of Christian doctrine, and downright battles over more substantial differences between, say, "positive atheists" and "fundamentalist Christians." While there are few opportunities for the arguers to actually need to know about each others reliability, I suppose it's good to stay in practice.