In todays discussion of "What is Religion", one of the ideas was that religion provides comfort and security and that it explains natural phenomena. By believing that there is "someone up there" watching and taking care of you, one can be certain that everything happens for a reason. Both bad things and good things are earned by the recipiant, so as long as you know and abide by the rules, you can control whether good things or bad things happen to you. The ancient greeks and Romans are perfect examples, offering sacrifices to particular gods when they want something, and blaming someone for offending a god if something bad happens to them. Its a very comfortable way to see the world, to know where everything came from. But that cant be all that religion is, a desire to manipulate a higher power and thus control one's destiny. Though I am an atheist, I am very spiritual, and the connection I feel with my beliefs cannot simply be explained as guidelines to get "good things" instead of bad. With my beliefs comes a sense of fulfulment and wonder that doesn't lie in the security is gives me but rather the unknowns it leaves me to answer.
It seems likely to me that in the earliest days of religion, it's sole purpse was to reassure the believer that they were in control of their fate, that the world wasnt a vehicle of random chance. Evolutionarily, this makes sense-a hunter will be more fearless after performing rituals, the confidence his certaintly gives him will attract a mate. However, today, the evolutionary advantages have become irrevolent, and left the brain with the structures which desire religion, leaving our more complex brains to develope huge societal structures around the originally simple idea of surety. Like Henig's example in "Why Do We Believe", religion is like breasts. Desiring large, full breasts has a definite evolutionary advantage, but that desire has been expanded to be used in unnecesary and unrelated areas such as selling beer. Thus has religion moved away from its original evolutionary motives and been developed into something widespread and incredibly complex. Our brain doesn't even know why it wants it anymore. Like a man watching a beer commercial, it only knows that it looks mighty fine.