Religions are a product of ancient mans lack of knowledge. They are systems of thought based on the belief that there is a supernatural entity (god) who has the power to reward or punish based on someones actions. Religion are ancient societies misunderstanding of reality prior to modern science.
Supernatural means it (god) can override the laws of nature (walk on water, part the red sea, etc.)
Religion is the system that teaches people what to do in order to earn his rewards and avoid his punishment. Both here on earth and in the afterlife.
The major religions have sacred texts (user manuals) to teach from and instruct their followers about it’s rules and regulations. They also have a formal leadership structure and certified teachers to advance their cause.
Cultures used to be very homogeneous so religious affiliation was predictable by geography. But even though cultures are getting more and more mixed now, the dependent variable is still the same: the religion of the parents.
The percentage of the population that “believes” in these religions is steadily decreasing as people become more educated. But there are still large pockets of intellectual isolation where they continue to survive and thrive.
Except for the supernatural part, religions function very much like culture in general to promote or discourage a range of behaviors. Except for one major difference: Cultures can change and adapt in response to advances in knowledge and science.
But religions are based on static historical texts so they can’t change far enough and fast enough to stay relevant. They were nothing more than a stop gap measure to manage society until mans knowledge could catch up with his intellect.
Within the last few hundred years religions have reached their useful limits and are losing their influence at an accelerating rate. They are in their twilight years and will soon fade away and disappear.