Religion
Religion has served crucial purposes in ancient societies, as it does today. Beginning at least 50,000 years ago, bands of hunter-gatherers acted according to rules and rituals that became a religion for survival. Watching a shadow dance on the cave wall as they moved about their protective fire, trying to avoid being eaten by an unseen beast. This had to be as frightening an experience as ever existed. They began to try to find answers for the abundance of unknowns that was their world. Leaders arose from this fireside collective, and a set of behaviors evolved, the "do's" and don'ts" of being in this collective for survival. This behavior fostered moral standards that held the groups together. The societies that benefited most from the unifying power of shared beliefs, out-competed rivals, and thus left more survivors. This is basic Darwinian evolution----to leave more survivors!
But, this does not discount the fact that the human animal tends to build a hierarchal system of control. These early campfire "leaders" began this system of control. Our whole government system is this hierarchal system. As such, a darker side of religion emerged to include all the wars that the human has engaged in, not to mention the inquisitions where we engaged in the cruelest forms of torture we could imagine. War, in my estimation, is nothing but an organized form of thievery. The have-nots want what the haves have, and they organize to take it. Quite possibly the first "war" was that perpetuated by the Mongols who stormed across the interior of Asia stealing what ever they wanted, and leaving a legacy of rape and disaster in their wake.
This differs from the basic variations that the different religions possess, that divide the world into its many religious fractions. I am still confused by the many permutation that account for the Muslim faith. None of this can be measured, none of it can be seen------we have to take it all on faith; faith that my god is better than your god, faith that a supernatural power weighs in on our decisions, and faith that his judgment is always there and correct.
As a scientist, faith does not work for me. I must be able to measure, to hold, to see, to hear, to feel, to smell that which is in question. My scientific training demands that I have data that support my conclusions. I have no use for "faith" in my conclusions. This is a dead-end road for a scientist, this is disaster. As a scientist, I have chosen to accept religion for the benefits that it originally came into being----to be the cohesive glue that helps society remain stable and to evolve in an increasingly complex world. But I also reject religion for it divisiveness, and for the totipotency of its omnipotence. It plays no part in my scientific inquiry, in the scientific method: the "method" is a self-correcting method of inquiry that has absolutely no use of "faith" in its discourse or execution.