Think of religion as a collection of viruses, specialists in modifying a host’s behavior in specific ways, that somehow got into our ancestors during the long period of human biological evolution. As they settled in and adjusted to their environment, they developed various degrees of symbiosis with the host and each other.
The host evolved both physically and in terms of cognitive powers; in the process, new needs appeared that some of the religion viruses were able to fill, including burial of the dead, ancestor worship, magic, explanatory narratives, rites of passage, and much more. The result was a host better able to cope with the arduous environment of the Pleistocene.
Enter the Holocene and agriculture. Population increased and brought new stresses on interpersonal relations. Some of the older viruses adapted and formed new combinations; an uneasy equilibrium was forged that allowed people to function in settled communities. Eventually, population density increased even more and conflicts ensued, on a new and larger scale. Group selection between cultures became a major driving force in the host’s evolution. Enter the bad virus.
Perhaps we should not call it a bad virus since at that time it met a need that was only marginally less vital than the need for physical survival of the individual hosts. Warfare in the Bronze and early Iron ages was often a matter of kill or be killed; if your group was on the losing end it didn’t much matter how physically fit you were. Check out the Old Testament. The new virus conferred the enormous practical advantage of substantially increasing the odds that your side would win. It did this by inducing a state akin to sexual arousal, adrenalin in full spate, blood diverted from the brain and viscera to the fighting muscles. It caused whole groups of people, especially the men, to enter a state of arousal that could last months or longer, and could focus on a distant enemy, not just an immediate threat.
Perhaps we should not call it a new virus, because most likely it had been in its host for a long time, along with other survival viruses, and simply expanded in its strength and efficiency when warfare became common. But it was new in the sense that it became transformed into something so much more powerful that it was for all practical purposes a new effect.
It was new in another sense as well. Other religion viruses had proliferated to fill emergent needs for social cohesion within the expanded group. During the neolithic the resulting religious practices were relatively benign and relaxed, but when the age of constant war began there was a need for stronger medicine. Enter Yahweh, father image, war god, smiter of the tribe’s enemies. Yahweh and the arousal virus went into battle together, and very shortly Yahweh became infected irremediably. Reading the Old Testament, it is easy to get the impression that Yahweh went through the second and first millennia BC with a permanent erection.
The early Christians weren’t too affected by the bad virus at first, but it wasn’t long before it took hold with Christ’s followers. Islam never had a chance, it was prime material for the bad virus from the word go. The Viagra of Yahweh took over the western world, and has been with us ever since.
Nowadays, when there is no enemy in sight, the virus stays below the horizon, the only visible manifestations being aggressive and competitive missionary activities. But it is a beast lying in wait that can be aroused by clever symbolic manipulation, and once aroused it is not easily put back to rest.
So-called religious wars have usually not been exclusively or even mostly about religion. They start with some other cause, but when armed conflict becomes imminent, or if a party is actually attacked, it is normal to invoke religious symbolism to awaken the bad virus and prepare for battle. Even when belligerents share the same faith, each will invoke religious symbolism, undeterred by any suspicion that their deity might have trouble choosing which side to be on.
If this analysis has any merit, it suggests a possible approach to the scientific study of religion that is aimed at a more specific target than most of the efforts to date. The recent books by Dawkins and Harris have been aimed at demolishing the whole structure of religious viruses as they have evolved over the ages, and it isn’t entirely clear even to me, a committed humanist, exactly how we might replace the empty space that that excision would create. But if we could discover an antidote that would counter the specific bad virus described here, we might be getting someplace.