Violence often breaks out between religious groups. Yet, it is a mistake to blame religion for violence. Unfortunately, warfare is a universal human potential that would still exist if we were all atheists.
Not all societies are warlike, however. Anthropologists contrast the peaceful Shoshone with the more belligerent Paiute in North America for instance. The Shoshone wandered widely in small groups in search of food. They did not fight because they had no territory worth defending, as the Paiute did (1).
Land (or territory) remains an important bone of contention around the globe, in places as diverse as Israel and the Ukraine but there are many other resources that stimulate aggression, from oil and minerals, to spices, and opium. Many seemingly religious conflicts have nothing to do with theology even if religion serves as a convenient label for opposing groups.
Ireland's War between Catholics and Protestants Was not a Religious War Wars fought across lines of religious membership are easily mistaken for wars about religion. Yet, most involve conflict over over vital resources. The problem in Northern Ireland was that Catholics were a discriminated-against minority who were cut out of well-paid jobs and scraped by in substandard housing with minimal political power and plenty of intimidation by police. Of course, Northern Ireland tensions were also fueled by a territorial dispute between England and the Republic of Ireland where Catholics were considered disloyal to the colonial Stormont regime.
So the violence in Northern Ireland had little or nothing to do with theology as such. If both sides had belonged to the same religion, or no religion at all, they would have had just as much reason for conflict.
In Northern Ireland, religion served as a convenient line of demarcation within the population across which the conflict was fought. Religion functioned as a group identifier that evoked an us-versus-them mentality. Social psychologists recognized many decades ago that any arbitrary identifier can be used to foment hostilities between groups that are otherwise equivalent.
Established Religions Mostly Favor Peace Mainstream religions mostly discourage warfare. There are some historical exceptions, including the days of Papal armies and empires, and the medieval Crusades where the Catholic Church wanted to capture Jerusalem and claim it as a Christian city.
In general though, religious leaders are content to exercise their power indirectly by influencing secular leaders and the public). They promote peace of mind through their rituals rather than stirring up hostility.
Unfortunately, there are some firebrand clerics who ignore that playbook and use their pulpits to inspire aggression against other religious groups. The fact that they cloak their message of hate in religious rhetoric tells us nothing about the mainstream churches that they choose to pervert. Such messages find receptive soil in communities that feel marginalized, despised, or deprived of job opportunities and social mobility.
Radicalization of a small number of individuals can have devastating consequences as recent events in Europe demonstrated. That is particularly true in the context of a global Jihadi movement organized over the Internet. It is disturbing in a world where violent extremists are permitted to hold territory, and even to form governments.
Pirate Societies Phenomena like the Lord's Resistance Army, ISIS, and Boca Haram, are more dangerous than Al Qaeda because they aim to hold territory by terrorizing civilians and are willing to take on large armies such as those of Iraq and Nigeria, sometimes with stunning success. That success is partly due to having superior equipment purchased with the proceeds of various crimes from stealing oil, to kidnapping, and human trafficking.
Apart from their religious rhetoric, these terrorist groups have many similarities to pirate societies of the past, complete with a large treasure chest, brutal system of punishment, and distinctive clothing and flags.
With their safe havens in the Caribbean and elsewhere, a relatively small number of pirates defied the great navies of the world for centuries. Some, like Blackbeard, used carnival tricks - such as placing a lighted fuse under his hat - to intimidate his victims. ISIS and their ilk are little more than the pirate communities of old. They may use religious rhetoric to rationalize their grisly crimes, to justify their punishments, or to attract new recruits from abroad. Yet, their agenda is not religious and it is not new. Their ambition is the same as that of Blackbeard. They enjoy scaring people but they also want the loot.