07/12/2010 07:55 am ET | Updated May 25, 2011

Why Religion Does Not Equal War

After ferrying the Crusaders across the Bosphorus Straits, Byzantine Christians reported their horror at witnessing the Crusading knights and peasants skewering and roasting children on spits, as the invaders advanced from Nysea in Marj Uyun in Lebanon. When the soldiers finally took Jerusalem in 1099, they celebrated their victory by burning alive all the Jews they could find, massacring Moslem women and children, and destroying most mosques and every synagogue in the Holy City. For two hundred years, claims James Reston, the Crusades unleashed 'a frenzy of hate and violence unprecedented before the technological age and the scourge of Hitler.'

So goes the description from anthropologist Scott Atran's book In Gods We Trust (Oxford Press 2002, p. 289). Exhibit A among the gruesome atrocities committed in the name of religion. But are the crimes of the Christian Crusaders any worse than, say, what the Romans did after sacking Jerusalem in 70 AD? Maybe not, but there is experimental evidence showing that religious motivation can intensify violent inclinations. Brad Bushman (and colleagues) at the University of Michigan had subjects read a biblical passage endorsing violence and later found that these subjects behaved significantly more aggressively in a competitive game compared to those who believed the passage was from a (non-divine) ancient text. So would we be a more peaceful species without religion?

To my knowledge there has only been one attempt to actually quantify religion's role in war-making throughout human history. As part of a special they were airing on the subject, the BBC asked Dr. Greg Austin, a research Fellow in the Department of Peace Studies, University of Bradford, to investigate religion's role in the history of war. Austin, with the help of colleagues Todd Kranock and Thom Oommen, conducted the War Audit, where they evaluated all the major conflicts over the past 3,500 years -- 73 wars in all. The wars were rated on a 0-5 scale for religious motivation, with 5 indicating the highest religious motivation. So for example, The First and Second Punic Wars (264-241 and 218-201 BC respectively) rated a 0, while the Crusades (1097-1291) rated a 5. While conceding that subjectivity always plays some role in these sorts of assessments, Austin and colleagues, nevertheless, maintained that the general trend they observed was "beyond debate" (p. 12).

Brace yourselves, those for whom religion equals war. The majority of all wars (44/73 or 60 percent) had no religious motivation whatsoever -- a zero rating. Only three wars -- the Arab conquests of 632-732, the much ballyhooed Crusades, and the Reformation Wars of the 16th and 17th centuries - earned a 5, and were thus considered to be truly religious wars. Only seven wars earned a rating of 3 or more -- less than 10 percent. Thus, the vast majority of all wars involved either no religious motivation or only a modest one. The authors concluded by noting that "there have been few genuinely religious wars in the last 100 years. The Israel/Arab wars were wars of nationalism and liberation of territory" (p. 16).

The authors of the War Audit claim that their work was not intended as "a piece of original academic analysis" (p. 1), but instead as something that would "stimulate discussion rather than provide the final word on the role of religion in violent conflict over time" (p. 15).

As a committed evolutionist, my pet theory is that ultimately most (maybe all) wars are about men fighting over resources critical to reproductive success (status, power, land, money, women, etc.). War requires large-scale coordination and motivation, and here is where religion can play a role -- it is a powerful unifying and motivating force. But in the absence of religion, I think it is hopelessly naïve to believe that we'll all just give up our ambitions, drop our rocks and hug. We'll find some other reason to kill each other, if we're convinced that there is gain to be had by doing so.

More so than any other creature (some would argue uniquely so), we humans have been adapted for culture. All the high-minded talk about a "common human family" is fine, but pretty useless when comes to solving real human conflicts. We are cultural creatures and it is culture that unites and divides. With that in mind, try this little exercise:

Take your pointer finger and place it on Marrakech, Morocco in North Africa. Now run your finger across the vast expanse of Northern Africa, across the Red Sea and Arabian Peninsula, now north to the Caucasus Mountains, east across Iraq, Iran, Afghanistan, Pakistan, down around India, and across the Andaman Sea to Indonesia. Ponder for a moment the multitude of nationalities, ethnic groups, tribes, cultures, languages, and life ways your finger past across. What's the only possible cultural product that these wildly diverse peoples might have in common? Like it or not, the answer is religion -- in this case Islam. You could repeat this little exercise starting in Budapest, Hungary and tracing across southern Europe, over the Atlantic to Canada, down North America to Central and South America and all the way to the tip of Tierra del Fuego -- and again the only thing all these people might share would be religion, in this case Roman Catholicism.

If you want more peace, does it make rational sense to start by getting rid of the one thing that the largest number of people have in common? Outside of kinship, nature has come up with nothing more effective for creating group cohesion than religion. Sadly, that in-group unity often carries with it greater out-group animosity. But we might take a lesson from nature. She works with what she is given, adapting structures piecemeal to fit better with the current environment. Our best shot might be to do the same with religion; working with it, adapting it so as to retain its unifying benefits while trying to minimize its tribalistic dangers. An important message from the War Audit is that religion's record on war may not be anywhere near as bad as is popularly believed, and therefore its potential for peace may be far greater than what many have imagined.