The causes of religious violence have attracted numerous explanations in the years since the 9/11 attacks on the Pentagon and the World Trade Towers. However, most forms of religious extremism do not ...result in violence (e.g., the Amish, Hasidim, Jains) and religious groups have not cornered the market on egregious violence. Nevertheless, religious violence does occur, and this paper examines the interplay of social networks and religious violence. It builds on Cass Sunstein's "law of group polarization," which predicts that when like-minded people deliberate as an organized group, the general opinion shifts toward extreme versions of their common belief. It argues that internally dense religious groups that maintain few ties to the wider society are more likely to embrace extreme views and behavior than are those that are not as dense and/or remain tied to the wider society. The argument is then tested using social network analysis methodologies to examine the evolution of the Hamburg Cell, which played a critical role in the 9/11 terrorist attacks. It concludes with a series of policy recommendations that can limit but not eliminate religious extremism and violent behavior in the future.
