“Islam” and “Christianity”, as umbrella terms, are actually not has helpful as you might imagine. Each religion has a huge variety of believers even within their many different sects. These sects (or “denominations” as Christians prefer to call them) can differ from each other so much as to make their shared name (“Christian” or “Muslim”) completely uninformative. We should not fall into this temptation of simplicity but instead, as the diagram below, remember that any given believer has a huge variety of thoughts, attachments and practices.
As a simple Christian example, compare Appalachian Christian Snake Handlers to formal urban Episcopalians. Values, expressions, economics, language and much more separate these folks from each other enough so that calling them both “Christians” or “believers in Jesus”, as telling you almost nothing important.
Likewise, as a simple Muslim example, compare lower-class Whirling Sufi Dervish Muslims in Turkey to the higher-class Wahhabi conservatives in Saudi Arabia. Sure, I can tell you they are both “Muslims”, but that tells you nothing of their real values, practices, lifestyles and/or politics.
So, as you can see in my diagram to the right, understanding the “varieties of believers” of any given religion helps us understands a religion. But ironically, it helps us also to understand that what is important about a believer is not their umbrella-term name, but the particulars about their world. I made the diagram above to illustrate how the umbrella term blocks us from understanding all these very important particulars (the rain drops).
Could a snake handling, absorbed-bouncing West Virginia snake-handling Christian have more important elements in common with a poor Turkish whirling Dervish than they do with their counterparts mentioned above? Are these types of small communities which are drawn to trance-inducing religious fervor best understood for that trait, or for their umbrella term. I contend that it is the constellation of practices, social networks, demographics and more that we need to really understand each other. Relying on broad terms like Christian or Muslim does these individuals injustice — though they may claim otherwise. But we do this because of the temptation of simplicity.
As to keep this post “short”, I supply links to supplement the above: