Why do people (for example Huntington) so often identify civilization with religion? Isn’t there more in the world that makes a civilization a civilization? But as the Thomas-theorem says: "If men define situations as real, they are real in their consequences". So, once civilization is identified with religion people behave as if civilization can be identified with religion. That’s the danger of doing this, of narrowing a broad concept to one dimension.
Amartya Sen expressed the same, when he wrote: "... the social world constitutes differences by the mere fact of designing them. Even when a categorization is arbitrary or capricious, once they are articulated and recognized in terms of dividing lines, the groups thus classified acquire derivative relevance" (Sen, Identity and violence, p.27).