The dictionary definition of "fact" is "something known to exist or to have happened," whereas "faith" generally is described as "belief not based on proof." There are 10,000 religions worldwide, eighteen of which are major Christian religions, and among Christians there are 9,000 separate denominations. Each of those religions and denominations has its own belief system—its followers act on faith—even though, as author Jack Gage points out, "all the adherents of these different belief systems inhabit the same world, with the same physical facts, with access to the same knowledge." So how and why did so many religions come into existence? And how do the various religious explanations—whether Christian, Jewish, Buddhist, Muslim, or any other—for how the world and the people in it began stack up against scientific fact?