Humans crave order. If given the chance, we will organize ourselves into cliques and factions; we will create rules and regulations; we will exclude and elect. Every human institution is a testament to this, and none more so than the church. In the Hebrew Scriptures, God acknowledges and accommodates this yearning. As we know, the Ten Commandments are only the tip of the iceberg of the law.

Then Jesus came. Where the old law was comprised of thousands of commandments, Jesus gave two: Love God and love your neighbor. These have to be two of the most open-ended, interpretable rules ever written, and yet, that's all we get. Well, that's not all; we also get stories on top of stories, parables that teach through interpretation.

Then, Jesus died, is raised, ascends, and, on his way out, tells his followers to go and tell people the good news. Fast forward 2,000 years and we have hundreds of denominations made up of millions of Christians on every continent on earth. We have the hierarchy of the Roman Catholic Church and the casual fellowship of house churches; we get the strict guidelines of Presbyterianism and the quiet meetings of the Quakers. All that to say that given a couple of commands and a bunch of stories, we've made rigid structures, creeds, hierarchies, and doctrines. We've done this because we have to. It's what we do.

This desire for order and straightforward answers is what New York Times columnist David Brooks says is the impetus for "religions that grow, succor and motivate people to perform heroic acts of service" in his column last week. He begins with a review of the new, controversial Broadway musical "Book of Mormon," and ends up considering why some religions thrive; rigorous theology and arduous practice, he asserts. In short, doctrinaire religious expression succeeds because it answers questions that humans want answered: what is right and wrong, why do bad things happen to good people, where should I spend my money?

Southern Baptist Theological Seminary president Al Mohler picks up where Brooks leaves off, but, not surprisingly, goes even further. This phenomenon can't be understood purely in sociological terms, he says; it's not just that humans want answers, but that Christianity has the truth. It is this truth that people are attracted to, even more so than rigorous theology and arduous practice. The assumption here, of course, is that more progressive forms of Christianity, those that are not growing at the perceived rapid pace of conservative evangelicalism, do not grant access to that truth.

But if we're reasonable, if we're willing to grant that although there may not always be agreement on particular theological issues, mainline, non-evangelical, or progressive evangelical Christians also believe in the truth of the Gospel, then we're back to Brooks' sociological conclusion. The spread of conservative Christianity is not a ratification of Mohler's brand of fundamentalism because it is more truthful, but because it does what humans want religion to do: it provides hard and fast answers to the questions we ask. It dictates rules and allows us to bypass the uncomfortable mystery inherent in trying to understand supernatural things.