Core theology

One objection some atheists lob against Christianity goes like this: since Christians can't agree about what the Bible means, why should an atheist take it seriously? On a related note is the Catholic trope that Protestants can't agree on anything. 

1. As I've noted in the past, that's a duplicitous objection. Most atheists are, if anything, supremely overconfident about their grasp of Scripture. They are sure that Scripture is riddled with moral errors, factual errors, and contradictions. Well, you can't say that and simultaneously say you don't know what it means. But consistency has never been an intellectual virtue for atheists. 

2. However, I'd like to make a different point. The number of denominations doesn't tell you what Christians believe. The fact that a Christian may belong to a Baptist church, Presbyterian church, Lutheran church, Anglican church, &c., doesn't carry the implication that his theology coincides with the church he happens to belong to.  

It's my impression that many or most evangelicals have a core theology. For better or wore, that represents their essential theological commitments. 

They will attend or join a church that shares their core theology. The official theology of the denomination may go well beyond that, with a number of doctrinal distinctives. However, many evangelicals select a church not because their theology coincides with the whole theological package of the denomination, but because it dovetails with a common core. We can see the disconnect in at least two respects:

i) The standard for ordination is typically much more specific and detailed than the standard for membership. To be a church officer makes you an official representative of the denomination, so you must adhere to the whole theological package of the denomination. By contrast, laymen don't have that role. In addition, lots of churches don't wish to drive away prospective members by raising the doctrinal bar too high.

ii) I think it's not uncommon for evangelical couples to marry a spouse from a different denomination. To take a striking example, Billy Graham was the world's most famous Southern Baptist minister, yet his wife was Presbyterian. In that respect he as a man first and a Baptist second! 

It's then a question of whose church to attend: the husband's or the wife's. And it's not a big deal. If that was a deal-breaker, they wouldn't get married in the first place. After marriage, one spouse switches denominational attendance. But that doesn't mean he or she changed their theology.

Now, I'm not a sociologist of religion, so I don't claim to be an expert, but that's my impression. Point being: there's no reliable correlation between doctrinal affiliation and denominational affiliation.

Of course, that's not to deny that in however many cases, there is a matchup between a layman's theology and the whole package of the denomination they belong to. I'm just making the observation it's misleading to imagine there's generally a one-to-one correspondence. So appearances are misleading if you think church membership is pegged to denominational theology.