In debating with atheists, we have all heard something like this:
“Yeah but you Christians cant even agree on what it means to be a Christian? Why should I be your kind of Christian and not one of the other 40,000 denominations out there? How can Christianity be true if you all cannot even agree on what it is?”
This is a bad argument from the atheist for several reasons.
First, even if there were 40,000 denominations, and even if they were all uniquely different in substantive ways, it does not follow that the Christian with whom they are talking to believes that all or most of the other denomination that they do not belong to are not Christians or not "real" Christians or whatever. For example, I belong to a rather small American denomination within the conservative Reformed and Presbyterian tradition called the Presbyterian Church in America (the PCA). I have no problem saying that I have Christian brothers and sisters (even theologically incorrect ones) who hold to the core aspects of the Christian faith in nearly all other orthodox denominations – Baptists, Anglicans, Methodists, Episcopalians, Roman Catholics, Eastern Orthodox, and so forth. We have some disagreements to be sure, but we can all stand shoulder to shoulder on the core aspects of the nature of God, the Trinity, the person and work of Jesus Christ (namely expressed in his death, burial and bodily resurrection), and the commission to share the gospel to the world as much as we can before the return of Christ at the end of the present world.
Second, the existence of disagreement does not necessarily count as evidence against a view or in favor of its opposition. There are at least 10 different interpretations of Quantum Mechanics that are all consonant with the observable data. The fact that scientists disagree about the interpretation is not evidence against the existence of a quantum world, nor can the mere presence of disagreement with other views be an argument against any one view over the other. It also cannot be used reasonably as evidence in favor of some position that would deny quantum mechanics altogether. So too, the existence of theological disagreement between denominations on largely tertiary issues cannot function as an objection to Christianity or in favor of atheism. Think about what would happen if we allowed this kind of argument for worldviews more generally. Would the existence of mere disagreement between worldviews mean that ALL worldviews are wrong? Or could we, in a debate, tell one side that they are probably wrong simply because other worldview advocates disagree with them? Of course not. That would just be an objection which is trivially easy to dispatch.
Third, when someone makes a claim like this, we should always check their sources. The statistic for this number appears to be from the World Christian Encyclopedia (WCE) by Barrett, Kurian, Johnson (Oxford Univ Press, 2nd edition, 2001). While it does come to a total of 33,000 denominations, the problem with how the atheist uses the stat lies in how they understand what a denomination is compared to how the encyclopedia in question understood it. The atheists are using the objection to try and say that all of these denominations are totally different and do not agree and that each denomination is an instance of evidence for that. However, that is not how the WCE defines what a denomination is in their study. WCE defines a denomination as follows:
'Denominations. A denomination is defined in this Encyclopedia as an organized aggregate of worship centers or congregations of similar ecclesiastical tradition within a specific country; i.e. as an organized Christian church or tradition or religious group or community of believers, within a specific country, whose component congregations and members are called by the same denominational name in different areas, regarding themselves as one autonomous Christian church distinct from other denominations, churches and traditions. As defined here, world Christianity consists of 6 major ecclesiastico-cultural blocs, divided into 300 major ecclesiastical traditions, composed of over 33,000 distinct denominations in 238 countries, these denominations themselves being composed of over 3,400,000 worship centers, churches or congregations.' (Barrett et al, volume 1, page 16, Table 1-5, emphasis added)
From this definition, two things should be brought into focus about how WCE defined a Christian denomination,
1. Denominations are defined primarily geographically. That is, there may be one denominational body but it is counted as a new denomination for every country that it operates in. I mentioned my denomination, the PCA, previously. The PCA has church plants in a couple dozen countries. This means that while the PCA is the main ecclesiastical body, and we all agree and adhere to the same confessional standards, this one denomination will be counted as a couple dozen denomination in the WCE survey.
2. The WCE has no problem classifying these 33,000 denominations into 6 “ecclesiastico-cultural blocs.” This means that the vast majority of these fall into just a handful of buckets.
Therefore, the main problems with how the atheists use the final number from this list is that they completely ignore the causal factors that lead to denominationalism in the first place. Often the dividing line between denominations or for why one church will plant a new one is geographical, or if there is a split and the new church is one that is unaffiliated with the prior church (either peacefully or by a split) has absolutely nothing to do with anything remotely like substantive theology. Denominations and churches are established as distinct from others because of language barriers, cultural distinctives, personality differences, geographical differences, socio-economic, missional purposes, stylistic differences (such as the kind of music played or even, sadly, the kind of carpet that got installed) as well as a whole host other reasons. There are even micro-geographical reasons since the advent of the automobile and the invention of the suburb. We no longer see new churches being called “The 1st Methodist Church of Townsville” but rather “Curve” or something trendy like that. This is because people now have options. There are churches the missionally cater to Baby Boomers and Millennials and everything beyond and between. While many bemoan this kind of consumeristic segmentation and its effects on the church to water it down and juvenilize the church (myself included) this cannot be denied as a real factor in the segmentation of denominations even in small geographical areas. Within my rather small town, there are approximately 2 dozen baptistic churches that likely believe almost identical things as doctrine (at least on core essentials). But one may be a mega church because it was more successful in implementing modern church growth tactics while another fills a need for those with families but who may not like the faceless environment of a megachurch, and another may appeal to those who want to sing hymns and another those who want to sing contemporary songs, and so forth. Many of these churches are Independent, which leads to the next issue with the atheistic use of these statistics.
Sometimes, a certain strong view on the independent nature of the church, that is, that as a matter of course, these Christians may think that the most ethical, functional, and pure way to organize and lead a church just is for it to be independent of the institutional structures that we have seen in history can potentially lead to so much division. We can see this further in the list of denominations that the WCE labels as “Independents” where over 8,000 of the denominations listed just were independent (that is, entirely unaffiliated) Baptist churches. These churches would in most cases be almost doctrinally identical to what we would find in the major American free conference of churches known as the Southern Baptist Convention. In addition, the Roman Catholic and Anglican churches are counted by their various Rites and Orders even though they all are part of one institutional denomination.
Another problem with trying to use the list provided by the WCE the way atheists do, is that the list includes any group that self-identifies as a Christian church (e.g. Mormons, Jehovah’s Witnesses, Christadelphians, Oneness Pentecostals, Gnostics, Unitarians, Prosperity cults, Divine Science, Swedenborgian, Universalist Unitarians, etc.) This means that groups which are historically not part of orthodox Christianity and have been identified as cults (multiplied by their various country counts) are included in the list to the tune of several thousands.
I would then recommend a taxonomy of Christian Churches as follows (here I am even allowing the taxonomy to include self-identification as a means of entry to the list):
1. Roman Catholic
2. Eastern Churches
3. Reformed/Lutheran Protestant
4. Arminian/Anabaptist Protestant
5. Pentecostal/Charismatic
6. Theologically Liberal Churches
7. Cultic/Marginal Churches
This is simply a far more accurate way of looking at the various denominational traditions in a way that best eliminates the noise from the statistics dealing with geographical, linguistic, cultural, stylistic, personality, etc. differences that actually drive most of the denominationalism that we observe in reality.
The great irony of all of this for us who are watching the rise of atheist and secular groups, churches and Sunday assemblies, is that they are already showing the early signs of denominationalism. They form in different areas because of geography; several will form in the same area due to demographic or missional differences; some are parts of broader national affiliations, and some are not; some are active politically and some want to be intentionally non-partisan; some are geared toward involvement in education and local schools and colleges while some want to equip the “every man” and others just want to give a "fellowship" environment for unbelievers to gather and break bread together. We have even started to see "church splits" in groups like the Sunday Assembly and the Godless Revival. If we started counting atheist groups and assemblies like the WCE does with denominations, we would see the early seeds of denominationalism on a global scale within secular groups. I wonder what will happen with a group that generally prides itself on independence and having no creedal foundation that ties them all together - which we know serves as a unifying feature within Christianity. Give atheism the 2000 years that Christianity has had, and I wonder just how many millions of denominations such a group will have.