Why is Christianity so big?

King’s College Chapel

Photo Credit: By Dmitry Tonkonog [CC BY-SA 3.0], via Wikimedia Commons

I used to have other reasons (meta arguments, in the sense that they do not use the text of the Bible directly) for accepting the validity of the claims of the Bible. Ultimately they do not matter—for me, the whole thing falls apart with the lack of credibility of the Bible, taken on its own terms, rather than based on some meta-argument. In other words, the biblical text is itself not credible where it matters (discussed in Section 3). But people use these meta-arguments to establish the credibility of the Bible, regardless of how incredible the text is, so I wanted to look at a few of them, and one in particular, which is the continued existence of the Christian church. I do not intend to look at this rigorously, but rather to point out a way that might be helpful to understand this and to explore where this kind of thinking might get us. Daniel Dennett discusses the broader idea in his book Breaking the Spell: Religion as a Natural Phenomenon.

Some of the other meta-arguments are, for example, the Lord, lunatic, liar or legend argument, which is the logical fallacy of false alternatives: surely Jesus can be a complex mixture of the last three just like everyone else? Another is the question of martyrdom: these eyewitnesses were tortured to death rather than admit that they had not seen Jesus risen. But people choose to die for all sorts of things (including a variety of mutually incompatible religions), and, though impressive, it does not make them right. It probably means that they believed it, but that is not the same thing at all. I discussed this in Chapter 35.

So why is the Christian church so big? I used to work for a consulting company, which had survived for a long time and was well-regarded even though it was frequently a miserable place to work, did work that was not uniformly of high quality, and cost a fortune to hire. I came to view its success in evolutionary terms: there were characteristics that did not make it the best at what it did but made it successful in terms of its continued existence and profitability. Internally, it promulgated the myth that it was the greatest place to work. Obsessive secrecy and brutal hiring practices created a mystique around the company, which fed the system. It was not that it was the best at consulting—it was that there was a concatenation of circumstances that made everyone think that it was the best which allowed it to grow and thrive.

I think a similar thing on a much larger scale happened with Christianity (and much of this probably applies to other religions). Imagine that there are people who see something or do something or teach something that starts a religion. We know this happens all the time because of the amazing stories of the cargo cult type. But major religions with mutually incompatible claims cannot all be true, which means that false religions have started and been hugely successful in the past. And, if you think it has only happened in the pre-enlightenment age, you need only look at Scientology (Going Clear is a documentary about this that is well worth a watch) and Mormonism. Now each time, the early founders and adopters create a particular set of beliefs, and these, in turn, determine whether the religion will be successful in the world. It has nothing to do with truth—just the religion’s growth or decline.

So what are some of the characteristics of Christianity that might combine to make it a successful religion?

Control and authority

Christianity tells us to have faith; to believe things without evidence; to suppress doubts (e.g. Mark 16:14b “he rebuked them for their lack of faith and their stubborn refusal to believe those who had seen him after he had risen”). All these things were, supposedly, inspired by God. Some religions even tell us that God wrote some of their holy texts. But these texts are, nonetheless, spread around by people. Lots of people think their ideas are better than all the dolts surrounding them. It can be very frustrating when people do not listen, so it is easy to imagine that people want to imbue their statements with a little more authority.

Christianity has a strong ethos of sin which gets mixed up by Christians with morality and legality and all treated as the same. People who disagree are labeled as non-Christians. Even Christians who disagree are sometimes labeled as “not real Christians,” which I have heard from well-meaning Christians.

In the end, Christianity tries to convince everyone that they are worthless. Incidentally similar to the sales technique of the consultancy for which I used to work. Everything is falling apart for you—you had better hire us quickly! But I am not so bad, you say. Well, did you know that even thinking bad thoughts is a sin? And that you deserve death, just for that? How do I know? God says so. You still believe you know better? “Trust not in your own understanding” (Proverbs 3:5). “The fool says in his heart, ‘There is no God.’” (Psalm 14:1).


After first convincing us that we are all rotten, Christianity tells us that we are all loved and accepted. You can have peace if you sign up with us. Wait a minute, do you have peace? Yes, of course, we all do. But you seem just as screwed up as the rest of the world. Of course—we are all sinners. But we have been called by God.

The creator of the universe cares for us and listens to all our prayers. But does He answer? Of course. Option a: He answers, but not always as you expect. We must trust in His divine will, even if he says no. “Says no” is code for ignores your prayer, but we do not mention that. Option b: If it did not work then you must not have had enough faith.

But either way, you are loved and looked after by the creator of the universe, even if you die or are maimed or your children die. It is all part of His mysterious will. The appeal of this type of theology is that it cedes control to a greater power. We can feel that despite all the issues that we see in ourselves and the world we can know that God is in control of the bigger picture. The human mind seems to have found this idea attractive for a long time with our superstitions, seances, prayers, and religions and perhaps the Christian version of it strikes a chord.

There must be more to life

It is hard to face your own mortality; to believe that this short life is all you have. We want to believe that we will one day be reunited with our loved ones. We also yearn for justice, and it seems to occur so rarely. Idi Amin dies at a ripe old age in a high-quality hospital, despite the atrocities he committed. How we want all the injustice that exists in this world to be set right.

Christianity comes along, offering you eternal bliss not just for you, but for your loved ones too. Justice will prevail. And the wrong you did will be washed away. It sounds too good to be true.

Wishing does not make it so. It just makes for an appealing set of beliefs.


Go forth and make believers of the whole world (Matthew 28:19). Do not worry if your beliefs seem foolish—that is done deliberately to show up humanity’s weaknesses. God’s ways seem foolish to humans. But if you study it carefully, you will get a feeling that seems like a glimpse of understanding, which you can help other people to gain.

Do not worry if you are martyred or persecuted. This is just the devil working through people to attack you. It is proof that you are right. People laughing at your beliefs just shows how little they understand. But they are lost, so you should pray for them and help them find their way. And, if it is God’s will, he will help them come to Him. This exhortation to proselytize means that converts will at least try to spread the religion.

This is not necessarily appealing; many Christians quail at the thought of trying to proselytize. But if enough of them believe that it is part of the package, then they might just do it. The fact that someone is willing to do this may be impressive to others as they consider their own beliefs, and at the least, it gives Christian beliefs the opportunity to spread. Also, the history of Christianity is littered with cases where the proselytizing was not consensual.

Religious natural selection

Factors like these make Christianity survive and thrive in the world. It does not mean it is true. It just means that it fits well with some proportion of human psychology. The desire to receive approval, to fit in, to help others, to have justice, meaning, and secret knowledge are all met in Christianity. It is a potent cocktail that, through a kind of societal evolution, has spread Christian beliefs successfully around the planet. Of course, it helped that Constantine converted to Christianity: Christians went from a persecuted minority (perhaps 5%) before Constantine to a persecuting majority by the end of the fifth century [3].

It does not make it true or false. It just is. What makes it false is the lack of credibility of the texts. But the existence of the modern church might as well be used as a (rather ironic) demonstration of evolutionary principles.

We have seen several examples of the rapid evolution of theology, and, just as in biology, stresses are often the cause. In this case, a moral quandary or a contradiction provides the stress. For example, we saw this in the discussion of the birth narratives (Chapter 27); Jesus as God (Chapter 31); the increasing physicality of Jesus’s resurrection appearances (Chapter 34); the criminals crucified with Jesus (Chapter 36); the Trinity (Chapter 37); the influence of Paul (Chapter 41); the imminence of the apocalypse (Chapter 48); and the culpability of Judas (Chapter 50). This is just a selection since the evolution is clear to see throughout this book.

And similar to what you would expect from evolution, Christianity is in no way homogeneous. The various forms are so different from each other they may as well be different species altogether. We find it incredible that the vast variety of biological life could come into being without God. And we find it incredible that the church, with all its variegated forms, could exist and thrive without God. But hard to believe means complex, not false.

Daniel Dennett (referenced above) calls for a willingness to study religions and beliefs dispassionately. This essay hints that such an approach can help us understand why a set of beliefs may spread. This could apply to political, scientific, religious, or spiritual beliefs. We should not determine the truth of the beliefs based on this alone: evidence and rationality should fill that role. But the notion that a dearly held belief could be more the result of your mind providing fertile soil for it than an objective measure of its accuracy should be disquieting. Christianity has several characteristics that might suppress our ability to reject it, appeal to our sense of the numinous, and encourage us to spread its ideas around. These characteristics could cause wide-spread belief in a false set of ideas. As an atheist, I need to consider whether something similar is going on with atheism. It does not matter what ideology you are following: democrat, republican, capitalist, communist, socialist, Christian, or atheist. That idea is not who you are; it is merely something you accept or believe. And we need to assess the truth of it based on reasonable evidence including an understanding of what causes us to believe in the first place.

People have argued that Christianity supported the scientific revolution by separating God from nature, allowing us to investigate the latter without blaspheming the former. That may or may not be true, but I argue that we now need a similar revolution in the way we study religious beliefs and religion itself. We need to separate who you are from what you believe, allowing us to study belief without offending believers. The above discussion is a starting point, not a conclusion. It is a hypothesis, not a theory. It is something we should test and reject if it does not work. Christians should also advocate for this kind of study, as they should be unafraid of where a search for the truth will lead.