Why are monotheistic religions so popular?

I asked a similar question on Wikipedia’s reference desks before, and the final response was something along the lines of “There is no answer. This is something people love to gab about and opine, but we really don’t know.” So, I am going to assume that there is no answer, and because of that, I am going to add this question to IMHO. I consider the question is a matter of opinion and best educated guesses.

Anyway, why are monotheistic religions so popular? With Christian Europe and Muslim Africa and the Middle East, there must be some sort of appealing factor to it, does it not? Why choose one god over many gods? Wouldn’t the belief of many gods be far more safer than the belief of one? Are there any cultures with complete disbelief of gods? Why is that so many cultures use nature to depict a god (i.e. the sun god, the sea god, the sky god, the death god)? What’s the big deal with the god’s gender? Why are some gods female and some gods male? If the gods can reproduce and their children grow up, then how come they never experience age or wither away (die)? Why do people believe that they are “punished” by a god? Have you ever believed that you were “punished” by a god? Maybe your mommy and daddy said you should put on sunblock before you go outside, but you failed to put it on and the blistering heat of the sun really damaged your skin so you got a sunburn. Then, for once, you thought, “OMG, my god is punishing me for disobeying my parents!” rather than, “Oh dear. I think I have a sunburn. Hope I don’t get melanoma.”

One God, only one Sacred Name to remember. Makes services shorter, and the worshipers do not need to worry about getting in between two gods haveing a disagreement.

With a single deity, at least they can be guaranteed that the smiting is not going be just collateral damage.

If I’m selling you on one god who handles everything, I can explain that he has the quirk of working in mysterious ways and largely prefers to settle scores in the afterlife instead of showing up to deal with worldly problems. Sure, he didn’t send that rain you prayed for – but you shall have treasures in heaven, right? He handles both of those things.

If I’m selling you on a bunch of gods who each happen to have the quirk of never showing up, things get pretty awkward pretty fast. You ask me why the rain god, who doesn’t handle anything else in general or preside over the afterlife in particular, didn’t respond to your sacrifice? What the heck can I say? He’s the rain god! That’s all he does!

You see here there was this empire called Rome. It was kinda great and after it got tired of persecuting the adherants of this gentleman one of their own had crucified they actually decided to start following them as well.And many of the former parts of this Rome, went out on their own and conquered lands elsewhere and brought that worship with them. Elsewhere a strange thing happened. In a backwards province of this Rome, a man began to preach a new religion. THis new religion not only took away most of this Romes territories and destroyed its main enemy, but it went and for good measure took new lands to the east and north as well, raking that religion with them./

It easier to remember which name to call while having sex.

Personally, I don’t think there’s anything intrinsically more appealing about it, it’s just that there are a lot of missionaries spreading it around. If some other culture went around colonizing the world and sending missionaries, then whatever their religion was would probably spread around, too.

It isn’t monotheism as much as exclusivity. Jews were monotheists for quite a while, but we didn’t really care what anyone else thought, and didn’t have the concept that anyone outside the tribe who didn’t believe in our God was in trouble. Christianity’s great innovation was religious bigotry. Greeks and Romans believed that their gods existed, but that it was perfectly plausible that other gods did also. Christians not only denied other gods, but claimed that anyone believing in them was in for damnation. Very powerful for the weak of mind, and I wouldn’t be surprised if there was some early version of Pascal’s Wager around. Christianity invented mass conversion. Maybe the Romans required you to worship the emperor as divine (unless you were Jewish) but that didn’t mean you couldn’t worship all your other gods too. Try that after the emperor converted and you were in trouble.
You might know in your heart of hearts that the church service you had to go to was bull, but your kids grew up in it.
Islam figured this out also, and diverse lands became nearly 100% Muslim. It takes the concept of religious liberty, which seems to have arisen after Christian splinter group battled themselves to a stalemate, to make it okay to worship something different again.

I’ll ignore some of the more hateful responses on the thread and actually answer the question.
First of all, monotheism gave people the appealing idea that God cared about them. Anyone with even a passing acquaintence with Greek or Roman mythology knows how little these gods cared about humanity. By posting the idea of a single caring God, Christianity gave large numbers of people hope about their overall situation. Of course that opens up the issue of how a omnipotent God could allow suffering, but that’s a seperate topic.
Secondly, Christianity was far more interested that others believe in a single God than the polytheistic societies. Polytheistic societies tend to only care that their own region or ethnicity stay loyal to their gods. That means they rarely bother with missionary activity. But if you think there’s only one true god and salvation is only possible through that god, don’t you want to spread that word as far and wide as possible? Therefore Christianity put a lot more emphasis on converting as many people and societies as possible.

Because their followers have obsessively tried to convert others, and killed entire cultures of unbelievers. Consider America; the non-Christian Native Americans were systematically exterminated, while blacks were enslaved, their original cultures erased and Christianity forced on them in its place. Morally bankrupt, but very effective for spreading Christianity.

Except Christians did not limit this kind of treatment to non-monotheists. They were quite happy to persecute monotheistic Jews at around the same time they were persecuting Native Americans. Isabella and Ferdinand expelled monotheistic Muslims and Jews from Spain. Christian rulers even persecuted other Christians, generally those who held to a different variant of Christianity.

Also, when traders were looking for slaves in Africa, I don’t think “not being a monotheist” was a key criterion for selecting slaves. Some slaves were Muslims before they were kidnapped from Africa.

If you really want to see people wipe out other people because they disagree with with their religion, try Islam…or even more violent try atheism. Try counting the bodies that Communist nations such as Red China, USSR, Cambodia. Or Tacitus quotes one “barbarian” saying a pre Christian Rome “created a desert and called it peace”.
Keep in mind that slavery existed for a thousands of years before Christianity yet it was the Christian church that ultimately turned what was regarded as normal human behavior into something detestable.

One aspect may be that in polytheistic religions, the “gods” are much more like powerful humans than all-powerful omnipotent beings. They have their skills, and magic, and such, but it’s the reason that someone like Thor (based off a polytheistic god) can be a member of the Avengers with normal humans. God or Allah? Not so much. So praying to an all-powerful, lone god may seem more appealing in many ways (including The Other Waldo Pepper’s point about “mysterious ways”).

Or it could easily just be happenstance that the two religions who happened to become entrenched and conquer lots of the world, leaving their imprint, happened to be the monotheistic religions of Christianity and Islam. After all, the Jews are monotheistic, and they’ve certainly managed to outlast other religions, but I wouldn’t say they were ever popular.

There’s also probably a Eurocentrist tinge to the assumption underlying your question - by asking why monotheistic religions are popular, you seem to be implying that polytheistic ones are unpopular. However, depending on how you count, there are almost as many Buddhists and Hindus as Christians or Muslims.

There are monotheistic religions that didn’t go far. Zoroastrianism is regaled to parts of Iran.

The big question is ‘why are Islam and Christianity the 2 biggest religions on earth’. Because they are both Abrahamic religions and they are the 2 monotheistic religions that have conquered the globe (something like 70-80% or so of countries are majority Islamic or Christian).

The big reasons I would assume would be that Christians converted Emperor Constantine of Rome. He converted the Roman empire, and as Jared Diamond said western Europe was geographically placed in a spot where they could conquer the world by force. It is not a coincidence that the majority of the lands conquered by Europe are mostly Christian and speak European languages.

Islam is big because they conquered all their neighbors.

Compare that map of countries conquered by Muslim caliphates with the list of modern Islamic countries. They are pretty much a geographic match.

So why are Islam and Christianity so popular? Because hundreds of years ago people who believed those religions (of the thousands of religions on earth) had the best militaries.

Evangelical religions have spreading themselves embedded in their design. Christianity and Islam are the only religions that really embraced the idea that they hold the exclusive truth for all of humanity, rather than just their specific tribe or social group. This turns out to be an amazingly effective way to perpetuate your meme.

Political leaders, in the meantime, were quick to recognize that they could piggyback on that. Evangelical religions give empires motivation to expand, and also give them a means of developing staying power in the areas they take over.

Monotheism makes it easier to have an evangelical religion (it’s easier to say there is only one real god than there are 20 real gods) and lends itself better to having a central authority.

And? I never said they did; they attacked everyone they thought they could defeat.

No; but converting them into Christians was an explicit goal of the slavers, as well as one of the excuses they used to justify enslaving people.

This again. Communism is not atheism. And Islam isn’t any worse than Christianity; it’s just more powerful in the societies it infests. Back when Christianity was stronger, it was slaughtering unbelievers on a very large scale with great enthusiasm. There really isn’t much to choose between Islam and Christianity.

That’s besides the point of this thread, unless they did it to convert people to their religion.

And other Christians supported slavery quite enthusiastically. Christianity didn’t free the slaves; where the slavers were dominant, it supported slavery; where they were weak, it opposed slavery. Christianity is amoral at best.

Using Christianity as an excuse, I recall, occurred in the antebellum era, when Northern abolitionists tried to free the slaves. Northerners did own slaves as well, but since the North was more industrial whereas the South was more agricultural, the slaves probably weren’t very useful in the North. Slaveowners used Christianity to justify enslaving people. Owning slaves was expensive, so slaveowners had to devise many reasons why they should keep their slaves.

Communism is not atheism as much as the United States during the Civil War is not Christianity. If you separate religion and politics for China, then you have to separate religion and politics for the United States. Also I think it’s important to consider that there are many kinds of Christians. There are liberal Christians, and there are conservative Christians. Some may use religion to defend their political views; some don’t. However, in the United States, I do not think that using religion to defend a political position would be very successful.

Why is monotheism popular? Perhaps because it’s true?

Yeah, plenty of you are going to disagree with me. And yeah, it’s not that good an answer, because monotheism could be popular without being true, or vice versa. But it could well be that reality as many people experience it looks like something created or governed or inhabited by or transcended by One God rather than many gods.

It does certainly gibe with our experience that most novels have one Author, most movies have one Director, etc.

Or, here’s theologian H. Richard Niebuhr’s perspective:

If that is so, one must then turn around and ask why monotheistic religions are not even more popular. Why didn’t most of the world adopt a monotheistic view even before the foundation and spread of Christianity and Islam?

Are most religions monotheistic? The Abrahamic religions and Zoroastrianism (which I believe influenced the Abrahamic religions back in the day?) spring to mind immediately, but I can’t really think of many others. There are historical reasons already mentioned for Christianity/Islam having many adherents today, but I don’t think they are popular because they’re monotheistic. For instance, if early Christians believed in three distinct gods instead of one Trinity, I don’t think that would have much effect on the spread of Christianity over the years.

This is the answer. It’s an accident of history. If a polytheistic civilization had flourished, then there would probably be many of them. Greece and Rome each lasted a long time.