What makes a religion popular? [closed]

Question

There have been many things asking on how to make a fictional religion. As I was making my world's religion, I wondered: what would make people want to believe in it? What also gave me the idea is of how strict religions, like the Abrahamic ones such as Christianity and Islam, are far more popular the the accepting Sikhism. I am aware that these religions have survived by forcing beliefs on others and through violence, but what factors would make people want to keep their faith in these religions? Can a polytheistic religion be more dominant than monotheistic, and how?

Note: This is for worldbuilding, and I am asking for advice on how to make a religion popular in my world, what factors do most popular religions have, and if it has to necessarily be strict.

Answer 1

Here is my take on what a religion needs in order to persist. How to get a religion started is out of scope - it would require many books and the parameters are highly dependent on the society that one is trying to start a religion in.

It must successfully recruit and retain members. In order to get really big, a religion must proselytise - that is, actively go out and seek to convert people to that religion. However, at a bare minimum the religion needs to successfully encourage enough children of adherents to become part of the religion. In practice, this means that most children of adherents are brought up with the validity of their parent/s' religion being treated as a fact rather than a choice.

It must claim a benefit. No one is going to subscribe to a religion that says "...and if you obey all these commandments then it will cost you 50% of your income every week and when you die you will be tormented by spambots and badly designed webpages in the hereafter." There must be a payoff involved, that if you are "good" then your spirit will go to a better place when you die, whether in some "heaven" or with all the other alien spirits on the mothership, or you will get reincarnated with a better starting position.

It must be enforced. There must be a hierarchy that maintains the unity of the church, appoints clerics, liaises with any secular governments (lobbyists in modern terms) and creates and updates rules as required. Without this kind of adjudication the religion will quickly splinter like a badly organised social club - people will come up with their own interpretations of the rules, pick different days to worship on etc. Note that if your religion includes a deity or deities that intervene directly or via avatars - as happens in some high fantasy worlds - then it may not require a mortal hierarchy.

It must provide a sense of belonging. Adherents must be feel that they are part of a special and desirable community. Adherents should be afraid of losing that social connection if they fail to uphold the behaviours associated with the religion.

In some religions this will go beyond "belonging" to "superiority and/or secret knowledge". The "superiority" aspect is almost universal, practically every religion portrays itself to its adherents as superior to all other religions. Some of the ancient Roman religions had various levels of "mysteries" that practitioners were initiated into as they progressed.

It must require sacrifice. "Sacrifice" does not necessarily mean blood-soaked altars, it can be a weekly tithing of income, time taken to attend weekly and other ceremonies and/or adhering to certain rules that you would sometimes prefer not to. People are more likely to believe that something is valuable if it costs them something than if it is given away for free. However, different people will have different tolerance thresholds for sacrifice, so if a religion is too strict then it is likely to lose members.

It must be practical for adherents and acceptable to the state. It must be possible for adherents to follow the requirements of the religion. As soon as a requirement becomes unsustainable (eg stop having children and do not recruit outside the church) or socially/politically unacceptable the religion will disappear if it does not adapt. (Hint: if a religion has a "kill all tax collectors" commandment then don't expect the government to tolerate that religion. How governments will treat religions they don't like is complicated - it can range from pogroms to "reeducation" to bureaucratic harassment. Some religions may thrive in limited adversity, especially for short periods, others may be wiped out.)

Within these parameters - anything goes. Monotheistic, polytheistic, dedicated to an abstract ideal - none of it matters as long as it checks off on each of the above points.

Answer 2

Religions do not rely on popularity. They leverage the system of people being born into a religion, which is why the heyday of religion was back when fertility was high... each woman and each man ended up creating up to another dozen or so believers, who would then go on to do the same themselves. For those religions that innovated and allowed (or even encouraged conversion via proselytization) brought in a few new zealots, but this was dwarfed by "organic growth".

Therefor, your people do not need to "want to believe in it". This is difficult to understand (or for me to explain) because you were born into a world where people pursue activities based on popularity, and have largely eschewed religion. Your model for religion is that of surfing, or watching professional basketball. More people watch basketball than hockey, because basketball is more popular. Fewer people surf than do yoga, because surfing is less popular.

But Earth's religions never used that model, or at the very least, never used it until recently. There are over 1 billion Catholics, because if you weren't Catholic in this one place, you were killed or run out of town. There are over 1 billion muslims, because if you're not muslim you're an apostate, and apostates can be killed for that sin. Every child born to a muslim is also muslim, every baby born to Catholics was baptized Catholic.