Comment by somenameforme | Hacker News Reader

Comment by somenameforme | Hacker News Reader

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People leaving some faith would obviously be the inverse of those who stay with it. So for Protestantism, it'd be 16%, or 11% for highly religious households. In deciding to look up the numbers for Islam, it's somewhat unsurprisingly only 1%. [1]

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"Based on survey data collected in 117 countries and territories from 2008 to 2024, we estimate that about 1% of people who are raised Muslim leave the faith. This loss is offset by a comparable influx of people joining Islam."

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Wiki has a nice table on Islam in particular here. [2] They broke 10% of the world population sometime around 1820. They broke 20% 170 years later, around 1990. And they're expected to to break 30% about 60 years after that, by 2050. We're trending towards a majority Muslim world, simply because of fertility, all the while people not having children somehow think people in the future will somehow share their values.

[1] - https://www.pewresearch.org/short-reads/2025/06/10/islam-was...

[2] - https://en.wikipedia.org/wiki/Muslim_population_growth#Histo...

Not really, if you look at the actual birth rates, it maps to economic success more than religious identity.

Yes, we all know that global population growth is mainly happening in Africa and other poor countries.

You also cite global retention rates for islam. Those retention rates are memetic and highly dependent on the same set of poorer, non-western countries so you are comparing applyes to oranges. If you look at western countries, the retention rate is pretty similar.

You keep stretching statistics to reinforce your world view without trying to actually understand the statistics, which is why I assume you keep repeating garbage like "Any group that maintains a positive fertility rate will multiply indefinitely."

You are misinformed here. Islamic fertility rates within Europe remain high with an average of about one more child per woman. [1] This is why Muslims are expected to continue rapidly growing as an ever larger percentage of all Europeans, even in the scenario of 0 immigration. And this will continue indefinitely unless fertility rates markedly change.

The same follows in places like the US, even just amongst Christians. [2] See the first figure (about 2/5ths of the way down the study) for an extremely informative graph. Intended and actual fertility rates for those who consider religion important remains healthy - at around 2.5 children. For those who it is not important or have no religion, it's around 1.5 children.

It's easy to just handwave the fertility rate of developed economies while failing to consider the issue that fertility isn't just a random distribution within these countries. It's extremely biased, and religiosity is one of the most predictive factors.

[1] - https://www.pewresearch.org/religion/2017/11/29/europes-grow...

[2] - https://pmc.ncbi.nlm.nih.gov/articles/PMC2723861/

> unless fertility rates markedly change.

Which seems highly likely. Fertility rates change far faster than they influence population demographics.

> It's extremely biased, and religiosity is one of the most predictive factors.

If you ignore income, education, economic opportunity and how many generations ago the family immigrated and all the other important factors.

You keep trying to paint a simplistic picture of a complex dynamic.

You have, and continue to, make endlessly false claims, only to shift the goal posts onto more false claims each time you're debunked, with plentiful ad hominem on top.

If you would like to continue this discussion then (1) acknowledge the falsehoods you make instead of just endlessly shifting the goal posts and (2) in order to prevent an endless series of #1, cite things instead of continuing to just 'invent' false facts. And I mean actual data, not some Ted Talk, Reddit, pop media, or wherever you're getting much of the nonsense you're saying like calling Islamic fertility rates 'memetic' or now deciding to claim that fertility rates change faster than they effect populations which is going absurdly far off the deep end.

So if you have some meaningful citations for these things, great. Perhaps I can see what you missed - maybe you yourself might even see that. Or maybe indeed I'm the one missing something. But otherwise, I can only assume that you're just randomly stating, as fact, whatever you happen to want to be true.

You means stuff like "Any group that maintains a positive fertility rate will multiply indefinitely"?

That statement is not only true, but a tautology. The multiplication will only cease if the fertility rate declines. For traits and values that are highly heritable, these too will consequently increase in a rate that is, at the minimum, proportional to the rate of fertility. Especially in modern times this is literally how Islam is 'spreading', and it's spreading rapidly, everywhere.

And bear in mind that fertility is an exponential system, in both increases and decreases. So groups that are removing themselves from the gene pool will do so with a rapidity that is quite counter-intuitive. Like a fertility rate of 1 doesn't sound that insane (it obviously translates to literally every single woman having one child on average), yet it results in a generational decline of 50%, with a generation tending to be around our window of fertility - about 20 years.

So imagine two groups start at 16 people and one group maintains a fertility rate of 1, and the other group maintains a fertility rate of 3. After just 5 generations, about a century, the low fertility group will have 1 person, and the higher fertility group will have 81. You went from equal size to an 8100% difference, after a single century! And that's with fertility levels that are entirely realistic and not just comparing extremes like Nigeria or South Korea.

[1] - https://www.pewresearch.org/short-reads/2017/04/06/why-musli...

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