Tal Bachman Wrote:
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> Yes, I can see that in certain situations, the
> more people, the harder group survival might be.
> But I think we are talking here about a much
> broader and more influential phenomenon.
I think it is safe to assume that for most of history, populations have been at their environmental limit. Thus the last few hundred years, with unprecedented population growth due to technological advances are an exception. Evolution therefore needs to be weighted towards a situation of overpopulation, when additional children are not an advantage.
> On your second point:
>
> Religions indeed can be converted to, but it is an
> empirical question whether religions grow mostly
> from being passed on from one generation to the
> next, that is, from parent to child (or
> *vertically*, as it were), or through conversion
> (*horizontally*, as it were). Numerous studies
> have provided the answer to this question:
> religions grow mostly vertically. (Mass
> conversions do occur, but are historically quite
> rare).
It is not a question of whether religions grow mostly from being passed on through generations. It is a question of whether sufficient genetic diversity is obtained through occasional conversions to result in populations within the religion and outside the religion that are essentially the same.
> The next question I think is whether "religiosity"
> as a personality trait is heritable. In fact it is
> (again, for starters, see, e.g.,
>
http://www.popsci.com/science/article/2013-08/what> -twins-reveal-about-god-gene ).
What makes me very uncomfortable about reading too much into the twins studies is that "religiosity" is not well defined, and it is a compound of other more elementary traits. Those more elementary traits are themselves subjective. The end result is too fluffy to be reliable.
> Given that it is
> also a fact that the more religious a population
> is, the more they tend to reproduce (again, see
> Kaufmann's "Shall the Religious Inherit the
> Earth?"), it becomes easy to see how religiosity,
> that is, a genetic predisposition to religious
> belief, behaviour, and belonging, could propagate
> itself in our species.
Indeed, but does it propagate itself in our species as a virus or as part of our genome?
> The universality of
> religious belief, behaviour and belonging around
> the world seems to testify of this commonsense
> supposition.
Tal, your definition of religion was:
"A religion is a unified system of beliefs and practices relative to sacred things, that is to say, things set apart and forbidden - beliefs and practices which unite into one single moral community called a Church, all those who adhere to them".
According to your definition, most indigenous populations do not practice religion since they don't have churches. That is why a very carefully worded definition of religion is required to have a meaningful discussion. You can't just change the definition whenever it supports your hypothesis.
> I guess it might still be objected that
> religiosity, though heritable, and in fact
> inherited by most humans, might not necessarily
> have conferred any survival advantage. Maybe it
> was just along for a ride.
Indeed, and it is much more likely to be along for the ride if religiosity is actually a compound of elementary traits, each of which independently gives an survival advantage.
Re Charles Darwin: don't believe everything that Charles Darwin said. He was years ahead of his time (DNA hadn't even been discovered yet) but much of what he said, with the benefit of hindsight, was educated guesses or speculation. For example, he came up with the laughable idea that whales descended from bears, LOL. We all know that whales really descended from a wolf-like creature ;)
I would love to have a discussion of whether group selection is really a "thing", preferably in a new thread. I used to like the idea of group selection, then I read Dawkins and threw the idea in the bin. I would be surprised if there was any valid examples of real-world group selection.