Natural selection is a common 'bottom line' religion for many people nowadays
But, natural selection as a religion does not make any sense, I mean it is strictly incoherent, unless underpinned by other assumptions. And this is what we find.
I know this from experience, because I tried very hard to have Natural Selection as my bottom line religion - but to do so requires adopting several non-obvious assumptions. The result is a version of systems theory, especially as formulated by Niklaus Luhmann
See Appendix to:
But systems theory is extremely abstract and unintuitive, and the most typical assumptions which underlie natural selection are implicit, and of a broadly Platonic type.
These include the idea that Mathematics and the Laws of Physics are close approximations for being basic attributes of the universe.
Within this implicit structure, natural selection is assumed to operate. Thus (implicitly) natural selection is not truly the bottom line of reality, but Maths and Physics are.
(In this kind of evolution-as-religion, Maths and Physics, the 'laws of nature' are assumed not to evolve by natural selection - but to consist of eternal and necessary truths.)
But even this does not describe the range of assumptions implicit among those who have natural selection as their religion: in addition to this is a set of (again implicit) moral imperatives which assert that it is the duty of humans to work with the grain of Nature; to cooperate with the workings of natural selection - that is, humans are assumed to have a duty to believe in natural selection, and to make choices primarily to promote their own genetic selection (and secondarily the selection of their genetic relatives: family, tribe, race).
In a nutshell, the morality is that reproductive success is good, while extinction is evil.
So, this is an outline of the religion of natural selection -
1. Explicitly natural selection, plus
2. Implicitly an underlying Platonism, plus
3. An implicit moral system based on the goodness of reproductive success.
The combination of all these aspects does indeed make a coherent religion of natural selection - coherent enough for living purposes; but a religion that is arbitrary, nihilistic, alienating; and lacking in any human appeal beyond being a rationalization for selfishness: selfishness at various levels and on various scales between short-termist attempts to spread one's own genes in the here and now, via familial or tribal expansionism, up to the long-termism of racial nationalism.
So this is the traditional form of natural selection as religion - Social Darwinism - which is a Right Wing type of atheistic progressivism.
And naturally this has led to a leftist reactionary elaboration, which I first saw explicitly characterized in Keith E Stanovich's book The Robot's Rebellion - but the book was describing an established situation, and Leftist Natural Selection can be seen all over the place in academia among those who reject the Rightist implications of natural selection: it is indeed mainstream.
Leftist natural selection is the same as the religion described above, except for the assumed morality - Leftists replace the morality of increasing reproductive success with the usual (supposed) Leftist morality of increasing happiness/ reducing misery.
So Leftist natural selection is hedonic and not based on reproductive success.
Hedonic for whom? - since what makes one animal happy may make another miserable (or dead), and what makes one animal miserable may make another happy?
In theory, hedonic for 'everybody' - in practice, the test is an inversion of Rightist natural selection: hedonic for non-genetically related persons, for 'others'.
So, Leftist natural selection is a universalist kind of religion - in theory. In practice, since universal happiness maximization is nonsense, it is an inversion of Social Darwinism: whatever Social Darwinism says is good is bad, and vice versa, and by this Leftists demonstrate to themselves and like minded persons that they have transcended Social Darwinism.
The basis for doing this is that humans are presumed to have transcended the imperatives of lower animals, or rather that humans should transcend the imperatives of lower animals (that 'should' is adding yet another undefended assumption), and therefore that humans have transcended the moral imperative of Social Darwinism to increase reproductive success - or indeed to take any notice of reproductive success whatsoever.
(Note: the idea that reproductive success is morally good is an assumption of Social Darwinism. An assumption, not a discovery.)
Hence the modern, typical, mainstream religion of Leftist natural selection is incoherent and dishonest; since in practice it is simply Leftism capturing natural selection, Platonism and everything else which contradicts its universalist, fake-hedonic imperative.
So Leftist Natural Selection is not a viable or coherent religion of natural selection, because it has in practice rejected the application of natural selection to humans, and replaced natural selection explanations with 'whatever is the current Leftist consensus'.
In conclusion - the religion of natural selection is made possible by adding two sets of assumptions - a Platonic metaphysical framework of transcendental physical laws within which natural selection can operate, and a moral assumption which relates humans to the system so-described by giving life a direction, a system of evaluation; and this is typically the moral assumption that reproduction is good, growth in genetic representation is good.
This is the religion of Social Darwinism, but it has few modern adherents because it contradicts the mainstream religion of secular Leftism, or Political Correctness.
Attempts to make Social Darwinism compatible with modern Leftism simply subordinate natural selection to political correctness, which results in incoherence covered-up by dishonesty.