Of all the mental shortcuts embedded in human languages which impede understanding of mindless processes (such as natural selection), few are more obnoxious than “because.” From this comes a tendency to anthropomorphise, and read all outcomes in nature as if they were ordained by something approximating an “intention.” Religion has to be an adaptation, because the religious (currently) outbreed the irreligious.” The second clause in that sentence is (currently) correct, but the “because” makes it sound as though the current religious selection advantage represents some “design feature” with the desired (by what?) end of promoting reproductive fitness (adaptation). And fitness is where the matter rests. Contrast with the following sentence:
“Under current conditions in which the religious outbreed the irreligious, religion is adaptive.” This statement is of course tautologous, since to say that a trait or behaviour is adaptive means merely that under condition X it gives one a reproductive edge. The term “adaptation,” though, is often applied to traits or behaviours which are selectively neutral or even counter-adaptive in particular environments. Genes which contribute to an overzealous appetite may be fitness-neutral to a subsistence farmer but become obesogenic in the modern world of easily available food. The genes’ carrier still exercises this “adaptation,” but it is no longer adaptive, reproductively useful, except in an environment full of fat-fetishists.
Human society has changed so dramatically in the last two centuries that it would be hasty to say the least to assume that everything with a current selective disadvantage is an “illness” (due to pathogens, mutational load, or whatever). Just as equally, one cannot assume that something with a current advantage exists having evolved by resolving an adaptive problem. Religion was ubiquitous across cultures before the 20th century, yet now the religious fraction represent an ever tinier percentage of the population in many countries, and it remains to be seen just how tiny the “genetic hard core of religiosity” will get before the trend is reversed. If the presence of religion were explicable in terms of fitness benefit, why are the genes not already more widespread? This alone should be enough to tell you that genes (and thus, adaptation) per se had little to do with religion’s evolution.
But apparently this is not obvious to some. Many people are inclined to view adaptations as intricate mechanisms, which by dint of their intricacy are delicate and susceptible to dysfunction, rather like the springs and levers of a pocket-watch. All analogies are imperfect, but this is a useless one. Some traits, and indeed behaviours, are more prone to changing by exogenous insults than others. For instance, a particularly naive person might imagine that in a pandemic of severe endometriosis, whereby female beauty and youth cease to be predictive as indicators of fertility, males would be disincentivised from their sexual attraction to these traits because the attraction would no longer perform its original “functions.” Needless to say, this would not happen. Male callogamy (“attention to beauty”) has proven so reliably fitness-enhancing over the eons, since even before the human species, that it is extraordinarily resilient to any incentive change: selection will always favour a deterministic developmental pathway for such consistently valuable traits. General intelligence is yet another example: the current dysgenic trend is a product of the last few generations and on the order of ~1 point per generation despite ramping up of mutational load globally (we’ll see how long it can last), and almost no non-genetic factors seem capable of depressing its expression to any appreciable degree. Lead looked plausible at some point, but then you remember that Victorians liked to use mercury in their make-up, and yet the 19th century was the most intellectually productive in human history.
Viewed under this light, the “religion as adaptation” thesis looks all the more dubious. Evolutionary forces – selection, mutation, drift, etc – are just as capable of acting on general intelligence and other psychological traits as anything else, hence the well-documented evolved changes in the European peoples since around AD1000: declines in violence, and probably gains in intelligence, culminating ultimately in the zenith of the 19th century. Evolution can indeed happen fast, but not that fast. The bulk of these changes took place over a period of, at minimum, 20 generations, not 2-3, and our intelligence has more or less survived the last 2-3 generations intact. Religion has not. It has none of the hallmarks of an adaptation, but all the hallmarks of a complex socially learned behaviour, maintained by powerful norm-enforcers and epistemic authorities, which has lost currency in recent decades for a variety of reasons, the most commonsense explanation being that it no longer appeals to the educated because the answers it gives are inferior to those of other epistemic authorities, i.e. scientists.
The human capacity for cultural transmission through language makes a nonsense of the notion that anything which is not adaptive, even across all environments, should be impossible to sustain. The most obvious example in Christian cultures is the vow of celibacy, and there are numerous others such as taboos against eating highly nutrient-dense foods, which persist among the undernourished tribes of Papua New Guinea. So too with the European wars of religion, which resulted in millions of young men dying childless in their haste to protect a non-existent natural resource, i.e. God’s favour.
Group selection is another temptation when formulating theories about the origin of religion – the idea that even a behaviour which reduces fitness at the individual level can persist if it provides some advantage at the level of the social group. It is a neat idea, but clearly unworkable in practice. Suppose some cohort of one’s country likes spreading the word of God through warfare – call this behaviour X. They can seize new territory in God’s name and provide new land for others in their group who are not quite so zealous, and this may look like a “success” to the people who reap those rewards, but at the end of the day: the behaviour is still going to diminish because everyone who engages in it is at a massively elevated risk of dying before reproduction. Evolution does not care about states or dominions.
It is understandable why post hoc stories about religion as adaptation are popular, even among well-informed people. Intelligence is not a good predictor of having sensible views where political matters are concerned, since politics is about group loyalty more than anything else. This is why the number of US Democrats who thought immigration was an important social issue declined precipitously in the 2010s when it became the issue “of” the right; what mattered was showing solidarity against rival political coalitions (i.e. the right) rather than the truth. Adaptive stories about religion seem to appeal an awful lot to European traditionalist-nationalists who are hoping to use Christianity as the conduit for some kind of renewed ethnocentrism to uplift the European spirit. The Chinese do not seem to need it, oddly enough. Nor even the Czechs, much closer to home. It did not work for Rome, and it sure as fuck won’t for us.