Nicolas Baumard, an evolutionary psychologist at the École Normale Supérieure begins by asking how did Jesus go from dying on the cross with a few dozen followers to, inside four centuries, being celebrated as the central figure in the official religion of the Roman Empire – and reasons that this is because the moralising religion of Christianity suited the evolutionary/ideological needs of the Empire’s elite at a moment of profound societal transition.
Christianity, reasons Baumard, was very different from the religions it replaced because it emphasised rewards in the afterlife for morally correct behaviour, as opposed to the material focus on the here and now of the sacrificial approach of ancients. This, he argues, reflects a process seen in evolutionary psychology: when resources are scarce organisms pursue a “fast” psychology, seeking immediate rewards, both sexual and material and eschewing longer-term approaches even if they might bring bigger rewards: if you risk dying young, you sow your wild oats quickly.
In environments where resources are more plentiful then a “slow” psychology dominates – Baumard gives the example of falling birth rates and older parents in affluent societies: babies get more care and attention in wealthier homes.
The key here, he argues, is that around 2500 years ago humans in the Eastern Mediterranean began to enjoy better, more affluent, lifestyles – as measures by the proxy of energy use the per capita usage rose from around 15,000 kcal per day to something over 20,000.
Such affluence was not evenly spread, of course, and those who could afford to practise a “slow” lifestyle were threatened materially and sexually by the continuing “fast” livers – so it suited rulers to promote an ideology and religion that encouraged “slow” living.
Christianity, argues Baumard, was not the only sign of this – the Augustan turn towards morality was another symptom.
So what do I think are the flaws of this? Well, firstly, it does not really explain the first 350 years of Christian growth. Christianity is estimated to have grown by 40% a decade in its first two centuries. There seems to be good evidence that the new religion had a wide appeal across all social strata, not simply for the well off. (I am discounting the idea that the religion grew because of divine providence – after all Islam could make exactly the same, inherently unfalsifiable, claim.)
As Baumard makes clear, exhortations of morality were nothing new – and Augustus’s claim to found a new golden age of morality and honour, strongly supported by his propagandist poets, are the most obvious example. But this ideology seems to be about suppression of revolutionary agitation after a long period of civil war and upheaval – Rome’s need for stability around the turn of the millennium was much more immediate than because of a change in long-term economics.
Then we have the present day – Baumard suggests that as affluence spreads then the need to condemn the remaining “fast” livers will decline and moralising religion will fade too. Yet the world’s most prosperous country, the United States, is significantly more religious than almost anywhere in Europe.
To borrow a term from the Marxists, the argument seems to ignore the relative autonomy of ideology: in other words this religion spread because people liked what it said as much as because it reflected a material change in circumstances.