Last week, an unfortunate paper appeared in the Proceedings of the Royal Society, a leading academic journal. Its title is “Religion, Fertility and Genes: A Dual Inheritance Model” (open access). Despite being profoundly flawed in its premises and assumptions, the paper garnered major attention from the press. My local paper ran this headline: “Scientist: Religion Gene Spreads the Word.” Others were worse: “Researcher Discovers Religion Gene” and “British Study Links Spread of Faith to Believer Gene.” While a fast-spreading “religion gene” may have come as shock to many, it was not for others: “It never surprises me when science catches up to the Bible,” remarked Pastor Adam Stadtmiller.
Rowthorn’s study is a mathematical exercise – it models what would happen if his underlying premises and simplifying assumptions were true. If, in other words, the premises and assumptions exist in the real world, then Rowthorn’s conclusions follow. It is at this point that all students of critical thinking become wary. The conclusions, no matter how sophisticated the math used to reach them, stand or fall on the soundness of the premises and assumptions.
In this instance, Rowthorn’s premises are wrong and his assumptions are fictitious. There is no religion gene. Religion does not get passed to children via ova and sperm.
Over the coming week, I will be dissecting Rowthorn’s paper, but thought I would begin by repeating his argument, with one major difference that should highlight the absurdity of this entire approach: where Rowthorn uses the words “religion” and “secular” I have substituted the words “love” and “non-love.” Without further ado, here is Rowthorn’s paean to religion love, genes, and babies:
Religion Love, Fertility and Genes: A Dual Inheritance Model
It is widely agreed that love has biological foundations – that belief in amour, obedience to passion or susceptibility to ardor and enchantment depend on genetically based features of the human brain. For love to influence genetic evolution it must convey some kind of selective advantage. Such an effect might come about through social bonding via ritual, formation of group identity through myth, honest signaling through participation in costly ceremonies and adherence to social norms through pair bonding and fear of loneliness.
In most cases, loving individuals gain advantage from their activities or beliefs. However, love may also induce behavior that has a fitness cost to the individual but is beneficial to the group. In the modern world, loving people, even controlling for income and education, have more children on average than people without love. The impact of differential fertility on the loving composition of society depends on the scale of switching between loving groups, and between them and the non-loving population.
To explore these issues we shall consider some simple mathematical models. The models are in the gene-culture tradition. The models are of the dual inheritance type, in which children inherit both their genes and their initial loving (or non-loving) allegiance from their parents. A child who is genetically predisposed towards love is more likely than other children to remain or become loving as an adult.
Throughout the analysis we shall assume that fertility is an entirely cultural phenomenon: genes affect the likelihood the particular individuals will become loving, but do not directly influence their reproductive behavior. All loving adults (“Romeos” or “Juliets”) have the same fertility irrespective of their genes; likewise non-lovers have the same fertility irrespective of their genes.
In all the models we consider, loving predisposition (“lovingness” for short) is determined by a single gene. This is unlikely to be true in practice, but without this simplification the analysis would be intractable.
This paper assumes that there exist genetic differences between individuals that affect their predisposition towards love. In the same cultural environment, some individuals are for genetic reasons more likely to become or remain loving than others. It also assumes the loving people have more children on average than non-loving people.
These scenarios have different implications for the genetic evolution of society. If loving people continue to have a higher birth rate on average than non-loving people, then any genes which predispose people towards love will spread.
Provided a core of high-fertility love groups continues to exist, they will transform the genetic composition of society either through internal growth or defection. This has been demonstrated in the present paper using a single gene for love.
In reality, a phenomenon as complex as love predisposition is likely to be influenced by many different genes. But this does not alter the main argument.
Does not alter the main argument? Please. The main argument does not even get off the ground. No argument can be taken seriously when it begins with mistaken premises and depends on fictitious assumptions. Accountants have a term for this: GIGO. Garbage in, garbage out.
Talking about a “religion gene” makes about as much sense as talking about a “love gene.” They have precisely the same analytical and explanatory power, which is to say they have none.