Breaking the Spell: Religion as a Natural Phenomenon

With alcohol, a somewhat different perspective emerges. What pays for the breweries, the vineyards and distilleries, and the massive delivery systems that bring alcoholic beverages within easy reach of almost every human being on the planet? We know that alcohol, like nicotine, caffeine, and the active ingredients in chocolate, has quite specific effects on receptor molecules in our brains. Let us suppose that these effects are just coincidences at the outset. That some large molecules in some plants happen to be biochemically similar to large molecules that play important modulating roles in animal brains is, let us suppose, as likely as not. Evolution must always begin with an element of brute chance. But, then, it is not surprising that, over millions of years of exploratory ingestion, our species and others should discover the plants with psychoactive ingredients and develop preferential or aversive dispositions regarding them. Elephants—and baboons and other African animals—have been known to get falling-down drunk eating fermenting fruit from marula trees, and there is evidence that elephants will travel great distances to arrive at the marula trees just when their fruits ripen. It seems that the fruit ferments in their stomachs when yeast cells resident on the fruit undergo a population explosion, consuming the sugar and excreting carbon dioxide and alcohol. The alcohol happens to create the same sort of pleasurable effects in the elephants’ brains that it does in ours.

It may be that the basic bargain struck between fruit trees and frugivores—the seed-spreading-for-sugar deal—is enhanced by an additional partnership of yeast and fruit tree. This would create an added attraction that pays off by enhancing the reproductive prospects of both the yeast and the trees, or it may be just an accident in the wild. In any case, another species, Homo sapiens, has closed the loop and initiated just such a coevolutionary bargain: we domesticated both the yeast and the fruit, and for thousands of years we have been artificially selecting for the varieties that best engender the effects we love. The yeast cells provide a service for which they are paid off in protection and nutrients. That means that the yeast cultures carefully husbanded by brewers, vintners, and bakers are human symbionts just as much as the E. coli bacteria that inhabit our intestines. Unlike endosymbiont bacteria, such as Toxoplasma gondii, which have to get into the bodies of both rat and cat, the yeast cells are a sort of ectosymbiont, like the “cleaner” fish that groom larger fish, depending on another species, us, but not having to enter our bodies. They may—like a wayward cleaner fish—get ingested by us more or less by accident, but it is really only their excretions that need to get inside us for them to prosper!

Now consider a strikingly different sort of good thing: money. Unlike the other goods we have considered, it is restricted (so far) to a single species, us, and its design is transmitted through culture, not genes. I will have more to say about cultural evolution in later chapters. In this introductory overview I want to point out just a few striking similarities between money and the “more biological” treasures we have just surveyed. Like eyesight and flight, money has evolved more than once, ⁵ and hence is a compelling candidate for what I call a Good Trick—a move in design space that will be “discovered” again and again by blind evolutionary processes simply because so many different adaptive paths lead to it and thereby endorse it (Dennett, 1995b). Economists have worked out the rationale for money in some detail.