Breaking the Spell: Religion as a Natural Phenomenon

None of these sugar-related expenditures of time and energy would exist if it weren’t for the bargain that was struck about fifty million years ago between plants blindly “seeking” a way of dispersing their pollinated seeds, and animals similarly seeking efficient sources of energy to fuel their own reproductive projects. There are other ways to get your seeds dispersed, such as windborne gliders and whirligigs, and each method has its associated costs and benefits. Heavy, fleshy fruits full of sugar are a high-investment strategy, but they can have a bonanza payoff: the animal not only carries away the seed, but deposits it on a suitable bit of ground wrapped in a large helping of fertilizer. The strategy almost never works—not even once in a thousand tries—but it only has to work once or twice in the lifetime of a plant for it to replace itself on the planet and keep its lineage going. This is a good example of Mother Nature’s stinginess in the final accounting combined with absurd profligacy in the methods. Not one sperm in a billion accomplishes its life mission—thank goodness—but each is designed and equipped as if everything depended on its success. (Sperm are like e-mail spam, so cheap to make and deliver that a vanishingly small return rate is sufficient to underwrite the project.)

Coevolution endorsed the bargain between plant and animal, sharpening our ancestors’ capacity to discriminate sugar by its “sweetness.” That is, evolution provided animals with specific receptor molecules that respond to the concentration of high-energy sugars in anything they taste, and hard-wired these receptor molecules to the seeking machinery, to put it crudely. People generally say that we like some things because they are sweet, but this really puts it backward: it is more accurate to say that some things are sweet (to us) because we like them! (And we like them because our ancestors who were wired up to like them had more energy for reproduction than their less fortunately wired-up peers.) There is nothing “intrinsically sweet” (whatever that would mean) about sugar molecules, but they are intrinsically valuable to energy-needing organisms, so evolution has arranged for organisms to have a built-in and powerful preference for anything that tickles their special-purpose high-energy detectors. That is why we are born with an instinctual liking for sweets—and, in general, the sweeter the better.

Both parties—plants and animals—benefited, and the system improved itself over the eons. What paid for all the design and manufacture (of the initial plant and animal equipment) was the differential reproduction of frugivorous and omnivorous animals and edible-fruit-bearing plants. Not all plants “chose” the edible-fruit-making bargain, but those that did had to make their fruits attractive in order to compete. It all made perfectly good sense, economically; it was a rational transaction, conducted at a slower-than-glacial pace over the eons, and of course no plant or animal had to understand any of this in order for the system to flourish. This is an example of what I call a free-floating rationale (Dennett, 1983, 1995b). Blind, directionless evolutionary processes “discover” designs that work. They work because they have various features, and these features can be described and evaluated in retrospect as if they were the intended brainchildren of intelligent designers who had worked out the rationale for the design in advance. This is not controversial in the general run of cases. The lens of an eye, for instance, is exquisitely well-designed to do its job, and the engineering rationale for the details is unmistakable, but no designer ever articulated it until the eye was reverse-engineered by scientists. The economic rationality of the quid pro quo bargains of coevolution is unmistakable, but until very recently, with the advent of human trade a few millennia ago, the rationales of such good deals were never represented in any minds.