Religion and the arts as byproducts? Why byproducts are a “just-so” story.

A slew of anthropologists, psychologists, and other academics have embraced byproduct theory to explain the more mysterious human behaviors such as the origin of arts and religion. This includes some of the most well-known evolutionary biologists such as Richard Dawkins, who claims religion has no functional purpose.

In his book, How the Mind Works, Steven Pinker spends 500 pages deconstructing the mind within an evolutionary framework. Then Pinker confesses, “I will conclude by arguing that some of the activities we consider most profound are nonadaptive byproducts.” (p. 525) Pinker says arts and religion do not improve evolutionary fitness and success because they don’t exhibit all characteristics of an adaptive behavior. To be adaptive, he says, behaviors must be universal, complex, reliably developing, well-engineered, and reproduction-promoting.

Arts and religion are certainly complex and universal behaviors. Evidence exists that they are well-engineered and reliably developing. The only obvious deficiency from adding them to the biologically adaptive club is no one has adequately accounted for how they are reproduction-promoting. In other words, are they functional, and do they contribute to evolutionary success?

But what is a biological byproduct in the first place? We know what a chemical byproduct is: carbon dioxide and alcohol are waste byproducts of anaerobic fermentation (although for people, alcohol is the goal). Carbon dioxide is also a waste byproduct of animal metabolism and respiration. On the other hand, CO2 is the raw material for photosynthesis, and oxygen is the waste product. Chemical byproducts are relative, not absolute, depending on the application. But what is a byproduct when it comes to actual genotypic or phenotypic biological traits? How do we determine if something is a biological byproduct?

The biological byproduct concept was popularized by Harvard evolutionary biologists Richard Lewontin and the late Steven Jay Gould in a 1979 paper called The Spandrels of San Marco. The article criticized biologists for excessively invoking evolutionary adaptations to explain traits. The authors purported that not all biological characteristics arose due to natural or sexual selection, but rather were due to either random factors such as gene drift or are byproducts of other adaptive characteristics. Gould and Lewontin introduced the architectural concept of spandrels, a non-functional side-effect of arches and column construction. They cited these triangular spaces formed by the intersection of two rounded arches as the germane example on which to base their argument against the overuse of biological adaptation and selection. They claimed they were doing their readers a favor by avoiding biological examples. “We deliberately chose non-biological examples in a sequence running from remote to more familiar: architecture to anthropology. We did this because the primacy of architectural constraint and the epiphenomenal nature of adaptation are not obscured by our biological prejudices.” (p. 584)

Such a statement seems immediately and oddly disingenuous. Would it have been because they were unable to identify and describe convincing biological examples of non-adaptive byproducts? In any case, Gould’s impenetrable prose mystifies rather than elucidates. Almost no one understands what he means by this excuse for offering no biological examples of byproducts.

On the other hand, actual examples of biological byproducts are the whale’s pelvis and the belly button. In the first case, the pelvis was adaptive when whales’ ancestors were still land mammals. As they transitioned to become marine animals, the pelvis atrophied over evolutionary time. Similarly, the belly button was part of a structure — the umbilical cord — that was adaptive early in the animal’s life but became a byproduct at birth. In both cases the feature was functional at one point in the species’ evolution or organism’s lifetime. In contrast byproduct proponents say the arts and religion were never functional or adaptive.

For any scientific topic there are thousands of papers in the academic literature, except not so for biological byproducts. There are plenty of papers that invoke byproducts as if they are a known quantity, but there are literally only a handful of scholarly articles that address what a byproduct is itself. Take away Gould’s articles and most of the rest are critical of so-called byproduct science. Lead author of such a paper, David Buss, says, “We could not find a single example of an empirical discovery made about humans as a result of using the concepts of exaptations or spandrels [byproducts].” There is no empirical model for the completely functionless biological byproduct.

Not only does Richard Dawkins claim religion has no purpose, he states that religion is a virus of the mind and denounces it as irrational foolishness, even a kind of mental illness. Yet in God Delusion, Dawkins says, “Darwinian selection habitually targets and eliminates waste. Nature is a miserly accountant, grudging the pennies, watching the clock, punishing the smallest extravagance.” (p. 163) Despite the very recent changes in some societies away from religious affiliation, religion has existed continuously since it first arose both historically and geographically. But according to Dawkins, something that is ever-present across both time and space should not persist if evolution punishes the smallest extravagance and eliminates those things that don’t contribute evolutionary benefit. One can only conclude from this that religion perseveres because it’s adaptive.

Biological byproducts have been appropriated and distorted to discount the role of religion and the arts, in part because religion doesn’t fit into the world view of many scientists. In fact, it is the application of biological byproducts that is a “just so” story fabricated to discount these behaviors and to achieve an ideological agenda.

Buss, David M., et al. “Adaptations, Exaptations, and Spandrels” American Psychologist. 1998.

Dawkins, Richard. “The God Delusion” New York: Houghton Mifflin. 2008.

Gould, S.J. and Lewontin, R.C.. “The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme.” Proceedings of the Royal Society of London. Series B, V. 205, №1161 (1979), PP. 581–598.

Pinker, Steven. “How the Mind Works” WW Norton & Company. 1997.



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Mitchell Diamond

Mitchell Diamond

Author of Darwin’s Apple: The Evolutionary Biology of Religion, a new take on the function and purpose of religion.