Nowhere is the duality of natural and supernatural causes divided by a line so thin and intricate, yet, if carefully followed up, so well marked, decisive, and instructive, as in the two most fateful forces of human destiny: health and death…by far the most cases of illness and death are ascribed to [sorcery] - Bronislaw Malinowski, Magic, Science, and Religion, 1925.

In The Afterlife is Where We Come From (2004), anthropologist Alma Gottlieb describes her fieldwork among the Beng farmers of West Africa. In this book, Gottlieb recounts her failure to persuade Beng villagers to boil their drinking water;

During our stays in Beng villages, Philip and I have always either boiled or filtered our own drinking water. To our dismay, our neighbors often derided our laborious efforts. One day we thought to explain our mysterious actions. The village had been experiencing an especially crippling outbreak of Guinea worm. After reading about the disease, Philip and I were convinced that polluted drinking water was the cause of our neighbors’ misery. We urged our friends to boil their water as protection against future infestation. But even our closest and most open-minded friends dismissed our suggestion with casual laughter.

“Can you see the worms in our water?” our friend Yacouba challenged us. We admitted we couldn’t.

“There’s nothing wrong with the water,” he insisted. “Anyway, even if the Guinea worms come to us through the water, they’re put there by witches.” Yacouba added emphatically, “Boiling the water wouldn’t stop the witches.” (Gottlieb, 189).

There are a few interesting elements to this passage.

First, there is the belief, common across cultures, that illness is due to witchcraft or sorcery. I discussed this in my last blog post, where I wrote that,

Sorcery beliefs can be used to understand the world, seeking out causes of uncertain events, and may [also] be embraced by self-interested parties to scapegoat enemies and promote collective violence. Functioning as a legal system, a practical tool of manipulation and control, a social philosophy, and a conceptual framework for understanding the world, sorcery beliefs have been a fundamental component of human societies the world over.

Second, while Yocouba’s position may seem absurd to many educated Westerners, his logic seems to me no less sound than that of Gottlieb. Gottlieb posits invisible worms causing disease in the water, while Yocouba posits invisible magic causing the sickness. In both cases, each of them are working from the body of knowledge they have inherited from their society. Further, in his objection to Gottlieb’s assertion that worms are causing the disease outbreak, Yocouba is making a distinction between levels of causation that, in many cases, is quite an important one. Namely that, even if it’s true that worms are causing the disease outbreak, that would only be the proximate cause, in contrast to what he asserts is the ultimate cause: withcraft.

Now, obviously we know that Gottlieb’s explanation comes from centuries of empirical work demonstrating the existence of disease causing parasites, but the point is, no less than Yocouba’s sorcery beliefs, Gottlieb (and us) have inherited this knowledge, not generated it independently.

In other words, it is not that Gottlieb’s logic here is superior to that of Yocouba’s, it’s that the body of knowledge she has inherited was generated through the rigors of the scientific method. It is information that we are fortunate indeed to have inherited, and that none of us could have come up with on our own. As anthropologists Robert Boyd, Joseph Henrich, and Peter Richerson write in ‘The cultural evolution of technology’ (2013);

Isaac Newton remarked that if he saw farther it was because he stood on the shoulders of giants. For most innovations in most places at most times in human history, innovators are really midgets standing on the shoulders of a vast pyramid of other midgets. Historians of technology believe that even in the modern world the evolution of artifacts is typically gradual, with many small changes, often in the wrong direction. Nonetheless, highly complex adaptations arise by cultural evolution even though no single innovator contributes more than a small portion of the total.

The third and final element of Gottlieb’s anecdote that I find interesting is the dilemma anthropologists face in trying to ‘change’ the culture they study. There are obvious and sad public health implications to the refusal of Yocouba and other Beng villagers to boil their water, and the difficulties of persuasion in this kind of context can come at a severe cost to the population in question. I think a comparable issue in the United States would be opposition to vaccines.

Persuasion is more than simply being right; you have to understand the attitudes and social contexts people’s beliefs come from (and even when you do have such knowledge, it may not be enough, as we can see with Dr. Gottlieb's difficulties among the Beng). As psychologists Michele J. Gelfand and Joshua Conrad Jackson write, “many studies have shown that people often rely on intersubjective consensus to a greater extent than objective information.” One of main virtues of the scientific method is the manner of subjecting the intersubjective consensus to falsification, with ideas continuously tested and retested, which has led to a more accurate understanding of the causes of death and disease. As I wrote in my last article at Quillette, you can see this reflected in the substantial decline in infant and child mortality throughout the world over the last few decades, due in no small part to the expansion of vaccinations and effective sanitation practices.

The knowledge passed down that provides us with a more accurate picture of the causes of sickness came about through a cultural evolutionary process that we are the fortunate beneficiaries of.