Jonathan Kennedy, Pathogenesis: A History of the World in Eight Plagues (2023)

The first 90% of this book is scintillating, the final 10% perplexing and disappointing. Kennedy's work aims to update William McNeill's pioneering 1976 work on the interplay between people and germs, Plagues and Peoples. Five decades ago, we simply didn't know much about ancient plagues. In the intervening years, the revolutionary growth of biological knowledge, especially the sequencing of contemporary and ancient genomes, has put us on much more secure ground. Kennedy begins by making a plausible case for a revolution in our thinking about human history: just as Copernicus and Darwin (and perhaps Freud) decentered man, our increasing understanding of microbes should now do the same. Humans don't make history on their own (even in circumstances not of their choosing a la Marx) - humans and microbes (bacteria and viruses) together make history. After all, the number of bacteria in each of us is apparently about the same as the number of "our own" cells. These bacteria attack us occasionally, of course; they help us digest food; and they play a role apparently in modulating our moods. Their even more numerous cousins, viruses, have become incorporated in our DNA. Who am I, indeed! Kennedy doesn't spend much time on microbes' role in influencing out behavior (perhaps for the reasons David Reich gave - see previous post) and instead focuses on their role as agents of destruction. He makes plausible arguments that microbial diseases have played a much more decisive role in turning points in human history: the triumph of homo sapiens over other humans, such as Neanderthals, Denisovans, and the Hobbits of Flores; the displacement by early Indo-Europeans of neolithic farmers in Europe; the Europeans' preference for African slaves rather than European indentured servants. These first 90% of the book changes my picture of big history in major ways. Then we get to the last part of the book. Kennedy barely mentions the breakthrough due to the germ theory of disease, the development of antibacterial and antiviral drugs, and the exponential growth of biotech thanks to genetic manipulation. He discounts the role of medicine and rising living standards in improving health. Instead, he claims, improvements all due to political commitments to public health. I wish he had consulted Angus Deaton's magisterial The Great Escape. In his coverage of the last 150 years, Kennedy focuses on politics, especially baleful political decisions made by "neoliberal" leaders. Bizarrely, in a book about plagues, he switches from microbial to lifestyle diseases. In the end, he suggests, most people today live in "what must feel more like a dystopia" (226). All in all, this last section seemed like it was shaped by what I take to be Kennedy's political commitments. It's a perplexing ending to what otherwise is a thought-provoking, persuasive book.