David Sepkoski


On his book Catastrophic Thinking: Extinction and the Value of Diversity from Darwin to the Anthropocene

Cover Interview of September 30, 2020

The wide angle

Scientific and cultural spheres are not separate but intertwined, and have been, since the emergence of professional scientific disciplines more than 200 years ago. Science is, like art, politics, economics, or religion, a product of human culture, and is as responsive to—and influential for—prevailing cultural norms and beliefs as any other aspect of history.

Science is a somewhat self-correcting process, and we genuinely have, as a species, increased our empirical and theoretical understanding of the universe around us in quantitative terms. But that doesn’t mean that science today is any less a product of prevailing cultural values and beliefs than it was in the nineteenth century—we just have different beliefs and values now.

Recognition that mass extinctions are a fact has led to theories about how they work, which in turn have conditioned the belief that extinction has been a major force in the history of life. But the implications of that belief—how it makes us feel, how it informs our political concerns, what it portends about the present and future of humanity—remains a cultural as well as scientific matter. Understanding how mass extinctions have worked in the past doesn’t automatically tell us whether and how we should address them in the present.

Moreover, science itself is conditioned by cultural values that affect the very questions scientists ask and the categories they employ. The biologist E.O. Wilson—a major figure in the final chapter of this book—has tirelessly promoted the cause of biodiversity since the 1980s. He has extrapolated a number of consequences for current species loss from analogous events in the geological past—including, notably, the claim that humanity is currently causing a “Sixth Extinction”, which is an explicit reference to the five major mass extinctions documented in the fossil record. But he has also been forthright about how his basic love of nature—and in particular, humble forms of nature like the ants he has devoted a career to studying—have influenced his arguments in favor of the preservation of all life. He believes that diversity is valuable, in other words, as much as he knows it is.

I came to write this book after spending many years studying the history of biological and paleontological theories of evolution and extinction. (I should confess that my father, the late paleontologist Jack Sepkoski, was a major contributor to current understanding of extinction dynamics). The emergence of modern ideas about extinction was central to much of my past work, in which I considered the perspective of scientific theories, methods, and institutions. Somewhere, I realized it was a story that should be meaningful to a broader audience. If history is to be useful or valuable, it should illuminate some ongoing concern for human society—and, as I realized, there is no more important ongoing concern than the problem of human impact on the global environment.