Models all the way down

When I entered graduate school in 1984, there was scant serious work in history or philosophy of the modern earth sciences. Excellent scholars had written on Darwin, Lyell and nineteenth century geology, and some of that work heeded earth science qua earth science, but much of it attended to geology only as something that helped to lay the groundwork for an advance in biology: Darwin’s theory of the origin of species through natural selection. Few had written anything of note on twentieth century earth science, and few had taken earth science seriously on its own terms. In (1985), the ground shifted with the publication of Martin J. S. Rudwick’s Great Devonian Controversy. Here was a work that addressed the epistemic question of how geologists established a fact about the natural world, and how they did so without the aid of laboratories and nearly without the aid of instrumentation, save a rock hammer that scarcely differed from a workman’s tool, a rudimentary hand lens that any amateur could afford, and a notebook. Rudwick’s work charted a new academic landscape, and since that time scholars have increasingly recognized that the earth sciences—geology, geophysics, oceanography, meteorology—are substantively different from mathematics, physics, and chemistry. Their work is done out of doors and not in a laboratory, their goal has been primarily to describe and explain the past rather than to test theories by predicting the future, and they increasingly rely on computers to simulate the natural world, but not replicate or reproduce it. And these differences have social and epistemic consequences. Rudwick’s work was crucial to my own career, because as geologist in the process of metamorphosis into historian, it was painfully obvious to me that the ‘‘model’’ of science about which my colleagues in philosophy argued passionately was at best incomplete–based as it was mostly on physics with some nods in the direction of biology. It missed completely many interesting and important questions