What Is More Informative in the History of Science, the Signal or the Noise?

In many domains of knowledge, from mechanics (McCloskey, 1983) to thermodynamics (Wiser, 1987) to astronomy (Vosniadou & Brewer, 1992), it has been claimed that conceptual development in the individual resembles theory change in the history of science. Here, Kampourakis takes issue with that claim in the domain of evolution. In particular, he argues (a) that early evolutionary theorists never construed species as possessing essences and (b) that the distinction between pre-Darwinian and postDarwinian evolutionary thought is muddled and therefore an inappropriate analog for the development of evolutionary thought among today’s students of biology. (Kampourakis makes two additional arguments directed at Ware & Gelman, 2013; which I defer to Ware, this issue). My colleagues and I have argued that students’ evolutionary misconceptions resemble pre-Darwinian theories of evolution—in particular, the essentialist aspects of pre-Darwinian theories—on numerous occasions (Shtulman, 2006; Shtulman & Calabi, 2012, 2013; Shtulman & Checa, 2012; Shtulman & Schulz, 2008), and I maintain that this comparison is both empirically fruitful and theoretically meaningful. With respect to the first argument, Kampourakis notes that historians of science disagree about the veracity of the “Essentialism Story,” or the claim that Darwin’s predecessors and contemporaries essentialized biological kinds. “While it is true that scholars often wrote about the essences of life, of organs, etc.,” writes Kampourakis, “they never accepted that species had to have jointly necessary and severally sufficient conditions, or that members of a species should bear essential properties” (p. 1). Here, Kampourakis conflates two forms of essentialism: construing species in explicitly essentialist terms, which early evolutionary theorists arguably did not do, and positing theories of evolution that are inherently essentialist in their mechanisms of change, which early evolutionary theorists arguably did do (Gould, 1996; Hull, 1965; Mayr, 1982; Sober, 1980). That is,