Hacking’s Styles of Reasoning Between Positivity and Truthfulness

In this paper, I examine Ian Hacking’s theory of styles of scientific reasoning and its relationship to Michel Foucault’s archaeology of discourse. In his early writings on styles, Hacking draws on Foucault’s notion of “positivity,” which involves the introduction, by styles, of classes of propositions that are, as it were, “up for grabs as true-or-false.” However, beginning in the 2000s, Hacking replaces “positivity” with “truthfulness,” understood as “ways of telling the truth”—a concept he borrows from Bernard Williams. Hacking presents this shift as a recasting of the same thoughts using an alternate idiom, one intended to be more accessible to analytic philosophers. Contrary to Hacking’s own assessment, I argue that positivity and truthfulness are only apparently similar and that some of Hacking’s original intentions may risk being partially lost or overlooked in the transition from the former to the latter.