In a number of papers and in his recent book, Is Water H₂O? Evidence, Realism, Pluralism (2012), Hasok Chang has argued that the correct interpretation of the Chemical Revolution provides a strong case for the view that progress in science is served by maintaining several incommensurable “systems of practice” in the same discipline, and concerning the same region of nature. This paper is a critical discussion of Chang's reading of the Chemical Revolution. It seeks to establish, first, that Chang's assessment (...) of Lavoisier's and Priestley's work and character follows the phlogistonists' “actors' sociology”; second, that Chang simplifies late-eighteenth-century chemical debates by reducing them to an alleged conflict between two systems of practice; third, that Chang's evidence for a slow transition from phlogistonist theory to oxygen theory is not strong; and fourth, that he is wrong to assume that chemists at the time did not have overwhelming good reasons to favour Lavoisier's over the phlogistonists' views. (shrink)

A number of prominent defenders of the phlogiston theory identified phlogiston with hydrogen in the late eighteenth century, and I argue that this identification was fairly well-entrenched by the early nineteenth century. In light of this identification, I examine the ways in which retaining phlogiston could have retarded scientific progress, and also the ways in which it could have benefited science. I argue that it was rational for chemists to eliminate phlogiston, but that it also would have been rational for (...) them to retain it. I situate my arguments for these claims in relation to Hasok Chang's recent work on the Chemical Revolution. And I conclude that there is a sense in which scientific rationality concerns what is permissible, as opposed to what is required, so that retention and elimination may, at least sometimes, both be rationally permissible options. (shrink)