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 do so on the grounds that a number of prominent phlogiston theorists identified phlogiston with hydrogen in the late 18th century, and this identification became fairly well entrenched by the early 19th century. In light of this identification, I critically evaluate Hasok Chang’s argument that chemists should have retained phlogiston, and that doing so would have (...) benefited science. I argue that these benefits would have been unlikely, and I go on to consider some more likely benefits and harms of retaining phlogiston. 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)

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)

This is the first of a pair of papers. It focuses on the development of the most notable phlogistic theories during the period 1766–1791, including the main experiments that their proponents proposed them to interpret. There was a rapid proliferation of late phlogistic theories, particularly from 1784, and the accounts of composition and important implications of the main theories are set out and their issues analysed. Each of them either reached impasses due to internal problems, or included features that made (...) them unacceptable even to other phlogistians. The expositions and analyses of these theories are given in terms of details that were in the literature at the time or otherwise potentially understandable by the participants given contemporary practice. Some relevant methodological aspects of the history of science are discussed, and the secondary literature is briefly surveyed. The second paper deals with the contemporary development of the new chemistry, and with theory comparison and theory choice in the same period. (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)