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A hypothetical substance of negative mass that, according to the theory of G.E. Stahl, was given off by a substance when it underwent combustion, thus accounting for the decrease in mass of the ash over the original substance; abandoned after the discoveries of Priestley and Lavoisier concerning oxygen.
[G. phlogistos, inflammable]
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Positivist-whig historians claimed that Boyle's work was neglected because early-eighteenth-century chemists became engrossed in the erroneous and speculative phlogiston theory. Linking the progress of science to the actions of individual scientists -- the "children of light" -- who used the scientific method to overcome the "congeries of error, myth, and superstition" promulgated by the "children of darkness," positivist-whig historians traced Joseph Priestley's support for phlogiston and opposition to the oxygen theory to the disruptive effect of nonscientific, metaphysical, and religious, modes of thought on his reasoning.
Schofield contrasted Lavoisier's chemical interest in the "permutations and combinations of elements" with Priestley's physicalist concern with "the fundamental constituents of matter' and their "mechanistic modes and operations." Schofield incorporated whiggish sensibilities into his theoreticism when he blamed Priestley's physicalism for his failure to appreciate the "easy interpretations" that his experiments received "within the frame of the oxygen theory." (32) The postpositivist notion of the incommensurability of the phlogiston theory and the oxygen theory marked a moment of continuity with the positivist-whig idea that the Chemical Revolution constituted a cognitive "inversion," or a transition from the "looking glass chemistry" of phlogiston to the real world of oxygen.
Resisting this conclusion, the historian of chemistry Carleton Perrin placed a theoreticist construal on the historiography of the "crucial year," which recognized the worth of the phlogiston theory and Lavoisier's indebtedness to Stahl.
This killed the phlogiston theory, although a few important chemists continued to accept phlogiston for some decades longer.
Thus there are two major theses to the book: the primary one involves a cognitive analysis of such conceptual changes as the chemical revolution in which Stahl's phlogiston theory was overturned by Lavoisier's oxygen theory; the Darwinian revolution that replaced the conception of special creation; the geological revolution whereby the theory of plate tectonics superceded that of continental drift; the revolutions initiated by Copernicus, Newton, Einstein, and Planck; and the twentieth-century revolutions in psychology involving behaviorism and the rise of cognitivism.
Early scientists behaved in a similar way when they used the name "heat" and, because a name existed for "something", went looking for the substance represented by that name: the result was the phlogiston theory, ultimately replaced by Joseph Priestley's discovery of oxygen and the chemical nature of combustion.
Dudman (1981, 1983, 1984) argued hard for that relocation of Doesn't-will; and a paper of mine - insolently titled "Farewell to the Phlogiston Theory of Conditionals" (1988) - poured gasoline onto the fire.(1) I defended something like Dudman's relocation of the line between the two types of conditional without invoking his particular views about how each type should be analysed - views which are not widely shared.