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The new chemistry prevailed because it coordinated experimental accounting, a persuasive interpretation of gases and a reproducible language of composition. Its success cannot be reduced to the isolated discovery of oxygen, to the first use of a balance, or to the claim that every part of Antoine Lavoisier's system was correct.

The crucial experimental change was to treat gases as material participants that must enter the account of a chemical reaction. In a simple version of phlogiston theory, a metal lost phlogiston when it became a calx. Yet the calx could weigh more than the original metal. This was a serious explanatory challenge, although it did not make every contemporary version of phlogiston theory logically identical or instantly untenable. The question was how to organize changes in solid material, gas volume and the properties of the surrounding air into one consistent account.

Antoine Lavoisier's sustained heating of mercury under a connected air reservoir provides a concrete example. Red calx formed while part of the confined air disappeared; the residual gas no longer supported ordinary combustion or respiration. Heating the red material more strongly released a gas that supported these processes exceptionally well, while restoring the metal. Recombining the released gas with the residual gas recovered the behaviour of ordinary air. The explanatory advantage was a connected cycle of transformations, rather than a single unexplained weighing. Importantly, his own narrative acknowledges combining results from repeated trials into its presentation: the textbook sequence should not be mistaken for one effortless, perfectly complete performance.^[ref]

The oxygen theory of combustion interpreted the increase in the mass of a calx as addition of a constituent of air. A closed material account could then relate consumed gas to the transformed solid. Conservation of mass served as a rule for experimental reasoning: one had to examine all the reactants and products, including otherwise easily missed gases. Antoine Lavoisier stated this accounting principle explicitly in his discussion of fermentation. It was not necessary to claim that he invented every earlier practice of weighing or all previous ideas about material conservation to recognize the power of making such accounting central to a system.^[ref]

The new account also supplied a language that trained its users to recognize composition. In the 1787 nomenclature collaboration, Louis-Bernard Guyton de Morveau, Claude Louis Berthollet, Antoine-François de Fourcroy and Antoine Lavoisier linked related names to related substances. The 1789 textbook organized a route from relatively simple substances to compounds and then to operations and apparatus. Thus chemical nomenclature was not merely a convenient set of labels attached after an experimental victory. It made the proposed system easier to learn, communicate and extend, while requiring a reader to adopt some of its theoretical distinctions.^[ref]

This was a collective and contested transition. Joseph Priestley and Carl Wilhelm Scheele had independently investigated the gas subsequently interpreted as oxygen. Joseph Priestley's description of unusually respirable air did not entail adopting the same explanation of it as Antoine Lavoisier. A shared experimental object could therefore support competing theoretical descriptions. The achievement was the construction and dissemination of a coherent explanatory package, not the possession of a gas inaccessible to every rival.^[ref][ref]

The limits of the victory are equally instructive. The caloric theory remained part of the system, and the table of simple substances was explicitly related to the available means of decomposition. Antoine Lavoisier's universal association of acidity with oxygen was false: hydrochloric acid, with formula $\mathrm{HCl}$, is a concrete oxygen-free counterexample. The permanence of the new chemical nomenclature did not require retaining all the assumptions embedded in its first construction.^[ref] The system triumphed through explanatory and practical advantages that survived correction. Neither its errors nor the rationality of some contemporary objections makes that achievement disappear.

Selection is unavoidable in historical writing, but selecting only eventual winners corrupts the explanation of how scientific knowledge developed. A defensible account can judge a theory false while still asking why capable investigators accepted it, what it enabled them to do and how its rejection became justified. Historical explanation and endorsement are different activities.

The first problem is circularity. If significance means contribution to what is now accepted, the account first chooses its endpoint and then discovers a past that appears to have been moving toward it. Historical presentism substitutes later categories and standards for the questions available to the participants. Whig history of science then turns the selected sequence into a story of foreseen progress. The process looks inevitable because alternatives have been removed from the narrative, not because their historical impossibility has been demonstrated.

Phlogiston theory provides an instructive example. Rejecting it as an accurate modern account of combustion does not explain the experiments on different airs that were conducted within it. Joseph Priestley investigated a gas through its production, its effect on a flame and its respiratory properties. His description of dephlogisticated air records an important experimental achievement even though its theoretical name differs from the later account of oxygen. If his framework is omitted as merely foolish, the history loses both the investigator's reasons and part of the evidence on which the competing chemistry depended.^[ref]

The winner's side also resists tidy retrospective sorting. Antoine Lavoisier's Elements of Chemistry by Antoine Lavoisier integrated caloric theory and an erroneous universal acidifying role for oxygen with influential practices of material accounting and chemical nomenclature. Calling the entire package modern and therefore correct would be just as inaccurate as discarding all of Joseph Priestley's work. A historian needs to follow which practices, concepts and commitments were retained, modified or rejected, rather than assigning a single final truth value to a whole person.^[ref]

The second problem is causal omission. Published theories depended on instrument makers, assistants, collectors, translators, teachers and readers able to repeat or adapt operations. Restricting attention to celebrated authors treats these conditions as if they supplied themselves. The dedication in Sidereus Nuncius by Galileo Galilei demonstrates that even a canonical discovery claim was situated in patronage and reputation. Examining that setting explains part of its form and audience; it need not imply that the satellites of Jupiter were merely a social invention.^[ref]

The third problem is that an unsuccessful explanation can generate a productive investigation. Wilhelm Roux's interpretation of an injured frog embryo helped make controlled intervention central to embryology. Hans Driesch disagreed with important conclusions while explicitly crediting the experimental programme. A history that retained only the eventual lesson of regulative development would struggle to explain why the decisive manipulation was attempted, why its controls mattered or why the result was surprising.^[ref]

This is not an argument that all theories are equally good, or that a historian must reconstruct every discarded speculation in equal detail. Selection should be justified by the explanatory problem. An account of a particular measurement may concentrate on calibration and instruments; an account of a theory's acceptance may require rivals, teaching practices and institutional settings. Scientific evaluation can ask how well competing theories answered the evidence then available and how later tests altered the balance. Historical judgment can also identify unjustified claims. What it cannot do is use later success as a substitute for evidence about the earlier process.

The same caution applies to very large labels. Steven Shapin's discussion of the Scientific Revolution makes the category itself an object of investigation rather than an unquestioned starting point.^[ref] A good history can explain genuine advances and unequal achievements while keeping lost alternatives visible. Its aim is neither a procession of heroes nor a refusal to distinguish better from worse explanations, but an account of how particular judgments became possible and persuasive.

The replacement is philosophically significant because it challenges the inference from a theory's practical success to the existence of its proposed entities. Phlogiston theory interpreted ordinary combustion and metallic calcination as the loss of phlogiston; the oxygen theory of combustion instead treated these processes as combination with oxygen. This changes the account of what matter is doing, not merely the spelling of an agreed substance. Antoine Lavoisier's systematic treatment links the new chemistry with quantitative mass accounting and a revised chemical nomenclature.^[ref]

For scientific realism, the difficulty is that a once-useful theoretical term may fail to refer. If earlier success coexisted with a nonexistent unobservable entity, present success alone cannot guarantee that every central term of our theories refers either. This is the force of the pessimistic induction; it rebuts an unrestricted success-to-truth inference rather than deductively proving every present theory false.^[ref]

Several replies reduce, but do not erase, the problem. A scientific realist can distinguish successful empirical regularities from the particular mechanisms used to explain them, retaining only claims independently supported by varied experiments. Structural realism can emphasize preserved quantitative relations; it must identify the actual relations and their physical interpretation rather than declaring any recurring mathematics a vindication. A causal account of reference may preserve a term across some mistaken descriptions, but it cannot automatically identify phlogiston with oxygen: their proposed roles in the reaction differ.

A defensible conclusion is therefore selective and fallible scientific realism. The historical episode motivates stricter criteria for commitment, including independent manipulation, cross-checks and successful novel tests. It does not force the view that all theoretical entities are mere instruments. Conversely, calling the abandoned theory approximately true without specifying which claims survived simply restates the difficulty.