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Theory Rejection theorem (Barseghyan-2015) (view source)
Revision as of 03:37, 13 March 2018
, 03:37, 13 March 2018no edit summary
|Description=According to '''the theory rejection theorem''', a [[Theory|theory]] becomes '''rejected''' only when other theories that are incompatible with the theory become accepted. By the [[The First Law (Barseghyan-2015)|First Law]] for theories, an accepted theory will remain accepted until it is replaced by other theories. By the [[The Zeroth Law (Harder-2015)|Zeroth Law,]] the elements of the [[Scientific Mosaic|scientific mosaic]] must be compatible with one another. Thus, a theory can only become rejected when it is replaced by an incompatible theory or theories.[[CiteRef::Barseghyan (2015)|p. 167-172]]
{{PrintDiagramFile|diagram file=theory-rejection-theorem.jpg}}
=== Phlogiston: The Rise and Fall of a Theory===
Phlogiston theory was developed around the 1700’s by Joachim Becher (1635-1682) and his student George Ernst Stahl (1660-1734). They posited that all bodies had a common ‘component’ that carried with it the property of combustibility. It was in virtue of the existence of this inflammability principle (i.e., the ‘component’) that bodies were combustible.[[CiteRef::Barseghyan (2015)|pp. 54]] Stahl named this unobservable entity phlogiston.[[CiteRef::Wisniak (2004)|pp. 732]]
Chemists posited that phlogiston had certain properties. Some of the salient ones include: bodies that are easily burnt (e.g., wood, charcoal) have more phlogiston than bodies that are difficult to burn; and phlogiston could neither be destroyed nor could it leave the atmosphere. Insofar as the mechanism of ‘burning’ or combustion was concerned, the primary notion was that, during combustion, the phlogiston contained in the bodies was released into the air. The air was previously thought to be dephlogisticated. After combustion, however, the release of phlogiston made the air phlogisticated.[[CiteRef::Wisniak (2004)|pp. 732-733]]
Phlogiston theory was an integral part of the scientific mosaic of the time. It served to provide a “broad conceptual scheme into which could be fitted most of the chemical phenomenon known in the eighteenth century.”[[CiteRef::Wisniak (2004)|pp. 733]] In addition to explaining combustion, phlogiston theory explained diverse phenomenon such as fluidity and volatility, as well as physical properties such as color and ordour.[[CiteRef::Wisniak (2004)|pp. 740]] Consequently, virtually all of the chemists of the time, in countries such as Germany, France, and England, accepted the phlogiston theory.
However, phlogiston could not explain an empirical anomaly. Theoretically, phlogiston was thought to be released into the air when an entity was burnt. It was thought that the weight of the object being burnt would decrease. However, continuous experimentation showed that the weight of the body actually increased. This empirical anomaly contradicted the expectations of the chemists, leading to “inextricable confusion.”[[CiteRef::Wisniak (2004)|pp. 733-734]]
Lavoisier developed in 1778 his theory of combustion as an attempt to explain this anomaly. He accused the argumentation of phlogiston theory of circularity: “the supporters of the phlogiston theory ... fall in a vicious circle and are forced to reply that combustible bodies contain the matter of fire because they burn, and they burn because they contain the matter of fire.”[[CiteRef::Wisniak (2004)|pp. 735]]
Lavoisier postulated that combustion depended on the combination of combustible matter and air (oxygen). Unlike phlogiston, his theory not only explained the increased mass of the burnt bodies, but also predicted (with aid from the discovery of the composition of water) the compositions of the respective particles. Given the significance of these predictions, Academie de Sciences organized experimentation, which was conducted by the most renowned chemists of the time. They concluded that “if we doubt of a truth established by experiments so simple and palpable, there would be nothing certain in natural philosophy.”[[CiteRef::Wisniak (2004)|pp. 742]] Therefore, the experimentation corroborated the prediction of the novel facts, leading to the acceptance of Lavoisier’s theory.
This is a case in point of the theory rejection theorem. Phlogiston theory was rejected, because it was not compatible with the newly accepted theory. In particular, the new theory did not rely on the existence of unobserved entities such as phlogiston, and it could explain anomalies that phlogiston failed to explicate. Importantly, phlogiston was not rejected merely because it failed to explain the above-mentioned anomaly. Indeed, it was rejected only when Lavoisier’s new theory, which was incompatible with phlogiston theory, became accepted, thereby demonstrating the mechanism of the theory rejection theorem. As a result, the phlogiston theory was “now on its way out to be replaced by Lavoisier’s new chemistry.”[[CiteRef::Wisniak (2004)|pp. 742]]
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