Natural laws and ontological reflections: the textual and didactic implications of the presentation of Boyle?s law in general chemistry

Abstract

This study develops a tool to identify errors in the presentation of natural laws based on the epistemologyand ontology of the Scientific Realism of Mario Bunge. The tool is able to identify errors of different types:(1) epistemological, in which the law is incorrectly presented as data correlation instead of as a pattern ofcausality; (2) semantic, in which natural law is presented as a mathematical statement that relates variablesbut with an absence of ambiguous material reference; (3) deterministic, in which the relationship of naturalvariables is presented but with no causality statement; and (4) mechanistic, in which a causality statement ispresented with the absence of an explanatory mechanism. In this work, Boyle’s law was used as anexample of the applicability of the instrument. In this case, we found errors in most of the universitytextbooks that we analyzed. Most of the errors arose from the disconnection between the symbolic andmicroscopic levels. The presentations of Boyle’s law in general chemistry are given in textbooks thatinclude illustrations based in a macroscopic perspective, in which the macroscopic compressionmechanism is completely disconnected from the microscopic collision mechanism. This disconnectionresults in the incorrect presentation of gas pressure as the cause and gas volume as the effect.