Chemical Concepts in the Era of Computational Chemistry
Tyler Ahlstrom · D-Scholarship@Pitt (University of Pittsburgh) · 2020
Present work in the philosophy of chemistry has overlooked a foundational debate among chemists about the proper function of chemical concepts. The debate is fueled by a desire to connect computational models with traditional chemical concepts, and has divided chemists since the origins of quantum chemistry. By analyzing the history of the concepts of electronegativity and the atom in the molecule, I show that there are two camps with conflicting priorities. Theorists who favor rigor seek concepts that neatly summarize important elements of the underlying physical models. Theorists who favor understanding seek concepts that achieve a balance between simplicity and qualitative accuracy. The development of concepts for understanding is shown to involve the use of multiple quantification schemes in order to achieve consistency with other concepts. This practice might appear shortsighted if not for the diverse functionality of the resulting concepts. These concepts can i) help discover new reactions and structures, ii) allow comparison of different models in computational chemistry, and iii) guide chemists to develop more accurate and more interpretable computational models. Finally, it is shown that these conflicting modes of conceptual development have implications for the nature of chemical concepts. Chemists on each side of the debate adopt different positions, explicitly or tacitly, on reduction, pluralism, and the ontology of chemical concepts. Philosophers of chemistry who neglect this debate cannot responsibly interpret chemists’ statements on these issues.