Ontological Perspectives in Crystal Solids

Abstract

This paper addresses the issue of the different levels of description of matter and the relationships between them. Specifically, it focuses on the area of crystalline solids, a topic that has been scarcely analyzed in the philosophy of chemistry. Unlike other cases where the relevant levels are clearly defined, the scientific practice related to crystals introduces new entities, such as phonons, which complicate the ontological landscape. In order to organize the discussion, the conceptual implications of describing crystals through three distinct levels are explored: the atomistic, the phononic, and the crystal as a whole. Existing proposals for understanding the phenomenon are analyzed, and based on the introduction of the Tensor Product Structure approach, it is argued that the ontological perspectives of crystals depend on external criteria beyond the formalism that describes them. In the absence of external criteria, a pluralistic ontology is obtained, granting equal status to all entities. On the other hand, privileging the total system or the fundamental components leads to holistic or atomistic ontologies, respectively.