Scientific Realism and Chemistry

SCIENTIFIC REALISM Is a philosophical issue with relevance to all sciences, but there are some particularly interesting and distinctive ways in which it has manifested itself in chemistry. Paying proper attention to such aspects will deliver two types of benefits: First, it will aid the philosophical understanding of the nature of chemical knowledge; second, it will throw some fresh light on the realism debate in places where it has developed without much attention to chemical practices and chemical concepts. In the following discussion I will attempt to make a reasonably comprehensive survey of relevant literature, while also advancing some original points and viewpoints. Recall Bas van Fraassen’s now-classic formulation of the realism debate as an argument about whether we can know about unobservable entities featuring in scientific theories, and whether we should try to know about them (van Fraassen 1980). If this is how we understand realism, and if we take the long view of the history of science, chemistry is the most important science to consider in the realism debate. Until the development of atomic, nuclear, and elementary-particle physics starting in the early twentieth century, chemistry was the science in which debates about the epistemic and ontological status of unobservable theoretical entities took place with most ferocity and most relevance to practice. An interesting contrast is astronomy, in which the Copernican Revolution brought in a long and secure phase of realism about astronomical objects far out of reach of any human senses (including those that do not even register as tiny specks of light to our eyes). In contrast, the achievements of chemistry up to the early nineteenth century only deepened the sense of inaccessibility and unobservability concerning the putative fundamental entities postulated in chemical theories. Unobservability in relation to chemical theories is not only an issue about atomism, though surely the problem was clearly present with the atomistic particles imagined by a wide range of thinkers from Democritus and Leucippus of ancient times to Descartes and other early-modern mechanical philosophers.