Abstract

This dissertation reconstructs some aspects of the historical development of the concept of the electron from 1891, when the term "electron" was introduced, to 1925, when the notion of spin was put forward, in the light of the relevant historiographical and philosophical problems. The central historiographical tool employed is Karl Popper's notion of a problem situation. Furthermore, some of the historical episodes are reconstructed in terms of a "biographical" approach to theoretical entities that portrays them as active agents that participate in the development of scientific knowledge. Their agency is due to the heuristic resources that they embody and to the resistance that they exhibit to manipulation. The historical analysis begins with a reconceptualization of the "discovery" of the electron and aims at situating the principal historical actors within the wider process which led to the acceptance of the electron as an element of the ontology of physics. I continue with a reconstruction of the discovery of the Zeeman effect in the light of recent work on the history and philosophy of experimental science. The next three chapters are devoted to a reading of the development of the old quantum theory of the atom , which aimed at understanding the behavior and distribution of electrons bound within the atom, from the perspective of the electron's biography. Furthermore, I discuss the chemists' representation of the electron and contrast it with its physical counterpart. The main philosophical problem examined concerns the implications of meaning change for scientific realism . I discuss in detail that issue and argue against the widespread view that meaning variance is incompatible with scientific realism. Thus, I provide a way out for the aspiring realist, without however committing myself to a realist position. Finally, I argue that the historical development of the concept of the electron from 1896 to 1925 is compatible with a realist construal of its ontological status