Seminar on History and Philosophy of Science
Variables are everywhere in science. They are measured, controlled, varied, discovered, and discussed. And yet their nature is far from obvious. Though most philosophers and scientists have been reticent on the subject, I contend that the study of variables offers great potential as a tool for understanding the nature of scientific inquiry at large. The aim of this talk is to clarify that potential. I begin by distinguishing a set of descriptive and normative questions about variables. The normative questions prove to be the most informative, and involve (at least) two distinct problems: (i) Given that we can build new variables as functions of arbitrarily large collections of old variables, how do we decide which level is the most apt for describing the actual causal relations that obtain in the world? In other words, how do we know when to describe things in terms of the position and momentum of a baseball rather than the myriad positions and momenta of its constituent particles? and (ii) How ought we to recognize or introduce new variables that are not supervenient upon the old? For instance, what motivates the introduction of temperature or internal resistance as quantities to be considered and measured in their own right? I trace the modest history of proposed solutions to these questions, and show just how much progress has been made in the last few years. Rather than settle the issue, recent answers to the normative questions allow us to recognize a new series of relatively well-posed problems. Investigating these new problems promises to be a fertile area in the development of automated scientific discovery.