ABSTRACT
Scientific theories posit a number of unobservable entities and employ theoretical terms-e.g. ‘electron’, ‘proton’, ‘electromagnetic field’, ‘DNA molecules’, etc. (henceforth, t-terms). How is this theoretical discourse, the discourse involving t-terms, to be understood? There are two broad philosophical traditions-an empiricist and a realist tradition-each with an answer to this question. Broadly speaking, the empiricist tradition aims to show that theoretical discourse may be so construed that it does not commit to the existence of unobservable entities. The realist tradition, on the other hand, aims to show that a full and just explication of theoretical discourse in science requires commitment to the existence of unobservable entities. The dialectic of the debate between the two traditions which will be explored throughout Part I will show how forceful the realist position is.
