Scientific Practice and the Disunity of Physics

It is my aim in this paper to look at some of the arguments that are brought forward for or against certain claims to unity/disunity (in particular to examine those arguments from science and from scientific practice) in order to evaluate whether they really show what they claim to. This presupposes that the concept or rather the concepts of the unity of physics are reasonably clear. Three concepts of unity can be identified: (1) ontological unity, which refers to the objects physics is about; (2) descriptive unity, which addresses the descriptive devices physics employs in dealing with physical systems (3) unity of practice, which deals with what physicists actually do.