Diagrams as Part of Physical Theories: A Representational Conception

Throughout the history of the philosophy of science, theories have been linked to formulas as a privileged representational format. In this paper, following [8], I defend a semantic-representational conception of theories, where theories are identified with sets of scientific re-presentations by virtue of their epistemic potential and independently of their format. To show the potential of this proposal, I analyze as a case study the use of phase diagrams in statistical mechanics to convey in a semantically consistent and syntactically correct way theoretical principles such as Liouville's theorem. I conclude by defending this philosophical position as a tool to show the enormous representational richness underlying scientific practices.