Title: Species of structure and physical dimensions

Abstract: This study addresses the often underestimated importance of physical dimensions and units in the formal reconstruction of physical theories, focusing on structuralist approaches that use the concept of ``species of structure" as a meta-mathematical tool. We are pursuing an approach that goes back to a suggestion by T.~Tao. It involves the representation of fundamental physical quantities by one-dimensional real ordered vector spaces, while derived quantities are formulated using concepts from linear algebra, e.~g.~tensor products and dual spaces. As an introduction, the theory of Ohm's law is considered. We then formulate a reconstruction of the calculus of physical dimensions, including Buckingham's $\Pi$-theorem. Furthermore, an application of this method to the Newtonian theory of gravitating systems consisting of point particles is demonstrated, emphasizing the role of the automorphism group.