From rational numbers to Dirac's bra and ket: symbolic representation of physical laws. (Q1613285)

Since the 19th century, physicists have used symbols which interacted with their physical concepts. The author presents that line of the development, the key figures of which were Gauss, Weber, Maxwell, Schrödinger, Heisenberg, Dirac, and others. Stressing the role of Dirac, he argues that it was a transition from representing properties of a system to identification with the system itself. And he claims that ``today this new status of physical objects and of their symbols is accepted tacitly in the structure of elementary-particle theories''.