2005/03/16 by L. Lusanna, Lusanna, L., M. Pauri +1
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.48550/arxiv.gr-qc/0503069
revtex, 23 pages
arxiv created 2005/09/03 · arxiv updated 2009/12/01
"The last remnant of physical objectivity of space-time" is disclosed, beyond the Leibniz equivalence, in the case of a continuous family of spatially non-compact models of general relativity. The \it physical individuation of point-events is furnished by the intrinsic degrees of freedom of the gravitational field, (viz, the \it Dirac observables) that represent - as it were - the \it ontic part of the metric field. The physical role of the \it epistemic part (viz. the \it gauge variables) is likewise clarified. At the end, a peculiar four-dimensional \it holistic and structuralist view of space-time emerges which includes elements common to the tradition of both \it substantivalism and \it relationism. The observables of our models undergo real \it temporal change and thereby provide a counter-example to the thesis of the \it frozen-time picture of evolution. Invited Contribution to the ESF 2004 Oxford Conference on Space-Time