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Authors: L. Lusanna, M. Pauri

Date: Wed, 16 Mar 2005

Abstract: "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 physical individuation of point-events is furnished by the intrinsic degrees of freedom of the gravitational field, (viz, the Dirac observables) that represent - as it were - the ontic part of the metric field. The physical role of the epistemic part (viz. the gauge variables) is likewise clarified. At the end, a peculiar four-dimensional holistic and structuralist view of space-time emerges which includes elements common to the tradition of both substantivalism and relationism. The observables of our models undergo real temporal change and thereby provide a counter-example to the thesis of the frozen-time picture of evolution. Invited Contribution to the ESF 2004 Oxford Conference on Space-Time.

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