Work

Careful with those scissors, Eugene! Against the observational indistinguishability of spacetimes

Year: 2021

Type: article

Abstract: We discuss Manchak (2009a)'s result that there are locally (but not globally) isometric universes observationally indistinguishable from our own. This theorem makes the epistemic predicament of modern cosmology particularly problematic and the prospects of ever gaining knowledge of the global structure of the universe rather unlikely in the context of general relativity. We argue however that this conclusion is too quick; indeed, Manchak's theorem deploys spacetimes which are not physically reasonable, since they have features which are not the product of any physical process. This ultimately rests on the fact that local isometry between two spacetimes is not sufficient to guarantee that they are both physically reasonable. We propose an additional condition to properly define when a spacetime is physically reasonable, and we show that Manchak's spacetimes do not satisfy this further demand.

Source: Studies in History and Philosophy of Science Part A

DOI: 10.1016/j.shpsa.2021.07.007

Authors: Enrico Cinti, Vincenzo Fano

Institutions: University of Geneva, University of Urbino

Language: English

Topic: Relativity and Gravitational Theory

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,280

Funder: Ministero dell’Istruzione, dell’Università e della Ricerca