Generalised Manifolds as Basic Objects of General Relativity

Joanna Luc1
1Institute of Philosophy, Jagiellonian University, Kraków, Poland

Tóm tắt

In this paper non-Hausdorff manifolds as potential basic objects of General Relativity are investigated. One can distinguish four stages of identifying an appropriate mathematical structure to describe physical systems: kinematic, dynamical, physical reasonability, and empirical. The thesis of this paper is that in the context of General Relativity, non-Hausdorff manifolds pass the first two stages, as they enable one to define the basic notions of differential geometry needed to pose the problem of the evolution-distribution of matter and are not in conflict with the Einstein equations. With regard to the third stage, various potential conflicts with physical reasonability conditions are considered with a tentative conclusion that non-Hausdorff manifolds are more likely to pass this stage than is typically assumed. When dealing with some of these problems, the modal interpretation of non-Hausdorff manifolds is invoked, according to which they represent bundles of alternative possible spacetimes rather than single spacetimes.

Từ khóa


Tài liệu tham khảo

Allori, V., et al.: On the common structure of Bohmian mechanics and the Ghirardi-Rimini-Weber theory. Br. J. Philos. Sci. 59(3), 353–389 (2008) Allori, V.: Primitive ontology and the structure of fundamental physical theories. In: Albert, D.Z., Ney, A. (eds.) The Wave Function. Essays on the Metaphysics of Quantum Mechanics, pp. 58–75. Oxford University Press, Oxford (2013) Belot, G.: The representation of time and change in mechanics. In: Butterfield, J., Earman, J. (eds.) Philosophy of Physics: Part A, pp. 133–227. Elsevier, Amsterdam (2007) Healey, R.: Perfect symmetries. Br. J. Philos. Sci. 60(4), 697–720 (2009) Manchak, J.B.: What is a physically reasonable spacetime? Philos. Sci. 78, 410–420 (2011) Curiel, E.: A primer on energy conditions. In: Lehmkuhl, D., Schiemann, G., Scholz, E. (eds.) Towards a Theory of Spacetime Theories: Einstein Studies, vol. 13, pp. 43–104. Birkhäuser, New York (2017) Luc, J.: What does spacetime do? Manuscript (2019) Choquet-Bruhat, Y.: General Relativity and the Einstein Equations. Oxford University Press, Oxford (2009) Bourbaki, N.: General Topology. Reading Massachusetts. Addison-Wesley Publishing Company, Boston (1966) Munkres, J.R.: Topology, 2nd edn. Prentince Hall, Upper Saddle River, NJ (2000) Willard, S.: General Topology. Addison-Wesley Publishing Company, Reading (1970) Hicks, N.J.: Notes on Differential Geometry. Van Nostrand Reinhold Company, New York (1965) Chruściel, P.T., Isenberg, J.: Nonisometric vacuuum extensions of vacuum maximal globally hyperbolic spacetimes. Phys. Rev. D 48(4), 1616–1628 (1991) Hájíček, P.: Bifurcate space-time. J. Math. Phys. 12, 157–160 (1971a) Luc, J., Placek, T.: Interpreting non-Hausdorff (generalized) manifolds in General Relativity. Philos. Sci. (2019) Clarke, C.J.S.: Space-Time Singularities. Commun. Math. Phys. 49, 17–23 (1976) Malament, D.B.: Topics in the Foundations of General Relativity and Newtonian Gravitation Theory. The University of Chicago Press, Chicago (2012) Earman, J.: Pruning some branches from branching spacetimes. In: Dieks, D. (ed.) The Ontology of Spacetime II, pp. 187–206. Elsevier, Amsterdam (2008) Hájíček, P.: Causality in non-Hausdorff space-times. Commun. Math. Phys. 21, 75–84 (1971b) Earman, J.: Bangs, Crunches, Whimpers, and Shrieks. Singularities and Acausalities in Relativistic Spacetimes. Oxford University Press, Oxford (1995) Clarke, C.J.S.: Analysis of Space-Time Singularities. Cambridge University Press, Cambridge (1993) Penrose, R.: Singularities and time-asymmetry. In: Hawking, S.W., Israel, W. (eds.) General Relativity: An Einstein Centenary Survey, pp. 581–638. Cambridge University Press, Cambridge (1979) Hawking, S.W.: Singularities and the Geometry of Space-Time, Adams Prize Essay, Department of Applied Mathematics and Theoretical Physics, Cambridge University. Published later in European Physical Journal H 39, 413–503 (2014) (1966) Hájíček, P.: Extensions of the Taub and NUT spaces and extensions of their tangent bundles. Commun. Math. Phys. 17, 109–126 (1970) Hawking, S.W., Ellis, G.F.R.: The Large Scale Structure of Space-Time. Cambridge University Press, Cambridge (1973) Geroch, R.: Local characterization of singularities in general relativity. J. Math. Phys. 9, 4504–65 (1968) Placek, T., Belnap, N.: Indeterminism is a modal notion: branching spacetimes and Earman’s pruning. Synthese 187(2), 441–469 (2010) Placek, T., Belnap, N., Kishida, K.: On topological aspects of indeterminism. Erkenntnis 79, 403–436 (2014) Müller, T.: A generalized manifold topology for branching space-times. Philos. Sci. 80(5), 1089–1100 (2013) Placek, T.: Branching for general relativists. In: Müller, T. (ed.) Nuel Belnap on Indeterminism and Free Action, pp. 191–221. Springer, New York (2014) Placek, T.: Laplace’s demon tries on Aristotle’s cloak: on two approaches to determinism. Synthese 196(1), 11–30 (2019) Müller, T., Placek, T.: Defining determinism. Br. J. Philos. Sci. 69(1), 215–252 (2018) Friederich, S.: Fine-tuning. In: Zalta, E.N. (ed.) The Stanford Encyclopedia of Philosophy (Winter 2018 Edition). https://plato.stanford.edu/archives/win2018/entries/fine-tuning/ (2018) Grinbaum, A.: Which fine-tuning arguments are fine? Found. Phys. 42, 615–631 (2012) Williams, P.: Naturalness, the autonomy of scales, and the 125 GeV Higgs. Stud. Hist. Philos. Mod. Phys. 51, 82–96 (2015) Hossenfelder, S.: Lost in Math: How Beauty Leads Physics Astray. Basic Books, New York (2018) Callender, C. (ed.): The Oxford Handbook of Philosophy of Time. Oxford University Press, Oxford (2011) Placek, T.: A locus for “now”. In: Dieks, D., et al. (eds.) Explanation, Prediction, and Confirmation, pp. 395–410. Springer, Dordrecht (2011) Placek. T.: Past, present and future modally introduced. Synthese (2019). https://doi.org/10.1007/s11229-019-02302-w Wallace, D.: The Emergent Multiverse. Oxford University Press, Oxford (2012) Fine, K.: Varieties of necessity. In: Gendler, T.S., Hawthorne, J. (eds.) Conceivability and Possibility, pp. 253–281. Oxford University Press, Oxford (2002) Müller, T.: Branching in the landscape of possibilities. Synthese 188(1), 41–65 (2012) Williamson, T.: Modal science. Can. J. Philos. 46(4–5), 453–492 (2016)