Abstract
We analyse the possibility that string-theoretic dualities present a case of strong underdetermination of theory by evidence. Drawing on the parallel discussion of the hole argument, we assess the possible interpretations of dualities. We conclude that there exist at least two defensible interpretations on which dualities do not present a worrying case of underdetermination per se.
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Notes
Such claims are often made in the context of the so-called AdS/CFT correspondence, for example.
It should be emphasised here that the analogy between dualities and the hole argument will—and must—not be pushed too far: we simply look to the hole argument as a well-studied case of an underdermination-like scenario, which can inform our understanding of the possible approaches to dualities.
One might think that, on this second option, the underdetermination is only apparent. We shall see that this is not quite correct, and more is needed over and above an embedding the two relevant theories into an overarching theory to avoid the problem of underdetermination.
The \(\lambda _i\) are not free, but are in fact highly constrained. For example, the relevant \(\lambda _i\) parameterising the moduli space of vacua of a supersymmetric gauge theory often form an affine algebraic variety.
To illustrate, in General Relativity the abstract \(\lambda _i\) specify models labelled by \(\langle M, g_{ab}, \Phi \rangle \), where M is the spacetime manifold, \(g_{ab}\) is the metric field, and \(\Phi \) are matter fields. Any such triple is a kinematically possible model of the theory, but only those models which satisfy the Einstein field equations—the dynamical equations of the theory, which relate \(g_{ab}\) to the stress-energy tensor \(T_{ab}\) of the \(\Phi \)—are dynamically possible models.
Here, we assume that all internal degrees of freedom are, in principle, measurable, so that empirical symmetries are guaranteed to preserve the configuration of internal degrees of freedom. The author is grateful to Neil Dewar for this point.
In the sense that \(h_{\alpha \beta }\) is a new variable, a priori independent of the pullback of the spacetime metric to the world sheet.
One might reasonably ask: in what sense are \(g_{\mu \nu }\), \(B_{\mu \nu }\) and \(\Phi \) background fields? All we have shown so far is that they represent excited states of strings. The typical answer here runs along the following lines: when we introduce these fields as “background fields” in spacetime, we envisage them as coherent states of strings at all points in spacetime, at low energy so “stringy” effects can be ignored, so that they behave as typical quantum fields. There is much room for conceptual clarification and expansion here; the author hopes to explore such issues in a future paper.
It is worth noting that this equivalence has not been proven. Nevertheless, a vast number of non-trivial correspondences between theories linked by such dualities gives physicists confidence that the equivalence is correct.
In discussions of the hole argument, the focus is on manifold substantivalism, according to which spacetime is identified with the manifold M. The hole argument does not necessarily speak against metric substantivalism, which states that the metric field \(g_{ab}\) forms an essential part of spacetime.
Note that we are now using abstract (i.e. coordinate-free) indices, denoted by Roman letters.
This is Earman and Norton’s so-called acid test of substantivalism.
The same theory: recall that T-duality for the bosonic string is a self-duality.
Though there are subtle differences, discussed below.
One might reasonably question whether such observations do indeed warrant the inference to the existence of M-theory: certainly, the existence of such a theory does not appear to be implied by such observations as a matter of necessity. This point is discussed in more detail below.
The author intends to investigate in detail such candidate cases of dualities in the history of physics in a future paper.
I am grateful to Dennis Lehmkuhl and an anonymous referee for suggesting this possibility.
It is worth stressing that both option (1) above, and option (4) here, agree that dual models correspond to distinct possible words. By contrast, options (2) and (3) deny this.
Although Susskind talks of spacetime, we shall continue to talk of an abstract parameter space.
References
Ballard, M.R.: Meet homological mirror symmetry. In: Fields Institute Communications, vol. 54, pp. 191–224. American Mathematical Society, Providence (2008)
Becker, K., Becker, M., Schwarz, J.: String Theory and M-Theory: A Modern Introduction. Cambridge University Press, Cambridge (2007)
Blumenhagen, R., Lüst, D., Theisen, S.: Basic Concepts of String Theory. Series in Theoretical and Mathematical Physics. Springer, Berlin (2013)
Brighouse, C.: Spacetime and holes. In: Proceedings of the Biennial Meeting of the Philosophy of Science Association, pp. 117–125 (1994)
Brown, H.R.: Physical Relativity: Space-Time Structure from a Dynamical Perspective. Oxford University Press, Oxford (2005)
Butterfield, J.: On philosophy of quantum gravity. In: Seminar on the Philosophical Foundations of Quantum Gravity, Chicago (2013)
Cowen, R.: Simulations back up theory that universe is a hologram. Nature news. doi:10.1038/nature.2013.14328 (2013)
Dawid, R.: Constructive empiricism, elementary particle physics and scientific motivation. http://homepage.univie.ac.at/richard.dawid/Eigene%20Texte/11.pdf (2005)
Dawid, R.: Scientific realism in the age of string theory. Phys. Philos. 11, 1–32 (2007)
Dawid, R.: String Theory and the Scientific Method. Cambridge University Press, Cambridge (2013)
de Haro, S.: Dualities and Emergent Gravity: AdS/CFT and Verlinde’s Scheme. arXiv:1501.06162 (2015)
Dieks, D., van Dongen, J., de Haro, S.: Emergence in holographic scenarios for gravity. http://philsci-archive.pitt.edu/10606/ (2015)
Earman, J., Norton, J.: What price spacetime substantivalism? Br. J. Philos. Sci. 38, 515–525 (1987)
Faraoni, V., Gunzig, E.: Einstein frame or Jordan frame? Int. J. Theor. Phys. 38, 217–225 (1999)
French, S.: Science: Key Concepts in Philosophy. Bloomsbury Academic, London (2007)
Galilei, G.: Dialogue Concerning the Two Chief World Systems, trans. Stillman Drake, second revised edition. University of California Press, Berkeley, 1632 (1967)
Greene, B.: The Hidden Reality. Alfred Knopf, New York (2011)
Healey, R.: Gauging What’s Real: The Conceptual Foundations of Contemporary Gauge Theories. Oxford University Press, Oxford (2007)
Horowitz, L., Polchinski, J.: Gauge/gravity duality. In: Oriti, D. (ed.) Approaches to Quantum Gravity: Toward a New Understanding of Space, Time and Matter. Cambridge University Press, Cambridge (2009)
Huggett, N.: Philosophical paths into string theory. In: Seminar on the Philosophical Foundations of Quantum Gravity, Chicago (2013)
Huggett, N., Wüthrich, C.: Emergent spacetime and empirical (in)coherence. Stud. Hist. Philos. Mod. Phys. 44, 276–285 (2013)
Ismael, J., van Fraassen, B.C.: Symmetries as a guide to superfluous theoretical structure. In: Brading, K., Castellani, E. (eds.) Symmetries in Physics: Philosophical Reflections. Cambridge University Press, Cambridge (2003)
Kaplan, D.: How to Russell a Frege-church. J. Philos. 72, 716–729 (1975)
Knox, E.: The dimensions of duality. In: Seminar on the Philosophical Foundations of Quantum Gravity, Chicago (2013)
Kontsevich, M.: Homological algebra of mirror symmetry.arXiv:alg-geom/9411018 (1994)
Maldacena, J.: The large \(N\) limit of superconformal field theories and supergravity. Adv. Theor. Math. Phys. 2, 231–252 (1998)
Maldacena, J.: The illusion of gravity. Sci. Am. 293, 56–63 (2005)
Matsubara, K.: Realism, underdetermination and string theory dualities. Synthese 190, 471–489 (2013)
Maudlin, T.: The essence of space-time. In: Fine, A., Leplin, J. (eds.) Proceedings of the 1988 Biennial Meeting of the Philosophy of Science Association, vol. 2, pp. 82–91. Philosophy of Science Association, East Lansing (1989)
Mitchell, D.: Cloud Atlas. Sceptre, London (2004)
Muller, F.A.: The equivalence myth of quantum mechanics—part I. Stud. Hist. Philos. Mod. Phys. 28, 35–61 (1997)
Muller, F.A.: The equivalence myth of quantum mechanics—part II. Stud. Hist. Philos. Mod. Phys. 28, 219–247 (1997)
Norton, J.: The hole argument. In: The Stanford Encyclopaedia of Philosophy (2011)
Oriti, D.: Approaches to Quantum gravity: Toward a New Understanding of Space, Time, and Matter. Cambridge University Press, Cambridge (2009)
Poincaré, H.: Science and Hypothesi, 1905. Dover, New York (1952)
Poincaré, H.: The Value of Science, translated by G.B. Halsted, 1914. Reprinted. Dover, New York (1958)
Polchinski, J.: String Theory, vol. 1. Cambridge University Press, Cambridge (1998)
Polchinski, J.: Dualities of fields and strings. http://arxiv.org/pdf/1412.5704v2 (2014)
Pooley, O.: Substantive general covariance: another decade of dispute. In: Suárez, M., Dorato, M., Rédei, M. (eds.) EPSA Philosophical Issues in the Sciences: Launch of the European Philosophy of Science Association, pp. 197–209. Springer, Heidelberg (2010)
Pooley, O.: CL 121: Advanced Philosophy of Physics. Advanced Philosophy of Physics Lecture Notes (2012)
Pooley, O.: Substantivalist and relationalist approaches to spacetime. In: Batterman, R. (ed.) The Oxford Handbook of Philosophy of Physics. Oxford University Press, Oxford (2013)
Port, A.: An Introduction to Homological Mirror Symmetry and the Case of Elliptic Curves. arXiv:1501.00730 (2015)
Read, J.: Categories and Equivalence, in preparation (2015)
Rickles, D.: Quantum gravity: a primer for philosophers. In: The Ashgate Companion to Contemporary Philosophy of Physics. Ashgate, Aldersho (2008)
Rickles, D.: A philosopher looks at string dualities. Stud. Hist. Philos. Mod. Phys. 42, 54–67 (2011)
Rickles, D.: AdS/CFT duality and the emergence of spacetime. Stud. Hist. Philos. Mod. Phys. 44, 312–320 (2013)
Rickles, D.: Mirror symmetry and other miracles in superstring theory. Found. Phys. 43, 54–80 (2013)
Rovelli, C.: A critical look at strings. Found. Phys. 43, 8–20 (2013)
Smolin, L.: A perspective on the landscape problem. Found. Phys. 43, 21–45 (2013)
Susskind, L.: String theory. Found. Phys. 43, 174–181 (2013)
Teh, N.: Holography and emergence. Stud. Hist. Philos. Mod. Phys. 44, 300–311 (2013)
van Fraassen, B.: The Scientific Image. Oxford University Press, Oxford (1980)
Weatherall, J.O.: Are newtonian gravitation and geometrized newtonian gravitation theoretically equivalent?. http://philsci-archive.pitt.edu/11575/ (2015)
Weatherall, J.O.: Understanding gauge. arXiv:1505.02229 (2015)
Weatherall, J.O.: Categories and the foundations of classical field theories. arXiv:1505.07084 (2015)
Witten, E.: Duality, spacetime and quantum mechanics. Phys. Today 50, 28–33 (1997)
Witten, E.: Topological sigma models. Commun. Math. Phys. 118, 411–449 (1988)
Worrall, J.: Structural realism: the best of both worlds? Dialectica 43, 99–124 (1989)
Zaffaroni, A.: Introduction to the AdS/CFT correspondence. Class. Quantum Gravity 17, 3571–3597 (2000)
Acknowledgments
I am very grateful to Nick Huggett, Dennis Lehmkuhl, Dean Rickles, and the two anonymous referees for their valuable comments on earlier drafts of this paper; to Neil Dewar for helpful discussions; and to the audience of the Oxford Philosophy of Physics “PoP-Grunch” seminar (in particular Simon Saunders) for further useful remarks. I am supported by an AHRC scholarship at the University of Oxford, and am also indebted to Merton College, Oxford for their support.
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Read, J. The Interpretation of String-Theoretic Dualities. Found Phys 46, 209–235 (2016). https://doi.org/10.1007/s10701-015-9961-y
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DOI: https://doi.org/10.1007/s10701-015-9961-y