Abstract
Structural realists claim that structure is preserved across instances of radical theory change, and that this preservation provides an argument in favor of realism about structure. In this paper, I use the shift from Newtonian gravity to Einstein’s general relativity as a case study for structural preservation, and I demonstrate that two prominent views of structural preservation fail to provide a solid basis for realism about structure. The case study demonstrates that (i) structural realists must be epistemically precise about the concrete structure that is being preserved, and (ii) they must provide a metaphysical account of how structure is preserved through re-interpretation in light of a new theory. Regarding (i), I describe a means of epistemic access to the unobservable that I call “thick detection” of structure, which isolates the structure that will be preserved. Regarding (ii), I argue that thickly detectable structure is preserved across theory change through a process of extracting the old structure from the new structure, much like what has been done with geometrized versions of Newtonian gravity. With these two responses in hand, the structural realist can adequately account for the preservation of structure and can provide a strong argument in favor of structural realism.
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Notes
See Ladyman and Ross (2007) and French (2014) for defenses of ontic structural realism. See Votsis (2003), Morganti (2004), and Hanson-Park (2023) for defenses of epistemic structural realism. Lastly, see Ladyman (2021) for an argument that structural realism is not properly a form of selective realism, as I treat it in this paper.
The details of the equivalence principle are not essential for demonstrating the preservation of structural elements in the case study at hand. For more on the equivalence principle, see Einstein (1961: chapters 19–20), Poisson and Will (2014: 218–221), and Adler (2021: Section 7.2) for the physics, or see Rohrlich (2000) and Lehmkuhl (2021) for the philosophical implications.
To be precise, Worrall is appropriating Post’s (1971) “principle of general correspondence,” which involves the laws in the new theory “degenerating” into the laws of the old given the right limiting conditions.
Note that this is not to say that Ptolemy was a realist about epicycles. Instead, this may be a structural claim of Ptolemy’s theory according to the structural realist, and the structural realist must explain this in light of its falsity. For a different structuralist account of the similarities between Ptolemaic and Copernican astronomy not based on thick detection, see Saunders (1993).
For the sake of brevity, hereafter I will speak of the terms themselves being detectable rather than making the more metaphysically accurate but linguistically cumbersome statement that the properties represented by the terms are detectable.
I take measurement (as distinct from mere calculation) to be a form of detection, so anything that is measurable is detectable. However, it is not necessarily the case that anything measurable is thickly detectable, as I will discuss in Section 6. Since no gravitational force exists in reality, it is the magnitude of this ‘force’ that is detectable. This will also be clarified in Section 6.
As Knox (2014) argues, GNG may be preferable on Newton’s own terms, had he considered it.
One may worry that I am making structural realism vulnerable to Stanford’s (2006) problem of unconceived alternatives with this claim, but this is not the case. In short, it is my view that if scientists fail to satisfy the robustness criterion, this takes thick detection off the table but not truth or abductive justification.
For a further explanation of this event, see CERN’s press release (https://home.cern/news/press-release/cern/opera-experiment-reports-anomaly-flight-time-neutrinos-cern-gran-sasso) and Antonello et al. (2012).
See Melia and Saatsi (2006) for more details on how the structural realist can have higher-order knowledge of relations between first-order predicates. There are many forms this higher-order knowledge can take, and each of these instances will be another instance of structure about which we should be realists, but discussing this is in further detail does not advance the case of structural preservation that I am making here.
Remember that I take measurement to be a form of detection, and measurable properties are thickly detectable only if they satisfy the three criteria from Section 6.
In this paragraph, I make use of the very helpful explanations in Cheng (2005) of each of the terms in the Einstein field equations. Cheng’s explanations are standard, so nothing I say will stand or fall based on his account of the mathematics involved.
To be clear, the physical distances being represented by the Ricci curvature tensor and the scalar curvature are not themselves directly measurable. Instead, these are representations of the distances in a curved, pseudo-Riemannian metric. Since these representations can be detected by the phenomena predicted by general relativity (such as the motion of particles and the bending of light) and the detection of these phenomena are robust, refinable, and connectable, they satisfy the criteria for thick detection that I have set out in this paper.
References
Adler, R. J. (2021). General relativity and cosmology: A first encounter. Springer.
Ainsworth, P. M. (2009). Newman’s objection. The British Journal for the Philosophy of Science, 60(1), 135–171.
Antonello, M., Aprili, P., Baibussinov, B., Ceolin, M.B., Benetti, P.A., Calligarich, E., Canci, N., Carbonara, F., Centro, S., Cesana, A., Cieślik, K., Cline, D.B., Cocco, A.G., Dabrowska, A.M., Dequal, D., Dermenev, A., Dolfini, R., Farnese, C., Fava, A., . . . Serrano, J. (2012). Measurement of the neutrino velocity with the ICARUS detector at the CNGS beam. Physics Letters B, 713(1), 17–22.
Azzouni, J. (1997). Thick epistemic access: Distinguishing the mathematical from the empirical. Journal of Philosophy, 94(9), 472–484.
Barrett, J. A. (2008). Approximate truth and descriptive nesting. Erkenntnis, 68(2), 213–224.
CERN Press Release (2011). OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso. https://home.cern/news/press-release/cern/opera-experiment-reports-anomaly-flight-time-neutrinos-cern-gran-sasso. Accessed 6 Nov 2021.
Chakravartty, A. (2007). A metaphysics for scientific realism: Knowing the unobservable. Cambridge University Press.
Cheng, T.-P. (2005). Relativity, gravitation and cosmology: A basic introduction. Oxford University Press.
Cruse, P. (2005). Ramsey sentences, structural realism and trivial realization. Studies in History and Philosophy of Science Part A, 36(3), 557–576.
Demopoulos, W., & Friedman, M. (1989). The concept of structure in The Analysis of Matter. In C. Wade Savage & C. Anthony Anderson (Eds.), Rereading Russell: Essays in Bertrand Russell’s metaphysics and epistemology (pp. 183–199). University of Minnesota Press.
Einstein, A. (1961). Relativity: The special and the general theory. Three Rivers Press.
Fletcher, S. C. (2019). On the reduction of general relativity to Newtonian gravitation. Studies in History and Philosophy of Science Part b: Studies in History and Philosophy of Modern Physics, 68, 1–15.
French, S. (2014). The structure of the world: Metaphysics and representation. Oxford University Press.
French, S., & Ladyman, J. (2011). In defence of ontic structural realism. In A. Bokulich & P. Bokulich (Eds.), Scientific structuralism (pp. 25–42). Springer Science+Business Media.
Frigg, R., & Votsis, I. (2011). Everything you always wanted to know about structural realism but were afraid to ask. European Journal for Philosophy of Science, 1(2), 227–276.
Hanson-Park, Jared (2023). Structural realism and agnosticism about objects. Global Philosophy, 33 (online first). https://doi.org/10.1007/s10516-023-09682-2
Ketland, J. (2004). Empirical adequacy and ramsification. British Journal for the Philosophy of Science, 55(2), 287–300.
Knox, E. (2014). Newtonian spacetime structure in light of the equivalence principle. British Journal for the Philosophy of Science, 65(4), 863–880.
Kuhn, T. (1962). The structure of scientific revolutions (3rd ed.). University of Chicago Press.
Ladyman, J. (1998). What is structural realism? Studies in History and Philosophy of Science Part A, 29(3), 409–424.
Ladyman, J. (2021). Structure not selection. In T. D. Lyons & P. Vickers (Eds.), Contemporary scientific realism: The challenge from the history of science. Oxford University Press.
Ladyman, J., & Ross, D. (2007). Every thing must go: Metaphysics naturalized. Oxford University Press.
Lehmkuhl, D. (2021). The equivalence principle(s). In E. Knox & A. Wilson (Eds.), The Routledge companion to philosophy of physics. Routledge.
Malament, D. (1986a). Gravity and spatial geometry. In R. B. Marcus, G. Dorn, & P. Weingartner (Eds.), Methodology logic philosophy of science VII (pp. 405–411). Elsevier Science Pub. Co.
Malament, D. (1986b). Newtonian gravity, limits, and the geometry of space. In R. G. Colodny (Ed.), From quarks to quasars: Philosophical problems of modern physics (pp. 181–201). University of Pittsburgh Press. https://doi.org/10.2307/jj.5973221.7
Malament, D. (2012). Topics in the foundations of general relativity and Newtonian gravitation theory. University of Chicago Press.
Masoumi, S. (2021). On the continuity of geometrized Newtonian gravitation and general relativity. Foundations of Physics, 51(2), 1–33.
Melia, J., & Saatsi, J. (2006). Ramseyfication and theoretical content. British Journal for the Philosophy of Science, 57(3), 561–585.
Morganti, M. (2004). On the preferability of epistemic structural realism. Synthese, 142(1), 81–107.
Newman, M. (1928). Mr. Russell’s causal theory of perception. Mind, 37, 137–148.
Poisson, E., & Will, C. M. (2014). Gravity: Newtonian, post-Newtonian, relativistic. Cambridge University Press.
Post, H. R. (1971). Correspondence, invariance and heuristics. In praise of conservative induction. Studies in History and Philosophy of Science Part A, 2(3), 213.
Psillos, S. (1999). Scientific realism: How science tracks truth. Routledge.
Redhead, M. (2001). The intelligibility of the universe. Royal Institute of Philosophy Supplement, 48, 73–90.
Rickart, C. E. (1995). Structuralism and structures: A mathematical perspective. Series in pure mathematics (Vol. 21). World Scientific Publishing.
Rohrlich, F. (2000). The equivalence principle revisited. Foundations of Physics, 30(5), 621–630.
Russell, B. (1927). Analysis of matter. Mansfield Centre, Martino Publishing.
Saatsi, J. (2019). What is theoretical progress of science? Synthese, 196, 611–631.
Saunders, S. (1993). To what physics corresponds. In S. French & H. Kamminga (Eds.), Invariance correspondence heuristics (pp. 295–325). Springer.
Stanford, P. K. (2006). Exceeding our grasp: Science, history, and the problem of unconceived alternatives. Oxford University Press.
Votsis, I. (2003). Is structure not enough? Philosophy of Science, 70(5), 879–890.
Votsis, I. (2011). Structural realism: Continuity and its limits. In A. Bokulich & P. Bokulich (Eds.), Scientific structuralism (pp. 105–117). Springer Science+Business Media.
Worrall, J. (1989). Structural realism: The best of both worlds? Dialectica, 43(1–2), 99–124.
Acknowledgements
Thanks to Berit Brogaard, Otávio Bueno, Anjan Chakravartty, Steven French, Kari Hanson-Park, Shea Musgrave, Hwan Ryu, Ziren Yang, and the anonymous reviewers for comments and discussion that have greatly improved this paper.
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Hanson-Park, J. The preservation of thickly detectable structure: a case study in gravity. Euro Jnl Phil Sci 14, 27 (2024). https://doi.org/10.1007/s13194-024-00588-3
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DOI: https://doi.org/10.1007/s13194-024-00588-3