Abstract
Underdetermination of theories by empirical data is a central theme in debates surrounding scientific realism. Underdetermination undermines epistemological optimism: if empirical evidence cannot decide between theories, skepticism about the progress of science seems justified. Philosophical defenses have been developed against this skeptical threat. Typical themes in these defenses are that significant scientific examples of empirical equivalence (as opposed to imaginary armchair cases) are virtually non-existent, as it is already difficult enough in scientific practice to develop one single satisfactory theory; that in the rare instances where empirical equivalence can be maintained to occur it is defeasible and only temporary; and that there usually will be substantial differences in empirical support, even if theories are empirically equivalent. Examples are usually constructed cases within classical physics that have not played an important role in actual history. In this article we draw attention to the present-day situation in quantum mechanics, which we think is very relevant to the issue. There exist several realist interpretations of quantum mechanics, each of which depicts a quite distinctive physical world, and each of which has its own circle of devotees in the scientific community. Most of these interpretations are empirically equivalent in a quite strong sense: they predict the same results for all experiments that can be expected to be feasible. The usual arguments against the significance of theoretical underdetermination seem to lose a great deal of their effectiveness here. One may wonder whether non-uniqueness of theories is not part and parcel of the practice of modern science after all, and much less threatening than often thought.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
For example, Musgrave (1985, p. 200) confesses to know of only one serious example of empirical equivalence, which he takes from the writings of van Fraassen (1980, p. 46), namely that all Newtonian cosmological models that differ from each other in the absolute velocity they assign to the center of gravity of the solar system are in accordance with the same evidence.
- 2.
For instance, Fine (1984) describes Heisenberg , Schrödinger and Bohr as philosophically aware and convinced instrumentalists—he calls Bohr “the arch-enemy of realism” Curd et al. (2013, p. 1203). According to Fine the founding fathers of quantum mechanics succeeded in establishing nonrealism as an official philosophical doctrine of modern physics, “part of what every graduate physicist learns and practices” Curd et al. (2013, p. 1200). As will be discussed in the main text, in the latter case Fine confuses pragmatic considerations with philosophical principles, and in the former case misconstrues the positions of the founding fathers.
- 3.
In 1964 Bell (1964) showed that correlated submicroscopic quantum systems display behavior that is incompatible with a classical “local-realistic” description of these systems; this incompatibility with the classical world picture has since been verified in many experiments.
- 4.
See Dieks (2017) , and references contained therein, for an extensive discussion of Bohr’s philosophy of quantum mechanics and the way in which it is realist rather than instrumentalist.
- 5.
The difference is that in non-collapse interpretations “superpositions” remain intact, whereas these superpositions disappear during measurements if there are collapses. This difference is detectable in principle, and in fact recent progress has made it possible to detect superpositions of quite big systems.
- 6.
This formalism is the more consistent one in the sense that only standard quantum evolution is assumed and no special status is attributed to measurements. It seems that recent experimental results, which—as just said—verify that superpositions of semi-macroscopic states are possible, inductively support the hypothesis that standard quantum evolution, of the Schrödinger equation type without collapses, is generally valid. The view that “collapses” should be seen as “bookkeeping devices” rather than as physical processes is therefore gaining ground. However, the matter remains controversial.
- 7.
The observation that Bohm’s interpretation can be seen as a special case of the modal interpretation is due to Bub (1997).
- 8.
Note the difference with the quantum textbook rule that \(|\Psi (x)|^2\) is the probability of finding a particle at x, in an experiment: here there is no mention of any measurement and the standard realist assumption is made that the particle just is somewhere, even if it is not observed. Whether \(\Psi (x)\) should be considered a real physical field guiding particles or rather a mathematical quantity occurring in the particle laws of motion is a matter of debate between different adherents of the Bohm theory, which gives rise to a bifurcation of Bohmian world pictures.
- 9.
In order to guarantee this, the motion of the particles is posited to obey the deterministic “guidance equation” \(\overrightarrow{p} = \nabla S(x)\), with \(\overrightarrow{p}\) the particle’s momentum and \(\nabla S(x)\) the gradient of the phase S(x) of the (complex-valued) wavefunction \(\Psi (x)\).
- 10.
This is a criterion of adequacy: If a proposed interpretation is not able to reproduce our “ordinary world of experience”, it has certainly to be rejected.
- 11.
- 12.
There is also the odd double role of the wavefunction, which on the one hand specifies the particle dynamics via the guidance equation and on the other hand determines the probability distribution of the particles.
- 13.
In view of the perceived impossibility of an objective choice between the alternative interpretations, the proposal has recently gained popularity to be non-committal, by speaking only about the “information” that is present in the basic structure of the world; see, e.g., Bub (2016) and references contained therein. Opponents challenge this information-based approach in the foundations of quantum mechanics by asking what the information is information about—an implicit acknowledgment of realism.
References
Acuña, P. and Dieks, D. (2014). Another look at empirical equivalence and underdetermination of theory choice. European Journal for the Philosophy of Science, 4, 153–180. doi:10.1007/s13194-013-0080-3
Bell, J. S. (1964). On the Einstein Podolsky Rosen Paradox. Physics, 1, 195–200.
Beller, M. (1999). Quantum Dialogue: The Making of a Revolution. Chicago: University of Chicago Press.
Bohm, D. (1952). A Suggested Interpretation of the Quantum Theory in Terms of ‘Hidden’ Variables, I, II. Physical Review, 85, 166–179; 180–193.
Bub, J. (1997). Interpreting the Quantum World. Cambridge: Cambridge University Press.
Bub, J. (2016). Bananaworld: Quantum Mechanics for Primates. Oxford: Oxford University Press.
Curd, C, Cover J.A. and Pincock C. (eds.) (2013). Philosophy of Science—The Central Issues. Second edition. New York: W.W. Norton & Company.
Cushing, J.T. (1994). Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony. Chicago: University of Chicago Press.
De Regt, H.W. and Dieks, D. (2005). A Contextual Approach to Scientific Understanding. Synthese 144, 137–170.
Dieks, D. and Vermaas P. (eds.) (1998). The Modal Interpretation of Quantum Mechanics. Dordrecht: Kluwer Academic Publishers.
Dieks, D., van Dongen, J. and de Haro, S. (2015). Emergence in holographic scenarios for gravity. Studies in History and Philosophy of Modern Physics, 52, 203–216.
Dieks, D. (2017). Niels Bohr and the Formalism of Quantum Mechanics. In Niels Bohr and Philosophy of Physics: Twenty-First Century Perspectives, edited by H. Folse and J. Faye. London: Bloomsburg Publishing.
Dieks, D. (2017). Von Neumann’s Impossibility Proof: Mathematics in the Service of Rhetorics. Studies in the History and Philosophy of Modern Physics, to appear.
Dürr, D., Goldstein, S., Tumulka, R., and Zanghi, N. (2004). Bohmian Mechanics and Quantum Field Theory. Physical Review Letters, 93: 090402: 1–4.
Faye, J. (2014). Copenhagen Interpretation of Quantum Mechanics. The Stanford Encyclopedia of Philosophy (Fall 2014 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/fall2014/entries/qm-copenhagen/
Fine, A. (1984). The Natural Ontological Attitude. In J. Leplin (ed.), Scientific Realism. Berkeley: University of California Press, 83–107. Reprinted in Curd et al., (2013), 1191–1214.
Goldstein, S. (2016). Bohmian Mechanics. The Stanford Encyclopedia of Philosophy (Fall 2016 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/fall2016/entries/qm-bohm/
Griffiths, R.B. (2014). The Consistent Histories Approach to Quantum Mechanics. The Stanford Encyclopedia of Philosophy (Fall 2014 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/fall2014/entries/qm-consistent-histories/
Kochen, S. and Specker, E.P. (1967). The Problem of Hidden Variables in Quantum Mechanics. Journal of Mathematics and Mechanics 17, 59–87.
Kukla, A. (1993). Laudan, Leplin, and Underdetermination. Analysis, 53, 1–7.
Kukla, A. (1996). Does Every Theory Have Empirically Equivalent Rivals? Erkenntnis, 44, 137–166.
Laudan, L. (1990). Demystifying Underdetermination, in C. Wade Savage (ed.), Scientific Theories, vol. 14, Minnesota Studies in the Philosophy of Science. Minneapolis: University of Minnesota Press, 267–297. Reprinted in Curd et al., (2013), 288–321.
Laudan, L. and Leplin, J. (1991). Empirical Equivalence and Underdetermination. The Journal of Philosophy, 88, 449–472.
Leplin, J. and Laudan, L. (1993). Determination Underdeterred: reply to Kukla, Analysis, 53, 8–16.
Lombardi, O. and Dieks, D. (2016). Modal Interpretations of Quantum Mechanics. The Stanford Encyclopedia of Philosophy (Spring 2016 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/spr2016/entries/qm-modal/
Maxwell, G. (1962). The Ontological Status of Theoretical Entities. In H. Feigl and G. Maxwell (eds.), Scientific Explanation, Space, and Time, vol. 3, Minnesota Studies in the Philosophy of Science. Minneapolis: University of Minnesota Press, 3–15.
Musgrave, A. (1985). Realism versus Constructive Empiricism, in P.M. Churchland and C.A. Hooker (eds.), Images of Science. Chicago: Chicago University Press, 197–221. Reprinted in Curd et al., (2013), 1083–1108.
Vaidman, L. (2016). Many-Worlds Interpretation of Quantum Mechanics. The Stanford Encyclopedia of Philosophy (Fall 2016 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/fall2016/entries/qm-manyworlds/
Van Fraassen, B. (1980). The Scientific Image. Oxford: Clarendon Press.
Von Neumann, J. (1932). Mathematische Grundlagen der Quantenmechanik. Berlin: Springer. English translation by Robert T. Beyer: Von Neumann, John (1955), Mathematical Foundations of Quantum Mechanics. Princeton: Princeton University Press.
Wallace, D. (2012). The Emergent Multiverse. Oxford: Oxford University Press.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer International Publishing AG
About this chapter
Cite this chapter
Dieks, D. (2017). Underdetermination, Realism and Objectivity in Quantum Mechanics. In: Agazzi, E. (eds) Varieties of Scientific Realism. Springer, Cham. https://doi.org/10.1007/978-3-319-51608-0_16
Download citation
DOI: https://doi.org/10.1007/978-3-319-51608-0_16
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-51607-3
Online ISBN: 978-3-319-51608-0
eBook Packages: Religion and PhilosophyPhilosophy and Religion (R0)