Abstract
This essay offers a reaction to the recent resurgence of presentism in the philosophy of time. What is of particular interest in this renaissance is that a number of recent arguments supporting presentism are crafted in an untypically naturalistic vein, breathing new life into a metaphysics of time with a bad track record of co-habitation with modern physics. Against this trend, the present essay argues that the pressure on presentism exerted by special relativity and its core lesson of Lorentz symmetry cannot easily be shirked. A categorization of presentist responses to this pressure is offered. As a case in point, I analyze a recent argument by Monton (Presentism and quantum gravity, 263–280, 2006) presenting a case for the compatibility of presentism with quantum gravity. Monton claims that this compatibility arises because there are quantum theories of gravity that use fixed foliations of spacetime and that such fixed foliations provide a natural home for a metaphysically robust notion of the present. A careful analysis leaves Monton’s argument wanting. In sum, the prospects of presentism to be alleviated from the stress applied by fundamental physics are faint.
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
Notes
- 1.
Barbour (1999) can be read as offering a Parmenidean presentist view. Of course, there is lots more logical space available, e.g. containing a presentist position which subscribes to a moving Now without there being any change whatever. Furthermore, the basic presentist claim can be read as obtaining by necessity or merely contingently, which opens logical space for necessitarian and Humean brands of presentism. All these further varieties and distinctions, however, do not affect the present argument. I shall thus ignore them here.
- 2.
I understand that there is real worry about whether the debate between presentism and eternalism is well-formed and metaphysically substantive, cf. Callender (2000), Dorato (2006), and Savitt (2006a). As I argue in an unpublished essay, however, I believe that these worries can ultimately be dispelled. I wish to thank Steve Savitt for taking me to task on this issue.
- 3.
A foliation slices up the four-dimensional spacetime into space and time via an equivalence relation interpreted as “simultaneity”. A binary relation Rxy is an equivalence relation on a set S iff it is reflexive (for all x ∈ S, Rxx), symmetrical (for all x, y ∈ S, if Rxy, then Ryx), and transitive (for all x, y, z ∈ S, if Rxy and Ryz, then Rxz). Space at a time is then given by the corresponding three-dimensional “folium” and time is the one-dimensional linearly ordered quotient set induced by the equivalence relation, “lining up” the moments of simultaneity.
- 4.
At least standardly; Harrington (2008) has defended a “point present”, a radically solipsistic version of presentism according to which not only temporally present events exist, but also only spatially present ones. For the point presentist, not even all of my present brain exists. Harrington’s position evades the objection raised in this section–but at what price!
- 5.
While this paper focuses on presentism, a possibilist metaphysics defending a growing block or branching tree structure faces analogous challenges from SR. For instance, McCall (2000) maintains the reality of the past and the present, with the future as a branching set of four-dimensional alternatives. The “present” is the first branch surface, which is defined as a maximal set of pairwise spatially separated events. In order to uphold Lorentz invariance, the branch attrition along these surfaces is relativized to inertial frames. In this sense, McCall’s view is the possibilist analogue of Fine’s presentism, presented below.
- 6.
A total order on a set S is given by a binary relation R that is reflexive (Raa for all a in S), weakly antisymmetrical (for all a, b ∈ S, Rab and Rba entails a = b), transitive (for all a, b, c ∈ S, Rab and Rbc entails Rac), and comparable (for any a, b ∈ S, either Rab or Rba). A partial order on a set is a binary relation with the first three properties, but not the last one. Thus, in a partially ordered set, there exist pairs of elements in the set which do not exemplify the relation.
- 7.
For a more basic and detailed rendering, see Savitt (2006b).
- 8.
In a paper entitled “Experience of change and change of experience”, delivered at the University of Geneva on 19 December 2008.
- 9.
Zimmerman, together with a number of present-day presentists, is hard to classify as either compatibilist or incompatibilist as he accepts SR, but not in the role a naturalist usually would. He thinks that SR leaves room for an additional relation of simultaneity not to be found in physics. This relation would only clash with physics if the latter were committed to a principle prohibiting extra relations of this sort, but such a principle, he thinks, would not be warranted. Of course, this relation would still effectively foliate spacetime. Such a foliation could either be observed, or it couldn’t. If the former, Compatibilism would be denied; if the latter, we run into similar problems as the defense championed by Tooley and Craig, which is essentially of that type and shall be discussed below. I thank Jonathan Cohen for having reminded me of this connection.
- 10.
Craig also seems to think that SR is a kinematic theory that only underwrites electrodynamics, and not all or even most of physics. This is simply false. Physicists are working hard to make sure that all theories are Lorentz-invariant. If they fail in doing so, it is generally accepted that their theory faces a major problem.
- 11.
Monton agrees: “the proponent of fixed foliation quantum gravity will agree that there is a preferred frame of reference, and can admit that […] the theory makes sense only in one reference frame.” (ibid., 271)
- 12.
For an authoritative review of experimental tests of Lorentz symmetry, cf. Will (2005a, b); for a recent review on phenomenological indications that Lorentz symmetry may be broken at the Planck scale, cf. Amelino-Camelia (2008).
- 13.
Monton addresses remarks by Gordon Belot and John Earman (2001) that could be framed as an objection to his view. They argue that fixed-foliation approaches to QG have few adherents because “[t]o forsake the conventional reading of general covariance as ruling out the existence of preferred co-ordinate systems is to abandon one of the central tenets of modern physics” (241). Monton disagrees vehemently: He flatly denies that fixed-foliation approaches require a preferred coordinate system. He bases this denial on Kretschmann’s objection to general covariance as a physically contentful constraint on theories. While it is perhaps true that fixed-foliation theories can all be formulated in a generally covariant manner, the objection becomes impotent if general covariance is interpreted in the correct, substantive way, i.e. as a gauge symmetry of GR. Although the particular formulation chosen by Belot and Earman may be unfortunate, their point essentially stands: fixed-foliation theories break the symmetry for which we have excellent reason to believe that every viable theory must respect it.
- 14.
This section is inevitably more technical than the rest of this essay, although an effort is made to provide a self-contained characterization of the approach. For more extensive and rigorous presentations of the approach, consult Beig (1994, 74–77), Fischer and Moncrief (1997), Isenberg (1995), and Rendall (1996). Cf. also Belot and Earman (2001, particularly 239f).
- 15.
Cf. Bartnik (1988) and Rendall (1996).
- 16.
Cf. Smeenk and Wüthrich (2010) for more on non-globally hyperbolic spacetimes.
- 17.
“Essentially” because the space of conformal data must be quotiented out by the action of the group of conformal transformations, as well as by the action of the spatial diffeomorphism group in order for the correspondence to be one-to-one.
- 18.
When he writes that “[t]ypically such a foliation is unique when it exists, but existence is guaranteed only for a limited class of solutions to Einstein’s field equations, a class that does not exhaust solutions with causally nice features” (emphasis added). While I agree with every other part of the statement, I take issue with the first clause’s suggestion that there may be cases where such foliation is not unique, for which I see no warrant in the literature.
- 19.
Although the potential non-uniqueness of CMC foliations would surely undermine such a connection if borne out.
- 20.
Cf. also Belot and Earman (2001, 241).
- 21.
Monton (op. cit., 277) thinks that the presentist can evade the problem of time by simply maintaining that the position does not speak to fundamental reality, but only to time. Thus, if time is emergent rather than fundamental, presentism would be true as long as the emergent time fits the presentist metaphysics. While I acknowledge this possibility, it doesn’t offer an appealing option to the presentist.
- 22.
Monton recognizes this possibility when he offers an alternative move: the presentist could decide to give up scientific, but not metaphysical, realism.
References
Amelino-Camelia, Giovanni, “Quantum gravity phenomenology”, available online at http://arxiv.org/abs/0806.0339 (2008).
Barbour, Julian, The End of Time: The Next Revolution in Physics, Oxford: Oxford University Press (1999).
Bartnik, Robert, “Remarks on cosmological spacetimes and constant mean curvature surface”, Communications in Mathematical Physics 117 (1988): 615–624.
Beig, Robert, “The classical theory of canonical general relativity”, Lecture Notes in Physics 434 (1994): 59–80.
Belot, Gordon and John Earman, “Pre-Socratic quantum gravity”, in Craig Callender and Nick Huggett (eds.), Physics Meets Philosophy at the Planck Scale, Cambridge: Cambridge University Press (2001), 213–255.
Callender, Craig, “Shedding light on time”, Philosophy of Science 67 (2000): S587–S599.
Callender, Craig, “Finding ‘real’ time in quantum mechanics”, in William L Craig and Quentin Smith (eds.), Einstein, Relativity, and Absolute Simultaneity, London: Routledge (2008), 50–72.
Choquet-Bruhat, Yvonne and James W York, “The Cauchy problem”, in Alan Held (ed.), General Relativity and Gravitation: One Hundred Years After the Birth of Albert Einstein, Volume 1, New York: Plenum (1980), 99–172.
Craig, William L, Time and the Metaphysics of Relativity, Dordrecht: Kluwer Academic Publishers (2001).
Dieks, Dennis (ed.), The Ontology of Spacetime, Amsterdam: Elsevier (2006).
Dorato, Mauro, “The irrelevance of the presentist/eternalist debate for the ontology of Minkowski spacetime”, in Dieks (2006), 93–109.
Earman, John, “Reassessing the prospects for a growing block model of the universe”, International Studies in the Philosophy of Science 22 (2008): 135–164.
Fine, Kit, “Tense and reality”, in his Modality and Tense: Philosophical Papers, Oxford: Oxford University Press (2005), 261–320.
Fischer, Arthur E and Vincent Moncrief, “Hamiltonian reduction of Einstein’s equations of general relativity”, Nuclear Physics B (Proc. Suppl.) 57 (1997): 142–161.
Gödel, Kurt, “A remark about the relationship between relativity theory and idealistic philosophy”, in Paul A Schilpp (ed.), Albert Einstein: Philosopher-Scientist, New York: Tudor (1949), 557–562.
Harrington, James, “Special relativity and the future: a defense of the point present”, Studies in History and Philosophy of Modern Physics 39 (2008): 82–101.
Hinchliff, Mark, “The puzzle of change”, Philosophical Perspectives 10 (1996): 119–136.
Isenberg, James, “Constant mean curvature solutions of the Einstein constraint equations on closed manifolds”, Classical and Quantum Gravity 12 (1995): 2249–2274.
Isham, Christopher J, “Conceptual and geometrical problems in quantum gravity”, Lecture Notes in Physics 396 (1991): 123–229.
McCall, Storrs, “QM and STR”, Philosophy of Science 67 (2000): S535–S548.
Monton, Bradley, “Presentism and quantum gravity”, in Dieks (2006), 263–280.
Putnam, Hilary, “Time and physical geometry”, Journal of Philosophy 64 (1967): 240–247.
Rendall, Alan D, “Constant mean curvature foliations in cosmological spacetimes”, Helvetica Physica Acta 69 (1996): 490–500.
Rietdijk, C Wim, “A rigorous proof of determinism derived from the special theory of relativity”, Philosophy of Science 33 (1966): 341–344.
Savitt, Steven F, “Presentism and eternalism in perspective”, in Dieks (2006a), 111–127.
Savitt, Steven, “Being and becoming in modern physics”, in Edward N Zalta (ed.), Stanford Encyclopedia of Philosophy, available online at http://plato.stanford.edu/entries/spacetime-bebecome/ (2006b).
Smeenk, Christopher and Christian Wüthrich, “Time travel and time machines”, in Craig Callender (ed.), The Oxford Handbook of Time, Oxford: Oxford University Press (2010).
Stein, Howard, “On relativity theory and openness of the future”, Philosophy of Science 58 (1991): 147–167.
Tooley, Michael, Time, Tense, & Causation, Oxford: Oxford University Press (1997).
Will, Clifford M, “Was Einstein right? Testing relativity at the centenary”, in Abhay Ashtekar (ed.), 100 Years of Relativity; Space-Time Structure: Einstein and Beyond, Singapore: World Scientific (2005a), 205–227.
Will, Clifford M, “Special relativity: A centenary perspective”, Séminaire Poincaré 1 (2005b): 79–98.
Wüthrich, Christian, “Demarcating presentism”, manuscript (unpublished).
Zimmerman, Dean, “The privileged present: defending an ‘A-theory’ of time”, in Theodore Sider, John Hawthorne, and Dean Zimmerman (eds.), Contemporary Debates in Metaphysics, Malden, MA: Blackwell (2008), 211–225.
Acknowledgements
I am indebted to Craig Callender, Jonathan Cohen, John Earman, Storrs McCall, Bradley Monton, Thomas Müller, Vesselin Petkov, and Steve Savitt for discussions and comments, and audiences in Montreal and Geneva for their engagement with this paper. I also thank Vesselin Petkov for his almost infinite patience with my procrastination. This project has been funded in part by the Swiss National Science Foundation (“Properties and Relations”, 100011-113688), by the University of California, San Diego, and by the Hellman Family Foundation.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2010 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Wüthrich, C. (2010). No Presentism in Quantum Gravity. In: Petkov, V. (eds) Space, Time, and Spacetime. Fundamental Theories of Physics, vol 167. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-13538-5_12
Download citation
DOI: https://doi.org/10.1007/978-3-642-13538-5_12
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-13537-8
Online ISBN: 978-3-642-13538-5
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)