Abstract
What is the relation between material objects and spacetime regions? Supposing that spacetime regions are one sort of substance, there remains the question of whether or not material objects are a second sort of substance. This is the question of dualistic versus monistic substantivalism. I will defend the monistic view. In particular, I will maintain that material objects should be identified with spacetime regions. There is the spacetime manifold, and the fundamental properties are pinned directly to it.
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Notes
Newton is often cast as the arch-substantivalist, but I think that such casting is historically incorrect. Newton explicitly says that space “fits neither substances nor accidents,” not being a substance because it is “not absolute in itself” (Newton 2004, p. 21). When Newton characterizes space as “an affection of every kind of being” (2004, p. 21), he is presumably characterizing space as belonging to Aristotle’s category of affection, for which Aristotle gives the examples “being cut” and “being burned” (Aristotle 1971, p. 4). So for Newton, “being placed” is what happens to something when it comes to be, and space is the totality of such results.
Thus Esfeld and Lam say that in spatiotemporal structure “we get the relata and the relations at once as the internal structure of a whole” (Esfeld and Lam 2008, p. 34), and characterize their view as substantivalist—neutral between dualistic (‘Newtonian’) and monistic (‘Cartesian-Spinozean’) substantivalism, but opposed to (‘Leibnizean’) relationalism (Esfeld and Lam 2008, pp. 42–43).
Though see Barbour 2000 for a recent defense of relationalism. Also see Maudlin (Maudlin 2007, pp. 87–89) for a reply to Barbour which brings out a fourth motivation for substantivalism, namely being able to define distance via length of spatiotemporal path (metrical constraints like the triangle inequality follow from this definition, whereas on Barbour’s approach such constraints must be stipulated independently).
Terminology: monistic substantivalism is also known as “super-substantivalism” (Sklar 1974) and as “Cartesian-Spinozean substantivalism” (Esfeld and Lam 2008, p. 42), inter alia. My usage of “monism” and “dualism” is analogous to the usage in philosophy of mind as to whether mind and body are one sort of substance or two. Monistic substantivalism is not the same view as the doctrine I elsewhere call “priority monism”—though I will be arguing that the two doctrines are connected (§2).
The geometric property view guided the program of geometrodynamics in physics (Wheeler 1962). Geometrodynamics is now widely acknowledged to be empirically inadequate.
Thus van Inwagen’s (dualistic) formulation of the doctrine of arbitrary undetached parts runs as follows: “For every material object M, if R is the region of space occupied by M at time t, and if sub-R is any occupiable sub-region of R whatever, there exists a material object that occupies the region sub-R at t” (van Inwagen 1981, p. 123). Here it is presupposed that arbitrary sub-regions exist, and only questioned as to whether they always contain material objects.
Handedness is another holistic feature. Whether a right-handed and left-handed glove can be superimposed by rigid motion depends, as Nerlich notes, “on the dimensionality or the orientability, but in any case on some aspect of the overall connectedness or topology of the space” (1994, p. 53).
Historically, the priority of the whole of space to its parts was affirmed by Descartes (c.f. Carriero 2002, p. 53), Spinoza (c.f. Bennett 1984, p. 86), Leibniz (c.f. Adams 1994, pp. 232–234; Earman 1989, p. 16), and Kant, inter alia. For instance, Kant spoke of space as “essentially one,” arguing that “these parts cannot precede the one all-embracing space, as being, as it were, constituents out of which it can be composed; on the contrary, they can be thought only as in it.” (1965, p. 69). Indeed, Kant explicitly maintained that if space and time were not ideal but real, then Spinozistic monism would follow immediately:
[I]f this ideality of time and space is not adopted, nothing remains but Spinozism, in which space and time are essential attributes of the Supreme Being Himself, and the things dependent on Him (ourselves, therefore, included) are not substances, but merely accidents inhering in Him;…” (1996, pp. 124–125).
The parsimony argument is far and away the most popular in the literature. Thus Quine decries: “a redundant ontology containing both physical objects and place-times” (1981, p. 17), Lewis opposes “the dualist conception as uneconomical” (1986, p. 76), and Sider warns that we should not “gratuitously add a category of entities to our ontology,” and adds that given substantivalism “The identification of spatiotemporal objects with the regions is just crying out to be made” (2001, p. 110).
The dualist could also run the reply in reverse, and say that it is the material objects that have the geometrical and mereological properties intrinsically, and the spacetime regions inherit these properties from the material objects they contain. But this seems to strip the spacetime regions of much of what makes them spatiotemporal. Also, if the dualist wants to speak of unoccupied spacetime regions (§4) this will prevent her from assigning geometrical and mereological properties to her unoccupied regions (or else she will need to speak of the material objects that can occupy regions, making the geometry and mereology of regions into a modal property). So it seems best for the dualist to take spacetime regions rather than material objects as having the geometrical and mereological properties intrinsically, though nothing in the main text will turn on this.
I take it that the sort of conceivability involved is negative conceivability, in the sense that one can intellectually consider the scenario of there being an extended simple and not find any immediate contradiction lurking. Extended simples are not positively conceivable, in the sense of being visually imaginable. One can try to visually imagine an extended simple sphere, but it will not look any different from an extended composite sphere! In any case the monist will view the conceivability as non-ideal, being based on a conceptual distinction that she thinks should be erased. (See Chalmers 2002 for further discussion of conceivability.).
Elsewhere Einstein says: “We may therefore regard matter as being constituted by the regions of space in which the field is extremely intense… There is no place in this new kind of physics for both the field and matter, for the field is the only reality” (quoted in Capek 1961, p. 319).
Elsewhere Earman puts the point as follows: “In a modern, pure field-theoretic physics, M functions as the basic substance, that is, the basic object of predication.” (1989, p. 155).
There is controversy as to whether the spacetime manifold should be identified with M (Earman 1989, Norton 2004) or with M plus g (Maudlin 1993, Hoefer 1996). The argument of the main text is neutral here, and solely turns on the ontological status of T, which everyone in the debate understands as a feature of the spacetime. As Hoefer notes:
Mathematically, the matter field contents could also be thought of as ‘properties’ of space-time points—a perspective that seems to embody a kind of ‘supersubstantivalism,’ in that space-time (or its points) are the only real substances in existence. (1996, p. 13).
Here is another passage from d’Espagnat, on the field theoretic basis for ‘particles’:
In quantum field theory, reality lies at a deeper level than could be imagined by common sense or even by elementary quantum mechanics. A particle is not itself ‘a reality’; it is simply a more or less transient property of reality, a level of excitation (to speak as physicists do)… of reality, excited in a fashion corresponding to the field in question. (1983, p. 85).
In this vein Skow provides the following suggestion on behalf of the monistic substantivalist: “say that material objects differ from other regions of spacetime in their accidental properties—like, for example, mass and charge” (2005, p. 9). Robinson proposes a generalization of this view on which material objects are regions infused with “properties that propagate” (1982, p. 341).
Thanks to Phillip Bricker, Hud Hudson, Jim Kreines, Josh Parsons, Louis de Rosset, Denis Robinson, Ted Sider, Brad Skow, and audiences at Mereology, Topology, and Location (Rutgers), the History and Philosophy of Science group at Leeds, the AAP-NZ, the Australian National University, and Virginia Commonwealth University.
References
Adams, R. M. (1994). Leibniz: Determinist theist idealist. New York: Oxford University Press.
Alexander, S. (1950). Space, time, and deity: The Gifford lectures at Glasgow 1916–1918, Vol. 1. New York: The Humanities Press.
Aristotle (1971). In J. Barnes (Ed.), The complete works of Aristotle (Vol. 1). Princeton University Press, Princeton.
Armstrong, D. M. (1978). Nominalism and realism: Universals and scientific realism (Vol. 1). Cambridge: Cambridge University Press.
Barbour, J. (2000). The end of time: The next revolution in physics. Oxford: Oxford University Press.
Bell, E. T. (1951). Mathematics: Queen and servant of science. Mathematical Association of America, New York.
Bennett, J. (1984). A study of spinoza’s ethics. Indianapolis: Hackett Publishing Company.
Bricker, P. (1993). The fabric of space: Intrinsic vs. extrinsic distance relations. Midwest Studies in Philosophy, 18, 271–294.
Capek, M. (1961). The philosophical impact of contemporary physics. New York: Van Nostrand Reinhold.
Carriero, J. (2002). Monism in Spinoza. In O. Koistinen & J. Biro (Eds.), Spinoza: Metaphysical themes (pp. 38–59). Oxford: Oxford University Press.
Chalmers, D. (2002). Does conceivability entail possibility? In T. Szabo Gendler & J. Hawthorne (Eds.), Conceivability and possibility (pp. 145–200). Oxford: Oxford Univerity Press.
d’Espagnat, B. (1983). In search of reality. New York: Springer-Verlag.
Descartes, R. (1985). The philosophical writings of descartes (Vol. I) (J. Cottingham, R. Stoothoff & D. Murdoch, Trans.). Cambridge: Cambridge University Press.
Earman, J. (1989). World enough and spacetime. Cambridge: MIT Press.
Einstein, A. (1934). The world as i see it. New York: Covici-Friede Press.
Esfeld, M., & Lam, V. (2008). Moderate structural realism about space-time. Synthese, 160, 27–46.
Field, H. (1984). Can we dispense with space-time? In PSA 1984 Proceedings of the Biennial Meeting of the Philosophy of Science Association (Vol. 2, pp. 33–90). East Lansing, MI: Philosophy of Science Association.
Field, H. (1992). Physicalism. In J. Earman (Ed.), Inference, explanation and other frustrations: Essays in the philosophy of science (pp. 271–291). Los Angels: University of California Press.
Halvorson, H., & Clifton, R. (2002). No place for particles in relativistic quantum theories? Philosophy of Science, 69, 1–28.
Hobbes, T. (1839). De Corpore. In W. Molesworth (Ed.), The english works of Thomas Hobbes of Malmesbury v.1. London: John Bohn.
Hoefer, C. (1996). The metaphysics of space-time substantivalism. Philosophy of Science, 93, 5–27.
Hudson, H. (2006). The metaphysics of hyperspace. Oxford: Oxford University Press.
Kant, I. (1965). Critique of pure reason (N. K. Smith, Trans.). New York: St. Martin’s Press.
Kant, I. (1996). Critique of Practical Reason (T. Kingsmill, Trans.). New York: Abbott Prometheus Books.
Kuhlmann, M. (2006). Quantum field theory. Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/quantum-field-theory/.
Lewis, D. (1971). Counterparts of persons and their bodies. The Journal of Philosophy, 68, 203–211.
Lewis, D. (1986). On the plurality of worlds. Oxford: Basil Blackwell.
Locke, J. (1996). In K. P. Winkler (Ed.), An essay concerning human understanding. Indianapolis: Hackett Publishing.
Malcolm, N. (2002). Aspects of hobbes. Oxford: Oxford University Press.
Markosian, N. (2000). What are physical objects? Philosophy and Phenomenological Research, 61, 375–395.
Maudlin, T. (1989). The essence of space-time. In Proceedings of the 1988 Biennial Meeting of the Philosophy of Science Association (Vol. 2, pp. 82–91).
Maudlin, T. (1993). Buckets of water and waves of space: Why space-time is probably a substance. Philosophy of Science, 60, 183–203.
Maudlin, T. (2007). Suggestions from Physics for Deep Metaphysics. In T. Maudlin (Ed.), The metaphysics within physics (pp. 78–103). Oxfor: Oxford University Press.
McDaniel, K. (2004). Modal realism without overlap. Australasian Journal of Philosophy, 82, 137–152.
Nerlich, G. (1994). The shape of space. Cambridge: Cambridge University Press.
Newton, I. (2004). De Gravitatione. In A. Janiak (Ed.), Isaac Newton: Philosophical writings. Cambridge: Cambridge University Press.
Norton, J. (2004). The hole argument, Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/spacetime-holearg/.
Quine, W. V. O. (1981). Things and their place in theories. In W. V. Quine (Ed.), Theories and things (pp. 1–23). Cambridge: Harvard University Press .
Redhead, M. (1995). More ado about nothing. Foundations of Physics, 25, 123–137.
Robinson, D. (1982). Re-identifying matter. The Philosophical Review, 91, 317–341.
Schaffer, J. (2007). Monism, Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/monism/.
Schaffer, J. Monism: The priority of the whole, The Philosophical Review (forthcoming).
Sider, T. (2001). Four-dimensionalism: An ontology of persistence and time. Oxford: Oxford University Press.
Sklar, L. (1974). Space, time and spacetime. CA, USA: University of California Press.
Skow, B. (2005). Supersubstantivalism. In once upon a spacetime. Dissertation, New York University.
Spinoza, B. (1985). The collected works of Spinoza (E. Curley, Ed., Trans.). Princeton: Princeton University Press.
van Inwagen, P. (1981). The doctrine of arbitrary undetached parts. Pacific Philosophical Quarterly, 62, 13–37.
Weinberg, S. (1987). Towards the final laws of physics. In S. Weinberg & R. Feynman (Eds.), Elementary particles and the laws of physics: The 1986 dirac memorial lectures (pp. 61–110). Cambridge: Cambridge University Press.
Wheeler, J. (1962). Geometrodynamics. New York: Academic Press.
Zeh, H. D. (2003). There is no first quantization. Physics Letters, A309, 329–334.
Zeyl, D. (2005). Plato’s Timaeus, Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/plato-timaeus/.
Zimmerman, D. (1996). Could extended objects be made out of simple parts? An argument for ‘atomless gunk’. Philosophy and Phenomenological Research, 56, 1–29.
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Schaffer, J. Spacetime the one substance. Philos Stud 145, 131–148 (2009). https://doi.org/10.1007/s11098-009-9386-6
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DOI: https://doi.org/10.1007/s11098-009-9386-6