¹ There are some notable exceptions. See, for example, Elder, Crawford L., Real Natures and Familiar Objects (Cambridge, MA: MIT Press, 2004)Google Scholar; Thomasson, Amie L., Fiction and Metaphysics (Cambridge: Cambridge University Press, 1998)CrossRefGoogle Scholar and Ordinary Objects (Oxford: Oxford University Press, forthcoming); and Rea, Michael C., ‘Sameness Without Identity: An Aristotelian Solution to the Problem of Material Constitution,’ Ratio 11 (new series),1998: 316–328CrossRefGoogle Scholar. Some aspects of his Naming and Necessity (Cambridge, MA: Harvard University Press, 1972) suggest that Saul Kripke would also be sympathetic, but he is so cautious in his commitments that I hesitate to claim him as an ally.

² http://www.floria-publications.com/italy/italian_culture/the_bonfire_of_the_vanities.html. Accessed December 17, 2006.

³ Lutes were in use before 1497. Lutes are represented in The Nativity by Piero della Francesco in 1470.

⁴ van Inwagen, Peter (Material Beings (Ithaca, NY: Cornell University Press, 1990)) is an eliminativist with respect to inanimate objectsGoogle Scholar.

⁵ Lewis, David (Parts of Classes (Oxford: Basil Blackwell, 1991)) was a four-dimensionalist reductionistGoogle Scholar. Chisholm, Roderick (Person and Object (LaSalle, IL: Open Court Publishing Company, 1976)) was a three-dimensionalist who was a reductionist with respect to inanimate objectsGoogle Scholar.

⁶ Phillip Bricker was helpful in discussing three- and four-dimensionalism.

⁷ So, a three dimensionalist who rejects nonreductionism should turn to eliminativism, and say that, ontologically speaking, there are no lutes, just particles-arranged-lutewise. By contrast, four-dimensionalists can say that there are lutes, and that a lute is identical to particles-arranged-lutewise. On four dimensionalism, particles-arranged-in-way1 and particles-arranged-in-way2 are distinct objects, because difference in arrangement implies difference in time. And on four dimensionalism, particles existing at different times (i.e., particles that are parts of the same spacetime worm) are different objects (different temporal parts).

⁸ Another example: Consider the pieces of a jigsaw puzzle in the box, and the same pieces assembled to be a picture. If there is an ontological difference, then the picture is not reducible to the pieces.

⁹ In Chapter Ten of The Metaphysics of Everyday Life: An Essay in Practical Realism (Cambridge: Cambridge University Press, 2007), I have a detailed argument against Theodore Sider's four-dimensionalism.

¹⁰ There is no ontological difference between reductionists and eliminativists on a natural interpretation of the assumption that mereology is, as Lewis says, ‘ontologically innocent.’ It is reasonable to interpret the assertion that mereology is ontologically innocent to imply that the existence of parts is wholly sufficient for the existence of their sums. Parts of Classes (Oxford: Basil Blackwell, 1991): 81.

¹¹ Some eliminativists would not even take the sentence ‘there are lutes’ to be true. E.g., Trenton Merricks takes ‘chairs exist’ to be false, but introduces the term ‘nearly as good as true’ for false statements that Fs exist if there are things arranged F-wise. Merricks, Trenton, Objects and Persons (Oxford: Clarendon Press, 2001): 170–1CrossRefGoogle Scholar.

¹² cf. van Inwagen, Peter, Material Beings (Ithaca, NY: Cornell University Press, 1990): 109Google Scholar.

¹³ A number of prominent philosophers in recent years have endorsed some form of constitution-without-identity. The following are just a sample: Doepke, Frederick C., ‘Spatially Coinciding Objects,’ Ratio XXIV, (1982): 45–60Google Scholar; Lowe, E.J., “Instantiation, Identity and Constitution,” Philosophical Studies 44 (1983): 45–59CrossRefGoogle Scholar; Thomson, Judith Jarvis, ‘The Statue and the Clay,’ Noûs 32 (1998): 149–173CrossRefGoogle Scholar; Koslicki, Kathryn, ‘Constitution and Similarity,’ Philosophical Studies 117 (2004): 327–364CrossRefGoogle Scholar; Yablo, Stephen, ‘Identity, Essence and Indiscernibility,’ Philosophical Review 104 (1987): 293–314Google Scholar; Rea, Michael C., ‘Sameness Without Identity: An Aristotelian Solution to the Problem of Material Constitution,’ Ratio (new series) XI (1998): 316–328CrossRefGoogle Scholar; Johnston, Mark, ‘Constitution is Not Identity,’ Mind 101 (1992): 89–105CrossRefGoogle Scholar; Oderberg, David, ‘Coincidence Under a Sortal,’ Philosophical Review 105 (1996): 145–171CrossRefGoogle Scholar; Sosa, Ernest, ‘Subjects Among Other Things,’ in Material Constitution, Rea, Michael C., ed. (Lanham, MD: Rowman and Littlefield, 1997: 63–89Google Scholar; Burke, Michael B., ‘Preserving the Principle of One Object to a Place: A Novel Account of the Relations Among Objects, Sorts, Sortals and Persistence Conditions,’ Philosophy and Phenomenological Research 54 (1994): 591–624CrossRefGoogle Scholar; Simons, Peter, Parts: A Study in Ontology (Oxford: Clarendon Press, 1987)Google Scholar; Wiggins, David, ‘On Being in the Same Place at the Same Time,’ Philosophical Review 77 (1968): 90–95CrossRefGoogle Scholar. My construal of constitution differs from those of all the above.

¹⁴ For a discussion of whether or not spatial coincidence, when joined with the causal efficacy of ordinary things, leads to intolerable causal overdetermination, see Chapter Five of The Metaphysics of Everyday Life.

¹⁵ For detailed discussion, see Chapter Eight of The Metaphysics of Everyday Life.

¹⁶ To borrow some paraphrases about essential properties from Chisholm, if x has the property of being a horse essentially, then ‘x is such that, if it were not a horse, it would not exist’; or ‘God couldn't have created x without making it such that it is a horse’; or ‘x is such that in every possible world in which it exists it is a horse.’ Chisholm, Roderick, Person and Object, (LaSalle, Il: Open Court Publishing Company, 1976): 25–6Google Scholar.

¹⁷ See Wasserman's, Ryan ‘The Constitution Question,’ Noûs 38 (2004): 693–710CrossRefGoogle Scholar.

¹⁸ Many properties (unrelated to this discussion) may be had essentially by some things and nonessentially by other things. A planet has the property of having a closed orbit essentially; a comet that has a closed orbit has that property nonessentially. (This assumes that planets are planets essentially; otherwise it is only a de dicto necessity that planets have closed orbits.)

¹⁹ It is a profound error to take a distinction between what is mind-independent and what is mind-dependent as foundational for metaphysics. See The Metaphysics of Everyday Life, Chapter One.

²⁰ Atoms of these kinds make up amino acid molecules. See http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html (accessed March 1, 2007).

²¹ For greater detail, see Persons and Bodies. See also the Book Symposium on Persons and Bodies in Philosophy and Phenomenological Research 64 (2002): 592–635, and my ‘On Making Things Up: Constitution and its Critics,’ Philosophical Topics: Identity and Individuation 30 (2002): 31–51.

²² See The Metaphysics of Everyday Life, Chapter Six. Earlier versions appear in my Persons and Bodies (Cambridge: Cambridge University Press, 2000), and in ‘On Making Things Up’, op.cit.

²³ I later define parthood—ordinary parthood—in terms of constitution as well as of mereology. So, the property of having part P at t is excluded since it is defined in terms of constitution. The property of having P as a part at t may not be had derivatively.

²⁴ For an account of counting, based on Aristotle's notion of accidental sameness, congenial to constitution-without-identity, see Brower, Jeffrey E. and Rea, Michael C., ‘Material Constitution and the Trinity,’ Faith and Philosophy 22 (2005): 57–76CrossRefGoogle Scholar. Brower and Rea's construal of constitution is significantly different from mine. They take constitution to be a mereological notion; I do not. I take sameness of parts at a time to follow from constitution, not to be constitutive of the idea of constitution itself.

²⁵ Typically, philosophers who appeal to constitution (e.g., Michael Rea) take constitution to be a mereological concept, defined in terms of sameness of parts. By contrast, ‘constitution’ as I use it is not a mereological concept. Indeed, as we shall see, I use the idea of constitution to define part at t of ordinary things.

²⁶ For a classical statement of mereology, see Goodman, Nelson and Leonard, Henry, ‘The Calculus of Individuals and Its Uses,’ Journal of Symbolic Logic 5 (1940): 40–55Google Scholar.

²⁷ See Chisholm's, RoderickPerson and Object (LaSalle Ill., Open Court Publishing Company, 1976).Google Scholar

²⁸ See Inwagen's, Peter van ‘Can Mereological Sums Change their Parts?’ (Journal of Philosophy 103 (2006): 614–630)CrossRefGoogle Scholar. The only sums that van Inwagen countenances are living organisms.

²⁹ See Lewis's, DavidParts of Classes (Oxford: Basil Blackwell, 1991)Google Scholar.

³⁰ For example, on van Inwagen's account, sum A (the sum of your parts at t) and sum B (the sum of your parts at t') are identical even if none of the atoms in A is also in B.

³¹ The basic ontology of four-dimensionalism consists only of instantaneous spacetime “objects” and their sums, a few of which we select for attention. But there is no metaphysical difference between ordinary objects (putatively, the sums that we recognize) and arbitrary sums.

³² More formally: y is a sum of the xs = _df ∀z(z is one of the xs → z is a part of y) & ∀z[(z is part of y → ∃ w(w is one of the xs and z overlaps w)].

³³ Since ‘part’ is used in many ways—‘part of the problem,' ‘part of the curriculum,’ ‘part of being a girl’—(P) is not a complete definition of the ordinary word ‘part’. Notice, however, that ‘part’ is never used in English to denote ‘improper part’; the word ‘part’ is always used in contrast to some whole.

³⁴ Note that there is no property denoted by ‘the property of having a part derivatively.’

³⁵ See Zimmerman, Dean W., ‘The Constitution of Persons by Bodies: A Critique of Lynne Rudder Baker's Theory of Material Constitution,’ Philosophical Topics 30 (2002): 295–338CrossRefGoogle Scholar.

³⁶ If parthood were transitive, then we should be able to derive ‘x is part of z at t’ from ‘x is part of y at t’ and ‘y is part of z at t’. But because there is an existential quantifier in each premise and in the conclusion, (P) does not allow the derivation. We should have to derive ‘∃w₃(x ≠ w₃ & x < w₃ & Cw₃zt)’ from ‘∃w₁(x ≠ w₁ & x < w₁ & Cw₁yt’ and ‘∃w₂(y ≠ w₂ & y < w₂ & Cw₂zt)’, where the ‘w's’ are assigned different sums in each of the three statements. Although I do not believe that ‘x is part of z at t’ can be derived from ‘x is part of y at t’ and ‘y is part of z at’, I cannot think of any examples in which the premises are true and the conclusion is false.

³⁷ But, again, the sum of the top and four legs that constitutes the table is not part of the table, according to (P).

³⁸ There are other ways to reconcile constitution with mereology. E.g., one may take atoms to have two sums at one time. See Peter van Inwagen's review of Persons and Bodies in The Philosophical Review 111 (2002): 138–141. (This suggestion is as implausible to me as it is to van Inwagen.)

³⁹ Lewis, Parts of Classes, pp. 81–2.

⁴⁰ I am still assuming the necessity of identity (and no counterparts).

⁴¹ Combining the idea of constitution with mereological ideas yields an analogue of the venerable distinction between aggregates and ‘substances’ (full-fledged objects) that philosophers like Aristotle and Leibniz insisted upon, and that David Lewis and others have no ontological room for.

⁴² There may or may not be a fundamental level, a stopping point. See Jonathan Schaffer, ‘Is There a Fundamental Level?’ Noûs 37: 498–517. Since the Constitution View is not reductionistic, it is a matter of indifference whether there is a fundamental level or not.

⁴³ Roderick Chisholm, who took genuine objects (entia per se) to conform to mereological essentialism, would construe my table merely as a succession of objects. As far as I can tell, he never raises the question of how I can re-identify my table over time if it is only a succession of underlying objects. See Chisholm, Roderick M., Person and Object (LaSalle, Ill: Open Court Publishing Co., 1976), 98–104Google Scholar.

⁴⁴ This way of putting the point was suggested to me by Gary Matthews, who notes that the suggestion is just Aristotle's in modern dress.

⁴⁵ cf. Lewis, David, ‘Many, But Almost One’ in Papers in Metaphysics and Epistemology (Cambridge: Cambridge University Press, 1999): 164–182CrossRefGoogle Scholar.

⁴⁶ I am very grateful to Gareth B. Matthews and to Edmund L. Gettier for much help with the ideas expressed here.