We find it hard to believe that incars or outcars are really there, but do we have a good reason for thinking so? Aren't the persistence conditions we assign to natural formations and artifacts just as arbitrary and conventional as the conditions used by Hirschians? A simple solution is to deny the existence of all inconstant objects, cars and incars alike.
A TRUTHMAKER OBJECTION As we argued in Section 23.4, Mereological Inconstancy raises truthmaker worries. If A is mereologically inconstant, and B is a part of A, then what is the truthmaker for the truth of B's being a part of A? It can't be A itself, since A can exist without including B as a part. Could it be B? Only if B is a rigid part (Def D23.6) of A, something that couldn't exist without being a part of A. How could that happen? If neither A nor B is a truthmaker for the mereological truth, what is?
25.1.3 Responses to the objections
We'll break down the defense of inconstant objects into three parts: the defense of organisms, the defense of artifacts, and the defense of natural formations, like rivers and rocks. Finally, we will look at a second way of defending all inconstant objects through embracing ontological plenitude.
25.1.3.1 In defense of organisms: emergent powers and the unity of lives.
There are at least two ways one might respond to these problems with respect to organisms. One view is that living organisms possess emergent and essentially unitary powers (cf. Section 22.6). The persistence of an organism must then be a metaphysically fundamental fact, since it is the basis for the persistence of the emergent and unitary powers. If an organism did not survive, its powers would not survive, and the world would be different at a fundamental level. The second view is that biological lives are fundamental entities and that the persistence of the life of a given organism grounds the persistence of that organism itself. These fundamental facts about powers or lives provide an answer to each of the paradoxes. (We ignore the possibility of intermittent existence, since it just seems impossible for organisms to exist intermittently.)
1. The ship of Theseus. If a human being were reconstructed from the sloughed off parts of a human being, then the reconstructed human being would not be the same as the continuously existing human. What enables a human to survive is the continuous survival of either the emergent powers of human life or the life itself, not the persistence of the same parts.
2. Tib and Tibbles. Since what provides unity to a composite object are its unitary powers or its biological life, one can deny that there is any such fundamental thing as Tib prior to Tibbles's losing its leg. Fundamentally speaking, there is no such thing as Tib before the amputation or Tibbles after the amputation, where these are thought of as mere collections of atoms, since neither collection of atoms corresponds to a single, unified process of rabbit-life. Tib corresponds to only part of the rabbit's life before the amputation, and Tibbles includes atoms that are separated from the rabbit's life after the amputation. Thus the puzzles about the identity of Tib and Tibbles do not arise.
3. The Kafka Paradox. There will be some point at which the removal of a particle fatally disrupts the persistence of the powers essential to the human life or the life itself. At that point, one organism is destroyed, with the possibility that a new organism, with a new set of powers, is generated. There may be no way to know at what point a life will or does end, but that does not preclude there being a metaphysical fact of the matter. It is that metaphysical fact that is important here.
4. Fission and fusion. Like with the Kafka Paradox, in cases of fission or fusion, the fundamental facts about the persistence of emergent powers or biological lives will settle the question of whether the original person has survived, and if so, whether he has survived as Beta or Gamma. We may not always be able to tell whether it is Beta or Gamma or neither that is identical to Alpha, but there will nonetheless always be an answer. The answer will depend on how to explain the emergent powers or the lives of Beta and Gamma. In at most one of these cases can we explain the existence of the fission-product's emergent powers or life in terms of the persistence of Alpha's emergent powers or its life. For Alpha to persist is for it to persist with its essential powers or its life. Hence, persistence can be used to provide a metaphysical explanation for the presence of those same powers or that same life in the later entity. The kind of explanation involved is not explanation in terms of causes or the laws of nature but metaphysical explanation: giving the ultimate ground or truthmaker for the humanity of Beta or Gamma. Since it is metaphysically impossible for Alpha to persist as both Beta and Gamma, it is impossible for the persistence of Alpha to be the truthmaker or the metaphysical ground for the presence of the essentially human bundle of powers or essentially human life in both Beta and Gamma. The persistence of Alpha might ground the existence of one or the other or it might ground neither of them. In the first case, Alpha would be identical to one and not the other, and in the second case it would be identical with neither one.
Of course, this sort of solution to the problem of mereologically inconstant organisms depends upon a claim that could, in principle, be falsified by future biochemical and biophysical research, namely, the claim that there are genuinely emergent and essentially unitary powers (both active and passive) to be found at the biological level (see Section 22.6 for further discussion of this issue).
EXOTIC OBJECTS AND VAGUE IDENTITY Exotic objects and vague identity are no threat, since in neither of these cases do we have the survival of any emergent powers or of the same biological life.
25.1.3.2 In defense of artifacts: the continuous history theory.
One account of the persistence and unity of an artifact exploits certain practices of use and maintenance. For example, if a watch persists, it is because there is a certain ongoing history of use of the watch as a watch and of maintenance of the watch as a watch. Let's suppose that these social processes or practices have a kind of unity through time, that the process as a whole is metaphysically fundamental, not the various instantaneous events that make up the process. The maintenance and use of a single, persisting watch is greater than the sum of its constituent events of watch-use and watch-repair. If that is so, then the metaphysical unity of the process over time can be used to ground the persistence of the artifact. This is the “Continuous History Theory” of artifactual persistence.
1. The ship of Theseus. Let's call the ship that has been in continuous operation ‘Theseus-A’, and the ship that is reconstructed from the abandoned planks ‘Theseus-B’. The Continuous History Theory entails that it is Theseus-A and not Theseus-B that is identical to the ship as originally built. Theseus-A is associated with a continuous process of nautical use and maintenance, which is not the case with Theseus-B. When the abandoned planks are put together into a ship, a new ship is created because a new practice of use and maintenance is initiated.
2. Tib and Tibbles. There can be cases like Tib and Tibbles for artifacts. Consider, for example, a desk (the analogue of Tibbles) and a desk minus some small part of its top (the analogue of Tib). Plausibly, the desk minus some small part of its top is not what is being used as a desk. The whole desk is used as a desk. Thus, one can deny that there is any such thing as the desk minus some small part of its top, prior to that chunk of the top being separated from the desk itself. Given this, the puzzles about the identity of desk and desk minus do not arise.
3. The Kafka Paradox. Each kind of artifact has its own sort of associated process. The essential characteristics of the artifact are mirrored by essential characteristics of the process of use. In a Kafka-like paradox for artifacts, if at some point in the transformation this process of use is fatally disrupted, the artifact ceases to be (with the possibility that a new artifact is created).
4. Fission and fusion. This is perhaps the most difficult case for the Continuous History Theory. We would have a simple answer if we could say that the relevant processes of use can themselves never be divided or fused together, but an opponent might object that we have no princi
pled reason for saying so. The answer would have to be that it is essential to the processes involved that they remain focused on a single system, and it is also essential to them that they cannot be merged with any other process without being disrupted. Whenever that focus is lost or another process is brought into a complete intersection, the original process is brought to a halt, and the artifact is destroyed.
ARTIFACTS AND VAGUE IDENTITY We might here take the view that vagueness is merely a reflection of our ignorance. If we understood all there was to know about the processes of use and maintenance that are involved, we might always know the right thing to say about whether the artifact, like the restaurant Bookbinders, persists or not. Alternatively, we might suppose that the vagueness is ontological. Maybe restaurants are simply vague objects, sometimes indeterminate in existence or in identity.
ARTIFACTS AND CONVENTIONALITY The artifactual objects that exist do depend on our concepts and conventions, since those concepts and conventions shape our practices, and it is our practices that are the ground of persistence for artifacts. However, there may be natural limits to the kind of social practices that can exist. It is hard to imagine a set of social practices that would really die out or begin to exist simply by driving a car out of or into a garage. A car just isn't the sort of thing that can be built or maintained in that way.
There is an obvious objection that could be raised to the Continuous History Theory: doesn't it simply push the problem of persistence back a step? What is the principle that unifies the various spatial and temporal parts of a single practice of use and maintenance? Don't such practices simply correspond to myriads of overlapping microphysical processes, with no sharp boundaries in time or space?
These are deep questions, but the defenders of artifacts might well claim that social practices, including the practice of using and maintaining a particular artifact like a car or a watch, have emergent and strongly unitary powers, just as do living and sentient organisms. It certainly isn't obvious that all of the powers of such social practices are wholly grounded (without remainder) in a host of chemical and microphysical processes.
25.1.3.3 In defense of natural formations: the anthropocentric theory and natural processes.
It is much harder to find a principled answer to the puzzles about the persistence of natural formations. This is one of the reasons that Heraclitus's paradoxical claim that one cannot step twice into the same river continues to resonate with us so many thousands of years later.
One possibility would be to give an anthropocentric account. Natural formations sometimes become part of our human practices in such a way that we can think of them as something like artifacts. Take the stars for example. The visible stars, organized into constellations, have played an important role in human life for thousands of years. We could ground the persistence conditions of stars in those practices of use. This would mean that a star that ceases to be visible, say by turning into a red giant or a neutron star, would really cease to exist as a persisting whole. Similarly, rivers would only come into existence once they have been discovered by us and incorporated into our practices, by way of becoming a means of transportation or a border marker. This approach clearly has its limitations. For one thing, it would preserve only a fraction of our ordinary beliefs about formations as persisting things. It would also have some odd consequences: for example, it would mean that stars and planets first come into existence (as fundamental entities) only when they are discovered and used in some way by human astronomers. An uninhabited planet might have large quantities of water on its surface, but it couldn't have oceans, lakes, or rivers without intelligent agents that make use of them.
A second account of natural formations would avoid these counterintuitive consequences of the anthropocentric theory. On the alternative account, the persistence of a natural formation depends on the metaphysical unity of some underlying natural process. For example, the existence of a normal star is constituted by a single, nearly continuous process of gravity-induced nuclear fusion at its core. Similarly, a river consists of a continuous process of the flow of liquid water. If these astronomological, hydrological, and geological processes have a real unity, then the diachronic unity of the formations can be parasitic on the unity of the underlying process, as organisms depend for their unity on the unity of their lives and artifacts on the unity of processes of maintenance and use.
The greatest challenge to this account comes from the plausibility of microphysicalism. Are there really any macrophysical processes, like astronomical or geological processes, over and above the constitutive microphysical interactions? If the macrophysical processes supervene entirely on the activities and interactions of microparticles, then Ockham's Razor (PMeth 1) provides grounds for denying the real or fundamental existence of macrophysical processes. And without real or fundamental macrophysical processes, we can't ground the persistence of macrophysical formations.
25.1.3.4 Another sort of defense: Plenitudinous answers.
As we have seen, Physicalists or reductive materialists—those who believe that all fundamental powers are microphysical powers—have good reason to reject the theories we've offered on behalf of inconstant objects. Such physicalists face a choice. They must either deny that any inconstant objects are fundamental or offer a different sort of solution to the puzzles.
In search of a new sort of solution, we could return to Temporal Plenitude (24.3T.1). On this view, every spacetime worm corresponds to some kind of persisting thing. As we saw, most of these worms do not correspond to quality or dynamically first-class objects, but we already have learned that mereologically inconstant things, if they exist at all, are not quality objects. Temporal Plenitude populates the world with a very large number of complex, mereologically inconstant things. Each time-slice of any one of these things is shared by an innumerable multitude of temporally coincident objects, as the many different spacetime worms converge upon and diverge from that instantaneous object. Temporal Plenitude therefore implies Temporal Coincidence (24.4A).
On this view, RCK is not a single living organism with a single living body. Instead, he has trillions of mostly coincident human bodies, some older, some younger, some destined to live a long time, some ending at the present moment. If we allow discontinuous worms to correspond to living bodies, then there is an organism with RCK's past and present and THP's future, and another one with the temporal parts reversed.
It is pretty easy to see how Temporal Plenitude dissolves all of the puzzles. The ship of Theseus was really two ships to begin with, Theseus-A and Theseus-B. These two ships are spatially co-located at the beginning of the story and eventually become separated. The rabbit is in fact many rabbity-things, Tib and Tibbles included. When the leg is amputated, Tibbles is destroyed but Tib continues living. As Kafka is transformed into a cockroach, we see a large number of temporally overlapping organisms come and go. At first, Kafka is only human, and at some point we have both a human being and something sub-human that perfectly coincide. Eventually, the human being ceases to exist and only sub-human things are left, until eventually only cockroachy things remain.
In the case of fission, the original human being was really two temporally overlapping human beings all along. Both Beta and Gamma were in existence right from the start, and the two were never strictly identical to each other, since each one was destined to have a different future. The same story can be run in reverse in the case of fusion: both Alpha and Beta continue to exist after the fusion and they remain distinct from one another, even though they come to share the same time-slices.
In the case of vague identity, we can say that each artifact is actually a host of distinct artifacts, each with slightly different persistence conditions. We can say that this Bookbinders restaurant is the same as that one, or we can say that they are different. In both cases we will be right because there are more than three restaurants involved: one that is located in both places at different times, and two more that are each located in only one
place. The vagueness affects only our use of the name ‘Bookbinders’, a name we can legitimately apply to any of the relevant restaurants. We can use the same name to refer to different restaurants on different occasions without any danger of confusion, so long as the many restaurants involved all perfectly coincide during the relevant period of time.
Finally, exotic objects are no problem: they all exist! All of them and more, ones we can imagine and ones that are so complex and weird that we could never imagine them.
25.2 Coincident Things
As we have seen, by adopting Temporal Plenitude and Temporal Coincidence, a number of paradoxes involving mereological inconstancy can be dissolved. At the same time, there is something deeply counterintuitive about such coincidence. It preserves the existence and persistence of persons but only at the cost of utterly shattering the unity of the person. Whenever there is a thinking person, Temporal Coincidence entails that there are really a huge number of coincident and nearly coincident thinkers, all associated with the same body (or nearly the same body) at the same time. It as if Descartes should have reasoned, We think, and therefore we are. The first-person singular would never be appropriate.
The Atlas of Reality Page 91
