CHRISTOF RAPP

RUNGGALDIER ON THE COHABITATION OF MATERIALOBJECTS

1. INTRODUCTION

The aim of Runggaldier’s text is to defend the assumption of endurantsagainst the theory of temporal parts and thus avoid reducing diachronicidentity to a continuous succession of different states. He accomplishesthis in three steps. The first step consists in finding a meaningful modeof expression which describes how endurants are wholly present at everymoment of their history but which is also compatible with the fact that, ofcourse, endurants are not present with all their qualities at every point intime. The second step consists in showing that spatiotemporal continuityis not necessary or sufficient to trace an object through its history. Finally,it is argued that even for the defender of endurants the question concerningthe continuity of such objects can be meaningful, namely, when continuityis addressed in connection with the question, in what way can we reidentifyan object as one and the same over a period of time.

In his defence of endurants, Runggaldier works from some premiseswhich are not discussed in his paper. Among these are the assumptionsthat the thesis concerning the sortal dependence of identity is, in principle,correct (and, therefore, the relativity thesis of identity, false); that the use ofa four-dimensional space-time system does not rule out the assumption ofendurants; and, finally, that we can reidentify objects as the same in spiteof the changes they undergo. Runggaldier thus occupies a terrain whichhas been recently described as the “standard account” (STAC). Only atone point would Runggaldier not want to go along with STAC. This is theclaim that different objects can be at the same place at the same time (“co-habitation thesis”). Is the cohabitation thesis an inescapable consequenceof STAC? Is it possible to reject the cohabitation thesis but simultaneouslysubscribe to STAC? We will consider this point more closely.

Erkenntnis48: 371–375, 1998.© 1998Kluwer Academic Publishers. Printed in the Netherlands.

372 CHRISTOF RAPP

2. THE COHABITATION THESIS

For those who defend STAC, a copper statue and the piece of copper fromwhich the statue was created constitute two different objects. Their differ-ent persistence conditions are responsible for their being different objects.The piece of copper sustains a drastic change in form, while the statuedoes not (Wiggins 1968, 1980). The concession that we are concernedwith two different objects is necessary if, on the one hand, we presupposethat different species bring with them different identity criteria but, on theother hand, we reject the relativity of identity, according to whicha cansimultaneously be the same F but not the same G asb.

In recent years, some writers have stressed that the cohabitation ofdifferent material objects is counterintuitive (Burke 1992), even thoughSTAC in all other regards claims to correspond best to the ontology ofeveryday language. In this respect, no one who looks at the statue seriouslythinks that more than one object is concealed behind it. By the way, it isinteresting to note that in a certain sense Aristotle, who, because of hisproximity to everyday ontology, is eagerly embraced as an ally by theSTAC-defenders, could have hardly befriended the cohabitation thesis. Forexample, he rules out that one substance can comprise another substance.The objection that STAC leads to counterintuitive consequences, therefore,must prima facie be taken seriously.

For this reason Burke maintains a position which can be described as“STAC minus cohabitation thesis” (Burke 1994). This position assumesthat the copper from which the statue was made is not identical to the pre-existing piece of copper; for with the statue’s creation the piece of copperceased to exist. It follows that the copper from which the statue was madehas no persistence conditions other than the statue itself and, consequently,we are dealing only withoneobject. On this account, it can be objected thatBurke’s assumption is just as counterintuitive as the cohabitation thesis. Itseems to me, however, that for still another reason Burke’s approach issuspect. If along with STAC we assume that objects belonging to differentspecies are furnished with different persistence criteria and, then, if weare always prepared to speak of one object when there are sufficientlyunequivocal criteria present, it is obviously always possible to subsumeunder different species concepts what we see at the same place at thesame time in such a way that different identity criteria are fulfilled. Thosewho assume the above premises can, in fact, give only one answer to thequestion concerning the possibility of the cohabitation of different objects– an unequivocal ‘yes’. Either we subscribe to STAC together with thecohabitation thesis or we abandon ittout court.

RUNGGALDIER ON THE COHABITATION OF MATERIAL OBJECTS 373

Runggaldier’s position lies somewhere in between. It can be describedas follows:

1. We must distinguish true objects from their material which only in aloose sense can qualify as an object.

2. Although the statue and the copper from which the statue is made arenot identical (2.1), they are not two different objects (2.2).

3. They are not two objects which are of the same ontological standing.4. True objects are objects which are individuated by means of a sortal

term.

In connection with premises which Runggaldier’s conception otherwiseshares with STAC, thesis 2.2 is inconsistent, as shown (this is my firstobjection).

3. IS THE COHABITATION THESIS COUNTERINTUITIVE?

We said, we must take seriously the suspicion that the cohabitation the-sis is counterintuitive. If indeed STAC and the cohabitation thesis cannotbe disassociated, is it, therefore, necessary to reject STAC because of itscounterintuitive consequences? I do not think so. The impression of im-plausibility is solely due to the fact that everyday ontology, in whose namethe cohabitation thesis has come under attack, has in view another moreemphatic object concept than STAC, which acknowledges something asan object when it is furnished with sufficient identity criteria. It seemscounterintuitive that two different objects can occupy the same space, ifwe roughly understand by ‘object’ what is described in the classical Aris-totelian metaphysics as substance. This, however, is not STAC’s conceptof object. The argument against STAC, therefore, turns out to be a prob-lem caused by ambiguity. The cohabitation thesis remains unaffected by it(second objection).

4. WHAT KINDS OF ENTITIES ALLOW FOR COHABITATION?

According to Runggaldier’s theses 1 through 4, cohabitation is only pos-sible for objects which are not of the same ontological standing. But is itnecessary to treat cohabitation in such a restrictive way? For the classicalphilosophers who addressed this question, only the cohabitation of ob-jects belonging to the same species was generally regarded as problematic.Even Locke, whose name is linked to the cohabitation verdict (An EssayConcerning Human Understanding2.27.3), basically seems to tolerate the

374 CHRISTOF RAPP

cohabitation of objects belonging to different species. Leibniz, for his part,believes that Locke’s verdict cannot be upheld. According to him, evenobjects belonging to different species can cohabit. As an example, Leibnizcites how shadows and rays of light permeate each other (Nouveaux essaissur l’entendement humain2.27.1).

Much more recently Simons (1985) has shown that we have reason tobe even more broadminded. He does this by way of an example of heapscontaining not less than m or not less than n grains (Simons 1985). Anot-less-than-4-heap has other persistence conditions than a not-less-than-3-heap. It follows that examples of the species m-heap are not identicalto examples of species n-heap, if m6= n. On the other hand, starting witha 4-heap, we can generate in succession heaps with 5, 6 or 7 grains insuch a way that each heap is a not-less-than-4-heap. But because each ofthese not-less-than-4-heaps was generated at a different point in time, eachone is a different no-less-than-4-heap. Now, since the first 4-heap by nomeans ceases to exist during the accumulation process, different objectsbelonging to the same species cohabit in the 7-grain not-less-than-4-heap.In this way we have shown: first, cohabitation is also possible for materialobjects of the same species; second, cohabitation is also possible for ob-jects defined by sortal terms; third, this is also possible for objects definedby genuine, so-called substance sortals (those with necessary and sufficientpersistence conditions (Simons 1986)); fourth, cohabitation is possible forany random large number of objects belonging to the same species.

We cannot consider Simons’ example in more detail here. But assumingthat his arguments are conclusive, we also have every reason to treat co-habitation in a far more broadminded fashion than Runggaldier does (thirdobjection).

5. CAN A NONCOHABITATION THESIS BE DEFENDED FOR

SUBSTANCES?

We can now ask whether we want to go along with common-sense in-tuitions and concede cohabitation in general, but nevertheless in additiondefend a noncohabitation thesis for substances (Oderberg 1996).

Noncohabitation Thesis for Substances (NCS):It is not possible for two substances tooccupy the same place at the same time, even if this is possible for entities which belongto another category.

This thesis would suit Runggaldier, indeed; for it precludes that an ob-ject which cohabits with a substance is of the same ontological standing.

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How can we successfully defend NCS? We would have to find criteriafor substances which preclude cohabitation. What type of criterion couldthat be? For Runggaldier’s thesis 4 a possible criterion with regard tosubstances would be concerned with objects which are defined by sortalterms. For the sake of brevity, if we assume that Simons’ example of n-and m-heaps is conclusive, then this criterion would be too broad (lastobjection).

Now, we could object, and not entirely without good reason, that Si-mons’ n- and m-heaps are not exactly what we envisaged for substances.To what extent we are able to arrive at an argument in favour of NCS byway of this intuition depends, once again, on whether we can designatecriteria which adequately define substantial species. As long as we are un-able to provide such criteria, NCS proves nothing more than we recognizeonly those objects as substances which preclude cohabitation with othersubstances.

ACKNOWLEDGEMENT

This article was translated from the German by Cara Gendel Ryan.

REFERENCES

Burke, M. B.: 1992, ‘Copper Statues and Pieces of Copper: A Challenge to STAC’,Analysis52, 12–17.

Burke, M. B.: 1994, ‘Preserving the Principle of One Object to a Place: A Novel Accountof the Relations among Objects, Sorts, Sortals, and Persistence Conditions’,Philosophyand Phenomenological Research54, 591–624.

Oderberg, D. S.: 1996, ‘Coincidence under a Sortal’,The Philosophical Review105, 145–171.

Simons, P.: 1985, ‘Coincidence of Things of a Kind’,Mind 94, 70–75.Simons, P.: 1986, ‘Unkindly Coincidences’,Mind 95, 506–509.Wiggins, D.: 1980,Sameness and Substance, Basil Blackwell, Oxford.Wiggins, D.: 1968, ‘On Being in the Same Place at the Same Time’,The Philosophical

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