Review of Hoffman and Rosenkrantz

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Review: [Untitled] Reviewed Work(s): Substance: Its Nature and Existence. by Joshua Hoffman; Gary S. Rosenkrantz Dean W. Zimmerman The Philosophical Review, Vol. 108, No. 1. (Jan., 1999), pp. 118-122. Stable URL: http://links.jstor.org/sici?sici=0031-8108%28199901%29108%3A1%3C118%3ASINAE%3E2.0.CO%3B2-6 The Philosophical Review is currently published by Cornell University.

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BOOK FEVlEWS T h e truthmakers for modal truths are t h e actual states o f affairs ( a n d n o t , for instance, nonactual possible worlds). T h e connection between modality, universals, and states o f affairs illustrates a point m a d e earlier. Philosophers w h o pick and choose ontological theses because these solve particular problems m a y discover t h e y are committed t o further theses t h e y would find manifestly objectionable. W e should, t h e n , regard piecemeal ontology with suspicion. T h i s means, at t h e very least, that in taking u p a n ontological position, we m u s t have some idea o f its implications elsewhere-and b e aware as well o f t h e alternatives. Armstrong has, m o r e t h a n anyone else, m a d e t h e options, and their relative costs, clear. T h i s brief s u m m a r y scarcely does justice t o t h e d e p t h and breadth o f A World of States of ;?ffairs. N o r does it reveal what is b y m y reckoning t h e b o o k ' s c h i e f virtue: its author's ontological candor. Few readers will agree n l t h all Armstrong has t o say. But t h e author is his o w n harshest critic, highlighting trouble spots and difficulties with his o w n view and avoiding mystery-mongering and technical sleight o f h a n d . S u c h honesty-rare in t h e best o f times, and quite o u t o f fashion today-is something that all o f us, whatever o u r philosophical predilections, would d o well t o inculcate i n ourselves and i n our students. J O H NH E I L Dauidson College

The Philosophical R m i e y Vol. 108, N o . 1 Uanuary 1999) SLTBSfA,\TCE: ITS NATIIRO' AnD EXISTENCE. By J O S H V AH O F F M Aand N GARY S. ROSENKR~NTZ. L o n d o n : Routledge, 1997. Pp. xi, 218. T h i s b o o k addresses two basic questions: ( 1 ) W h a t is t h e proper philosophical analysis o f t h e concept o f substance? and ( 2 ) W h a t kinds o f compound substances are there? T h e second question is mainly addressed b y asking what relations a m o n g objects are necessary and sufficient for their c o m i n g t o compose a larger whole. T h e first 7 2 pages o f t h e b o o k contain a short history o f attempts t o answer t h e first question, and a brief presentation o f t h e analysis t h e authors d e f e n d at l e n g t h i n their earlier b o o k , Substance Among Other Categories (Cambridge: Cambridge University Press, 1994). In t h e remaining 119 pages, t h e authors take u p t h e second question. T h i s order o f presentation makes sense; b u t it m a y h e l p t o create a false impression i n those w h o only glance at t h e first few pages-that this b o o k is just a simplified version o f t h e earlier o n e , with a little bit o f history thrown i n . It would b e quite u n f o r t u n a t e , however, i f very m a n y potential readers get this impression; for it m i g h t discourage t h e m f r o m looking

BOOK RE?TEWS

closely at the bulk of the book, which is new. The issues discussed in the later chapters are at the center of one of the most lively debates in contemporary metaphysics; and the position Hoffman and Rosenkrantz stake out is appealing and carefully articulated. Their views deserve careful attention from philosophers working on the metaphysics of persistence through time, personal identity, artifact identity, and mereology. The first question, about the analysis of the concept of substance, will strike some philosophers as being rather sterile. It is certainly, in the hands of Hoffman and Rosenkrantz, an exceedingly dry problem to be solved only by relentless Chisholming. Since their views on the subject have already been discussed in these pages (see Charlotte Witt's review of Sub stance Among Other Categories, Philosophical Review 105 (1996): 562-64), I will confine my attention to the remainder of the book, which could have stood alone as an independent monograph: the Hoffman-Rosenkrantz metaphysics of compound substances. Peter van Inwagen's ikfaterial Beings (Ithaca: Cornell University Press, 1990) will surely be the benchmark for work in this area of metaphysics for the foreseeable future. Its impact is evident here on a number of levels. The authors set up their problem in the same way as van Inwagen: a middle way must be charted between "monadism" (van Inwagen's "nihilism") on the one hand-the view that no compounds exist, only simples-and "collectivism" (van Inwagen's "universalism") on the other-the view that, for every collection of discrete objects, there is a whole composed ofjust those objects. But how to chart an intermediate course without letting in too many objects? How to restrict the number of unity-making relations so that the same collection of parts does not end up simultaneously composing quite distinct kinds of whole? The authors also agree with van Inwagen on a number of important details. Like van Inwagen, they reject artifacts-there are no such things as cars and tables, at least not if cars and tables are supposed to be able to survive the gain or loss of even the smallest part-but are most interested in retaining living organisms as compound wholes that can survive complete replacement of parts. The analysis they offer of organic life involves an evolutionary account of the notion of a natural function. The broadly Aristotelian view of the unity of organisms advocated by Hoffman and Rosenkrantz has considerable currency; but no one else has attempted to work out the details of such a view in quite so serious a way. I suspect that, for many readers, this part of the book will be of greatest interest. It can be seen as an attempt to analyse van Inwagen's notion of "a Life" in terms of the overall functional unity of living organisms. Here their discipline and patience pays off: there is a lot of serious Chisholming, but in the service of a worthy goal, and the result is one of the clearest articula-

BOOK REVLEWS tions yet of a roughly Aristotelian approach to the unity of compound objects. Their views diverge most noticeably from van Inwagen's at nvo points: (1) they recognize "mereological compounds," nonliving wholes that cannot survive change of parts, and (2) they are reluctant to recognize "vague objectsn-that is, to admit that there may sometimes be no determinate fact of the matter about whether some individuals go together to constitute an object, or about whether a given object persists from one time to another. I suspect that some vagueness may creep back into their account in at least one place;' but I won't belabor that point here. In the space remaining, I shall discuss just the first, and most important, point of divergence. Hoffman and Rosenkrantz are anxious to preserve the following thesis: there are inanimate compound physical objects that can be created and destroyed by assembly and disassembly. I suppose they are right to say that this is a "datum" of common sense, to be preserved if at all possible; and I suppose that van Inwagen can at best provide a Pickwickian sense in which this is true. However, the only inanimate compound objects they recognize are "mereological compounds": wholes that cannot survive the gain or loss of any parts. And that there are such things is probably not something that could reasonably be called a datum of common sense. If there are wholes that cannot survive the loss of a part, and that can be destroyed by disassembly, then there must be some kind of relation of "attachment" that produces wholes out of parts. In Person and Object (La Salle, Ill.: Open Court, 1976), Roderick Chisholm advocated a similar view, and (rather tentatively-it wasn't enshrined in a definition) floated the suggestion that nvo things are "joined" just in case there's nothing else between them (153). Hoffman and Rosenkrantz offer a more restrictive

he notion of a "regulating cause" (126-27) is taken as undefined; but there is, I suspect, a wide range of possible relations between something like the central nervous system and a set of other organs or systenls it "regulatesM-a spectrurn beginning with situations in which the forrner clearly qualifies as regulating cause with respect to the latter, ending with some in which it doesn't, but shading off into indeterminacy in the middle. If someone dies because of damage to the brain, for instance, there nlust (if there is to be n o worldly vagueness) be a precise instant at which the dying person's nervous system ceases to f ~ ~ n c t i oas n a regulating cause with respect to the rest of the body. This degree of precision seems to me to be more than any intuitive notion of "regulating cause" can bear; and won't every sharpening of the concept be simply an arbitrary, and thus conventional, way of drawing the line between life and death? Given their strictures against "conventional objects" (166), denying vagueness at this point will require heroic measures-such as the epistemic approach to vagueness advocated by Roy Sorensen (Blinrlspot~(Oxford: Oxford Universtiy Press, 1988)) and Titnothy Williamson (T'ngurnr~s(London: Routledge, 1994)).

BOOK REVEWS view o f attachment: roughly, a pair o f things are attached i f and only i f each ( o r parts o f each-but this clause is t a k e n care o f without circularity) can b e used t o push o r pull t h e other i n any direction you like. A n d , clearly, this is a n i m p r o v e m e n t over Chisholm's account, at least i f what we're after is a philosophical analysis o f t h e ordinary n o t i o n o f "attachment." But I have nvo worries about their account o f t h e inanimate objects that can b e created and destroyed by attaching and detaching parts. First o f all, I wonder whether there is any special reason t o t h i n k that t h e objects d e p e n d e n t u p o n attachment o f parts are "mereological c o m pounds"-that is, things that c a n n o t survive changes o f parts. W h y t h i n k there are any objects that have all their parts essentially? H o f f m a n and Rosenkrantz d o little t o motivate t h e admission o f such things i n t o one's ontology; b u t , supposing o n e does recognize t h e m , why t h i n k that these are t h e kinds o f things that can b e destroyed merely b y disassembly? By m y lights, t h e best a r g u m e n t for t h e existence o f mereological c o m p o u n d s proceeds b y pointing o u t that t h e quantities o f s t u f f o f w h i c h c o m p o u n d objects are m a d e nlust b e taken seriously as individuals i n their o w n right ( t h a t is, t h e y c a n n o t b e identified with sets o r pluralities). Quantities o f s t u f f obey mereological essentialism, b u t they are n o t created or destroyed simply b y t h e attachment or d e t a c h m e n t o f parts.' My second worry is that recognizing b o t h mereological c o m p o u n d s created by attachment and living organisms will lead t o a version o f (what Michael Burke has d u b b e d ) ' " t h e n e w dualism": t h e thesis that there can b e two objects i n t h e same place at t h e same t i m e , m a d e o u t o f t h e same parts arranged i n t h e same way, b u t with d i f f e r e n t persistence conditions. H o f f m a n and Rosenkrantz agree that this would b e bad news (155-160). But t h e y t h i n k it w o n ' t h a p p e n because living things always ( a n d , t h e y m u s t suppose, of necesszty) have lots o f Puzd i n t h e m ; and t h e parts o f a fluid are

'1t will come as no surprise that this is my favorite argument for ~nereological compo~mds,at least not to those who have seen lny "Theories of Masses and ProbI h i e z u 104 (1995):33-1 10; and "Coincident Oblems of Constitution," Pl~ilo~opl~ical jects: Could a Stuff Ontology Help?" .4naljsi~57 (1995):19-27. Hoffman and Rosenkrant~like an argutnent for mereological compounds from the problenl of increase: Things call get bigger only by the addition of parts; but when an object a increases by the addition of an object b, neither one gets bigger; and the new whole co~nposedof both didn't get bigger either. So nothing can increase by gaining parts ( 1 3 4 5 6 ) .The only response they consider to this arg~unentis one that adnlits at the outset that there arr ~nereologicalcompounds. 4 canny opponent will simply insist that there aren't any; and that in a case of real increase, a comes to have b as a part, and the thing that they are calling "a" after the increase simply doesn't exist-although there will, then, exist some collection of parts of a that used to make up the wllole of a. "ee Burke, .'Persons and Bodies: How to Avoid the New Dualism," An~erican Pl~ilosophicalQunrterlj 34 (1995):437-65.

BOOK REVLEWS not attached one to another; so the whole of the organism does not qualify as a mereological compound (see 156-59). I have two qualms about this intriguing suggestion. First off, suppose it is a fact that all living things contain parts that are not attached to any other parts. Is this really a good candidate for a necessary truth? Is it absolutely impossible for there to be living things consisting of parts each of which can be reached from any other via a chain of attached parts? Recall that attachment only requires that each of a pair can be moved (perhaps only the slightest bit!) in any direction by moving the other. Now the molecules or atoms in a liquid are supposed to fail this test. Suppose that they do. Even so, as a liquid becomes more viscous, it must, I suppose, begin to qualify as a mereological compound long before it becomes hard as a rock. So couldn't there be living things made out of sufficiently slippery "goop"? If Hoffman and Rosenkrantz are right, they have uncovered a somewhat surprising (albeit reassuring) fact: the Blob (and the Son of Blob, and many another gooey science fiction monster) is absolutely impossible, not just highly improbable. My second reservation about attachment is this: objects are said to be attached if and only if there is a relationship of "dynamic equilibrium" holding between them in virtue of which it is "physically possible" to push or pull either in any direction by pushing or pulling the other ( 8 4 8 5 ) . It is clear that this "physical possibility" often obtains only in virtue of merely possible situations in which the surroundings of the pair are very different from actuality. To use one of their examples, a thin bit of thread can be attached to a heavy ball because there's a tiny piece of the ball that could be pulled by the thread- ij'the rest of the ball weren't attached to that tiny piece. Now, if we're allowed this much "imagining away of surroundings," I fear that the parts of fluids, at least, will qualify as attached. Take a pair of nearby particles in a fluid; if thq ruere the only things in the universe, wouldn't a movement of either one in any direction push or pull the other in that direction-even if only by a tiny bit? Moving either one closer to the other repels the latter, pushing it away; moving either one farther away from the other draws the latter after it. Hoffman and Rosenkrantz cannot very well deny that such repulsion and attraction count as pushing and pulling; if this isn't pushing and pulling, then no particle is attached to any other. But if the nvo particles satisfy the definition of attachment, then fluids become mereological compounds after all; and organisms end up coincident with objects that cannot gain or lose part^.^

DEANW. Z I M M E R ~ A U Cnzuersity of Notre Dame "~'m gratef~llto Trenton Merricks, hIichae1 Rea, and Peter van Inwagen for cornments and suggestions.