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Leibniz's Phenomenalisms Author(s): Glenn A. Hartz Source: The Philosophical Review, Vol. 101, No. 3 (Jul., 1992), pp. 511-549 Published by: Duke University Press on behalf of Philosophical Review Stable URL: http://www.jstor.org/stable/2186056 . Accessed: 24/01/2011 16:04

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http://www.jstor.org The PhilosophicalReview, Vol. 101, No. 3 (July1992)

Leibniz's Phenomenalisms Glenn A. Hartz

ocke's Essay is like a mail-ordercatalogue," writesP. T. Geach, "and you buy what suitsyou. To switchto a communication- theorymetaphor, the trouble is to make out which part is message and which is noise."' Something similarmight be said of the Leib- nizian corpus. It is large and diverse and rich-so rich that there are withinit tensions or outrightcontradictions. These the commentatorto choose which items to purchase and which to let well alone. Message and noise are alarminglyoften side by side in texts from the same or closely neighboringperiods of , in differentdrafts of the same essay,and sometimesin the verysame draft. When one turns to Leibniz's views of ,one is confronted withan astonishingcollection of distinctaccounts. One must adopt either (i) the so-called "Athenian" approach, drummingout all of the incompatibilityand presentinga single overarchinginclusive account, or else (ii) the "Darwinian" strategy,saying his views of

'The followingabbreviations are used in the text and footnotes:A = Robert Merrihew Adams, " and Corporeal Substance in Leibniz," MidwestStudies in Philosophy8, ContemporaryPerspectives on the Historyof Philosophy,ed. P. A. French, T. E. Uehling, Jr., and H. K. Wettstein(Minneapolis: Universityof Minnesota Press, 1983), 217-57; AG = G. W. Leibniz:Philosophical Essays, ed. and trans.R. Ariew and D. Garber (Indianapolis: Hackett, 1989); C = Opusculesetfragments ine'dits de Leibniz, ed. L. Couturat (Paris: Alcan, 1903); G = Die philosophischenSchriften von GottfriedWilhelm Leibniz, 7 vols., ed. C. I. Gerhardt(Berlin: Weidmannsche Buchhandlung, 1875-90); GM = G. W. Leibniz, MathematischeSchriften, 7 vols., ed. C. I. Gerhardt (Berlin: A. Asher; Halle: H. W. Schmidt, 1849- 63); L = GottfriedWilhelm Leibniz: Philosophical Papers and Letters,2d. ed., ed. and trans.L. E. Loemker (Dordrecht,The Netherlands: Reidel, 1969); LA = The Leibniz-ArnauldCorrespondence, ed. and trans. H. T. Mason (Manchester, England: Manchester UniversityPress, 1967; New York: Garland, 1985); P = Leibniz:Philosophical Writings, ed. G. H. R. Parkinson, trans. M. Morris and G. H. R. Parkinson (Totowa, N.J.: Rowman and Littlefield,1975); R = ,A CriticalExposition of thePhilos- ophyof Leibniz, 2d. ed. (London: George Allen & Unwin, 1937). The quo- tation is from P. T. Geach, ","Review of 21 (1967-68): 12.

511 GLENN A. HARTZ matterchanged significantlyduring his lifetime.2Though the Dar- winian view applies to some of his doctrines-for example, his views of and time3-it does not apply to his metaphysicsof matter.Instead of runninga single doctrineof body throughmany mutationsand emerging with a completelynew doctrine,Leibniz allows several doctrines to coexist and flourishtogether. The viewsare scatteredthroughout the maturecorpus, but I will note the date of textsI cite because theirinterpretation is affected cruciallyby the of other doctrinesLeibniz held at that time. I will follow Leibniz in using 'body' as the most general term des- ignating material objects. But I will somewhat diverge from his usage of the term 'phenomenon' and its cognates. Leibniz tends to use this as a specific,pejorative label for such ontologicallylight- weightitems as illusionsand aggregatesof substances.I will argue thata more general thatLeibniz sometimesattaches to the of phenomena is useful as a wayof characterizinghis over- all doctrine of body. At the outsetlet us set fortha pictureof Leibniz's overall system. From the perspectiveof perceivingsubstances ("monads" or "cor- poreal substances"),there are four possible objects of : (1) illusions:mere appearances that fail to cohere with other objects of perception. (2) aggregates:appearances thatare misleadinglyunified-they actuallyare collectionsof an infinitenumber of substances. (3) corporealsubstances: combinations of specially-organized groups of monads/corporealsubstances (formingthe "or- ganic body") and a perfect-unity-bestowing"dominant monad." (4) substantiallybonded corporeal substances: corporeal substances that have added to them a "substantialbond" that makes them perfectlycontinuous. (4) is not supported widely in the corpus, and (1) does not play a great role in the Leibnizian program. Thus I shall concentrate mainlyon (2) and (3).

2See Hector-Neri Castafieda, "Leibniz's and Their Coin- cidence Salva Veritate,"Nouis 8 (1974): 381-98. 3See Glenn A. Hartz andJ. A. Cover, "Space and Time in the Leibnizian Metaphysic,"No Ws22 (1988): 493-519.

512 LEIBNIZ'S PHENOMENALISMS

In the firstsection I clarifyLeibniz's use of 'phenomenon'. The second section is devoted to settingforth the accounts that high- light perceptual featuresas the nature of body. I explore mereo- logical accounts in the third section, followed by a supervenience construal. Finally, I combine several of the accounts to derive various versions of Leibniz's sufficientconditions for body. For most of these accounts I will ask: What conditionsmust obtain in order for there to be (i) a body at a time, and (ii) a body that endures fora period of time?More familiarand accessiblepassages will typicallybe quoted only briefly,less familiarpassages more fully.

1. 'Phenomenon'

In a seminal letterof 1687 to Arnauld, Leibniz uses 'phenomena' to referto illusionsand aggregates.He saysthat if matterlacked "true unity,"it would be "a phenomenon, lacking all realityas would a coherent dream" (G 2:99/LA 122). Of aggregates he writes that though there are various "degrees of accidentalunity," such unities "are made complete only by thoughtsand appearances, like colors and other phenomena. . ." (G 2:100/LA 126). How does the dole out unity?

Our mindnotices or conceivesof certaingenuine substances which have variousmodes; thesemodes embracerelationships with other substances,from which the mindtakes the opportunity to linkthem togetherin thoughtand to enterinto the accountone name forall thesethings together, which makes for convenience in reasoning.(G 2:101/LA126; cf. G 2:97/LA121; G 2:119/LA153)

There are two of 'phenomenon' here, both metaphysically pejorative. Either

ILL: x is a phenomenon = x is an illusoryappearance, which makes it quite ontologicallyflimsy; or

MEN: x is a phenomenon = x is the appearance of an aggregate of corporeal substances or monads whose unity is only apparent, since it is manufacturedby the mind,

513 GLENN A. HARTZ which makes it a bit less flimsybut neverthelessfar from funda- mental since its unity is not genuine. We can call bodies cor- responding to ILL Illusoryphenomena, and those corresponding to MEN mentalphenomena. Illusory phenomena are ontologicallynegligible, since they are nothingover and above appearances in . Mental phenomena belong to a higher caste, since there is somethingextra-mental- aggregates of substances-that theyrepresent. In MEN I've allowed those aggregates to be composed of either corporeal substances or monads. Why? Because Leibniz allows for the disjunction.In the Arnauld correspondence and elsewhere the constituentsare called "corporeal substances,""animals," or "living bodies" and are clearlythought of as the constituentsof phenome- nal aggregates (G 2:120/LA 154). Each corporeal substanceis com- posed of a dominant monad plus an "organic body" or "machine." Organic bodies are best thoughtof as fancyaggregates-typically collectionsof organs-that are speciallysuited to the role of acting as the body of a corporeal substance after that organic body has been joined to a dominant monad. Frankenstein's"monster body" before it came to lifewould be an example of an organic body. Like ordinaryaggregates, the organic body-which in the Arnauld ex- change Leibniz calls the "body apart,without the " (G 2: 100/LA 125) or "the of [a person's] body" (G 2:120/LA 154)-is said to be composed of other smaller corporeal substances. Leibniz maintained this position throughoutthe mature period, as is clear from his remark in 1699: ". . . corporeal substance has its mass or its secondary matter,which is, again, an aggregate of other smaller corporeal substances-and thatgoes to infinity"(G 3:260/AG 289; cf. G 7:501-2; G 2:205; G 4:572-73; G 6:550). But elsewhere Leibniz says monadsmake up aggregates and the organic bodies of corporeal substances.In a letterof 1705 to Prin- cess Sophia he says ". . . nothingprevents matter from com- posed of simple and indivisiblesubstances" (G 7:561), adding in a treatiseof 1712,

A substanceis eithersimple, such as a soul,which has no parts,or it is composite,such as an animal,which consists of a souland an organic body.But an organicbody, like everyother body, is merelyan ag- gregateof animals or ... of smallobjects or ;but these also are finallyresolved into livingthings, from which it is evidentthat all bodies are finallyresolved into living things, and thatwhat, in the

514 LEIBNIZ'S PHENOMENALISMS

analysisof substances,exist ultimately are simplesubstances-namely, ... or ... monads,which are withoutparts. (C 13-14/P175; cf.G 6:598-99/P196; G 2:282/L539; G 3:367)

Here, ratherthan findingcorporeal substances"all the way down," those substances themselvesare furtheranalyzed into "ultimate" constituentmonads. Though they are more ontologicallyweighty than illusoryphe- nomena, mental phenomena remain somewhat metaphysicallyin- ferior because the aggregates they represent are mostlymisrepre- sented.In particular,mental phenomena seem to be unified,but that unityisn't genuine. Often it is said to be the mind's sensoryside that is responsible for rounding up so many distinctthings-say, many water droplets-and consideringthem as one thing-a rainbow (G 2:119/LA 153; cf. G 7:563). Leibniz held thatsometimes-as in the case of a pile of rocks-we see the aggregate for what it is: a mere heap. But at other the mind is at least momentarilytricked into accepting aggregates as real unities because the senses smear out the divisionsbetween their parts (G 2: 100-101/LA 126-27). The senses get blamed forerroneously attributing not only unity but also secondaryqualities and continuityto aggregates.In the case of a rainbow,the aggregate appears coloredbecause the senses portray millions of colorless droplets as an arched color patch. Leibniz holds that color and other secondaryqualities mislead us as to the true nature of the : theyare merely"apparent" and "relative to our senses."4 (We will hereafter use 'color' as a brief way of referringto all of the secondaryqualities.) Finally,Leibniz ties the apparent continuityof bodies to the senses. In 1705, when discuss- ing the difference between truly continuous "ideal" items (like space, time, and "mathematicalbodies") and real, discontinuous material bodies, he explicitlyblames the senses for running the parts of the aggregate togetherso as to make the collectionappear to be a seamless, continuous whole:

There are thereforealways actual divisionsand variationsin the massesof existingbodies, to whateverdegree of smallnessone might go. It is our imperfectionand the faultof our sensesthat makes us

4See NotationesGenerales, in G. W. Leibniz, Textesinklits, ed. G. Grua (Paris: Presses Universitairesde France, 1948), 322. For a detailed discus- sion of Leibniz's view of secondary qualities, see A, esp. 225 and 240-41.

515 GLENNA. HARTZ

conceivephysical things as mathematicalbeings, where there is some indeterminacy....(G 7:563) Matterappears to us to be a continuum,but it only appears so, just as does actualmotion. It is rather.. . as a spokedwheel appears continu- ouslytranslucent when it turnswith great speed-without which one could tellthe location where the spokes are fromthe empty in betweenthe spokes-our perceptionrunning together the separate placesand times.(G 7:564)

A centuryago J. E. Erdmann got thispoint about continuityabun- dantly right:

[A] combinationof non-extendedsimple substancesbecomes ex- tendedthrough our perceptionof it,which is confused.We see the milkyway or a cloudof dustas continua,because our eyeis notsharp enoughto distinguishclearly the individual stars or particlesof dust.5

At the moment we'll concentrate on the unityof mental phe- nomena, and bring in color and continuitylater in our compre- hensive perceptual construalof aggregates. MEN's theme of the mind's takingmany thingsand makingone thingout of themis quite differentfrom another point thatLeibniz makes in many of these same passages-namely,

DER: x is a phenomenon = x is an aggregate of corporeal sub- stances or monads whose is completely derived from that of its constituents.

Phenomena corresponding to DER will be called derivativephe- nomena. DER's theme of an aggregate derivingits realityfrom its constit- uents is clearly set forthin the Arnauld correspondence:

[E]veryentity through aggregation presupposes entities endowed witha trueunity, because it obtainsits reality from nowhere but that ofits constituents, so thatit will have no realityat all ifeach constituent entityis stillan entitythrough aggregation. . . . [I]f there are aggre- gatesof substances, there must also be genuinesubstances from which

5J.E. Erdmann, Historyof Philosophy, 3 vols., ed. W. S. Hough (London: Swan Sonnenschein, 1891), 2:185.

516 LEIBNIZ'S PHENOMENALISMS

all the aggregates result. (G 2:96/LA 120; cf. G 2: 100/LA 125; G 2:261; G 2:267)

Derivative phenomena are, like mental phenomena, aggregates. The differenceis this: mental phenomena are only apparentlyuni- fied; derivativephenomena are only apparentlyreal. For example, a piece of sandstone seems to have a realityof its own, but on reflectionit is clear thatit owes its realitycompletely to itsconstitu- ent sand . Leibniz himselfblurs the border between mental and derivative phenomena by presentingthem merelyas alternativeways of ex- pressing the same point, as he does here when addressing De Volder in 1704: "Whatever thingsare aggregates of many are not one except for the mind, nor have any other realitythan what is borrowed, or what belongs to the thingsof which they are com- pounded" (G 2:26 /R 249). Thus I'll offerone construalaccording to whichmental and derivativephenomena are given the verysame metaphysicalanalysis. On the whole, however, I want to suggest that we not follow Leibniz in this. The concepts involved in MEN are strikinglydif- ferentfrom those in DER: certainlythere is more than a slightshift of idiom here. Mental phenomena are put togetherby the mind: that has a much more Kantian flavor than the mereological/ metaphysicalanalysis suggested for derivativephenomena. Mental phenomena are thoughtof as real because of somethinggoing on "in the head"; derivative phenomena seem real because of the realityemanating forth"outside the head" from their metaphysi- cally more basic parts. One reason for puttingasunder what Leib- niz has joined togetheris thatthere is littletextual evidence explic- itlylinking the unity-makingtendency of the mind with a reality- attributingfunction of the mind: the unityis typicallysaid to come fromthe mind, the realityfrom the parts. Thus I shall quicklypull them apart in the analyses that followthe one mentioned. There is a fourth of 'phenomena' I want to attributeto Leibniz. Actually,it is best seen as a sense of 'phenomenal',because it doesn't refer to appearances in minds. Instead, it refers to a general ontological level in his overarchingscheme:

LEV: x is phenomenal = x belongs on the middle ontological level of Leibniz's metaphysicalscheme.

517 GLENN A. HARTZ

A detailed argument in favor of attributingto him a three-level ontologyhas already been presented elsewhere.6Very briefly,one finds that after 1695 Leibniz endorsed a fundamentallevel where the monads and their states reside; just above that he has bodies, derivativeforce, , , and duration at thephenomenal level; and finallyat the top he has the itemsthat are furthestfrom being taken seriouslyontologically. These include space, time,and "mathematicalbodies," which are consigned to the ideal level. In this scheme, 'phenomenal' is a term that simplycalls attentionto the general fact that the item in question belongs on the middle phenomenal level in that scheme. Where does Leibniz use 'phenomenal' to indicatea level? I think it is visiblein the followingpassages. In SpecimenDynamicum of 1695 he writes,"[Miotion insofar as it is phenomenalconsists in a mererela- tionship.... For even though force is somethingreal and absolute, motion belongs to the class of relative phenomena, and is found not so much in phenomena as in theircauses" (GM 6:247- 48/L 445-46). He is using the phrase a 'class of relative phe- nomena' to pick out a group of items that includes bodies, force, motion, the extension of bodies, and duration. A decade later he writes,"I relegate derivativeforces to the phenomena. ... I also put corporeal forceswhere I put bodies, namely,among the phe- nomena" (G 2:275-76/AG 181-82). Once again "the phenomena" representsa place to put various items-it is a categoryor a level. 'Phenomenal' in this "levels-sense"will always be used as an ad- jective. The 'phenomenon' invitesus to thinkof an item as a sense datum or an appearance in a mind. The illusory mirage- phenomenon and the mental or derivative genuine-oasis- phenomenon might be construed as sense data. (On the typical analysis,they would both be images in the mind, withthe illusory/ genuine distinctionexplained by reference to the differencebe- tween a dehydrated,exhausted perceiverfar fromany oasis and a "normal" perceiver near one.) But Leibniz says motion and force belong "among the phenomena," clearly thinkingthat they exist

6See Hartz and Cover, "Space and Time in the Leibnizian Metaphysic," and J. E. McGuire, " 'LabyrinthusContinui': Leibniz on Substance, Activ- ity,and Matter,"in Motionand TimeSpace and Matter,ed. P. K. Machamer and R. G. Turnbull (Columbus: Ohio State UniversityPress, 1976), 290- 326.

518 LEIBNIZ'S PHENOMENALISMS

outside the mind. There is no esseis percipidoctrine in the Leibni- zian corpus. Thus, though force and motion aren't phenomena, they'rephenomenal-in the levels-sense.In Leibniz's ontologyall the phenomena-illusory, mental,and derivative-as well as such featuresas motion and force,are on the phenomenal level. What is the nature of items on this level? The ordinaryconno- tations of 'phenomenal' invite us to furnishit with fleetingsense data. But withthe exception of illusoryphenomena, thatwould be a mistake. What Leibniz says about mental and derivative phe- nomenon clearlyfavors Robert M. Adams's view (expressed in pri- vate correspondence) that the world "as it appears to us at any instanthas a historymuch longer than that instant."This "history of the world" is distinctfrom the historyof the mind whichis being appeared to, and so nonillusoryitems on the phenomenal level are in some sense external to the mind. But they are not to be con- strued as unperceivable material substrataor Kantian "things-in- themselves."They are relativelystable and enduring itemsin what we will call the phenomenalworld. In this phenomenal world are two verydifferent kinds of items: (i) corporeal substances like giraffesand humans; and, at least apparently (ii) aggregates (or "well-founded phenomena") like piles of rocks (G 7:501). When you look at your hand, you are looking at a corporeal substance-in this case (part of) an organic body whose constituentsubstances are attached to your soul-the dominant monad. Should thathand be amputated,it would imme- diatelybecome a "well-foundedphenomenon," a mere aggregate.

2. Perceptual Phenomenalisms

Perceptual phenomenalisms construe bodies as appearances in minds. We are going to follow Leibniz in leaving open the possi- bilitythat nonillusorybodies are more than mere appearances- that they are extra-mentalcollections of substances in the phe- nomenal world. In later sections we'll explore the extra-mental nature of body. Here we'll just be listingnecessary conditions re- lating to perception. For the moment we'll leave aside mental and derivative phe- nomena: they'llbe analyzed in the finalperceptual account below. What we need to deal withfirst are illusoryphenomena as contrasted

519 GLENN A. HARTZ withwhat Leibniz calls in a famous paper of 1686 realphenomena (G 7:319-22/L 363-65; cf. G 2:270/AG 181; G 2:276/AG 182). He says that phenomena are to be judged illusory or real according to certain internaland external marks. The internalmarks (that is, those purelyinternal to the perceiv- er's own ) are Berkeleyesque: they include vividness, complexity,intensity, and internalcoherence. I will refersumma- rilyto these by describingreal phenomena as ones that"cohere well with other phenomenal features of a person's experience." The main external refersto otherperceivers. Once again this is a coherence condition,explained as requiringof a real phenomenon "a consensus with the whole sequence of , especially if many others affirmthe same thingto be coherentwith their phenomena also" (cf. G 3:622). Real phenomena that meet that condition will be said to "cohere well withother itemsin the phenomenal world." Finally,a person mustbe able to predictfuture phenomena on the basis of her experience of ones (G 7:320/L 364). On the internal account this takes the form of requiring that real phe- nomena be usable as guides to anticipatingone's ownfuture expe- riences. In the externalstory it would require thatone's predictions are veryoften borne out by and cohere well withone's own as well as others'experience of the phenomenal world. Since there is no need to pursue persistenceconditions for illu- sory phenomena, we need not present a diachronic account. The synchronicaccount will specifynecessary and sufficientconditions, since it is unlikely that Leibniz there were any further conditionsthat had to hold "outside the head" in order forillusions to exist. In the followingaccounts x ranges over all objects,t over all times,7P over all finite(human and nonhuman) perceivers,s over all perceptual states,and {S} is the set {sl, s2, . .. , sn} of states assigned to P by God at creation. {S} is the embodiment of P's

7Referencesto timesare innocuousso longas we don'tthink that 'time' refersto someNewtonian absolute item that is metaphysicallybasic. Leib- nizholds that time itself is a mereabstract, perfectly continuous conceptual gridin the ideal realm.He allowsdiscrete duration, however, to charac- terizebodies at the phenomenallevel, and it seemshe also mustallow durationto characterizepersisting monads (though he doesn'texplicitly acknowledgethis). Thus I'll freelyhelp myself to discretetimes as waysof measuringspans of, and markingoff points in the courseof, a body's duration.

520 LEIBNIZ'S PHENOMENALISMS

complete concept in the form of a "law of the series" (G 2:262/L 533; G 4:512/L 504), according to which the unfoldingof P's per- ceptual states must follow a specific,determinate causal order.8 Leibniz says those states are characterizedby perceptionand appe- tite,using the appetitiveside of the state to account forP's striving to reach its next state. I'll streamline this by referringto these perceptual/appetitivestates as "perceptual states." We'll call the perceptual account of illusionsP-ILL.

P-ILL: x is an illusoryphenomenon at t iff:at t there is some P that is in some si E {S} such that:si's representationalcontent includes an extended appearance, x, that fails to cohere well with(i) other phenomenal featuresof P's experience and (ii) other items in the phenomenal world, assuming mechanisticlaws.

Here "representationalcontent" is meant to contrastwith the Car- tesian "formalcontent" of mental states,and to pick out its inten- tional content-that is, what the state is ofor about.9In connection with P-ILL (and P-REAL, which follows), I am eliminatingfrom considerationthe cases where si's representationalcontent includes bodies that are perceived unconsciously.In our central text,Leib- niz is consideringonly cases where the subjectis consciouslyjudging objects to be real or imaginary.'Phenomenal features'refers to any aspect of the perceptual contentof P's mind. Mechanisticlaws are meant to rule out idiosyncraticperception. They hold between bodies construed both as featuresof S's experience (thus assuring well-behavedsense data) and as more full-bloodeddenizens of the phenomenal world (well-behavedphysical objects). Next are nonillusorybodies, or real phenomena. To the synchro- nic analysis we here add a diachronic account, but specifyonly necessary conditions for the perceptual account of real phe- nomena, P-REAL:

8See R. C. Sleigh, Jr., Leibnizand Arnauld:A Commentaryon TheirCor- respondence(New Haven: Yale UniversityPress, 1990), 128-30, on the of "real causation" in a substance. 9The formal content would express the representationalcontent and contain nonrepresentationalappetitive and perceptual featuresas well. I don't bring it in explicitlyhere because only representationalfeatures are crucial in spelling out the perceptual account of body.

521 GLENNA. HARTZ

P-REAL: x is a real phenomenonat t only if: at t there is some P that is in some si E {S} such that: six'srepresentational content includes an extended appearance, x, that co- heres well with (i) other phenomenal features of P's experience and (ii) other items in the phenomenal world, assuming mechanisticlaws. x is a realphenomenon that persistsfrom ti to tn only if: at each tibetween ti and tn,some P1 is in some si E {S 1} such that: the representationalcontent of each si includes an extended appearance, x, that coheres well with(i) other phenomenal featuresof P1 's experience and (ii) other items in the phenomenal world, assum- ing mechanisticlaws.

In the diachronic version of P-REAL, we must require that a par- ticular P (P1 here) be the one that is in the various perceptual states.P1's set of career perceptual statesis thus dubbed "{S1}." x's duration is underwrittenby both internaland externalconditions. From the inside perspective,x persistsin virtueof the continuityof P1's experience of x. The external condition requires that P1's experience of x be confirmableby that of other perceiversof the public phenomenal world. Leibniz apparently was not satisfied with these two analyses. They seem to combine Berkeleyan "inside the head" conditions with some very non-Berkeleyanbut neverthelessvague require- ments for something to obtain "outside the head." Recall that in response to Berkeley's "paradoxical" doctrines he wrote: "[W]e have no need to say thatmatter is nothing,but it sufficesto say that it is a phenomenon like the rainbow; and thatit is not a substance, but a result of substances.'0 He chides Berkeley for not going furtherthan simplysaying that the true substancesare "Monads, or Perceivers"-Berkeley should have seen that there are "infinite Monads, constitutingall things."We'll come to the "constitution" accounts soon in the section on mereological phenomenalisms.

"0Quotationsfrom Adams's translationof Leibniz's commentson Ber- keley's ,in A, 222; original text in Willy Kabitz, "Leibniz und Berkeley,"Sitzungsberichte der preussischen Akademie der Wissenschaften, Philo- sophisch-historischeKlasse N. xxiv (Jargang 1932), 636.

522 LEIBNIZ'S PHENOMENALISMS

For now simplynotice thatthe texton whichP-ILL and P-REAL are based is, for Leibniz, uncharacteristicallyepistemic. He's offer- ing littlemore than five-fingerexercises for sortingout veridical from illusory . The analysis does not penetrate very deeply into the metaphysicsbeneath the perceptual process-as is evident especiallyfrom the factthat aggregates and corporeal sub- stances aren't given distinctaccounts. When the criteriaof P-REAL are fulfilled,a giraffeand the pile of stonesit's standing next to are both equally judged "real phenomena." Since these two accounts carry littlemetaphysical punch, theywill not be used to construct our finalcomprehensive lists of sufficientconditions for Leibnizian bodies. Most of the textsare like those we've already examined in section 1. In them Leibniz is hard at work on the metaphysicallyserious side of the perceptual process. One salient mark of this deeper concern is his insistencethat aggregates and corporeal substances be treated quite differently. When discussing distinctivelyperceptual features of objects, he nearlyalways concentrates exclusively on aggregates.Relatively little is said about how corporeal substances are perceived." Still, it is well to remember that theyare: the giraffeis just as visible as the pile of rocks. Following Leibniz's restrictionof the metaphysicallyserious per- ceptual analyses to aggregates,we'll splice togetherall the elements of mental and derivativephenomena (which representtwo differ- ent construalsof aggregates) so far examined and present a com- prehensive perceptual account of aggregates. They will be said to gain unity,color, continuity,and realityfrom the mind's activity.As I said above, Leibniz himselfseldom adds "reality"to the list of perceptual features. Among the rare texts that mightbe read as supporting such an approach is one directed to Des Bosses: "Ag- gregates themselvesare nothing but phenomena, for except the component monads is added by perceptionalone, from the very fact of theirbeing simultaneouslyperceived" (G 2:517/R 249; cf. G 3:622-23; G 2:270/AG 181). Since "everything"is added

"1What Leibniz does say is fairlyvague-though it's explained more fullyin Adams's nice reconstructionat A 231-36.

523 GLENN A. HARTZ by perception,and realityis attributedto the aggregates (and not just to their separate parts), realityseems to be added by the per- ceiving mind. If Leibniz considered mental and derivativephenomena to be amenable to a single metaphysicalanalysis, then the perceptual account of aggregates,P-AGG, representsthat claim:

P-AGG: x is an aggregateat t only if: at t there is some P thatis in some si E {S} such that: si's representationalcontent includes an extended appearance, x, thatis the resultof P's perceivingan infinitecollection of substancesin the phenomenal world; and P considers x to be a unified, colored, continuous,and real thing. x is an aggregatethat persistsfrom tI to tn only if: at each ti between tI and tn,some PI is in some si E {S1} such that: si's representationalcontent includes an ex- tended appearance, x, that is the resultof P1's perceiv- ing an infinitecollection of substances in the phenom- enal world; and PI considers x to be the same unified, colored, continuous,and real thing that it perceived at the other tis.

P-AGG assigns the mind rathera Kantian role. In the synchro- nic account, it constructsx by reading unity,color, continuity,and realityinto what is really a collection of many colorless, discrete, and only separatelyreal things.Apart fromthe mind's work, there is literallynothing in nature over and above the separate parts. As Russell says,Leibniz's positionis reminiscentof the "syntheticunity of apperception":

The mind,and the mindonly, synthesizes the diversityof monads; each separatemonad is real apart fromthe perceptionof it,but a collection,as such,acquires only a precariousand derivedreality from simultaneousperception. (R 116)

In the diachronic account, x's persistenceis just as "precarious" as its synchronicunity, given the fact that it is an unreliable "in the head" affair:it depends on P1's consideringx to be the same thing as was perceived at other times in x's career. There is no "outside

524 LEIBNIZ'S PHENOMENALISMS the head" constrainton the arrangementof the body's parts to well found x's persistence. In P-AGG, si's representational content must include un- consciouslyperceived bodies. Leibniz tellsArnauld thataggregates "exist only in our mind, which bases itselfupon the connexions or modes of genuine substances" (G 2:97/LA 121) and that the mind "takes the opportunityto link together"various modes of genuine substances as a matter of "convenience" (G 2:101/LA 126). Cer- tainlynot all of this"basing" and "taking"is carried out consciously. Of course, unconscious perceptionis easilyaccommodated in Leib- niz's system: expanding si's content in this way is unproblematic. The of unconscious perception here underscores the move fromlight-weight to heavier-weightanalyses: the "real phe- nomenon" criteriaapplied only to cases where fairlysophisticated minds were consciouslyjudging theirappearances coherentor not. With the advent of P-AGG, however, we begin to descend to the deeper monadic level, where much (or, in the case of the "naked monads" (G 6:61 1/L645), all) of what is perceived is below the level of consciousness.

3. Mereological Phenomenalisms

This sectionwill be divided into two parts. In the firstaggregates will be analyzed; in the second corporealsubstances. In P-AGG aggregates were said to be madereal bythe mind. But most often Leibniz describes them as having a realitythat clings to them independentlyof any mind: they seem to be composites of real, mind-independentparts in the phenomenal world. To Ar- nauld he writes:

[W]hatconstitutes the of an entitythrough aggregation is only a stateof beingof itsconstituent entities; for example, what consti- tutesthe essence of an armyis onlya stateof beingof theconstituent men. (G 2:96-97/LA121) I admitthat the body apart,without the soul, has onlya unityof aggregation,but the reality remaining to itcomes from its constituent partswhich retain their substantial unity because of theliving bodies

525 GLENNA. HARTZ

whichare includedin themwithout . (G 2: 100/LA125; cf.G 4:395-96/AG252-53; G 2:261/R249)

And from 1704 and 1711, respectively,we have these:

[T]hereare indivisibleunities in things,since otherwise there will be in thingsno trueunity, and no realitynot borrowed. (G 2:267) [A] mass is an aggregateof corporealsubstances. (G 7:501-2; cf. G 3:260/AG289)

There is a reality"remaining to" the "body apart,without the soul"; there is "in things"a realitythat is "borrowed"by compositethings. This realityisn't attributableto (P-AGG's) mental activity.Instead, it's due to the realityof theparts themselves. As he says in the final quotation, a sample of mass is an aggregate of substances.That is straightforwardmereology. The mereologicalaccount of aggregates,M-AGG, again listsonly necessaryconditions. Persistence conditions won't be offeredsince (1) unlike P-AGG, the mereologicalaccount can't underpin x's per- sistencewith the "considerings"of P: perceiversare altogetherleft out of this analysis; (2) in Leibniz's systemthere isn't any "meta- physical glue" (beyond that of the persistenceconditions on the parts) that can bind one "time-slice"of an aggregate to another; and (3) Leibniz doesn't commit himselfto any constrainton how much those slices must overlap. I shall now and then talk of aggregates as if they were mind- independent collections over and above their parts. This follows Leibniz's tendencyto accommodate the language of common sense and physicalscience for the sake of explaining "the phenomena." As he tells De Volder, strictlyspeaking entelechies can't impel bodies, but "in the phenomena, that is, in the resultingaggregate, everythingis explained mechanically,and masses are understood to impel one another" (G 2:250/AG 175-76). The analysis below should be read in thatspirit. Talk about extra-mentalaggregates is loose, but useful. The collection is just the parts taken together; those parts aren't sewn up withany kind of "metaphysicalthread" or unified by any metaphysicalprinciple.

M-AGG: x is an aggregateat t only if: at t there is some infinite collectionof substances,{C}, such thateach ci E {C} is a proper part of x.

526 LEIBNIZ'S PHENOMENALISMS ci is a proper part of x just in case (i) ci # x; (ii) x is divisible'2 into at least two parts, one of which is ci; (iii) is a properpart of is tran- sitive;and (iv) ci partlycomposes x in everypossible world in which x exists. One may doubt whetherLeibniz would endorse (iv). Certainlyhe allowed that overtime aggregates take on and lose parts (G 2:193/L 521). But the identityof indiscernibles,which in the New Essays (II.xxvii.3-4) is applied freelyto such aggregates as fallen leaves, seems to guarantee that a heap of rocks contains its constituent parts necessarilyat any given time. A differencein constituentsis the only basis for distinctnessbetween aggregates. It mightbe objected thatM-AGG hardly deserves to be called a versionof "phenomenalism,"since it is so far fromEnglish empiri- cistphenomenalisms. But it does deserve the title'phenomenalism' in the levelssense-that is, these aggregates that are pulling their realityfrom their parts are on the phenomenal level of Leibniz's scheme. In M-AGG I've included no constrainton the arrangementof the cis so as to formx. Typically the arrangementrelation between a body and its parts is construed as a spatial one. On the familiar Newtonian scheme, a body "contains"all its parts in the sense that it snugly fitsa region of space, and all of its parts are in proper subregions of that region. Will the same picture apply to Leibnizian aggregates? In an im- portantrecent article,Robert M. Adams has pressed this question of a " of aggregation,"and seems to favor the Newtonian model. He writes,

First... we have to considerwhat is theprinciple that determines howsubstances ... are groupedtogether to forma body.... I think it is fairlyclear that a bodywill be an aggregateof all or mostof the substanceswhose positions are withinsome continuous three- dimensionalportion of space. What portion of space that is, and which substancesare membersof the aggregate,may change over time, of

"2Here 'divisible'will have to be metaphoricalin the cases where monads are the constituents,since monads have no size, and so Leibniz can't mean that extended bodies are literallydivisible up into nonextended parts. Some of these constraintson proper parts are derived fromRoderick M. Chisholm, "Parts as Essential to their Wholes," Review of Metaphysics26 (1973): 581-603.

527 GLENN A. HARTZ

course.This spatialtogetherness is a necessarycondition for any cor- porealaggregation, but it is presumablynot a sufficientcondition.... Forsuch unity, additional, quasi-causal conditions on theway in which themembers of theaggregate change their positions relative to each otherwill also be necessary.(A 237)

Turning to the question of what determinesthe positionsof these substances, Adams says that in the case of corporealsubstances, "[t]he positionof the corporeal substancewill surely be the position of its organic body. The organic body is a phenomenon, spatial position is a phenomenal ,and the spatial position of the organic body is givenin appearance" (A 237). When the substances are monads,they are granted "spatial positions" by "assigning to each simple substance the spatial positionof itsorganic body (cf. G 2:253/L 531), for, according to Leibniz, each simple substance is the dominant monad of an organic body" (A 237). In support of Adams, a few textsfrom the mature period seem to indicate that bodies and monads are in space. The strongest passage is his remarkto De Volder in 1705 that "... no assignable part of space [spatii]is withoutmatter" (G 2:278/R 245). He had told De Volder two years earlier:

Althoughmonads are notextended, they nevertheless have a certain kindof positionsitsu] in extension,that is, they have a certainordered relationof coexistencewith others, namely, through the machine whichthey control.... Extendedthings involve a pluralityof things endowedwith position, but things which are simple,though they do nothave extension,must yet have a positionin extension.(G 2:253/L 531)

And to Des Bosses in 1709 he writes:

Perhapssomeone would say thatsouls ... are in a place [loco]only throughcorrespondence and thatthey are thusin thewhole organic body whichthey animate.... But because such a thingcannot be explainedby the phenomena and changesnothing in them,I cannot explainany more distinctly of whatthis union formally consists. It is enoughthat it is tiedup withthe correspondence. (G 2:37 I/L 598)

Clearly Leibniz is attributingsome sort of position to bodies, since he's using them as a way to locate monads or souls. But we should resistthe temptationto call it spatialposition. Notice that the term

528 LEIBNIZ'S PHENOMENALISMS

'space' isn't used in any but the firsttext, which seems to be a rare departure fromthemes found in the clear majorityof texts.In the others, vague gestures towards spatial conceptsare all we get-"a certain kind of situation in extension," "a position in extension," and "place," but never "space." In the last passage to Des Bosses he even puts the claim in the mouth of someone else, and handwav- inglydenies thathe can do betterthan the vague "correspondence in the body theyanimate." Recall from section 1 that Leibniz claims it's an errorto thinkof aggregates as having (P-AGG's) spatial continuity.It is the "faultof our senses" that we "conceive physical things as mathematical " thathave "some indeterminacy"-thatis, true continuity(G 7:563). As J. E. McGuire notes, ". . . extended things are . . . in realitya pluralityof substancesthat appear to be continuous.....13 The factthat extension involves spatial conceptsdoes not threaten the distinctionbetween it and space. Leibniz holds thatspatial con- cepts can be "useful" (G 7:401; cf. G 4:569/L 583; G 6:584/L 621- 22; G 2:282-83/L 539) in helping us keep track of the relative locations and movementsof bodies-providedthat we don't let them fool us into thinkingof bodies as actuallycontinuous in the sense of being arbitrarilydivisible. Thus spatialitydoes migratea bit from its home in the ideal realm down into the phenomenal realm due to the work of the mind. In the passage above, Adams seems to be thinkingof spatial position in this sense, since he construesit as a phenomenal qualityderiving from the way an aggregateappears to perceivers. But Leibniz says thatthere is one typeor "side" of extensionthat reallyis present at the phenomenal level-namely, the spread-out- ness of bodies. Let us call this extension of bodies concretebodily extensionto distinguishit fromabstract, ideal, trulycontinuous "ex- tension"-that is, space. He explains thisconcrete bodily extension when he writesin 1702:

[S]ince extension is a continuous and simultaneousrepetition . . ., it followsthat whenever the same natureis diffusedthrough many thingsat thesame time,as, forexample ... resistanceor impenetra- bilityis generallyin body,extension is said to have place locumm].

13McGuire, "'Labyrinthus Continui'," 306.

529 GLENN A. HARTZ

However,it mustbe confessedthat the continuous diffusion of color, weight,malleability, and similarthings that are homogeneousonly in appearanceis merelyapparent, and cannotbe foundin thesmallest parts.... (G 4:394/AG251)

And in a 1711 dialogue criticalof Malebranche there is this:

[E]xtension... impliessome , some attribute, some naturein the subjectwhich is extended,which is expandedwith the , whichis continued.Extension is the diffusionof thatquality or na- ture. ... [T]here is ... in body in general an extension or diffusionof antitypyor of materiality.(G 6:584/L621; cf.G 7:398-99)

Thus, whereas there is no such thing as a region of arbitrarily divisiblespace in the phenomenal world, there are regions of con- crete bodily extension-places in whichthe discreteparts of bodies actually are diffusingforce, resultingin a body with "resistance," "impenetrability,""antitypy" or "materiality."Notice just how non- perceptual this picture is. Leibniz isn't tellingus about how aggre- gates appear to us-that's a separate account, and one that is mis- leading to the extent that it attributesspatial continuityto them. But despite these differencesbetween them,Adams doesn't sun- der the perceptual account fromthe mereologicalone. Though he recognizes that they are conceptuallydistinct and that theymight be taken for "two competing analyses" (A 247), he keeps them together.Leibniz, he claims,regarded themas (1) consistent(see G 2:267; G 2:270/L 537; G 3:622f.) and (2) "at least materiallyequiva- lent." Adams explains the materialequivalence:

I think. . . that there is a true scientificstory [i.e., thatorganic bodies have positions in a coherent systemof phenomena that are repre- sentedby mostof the perceptionsof all perceivers]that is alwaysat least unconsciouslyperceived by all monads,that most of whatap- pears consciouslyto consciousperceivers fits at leastapproximately intothat story, that there are infinitelymany monads whose proper- tiesare expressedby organic bodies that would figure in a sufficiently detailedextension of thetrue scientific story, that aggregates of these monads ... can ... be regarded as the bodies that figure in the true scientificstory, and thusthat the bodiesof the truescientific theory are realaccording to bothaccounts, both as coherentphenomena and as aggregates of real things.(A 246-47)

530 LEIBNIZ'S PHENOMENALISMS

There is no doubt that on Leibniz's showing the accounts are con- sistent:aggregates can be apparentlyunified, colored, and continu- ous phenomena and yet actually be nonunified collections of colorless, discrete things. But it is Leibniz's explicit discountingof the perceptual qualities in favor of the mereological ones that makes the consistencypossible. Since Adams doesn't followLeibniz in this, Adams owes us an explanation of how the accounts are consistenton his interpretation. Material equivalence is even harder to establish,especially if the accounts are spelled out in detail. At a very abstract level they mightseem equivalent:

(i) x is a coherent phenomenon perceived (possibly uncon- sciously)by all monads iffx is an aggregate of an infinityof monads or corporeal substances whose properties are ex- pressed by those organic bodies referredto by the true scien- tificaccount of the world.

But when we include details the equivalence vanishes:

(ii) x is a unified, continuous, and colored coherent phenome- non perceived (possiblyunconsciously) by all monads iffx is a nonunified and discontinuous aggregate of an infinityof colorless monads or corporeal substances whose properties are expressed by those organic bodies referredto by the true scientificaccount of the world.

(ii) is incoherent because it attributesto x logically incompatible properties.It can regain coherence onlyby using Leibniz's maneu- ver-namely, changing 'x is a unified. . . phenomenon' to 'x appears to be a unified ... phenomenon'. So Adams's attemptto construe spatial position as a "phenome- nal property" that is "given in appearance" won't work for the mereologicalmodel. A logicalbarrier prevents us fromtransferring spatial continuityfrom the perceptual to the mereologicalaccount. Of the three main perceptual properties-unity,color, and spatial continuity-Leibniz says spatial continuityis, froma metaphysical standpoint,its mostmisleading feature. Thus, far fromspatial prox- imitybeing a necessarycondition for aggregates,it is irrelevantto theircomposition.

531 GLENN A. HARTZ

I emphasize that we are followingLeibniz in cuttingperceptual construals free from nonperceptual ones. Among the perception- independent properties Leibniz attributesto aggregates (in texts like those we'll examine presently)are discreteness,concrete bodily extension,duration, motion, derivative force, and antitypy,but not spatiality.The closest aggregates come to being in space is their having concrete bodily extension. But for Leibniz the fact that bodies are extended does not entail, as it did for Newton and others, that bodies are in space. Puttingthe Newtonian and Leibnizian theories to Locke's "vac- uum test" will help clarifythe differencebetween them. Suppose we have a body. Suddenly it's annihilated-say by God, to ensure there's no residue. What's left?Newton (and Locke) would say that the region of space it occupied is still there, serenely holding its spot in the eternal and immovable matrixof absolute space. Leib- niz, by contrast,must say that literallynothing is left. Concrete bodily extension is the diffusionof some quality or nature. By hypothesis,the quality or nature is no longer there to be "contin- ued" or extended, and so (per impossibile,for Leibniz (G 2:193/L 521)) we'd be leftwith an utterand complete metaphysicalvacuum. Here we have a much differentpicture of Leibniz's phenomenal world than the one offeredon Leibniz's behalf by Adams. By fol- lowing out the implicationsof the perceptual story,Adams is led to suggestthat Leibniz's phenomenal world is a lot like the Newtonian world, where one gets an aggregate by crowding parts into more and more closely neighboring regions of space. Leibniz can't be thinkingof aggregates as constructedon that model. But Leibniz himself is guiltyof generating confusion on this topic. He sometimes obscures his space/extensiondistinction by using 'extension' to mean what he normally would be calling "space"-especially when addressing an audience allied with the Cartesians. Fortunately,the context usually disambiguates 'exten- sion'. When he's using 'extension' to mean space rather than con- crete bodily extension, he typicallyclassifies it with motion, time, mathematicalbodies, and other ideal continuous items,as he does in his 1702 response to Bayle:

I acknowledgethat time, extension, motion, and the continuumin general,as we understandthem in ,are only ideal things-thatis, they express possibilities, just as do .... But

532 LEIBNIZ'S PHENOMENALISMS

to speakmore accurately, extension is the order of possible coexistence, just as time is the order of possibilitiesthat are inconsistentbut neverthelesshave a connection.... Butspace and timetaken together constitutethe order of possibilitiesof theone entireuniverse, so that theseorders-space and time,that is-relate notonly to whatactually is but also to anythingthat could be put in itsplace, just as numbers are indifferentto thethings which can be enumerated.The inclusion of the possiblewith the existent makes a continuitywhich is uniform and indifferentto everydivision.... [T]he actualworld does not re- main in thisindifference of possibilitiesbut arisesfrom the actual divisionsor pluralitieswhose resultsare the phenomena.... (G 4: 568/L583)

The "actual world" doesn't remain in an "indifferenceof possibili- ties": that means that actual bodies can't be in space, since other- wise they'dbe, like Cartesian bodies, indifferentlydivisible into an infinitevariety of parts. Puttingbodies in space would make them as continuous as the space itself.As C. D. Broad says of Leibnizian matter:

Matteris notcontinuous in thesense in whichthe space of thegeome- tersis said to be so. For thatkind of continuityconsists in havingno definiteunits, and beingdivisible in innumerablepossible ways but not actuallydivided in any. Matter ... is actuallydivided into natural in- trinsicextended units. 14

Bodies belong on the phenomenal level as "pluralities"of discrete substances; space belongs on the ideal level since it has no actual parts and is arbitrarilydivisible into merelypossible parts. It is importantto note that Leibniz is not denying the infinite divisionof bodies. That, he says, already holds in virtue of their being composed of an infinitenumber of discretesubstances. What he objects to is, as Broad says, arbitraryinfinite divisibility-that is, what we've been calling "spatial continuity."Were bodies spatially continuous, they would be indeterminate at the core and thus would lose all claim to reality. In 1703 he develops this theme, tellingDe Volder that there must be a radical metaphysicalsepa- ration of "real" actual bodies from ideal space and time:

14C. D. Broad, Leibniz:An Introduction,ed. C. Lewy (Cambridge: Cam- bridge UniversityPress, 1975), 75.

533 GLENN A. HARTZ

[I]t follows from the very fact that a mathematicalbody cannot be analyzed into primaryconstituents that it is also not real but some- thing mental and designates nothingbut the possibilityof parts, not somethingactual. A mathematicalline, namely,is in this respect like arithmeticalunity; in both cases the parts are only possible and com- pletelyindefinite.... But in real things,that is, bodies, the parts are not indefinite-as they are in space, which is a mental thing-but actually specified in a fixed way according to the divisions and sub- divisionswhich nature actuallyintroduces.... (G 2:268/L 535-36)

In this stretchof correspondence he returnsto the same motifin 1705, where he surroundsthe inconsistencymentioned earlier with lots of familiarthemes:

Matter is not continuous but discrete,and actuallyinfinitely divided, though no assignable part of space is withoutmatter. But space, like time,is somethingnot substantial,but ideal, and consistsin possibili- ties, or in an order of coexistentsthat is in some way possible. And thus there are no divisionsin it but such as are made by the mind,and the part is posteriorto the whole. In real things,on the contrary,units are prior to the multitude,and multitudesexist only through units. (The same holds of changes, which are not really continuous.) (G 2:278-79/R 245)

That problematiccomment might be an ill-expressedversion of his doctrinethat no part of natureis empty.If so, it was betterput here:

[P]arts can be replaced by others in every extended body. Thus no part has a necessaryconnection with any other part,even though it is true of matter in general that when any part is removed, it must necessarilybe replaced by some other part. (G 2:193/L 521)

Finally,there is this fromthe Des Bosses correspondence of 1709:

Mass and its diffusionresult frommonads, but not space. Space, just like time, is a certain order . . . which embraces not only actuals, but possibles also. Hence it is somethingindefinite, like everycontinuum whose parts are not actual, but can be taken arbitrarily.... Space is something continuous but ideal, mass is discrete, namely an actual multitude,or being by aggregation,but composed of an infinitenum- ber of units. In actuals, single termsare prior to aggregates,in ideals the whole is prior to the part. (G 2:379/R 256, 245; cf. G 2:336; G 2:282/L 539)

534 LEIBNIZ'S PHENOMENALISMS

Given those texts,it seems that if we want to know what "prin- ciple of aggregation"the historicalLeibniz had in mind for aggre- gates construed mereologically,the supposed "spatial positions"of their parts won't help us. Space is an ideal, abstract,continuous, arbitrarilydivisible grid that has no actual parts; aggregates are phenomenal, concrete, discrete, actually divided bodies that are made up of an infinitenumber of actual parts. It won't do to suppose this is a mere logomachy-as if Adams could correct his account by simply replacing all occurrences of ''space" and itsderivatives with those of"extension." This would be only a cosmetic change. Adams does recognize that in Leibniz's opinion, ".... the aggregation of monads by spatial , to formbodies, is ... dependent on perception since monads do not have spatial properties in their own rightbut are spatiallyrepre- sented in our perceptions"(A 241). Still,instead of followingLeib- niz in throwingthe perception-relative"spatial relations" on the scrap heap, he pushes them into earnest metaphysical service. They are to act as "the principle of grouping that defines the ag- gregate" (A 241). Those spatial relationsbring withthem the very "side" of extension Leibniz most wanted to avoid attributingto aggregates: perfectcontinuity. Thus Adams finallypays the price for ignoringthe perceptual- mereological distinction.He finds a perfectlyrepresentative text puzzling:

Can aggregatesof substancespossess the physicalproperties that bodieshave in thestory told by science? It mightseem, in particular, thatan aggregateof simple substances would not be continuousbecause itis composedof parts that cannot be dividedagain into parts and that do not adjoin or overlapeach other.Leibniz seems to say as much himselfin hislast letter to De Volder(G 2:282/L539); butthat passage is a difficultone in whichhe also appearsto have forgottenhis doc- trinethat aggregates, even aggregates of real things,are phenomena. (A 242)

One person's lapsusis another's locus classicus: here is the "difficult passage," crammed full of claims that accord perfectlywith the others we've examined:

... [I]n actual bodies thereis onlya discretequantity, that is, a multitudeof monadsor of simplesubstances, though in anysensible

535 GLENN A. HARTZ

aggregateor one correspondingto phenomena,this may be greater thanany given number. But a continuousquantity is somethingideal whichpertains to possiblesand to actualitiesonly insofar as theyare possible.A continuum,that is, involves indeterminate parts, while on the otherhand thereis nothingindefinite in actualthings, in which everydivision is madethat can be made.... [T]he partsare actuallyin the real wholebut not in the ideal whole.But we confuseideal with real substanceswhen we seek foractual parts in the orderof possi- bilities,and indeterminateparts in theaggregate of actual things, and so entangleourselves in the labyrinthof the continuum.... (G 2: 282/L539)

Adams misses a crucial turn in Leibniz's subtle way through that "labyrinth"when he offersthis "solution" to the puzzle:

We could say,however, that, though monads may be elementsof cor- porealaggregates, the relevant parts of theaggregate are notmonads butsubaggregates containing infinitely many monads. The aggregate willbe divisiblein indefinitelymany and variousways into subaggre- gatesof thissort, which will themselves be similarlydivisible into sub- aggregatesand whichmay overlap each otherin theirmembership or mayshare a common"boundary" of monads.In thisway, the aggre- gate as such can have the mathematicalstructure of continuity.(A 242)

Several thingsneed to be said about this passage: First,Adams can postulate "subaggregates"only by (i) assuming there's a prin- ciple of aggregationfor them-somethingthat, with the collapse of the "spatial position"line, is dubious; and (ii) assuming,against our textual evidence, that Leibniz would accept as coherent the notion thatmonads can have the spatial positionthey'd need in order to be located along the "boundaries" of subaggregates.Against (ii) there is an additional text from 1714 that seems decisive:

We mustnot conceiveextension as a real continuousspace, strewn withpoints. These are fictionsproper to contentthe imagination.... Nor mustwe conceivethat monads, like points in a real space,move, push,or toucheach other;it is enoughthat phenomena make it seem so.... (G 3:623/R255)

Second, even apart from the difficultiesof attributingspatial position to monads, there is the larger issue of squaring thisclaim with the thrust of Leibniz's mature doctrine of the continuum.

536 LEIBNIZ'S PHENOMENALISMS

What Leibniz saw as his most profound "solution" to the con- tinuum problem involvesthe claim thatno bodies in nature can be what Adams here says theycan be-"divisible in indefinitelymany and various ways." As we've seen, Leibniz'sparts for all bodies are exemplary in their discreteness: they are perfectlyone. (Adams seems to thinkit's onlysimple-substance-composites that would cre- ate problems,but corporeal-substance-compositeswould be just as problematic,since both types of substances are discrete.) Those perfectlydiscrete parts can't be taken and transferredto some intermediatelevel between the deepest monad level and the super- ficialaggregate level, there to be mixed up so thoroughlythat they finallysomehow lose their discretenessand get blended together into subparts of a genuinely continuous whole. It would be like tryingto turn a pile of sand into glass by placing some of the sand particles edge to edge. For Leibniz, only space is genuinely con- tinuous; it is a whole that can be divided up "in indefinitelymany and various ways." But bodiescan't: they're already divided into discrete parts in a determinate,nonarbitrary way. If Adams were right,God would in some cases have to make an arbitrarydecision about whichsubaggregate-sl or s2-monad mbelonged to since it would be on the "boundary" between the two subaggregates.This is dramaticallyat odds withLeibniz's claim thatthe parts of matter are "specified in a fixed way according to the divisions and sub- divisionswhich nature actuallyintroduces . . ." (G 2:268/L 536). Failing to uncouple the perceptual (P-AGG) and mereological (M-AGG) accounts of aggregatesresults in what Leibniz calls "con- fusingthe ideal with the real." By looking for the parts of bodies among indeterminatesubaggregates, Adams is doing what Leibniz says one can't do when handling questions about the continuum- searching for "indeterminate parts in the aggregate of actual things"(G 2:282/L 539). Can we answer Adams's originalquestion: what is Leibniz's prin- ciple of aggregation for aggregates considered mereologically? Adams rightlyrejects Russell's attemptto answer this by appeal to the pointsof view of monads (A 238-39). His onlyother suggestion concerns"quasi-causal conditionson the wayin whichthe members of the aggregate change theirpositions relative to each other." But the single text (G 2: 100/LA 126) marshalled in support of it seems readily construable as a perceptualfeature-a constrainton the

537 GLENN A. HARTZ

"connexions between the constituents"of aggregatesthat the mind notices when it unifies the aggregate. And if Adams's proposed substitutefails, what works?Nothing. Leibniz never tells us that any metaphysicalprinciple binds the parts of an aggregate together.In fact,if there were such a prin- ciple, it would contradict his claim to Arnauld that an entity through aggregation "is only a state of being of its constituent entities."There just is nothingthere over and above the parts, in metaphysicalrigor. Aggregates may be perceivedas colored, but it doesn't followthat they are. Similarly,their parts may be perceived as closely bound together in a continuous whole, but it doesn't followthat they are close togetherin any intelligiblesense of 'close'. Actually, it's unremarkable that he had nothing to say about principlesof aggregation. Aggregates are too sloppy to be united by any metaphysicalprinciple. In the case of such special aggre- gates as organic bodies, we aren't surprisedto find Leibniz saying a bit about how the parts must be arranged so as to form a "ma- chine" (G 4:480-82/L 455-56; G 2:251/iL529-30; G 6:598-600/L 636-37; C 13-14/P 175; G 4:396/AG 253; Monadology,secs. 63-64). Moreover, we'd expect such super-special,truly unified bodies as corporeal substancesto be united by a metaphysicalprinciple-and sure enough they are: by dominant monads. But a principle of unityfor a sand dune? That's completelyalien to Leibniz's cast of mind. The most we know about aggregates is that when they're perceived their parts seem to be close together,but there just is nothing to know about why those parts count as beingtogether. What he said to Arnauld seems to hold for nongenuine substances (aggregates) as well as genuine ones: "One willnever findany fixed principle for making a genuine substance from many entitiesby aggregation . . ." (G 2:101/LA 127). We turn now to Leibniz's mereologicalaccount of corporeal sub- stances. This involves what might be called an "enriched" mere- ology,since instead of lettingall the parts performan equal role in constitutingthe whole, it singles out one special part as thatwhich is mostcrucial in formingthe composite.That one part-the domi- nant monad-is assigned the role of supervisoror unifierof the others. We can begin witha passage to De Volder (G 2:252/L 530-31) in which Leibniz (conceptually)isolates four items thatjoin together

538 LEIBNIZ'S PHENOMENALISMS

to form a complete organism. Combining this anatomy of corpo- real substanceswith material from other textswe get the following:

(1) thesoul; "primitiveentelechy"; ""; "the first recipient of activity"originally possessing the "law of the series" (G 4:512/L 504; G 2:262/L 533); has primitiveactive force (GM 6:236/L 436; G 2:250-5I/L 529-30; G 3:622; G 7:502; G 2:270/L 537; G 4:395/AG 252; G 3:260/AG 290; G 3:356; G 3:457). (2) primarymatter; has primitivepassive force (GM 6:236-37/L 437). (3) thecomplete (dominant) monad formed by (1) and (2); pos- sesses the "law of the series" because it is partlycomposed of (1) (G 2:262/L 533); has primitiveactive and passive force (G 2:251/L 530), or simply"primitive force." (4) mass(Latin massa); "secondarymatter"; (composes) "aggre- gates"; is a "well-foundedphenomenon"; has unityper ac- cidens(G 2:76/LA 94; G 3:657); (appears as) "phenomena"; the "organic body" or "organic machine" composed of sub- ordinate monads; has derivativepassive force (GM 6:237/L 437). (5) Together (3) and (4) constitute"the animal or corporeal substance which the dominating monad makes into one machine" (G 2:252/L 530-31); has life(C 13-14/P 175); has unity per se (G 3:657); has derivativeactive and passive force,or "simplyderivative force."

We have (5) when the conditions for the mereological analysis of corporeal substance are realized:

M-CORP: x is a corporealsubstance at t only if: at t there is an infinitecollection, {C}, of substancesand a dominant monad, D, thatunites itself so completelywith {C} that togetherwith {C} it formsa livingthing, x. x is a corporealsubstance that persistsfrom tI to tn only if: at each tjbetween tI and tn,there is an infinite collection{Cj}, of substances and the same dominant monad, DI, which unites itselfso completelywith {Cj}

539 GLENN A. HARTZ

(which shares at least one part withthe {Ci} to which Dl was joined at the immediatelypreceding ti) that togetherwith {Cj} it formsa livingthing, x.

Leibniz explicitlyallows the "secondarymatter" or "organicbodies" of corporeal substances to take on and lose parts constantlyover time (G 2:193/L 521; C 16/P178; G 2:120/LA 153; G 6:601/L 638); thus in the diachronicversion of M-CORP there is no requirement that the same {C} partlyconstitute a persistingcorporeal substance during its entire career. Still,he insiststhat ". . . souls never leave the whole of theirbody, and do not pass fromone body to another which is entirelynew to them" (G 6:601/P 199). Thus each collec- tion must share at least one part withthe previous one. A given {C} is a "temporarily[pro tempore]immediate requisite" (G 2:120/LA 153) for an animal's at any time,but that particular{C} need not partlycompose it at any later time. DI, not {C}, carries identity.Here 'livingthing' means somethingthat is alive only in a very general sense-it may be like the naked monads. Adams asks forand doubts thathe can findan account of howthe dominantmonad "formsa livingthing" out of itselfplus an organic body:

GivenLeibniz's doctrine that "there is nothingin thingsexcept simple substances,and in themperception and appetite"(G 2:270/L537), thereis no wayfor the unity of a corporealsubstance to be anything over and above the systemof relationsamong the perceptionsof monads.(A 248)

Indeed, Leibniz offersus almost no account of how the dominant monad performsits magic. But acts of metaphysicallegerdemain are common in his philosophy: what could be a more spectacular stuntthan pulling monadsout of a hat? Even if no account of howis available, dominant monads must make corporeal substancesinto true unities-if not, Leibniz can't meet the demands of his "re- visionary"metaphysics. I said Leibniz offers "almost no account" because Leibniz ad- dresses this question very brieflyand obscurelyin the correspon- dence with Des Bosses. There he develops the vexed notion of a "substantialbond." It is vexed because in the course of expounding it he violates claims he makes repeatedly elsewhere, both before

540 LEIBNIZ'S PHENOMENALISMS and afterthe relevantletters. The bond is a "real unifier"everlast- inglyattached to a dominant monad, which in turn is supervising the monads in an organic body. This violatesthe famous "nothing in thingsexcept simple substances"claim. If thatis not enough, he says "substantiallybonded" corporeal substances have "real conti- nuity"(G 2:517)-that is, a nonperceptual continuitythat is actu- ally there independentlyof our minds. And that can't be squared with the textswe've just examined concerningthe discretenessof body. For the sake of completeness,I'll presenta mereologicalanalysis of substantiallybonded corporeal substances. It is so far fromthe considered doctrinesof mature Leibniz, however,that it won't be developed in the final section into a comprehensive doctrine of body, and only necessaryconditions for a synchronicaccount are provided:

M-BOND: x is a substantiallybonded corporeal substance at t only if: at t there is a corporeal substance,y, to whose domi- nant monad, D, a substantialbond, B, has been ever- lastinglyassigned so that B makes y into a perfectly continuous,real body, x.

Before leaving this section, I must respond to some objections: On this view, (i) any arbitrarycollection of monads will constitute an aggregate; (ii) a world might contain preciselythe same sub- stances as exist in thisworld, yet have no aggregates in it; and (iii) in 1712 Leibniz wrote,in a study for a letterto Des Bosses, that

thedistinction between the appearance bodies have with respect to us and withrespect to God is,in a certainway, like that between a draw- ing in perspectiveand a groundplan. For thereare differentdraw- ingsin perspective,depending upon theposition of theviewer, while a groundplan or geometricalrepresentation is unique. Indeed, God sees thingsexactly as theyare in accordancewith geometrical truth, althoughhe also knowshow everythingappears to everythingelse, and so he eminentlycontains in himselfall otherappearances. ... (G 2:438; AG 199)

As to (i), yes, any collection could constitutean aggregate-so long as it contained an infinitenumber of substances.The objector seems worried thatthe parts may be too "scattered"to be properly

541 GLENN A. HARTZ unified,but thatinvolves, again, bringingspatial mattersto bear on Leibniz's purely qualitative realm of substances. The substances exist and can be grouped in various waysby minds into collections, but the substances themselvesaren't grouped. The worryabout arbitrarinessseems not so much to conflictwith Leibniz's beliefsas to bear out his claim that they have mere unityper accidens(G 2:76/LA 94; G 3:657/R 226). To (ii) I replythat this world is the one described: it contains exactlythe substances it has, and no extra- mental aggregates. Finally,(iii). This textkeeps verybad company. In it Leibniz first adumbrates the notorious concept of a substantialbond that sur- vivesin the letteractually sent to Des Bosses. The bond is described here as a "relation through which one new substance arises from many substances"(G 2:438/AG 199). That's anathema to the Leib- niz who wroteto Arnauld thatone willnever finda fixed principle for generatinga genuine substance frommany by aggregation (G 2:101/LA 127). So when he says in the same breath thatGod knows things"exactly as theyare in accordance withgeometrical truth," I thinkwe'd bettertake it as noise, not message. Some support for this dismissal comes fromthe fact that this is one of the claims he withheldfrom the letteractually sent to Des Bosses. Des Bosses was to receive quite a few claims that compromised Leibniz's official positions,but thisone, we can suppose, was so far afield that Leib- niz wouldn't even send it to him. Of course, given the proper interpretationit mightnot be pure noise. God knowsall the substancesthoroughly and he knowswhat relationsthey hold to each other throughpreestablished harmony. Some of these relations hold between a corporeal substance's body's perceptual organs and the surroundingsubstances, allowing for its confused perception of a collection of them as, say, a red ball. As the textsays, God also knowswhat the red-ball-appearance looks like to finitesubstances. One could thinkof this on analogy with a set of monitors,one for each finitesubstance, that an om- niscient God is always scanning. But I am claiming, against any other interpretationof this text,that Leibniz's considered opinion is that whenall themonitors are turnedoff, aggregate-appearances, like colors,vanish in thatinstant. When God scans, not the monitors,but nature itself,he sees only substances-simple ones at the funda- mental level, and corporeal ones in the phenomenal world. This is confirmedby Leibniz's statementin a dialogue on Malebranche's

542 LEIBNIZ'S PHENOMENALISMS theories-dated to the very same year as the Des Bosses study: ". . . [A] body is not a true unity;it is only an aggregate,which the Scholasticscall a being peraccidens, a collectionlike a herd. Its unity comes from our perception. It is a being of reasonor rather, of imagination,a phenomenon"(G 6:586/L 623; G 2:306; G 2:250/L 529). (After translatingthat passage, Leroy Loemker, perhaps overcome by what I call "Leibniz scholar vertigo,"can't forebearto exclaim in a footnote:"Thus Leibniz reaffirmshis phenomenalism at the verytime of his discussionof the vinculumsubstantiate and the real nature of bodies with Des Bosses" (L 628). There simply is more than one Leibniz writingabout bodies in the mature period.) Thus on the textual matterI say: Leibniz issued the catalogue, but can't really offer everythingin it. The charitable commentator must order much less than everything,on pain of incoherence. So I'm declaring for the Leibniz who sent to several correspondents clear, bold claims that are almost never gainsaid elsewhere, and against the Leibniz who wrote but then withheld,in one tenuous exchange of letters,a radicallyinconsistent one. Notice thatin P-AGG, the subjectof predicationfor an aggregate is an "extended appearance, x." x is an appearance of an infinite collection of substances, but the aggregate isn't identified with the collection. It's identified with the appearancein a finitemind. This stands in marked contrastto M-CORP, where the subject of predication for a corporeal substance is an extra-mental"living thing,x."

4. A Supervenience Phenomenalism

The supervenience model provides a differentway of analyzing bodies. Since Leibniz saysall bodies have the propertiesspecified in the supervenience analysis,we won't need to specifyseparate con- ditions for aggregates (considered here as extra-mentalphysical objects in accord withthe scientificstandpoint) and corporeal sub- stances. All bodies will be said to have a derivative reality that supervenes on the primitivereality of their constituents,as gela- tinitysupervenes on the molecular structureof its constituents. If supervenienceis viewed, as it typicallyis, as a relationbetween familiesof properties, then it is quite a separate matterfrom mere- ology. Still,the topicsare related.Jaegwon Kim calls a keyprinciple closely allied to supervenience "mereological ":"the

543 GLENN A. HARTZ

Democritean credo that wholes are completelydetermined, caus- ally and ontologically,by theirparts, that if you make a replica of an object by puttingit togetheratom by , particleby , you get the 'same' object."15Thus a lake is reducible to the collec- tion of its constituentwater : this is a lake iffthese mol- ecules are so related. Supervenience, by contrast,is intended to be a nonreductive relation,and need not involve mereologyat all. Of course, as Kim argues, strong supervenience-the one Leibniz endorses-seems on close scrutinyto be a reductive relation after all.16 But with respect to ,I can claim that my moral goodness super- venes on-is determinedby-my purely descriptivefeatures with- out presupposing a particularanswer to the question, Am I reduc- ible to parts which have purely descriptive properties? As Kim notes, most people who make the supervenienceclaim about prop- ertiesdo so at least in part because they'recommitted to the mereo- logical claim-but the claims remain conceptuallydistinct. Mereologymay actually be sundered fromsupervenience in some unusual cases. For example, the properties of magnetic fields supervene on-are determinedby-those of movingelectric fields. But it is unclear how one mightconstrue the electricfield as partof the magnetic field. Perhaps this is sheer property-to-propertysu- pervenience, with no "mereological determinism"story tied to it. Since thereis a conceptual differenceand perhaps a real difference in some cases, I will followKim in distinguishingmereological super- veniencefrom the more mainstreamproperty supervenience. Still,Leibniz takes the usual tack and presentsmereological and propertysupervenience in tandem. As we have seen fromour dis- cussion of his mereologicalphenomenalisms, bodies are mereologi- cally supervenienton theirsubstances. To thishe adds the further claim thattheir properties are property-supervenienton the prop- erties of those more basic constituents. Especially after 1695 Leibniz often claimed that derivativeforce formsthe essential nature of all bodies and that it supervenes on the primitiveforce of the more basic substances"beneath" them. He

"5JaegwonKim, "Supervenience and Nomological Incommensurables," AmericanPhilosophical Quarterly 15 (April 1978): 149-56, at 154. '6Jaegwon Kim, "Concepts of Supervenience," Philosophyand Phe- nomenologicalResearch 45 (December 1984): 153-76.

544 LEIBNIZ'S PHENOMENALISMS

distinguishesbetween active and passive versions of these , but for our purposes we can ignore the active/passivedistinction. Representativetexts include these. First,from 1695:

Activeforce ... is oftwo kinds. The firstis primitive force, which is in all corporealsubstance as such.... The secondis derivativeforce, which is exercisedin variousways through a limitationof primitive force.... [W]e understandby derivative force ... onlythat force which is con- nected with ... local motion. ... For we admit that all other material phenomenacan be explainedthrough local motion.(GM 6:236-37/L 436-37; cf.G 4:396/AG253)

When writingto De Volder in 1703, he says we need only consider "derivativeforces" in aggregates,since the aggregates arise "from the realityof the monads" (G 2:250/L 529), adding that "[d]eriva- tive forces are in fact nothingbut the modificationsand echoes of primitiveforces" (G 2:25 I/L 530). A year later there is this:

[U]nlessthere were some primitive active principle in us, therecould be no derivativeforces and actionsin us, sinceeverything accidental or changeablemust be a modificationof somethingessential or per- petual... since... a derivativeforce [is a modificationor limitation] of thatwhich it varies.(G 2:270/L537)

That derivativeforce is in corporeal substances as well as aggre- gates is unmistakablyconfirmed in the last text,where he attributes it to "us," the paradigmaticcorporeal substances. From derivativeforce proceeds all bodilychange at the phenom- enal level, and through it all "material phenomena" are to be ex- plained. All other features of bodies-their extension, duration, and motion-flow out of this one "superproperty."As he says in the last quotation, derivativeforce is a determinantor "modifica- tion" of the "essentialor perpetual" determinable,primitive force. When a corporeal substance is a "large" one made up of many smallerones, the larger one's derivativeforce still ultimately finds its source in the primitiveforce possessed by those smaller corporeal substances' constituentmonads. Like the mereologicalaccounts, the supervenienceanalysis views bodies froma thoroughlyextra-mental standpoint. But the mereo- logical accounts trainedthe spotlighton the whole as dependent on its parts. By contrast,the supervenience analysis emphasizes the fact that the whole's propertiesdepend on the parts'properties.

545 GLENN A. HARTZ

We are nearly ready to define Leibniz's property-supervenience relation. The modal claim inherent in that relation requires a strong, but less than logically necessary, connection to hold be- tween "subvenient"and supervenientproperties. Leibniz endorses this strong connection when in the New Essayshe tells Locke why one can'tjust arbitrarilyassign "inexplicable"properties like gravi- tational attractionto matter:

[T]he modificationswhich can occurto a singlesubject naturally and withoutmiracles must arise from limitations and variationsof a real genus,i.e. of a constantand absoluteinherent nature.... Whenever we find some qualityin a subject,we ought to believethat if we understoodthe natureof boththe subjectand thequality we would conceivehow the qualitycould arise fromit. So withinthe orderof nature(miracles apart) it is notat God's arbitrarydiscretion to attach thisor thatquality haphazardly to substances.He willnever give them any whichare not naturalto them,that is, whichcannot arise from theirnature as explicablemodifications.'7

This means God keeps the supervenience-subveniencerelations nonarbitraryfor would-behuman knowers. He is not bound by the laws of logic to do so. Thus the ws in Df. 1 range over only non- miracle-containingworlds. A and B are taken to be representatives of typical supervening families of properties-say mental and physicalor, as in Leibniz's case, derivativeand primitiveforce.

Df. 1: PropertyA stronglysupervenes on propertyB iff for any object x and any world wi, if x has B in wi,then x has A in wt.18

"7G.W. Leibniz, New Essayson Human Understanding,ed. and trans. P. Remnant and J. Bennett (Cambridge: Cambridge UniversityPress, 198 1), preface,66; also p. 66 of vol. 6, vi of SdmtlicheSchriften und Briefe, Academy edition (Darmstadt and Berlin, 1923-). "8This construal of strong supervenience is a simplified version of Jaegwon Kim's in his article "Supervenience," in Handbookof Metaphysics and ,ed. H. Burkhardtand B. Smith(Munich: Philosophia, 1991), 2:877-79; The restrictionto "typicalsupervening families of properties"is designed to rule out the possibilitythat simple covariant properties like equilateraland equiangularmight stronglysupervene on each other by Df. 1.

546 LEIBNIZ'S PHENOMENALISMS

In typical applications of strong supervenience, more than one subvenientproperty can "ground" a given supervenientproperty, so that, for example, several differentmolecular structurescan ground the brittlenessof a plastic plate. Leibniz specifiesonly one possible kindof subvenientproperty-primitive force-for deriva- tive force, but he likelythought that many differentinstances of that propertycould underwritethe same derivativeforce upshot. Two qualitativelyidentical peanut butter sandwiches might have differentsubvenient bases-one with a total quantityof primitive force, F1, and the other a differentquantity, F2. Leibniz's supervenience analysisof body is captured in S-BODY. Again only necessary conditions are offered. No diachronic ac- count willbe given because some of these bodies are aggregatesfor which, as mind-independent collections,there are no perceivers whose "considerings"can provide even a weak persistence.

S-BODY: x is a supervenientbody at t only if: at t there is an ag- gregate or corporeal substance, x, that (i) mereologi- cally supervenes on an infinitecollection, {C}, of sub- stances and (ii) is in a derivative force state that stronglysupervenes on the primitiveforce states of the ultimatemembers of {C}.

The "ultimate"members of {C} are monads. When x is an aggre- gate, condition (i) requires thatit abide by the stricturesof M-AGG; when it's a corporeal substance,those of M-CORP.

5. Combining the Accounts

For a comprehensive account of aggregates,AGG, we'll meld to- getherthemes fromP-AGG and M-AGG. As we have seen, we must be careful to construe as merelyapparent the aggregate's perceived qualities (of unity,color, continuity,and reality)in the resulting synthesis.We'll followP-AGG in allowing unconscious representa- tional content into the sis, since Leibniz requires this in order to make plausible his claim thatevery perceiver (rather thanjust "some P(1)") perpetually perceives all the aggregates. As in P-AGG, the perceiving substances of AGG will ensure that a weaker "in the head" duration can be attributedto x. Finally,we'll take AGG's (and

547 GLENN A. HARTZ the followingCORP's) "infinitecollection of substances" to meet the conditions laid down in M-AGG.

AGG: x is an aggregateat t iff:at t each P is in some si E {S} such that: si's representationalcontent includes an extended appearance, x, that is the result of P's perceiving an in- finitecollection of substances in the phenomenal world; and P considersx to be a unified,colored, continuous,and real thing. x is an aggregatethat persistsfrom tI to tn iff:at each ti between tI and tn,each P is in some si E {S} such that: si's representational content includes an extended appear- ance, x, that is the result of P's perceivingan infinitecol- lectionof substancesin the phenomenal world; and P con- siders x to be the same unified,colored, continuous, and real thing that it perceived at the other tis.

Next, corporeal substances. By contrast with AGG, but like M-CORP, the persistencerepresented here is well founded: corpo- real substances have a true unityacross time ratherthan one that depends on the "considerings"of P. Also, unlike an aggregate's unity,which depends solely on P's "considering"x to be a unified thing,a corporeal substance'sperceived unity is well founded on the mind-independentunity of the corporeal substance itself.

CORP: x is a corporealsubstance at t iff:at t each P is in some sj E {S} such that: sj's representationalcontent includes an extended appearance due to the fact that P perceives a dominant monad, D, unitingitself so completelywith an infinitecollection, {C}, of substancesthat it formsa living thing,x. x is a corporealsubstance that persists from tI to tniff: at each tj between tI and tn,each P is in some sj E {S} such that: sj's representationalcontent includes an extended appearance due to the fact that each P perceives the same dominant monad, DI, unitingitself so completely withan infinitecollection, {Cj}, of substances(where {Cj} shares at least one part with the {Ci} to which DI was joined at the immediatelypreceding ti) that it forms a livingthing, x.

548 LEIBNIZ'S PHENOMENALISMS

We can now add the concept of supervenienceto elementsfrom these two analyses for a perfectlygeneral account of body:

BODY: x is a bodyat t iff: at t each P's representationalcontent includes either a supervenientaggregate, x, or a super- venient corporeal substance,x. x is a body fromtI to tniff: at each tibetween tI and tn, each P is in some si E {S} such that: si's representational contentincludes eithera supervenientaggregate, x, or a supervenientcorporeal substance,x.

Leaving aside substantialbonds, BODY representsall of Leibniz's doctrinesabout matter.Every material object has a derivativeforce that supervenes on the primitiveforce of monads. Some of those objects are mere aggregates that, strictlyspeaking, have all their features supplied by the mind. The rest are corporeal substances possessingtrue unity.Every monad constantlyperceives all of these aggregates and corporeal substances. Leibniz's mature metaphysicsof matterseems coherent,though enormously complex. The ways of phenomenalism are often dif- ficultto spell out. Unlike most empiricistphenomenalisms, which require care to "translate" physical-objectstatements into " statements,"the challenge facing Leibniz's commentatoris sorting out the various accounts and paying careful attentionto all the deep metaphysicalconstraints that were simultaneouslyat work in his system.19

Ohio State University

"9I'd like to thank Robert M. Adams, J. A. Cover, Catherine Wilson, the editors and referees of the PhilosophicalReview, Marshall Swain, Donald Rutherford,James van Cleve, Eric Sotnak, Maryann Kooij, and Ralph Hunt for commentson an earlier draftof thispaper. Also here gratefully acknowledged for providingme free time are Ohio State Universityfor a Seed Grant (through the Office of Research and Graduate Studies) and a research quarter, as well as the National Endowment for the Humanities for a 1989 Summer Stipend Grant.

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