IX. Intemationaler Leibniz-Kongress unter der Schirmhenschaft des Bundesprasidenten Natur und Subjekt Vortrage 3. Teil Herausgegeben von Herbert Breger, Jtirgen Herbst und Sven Erdner Hannover, 26. September bis 1. Oktober 2011 Veranstaltet von der Gottfried- Wilhelm- Leibniz-Gesellschaft ‫ם‬ Go lUED-WltHlLM E I B N I Z‫ז‬ ~ E S tL L S C H A f SRQPONMLKJIHGFE in Verbindu ‫ ם‬g mit Leibniz-Stiftungsprofessur der Leibniz Universitiit Hannover Leibniz Society of North America Sociedad Espafiola Leibniz Association Leibniz Israel Societas Leibnitiana (,‫א נ ו ר ת ל י י ב)""! י ש ר א ל ) א ל‬ Japonica Sodalitas Leibnitiana Institut ftir Philosophie der Leibniz Universitiit Hannover FUl' grol3zUgige Untersttitzung gilt unser Da ‫ם‬ den Sponsoren Deutsche Forschungsgemeinschaft iJFCi= ~ VGH Versicherungen VGH g~ g I • • • .-• • L a d Niedersachsen Ftir Sachspenden ‫ס‬ da ‫ם‬ en wir Akadernie Verlag Berlin Bahlsen GmbH & Co. KG ISBN 978-3-9808167-4-8 Redaktion: Stefan Mazur, Charlotte Milsch 2011 bei den Autoren. Alle Rechte vorbehalten. Ohne schriftliche Genehmigung ist es nicht gestattet, dieses Buch oder Teile daraus in irgendeiner Form zu vervielfiiltigen oder unter Verwendung elektronischer oder mechanischer Systeme zu speichern, auszuwerten odel' zu verbreiten. @ Herstellung: Druckerei Hannover 2011 Hartmann GmbH, Weidendamm 18,30167 Hannover Id a n S h im o n y W h a t is (th e ) M a tte r: C h a p te r if C O J 1 1 p a re d to s im p le id e a d e fin e it, L e i b n i z 's not on p o in t. L o c k e 's v ie w re a d in g th e L o c k e 's and by h a rd n e ss, tra c in g a n d re si to re s p o n d . ta n c e ln s te a d , T h e o p h ilu s im p o rta n tly , som e o f L o c k e 's m a tte r c o n s is ts L e i b n i z 's e s s e n tia l c la im s re v e a lin g of to P h ila le th e s g iv e s m ost on b e tw e e n is s h a rp e n e d B ut W e its s o lid ity s in c e cannot re la tio n s w ith it is a d ire c tly to o th e r im p e n e tra b ility , a n d im p a c t. in s o lid ity c h a p te r o f m a tte r. e x p e rie n c e . and re la tio n s supposed w h ile th a t se n so ry d is c u s s io n d is c u s s io n Essay concerning Human h is p ro p e rty so u rc e th e is b e h a lf, Nouveaux essais's its e x a rn in e P h ila le th e s is s u p p o s e d M o re it L ocke in d e fin in g th ro u g h of an odd o f L e i b n i z 's c h a p te r it o n ly th a t C o u ld n o t T a k e P la c e c o n s is ts T 1 1 e p e c u lia rity to b e th e g ra sp c la rify c h a p te r L o c k e 's s o lid ity can Thus a n d e x te n s io n , Nouveaux essais s s o lid ity . c o rre s p o n d in g ta k e s we o n ly n o tio n s . T h e o p h ilu s on L o c k e 's L ocke of sense but a s s o c ia te d In L e ib n iz ' a n d T h e o p h ilu s Understanding. space nof 4 of book P h ila le th e s (T e l A v iv ) L o c k e , L e ib n iz , a n d th e C o n tro v e rs y p re se n t L o c k e 's a t tim e s lo n g a n sw e rs s ig n ific a n t w h ic h p o in ts is n o t s u ffic ie n tly s o lid ity one c o n c e rn in g can s o lid ity m a in id e a s n 1 a k e s a s s e rtio n s a re o fte n a d d re sse d . h a rd ly a re o m itte d . a J 1 d m a tte r not th e In p a rtic u la r, a c le a r and a re to E v e n tu a lly , fo rrn and w h ic h a fte r p ic tu re th e ir of a g re e m e n ts a n d d is a g re e m e n ts . 1 1 1t l l i s p a p e r th a t in s te a d w e m ay c o n s id e r L e i b n i z 's over s o lid ity . s o lid ity T h is a s e ith e r firs t is in v ita tio n p e c u lia ritie s of sub and c o n firm e d an b e tw e e n on to d e e p e l· e x p lo ra tio n m o re "If any one asks 1 send a n a ly s is o r fu rth e r is a s im p le m o re id e a . c o m p le x but cannot in c o n te n ts and id e a s . I (1 ) J. L ocke: O x fo rd be o f m a tte r; s o lid ity and a re a re com posed. e lu c id a te th e T hey d ire c tly th e m of can use e x p lic a te d . b y re v e a lin g th e id e a An Essay concerning Human Understanding p. 1 2 6 . 1975, T h is b u ild in g th is is w h a t L o c k e o rig in is s u e s Thus w llic h b u b b le and th o ro u g h ly o n th e s ta tu s w h ic h ta k e n s ty le c o n tro v e rs y b e tw e e n a c h a p te r be a rg u e L o c k e 's not v ie w s c o n n e c tio n m ay c o n c lu d in g o f s o lid ity b a s ic concem a s th e ir and o r s lo p p y as m ay a b e lo w of s o lid ity seem fa s c in a tin g th e s u rfa c e . o n s o lid ity h im " !. n o tio n th e space. re a d in g s o lid ity a fo c u se d re la te d th e d if f e l·e n c e s in th e to in fo rm o f th e id e a s A c c o rd in g ly , fo r d e c la re s senses th e m s e lv e s in d ire c tly a c c o u n ts L ocke h is e x p la n a tio n tu rn fro m He to S im p le e x p e rie n c e o th e r m e", h im w h ic h such q u a lity a tte n tiv e on th o u g h t to c o n d u c t of o n s o lid ity , 1. L ocke s o lid ity , d is a g re e m e n ts e x a m in a tio n o f th e p re s s in g c h a p te r o f d is tra c te d it im p ra c tic a b le c h a p te rs o r d e riv a tiv e th e d is tin c tio n ta n tia l m ake by a n d L e i b n i z 's d is a p p o in tin g , o f L e i b n i z 's a s n 1 e re c o n se q u e n c e s s y m p to m s p rim a ry and s ig h t o f th e th e m o f n a tu re i n L o c k e 's a n d irn p a c t; som e th e m p h ilo s o p h ie s d is c u s s e d at 1 tra c e o f in te r p 1 ·e tin g s e c tio n is to beyond b lo c k s th o s e can th e ir s o lid ity , (b e re a fte r a lre a d y o th e r, so u rc e Essay) c h a p te r, m o re p e rc e iv e and II, rv fo r g iv e n . w o rld S o lid ity th e m id e a s , th ro u g h d iffe re n tia tin g d iffe re n tia te s § 6; ed. by P . is d ire c t o f w h ic h c o m p le x in h is c h a p te r (2 ) "w hat dem ands m e n ta l o n ly a irn s to a c h ie v e of any of our to c la rify W e o f h is d e fy th e m o n s o lid ity . it fro m H . N id d itc h , - 1071 - zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ impenetrability, (3) argues that it is essential to matter, and discusses it i ‫ ם‬relation to (4 ) space a ‫ ם‬d extensio ‫ ם‬, ( 5) hardness, and ( 6 ) resista ‫ ם‬ce and impact. 1 will brief)y discuss tbese points in turn . I book 1 of the WVUTSRQPONMLKJIHGFEDCBA E s s a y Locke set out to refute the view that there are iru1ate ideas and principles in the human mind. Book II the ‫ ם‬intends to establish the positive doctrine that experience is the sole source of our ideas. Locke's principal thesis is that we get simple ideas through sensory perception of things outside us or by reflecting on the internal activities of the mind. From the opening chapters of book II we know that the idea of solidity is a simple idea whose origin is in one sense (and not in ref)ectio ‫ ם‬or several senses together)2. It is left to find the one sense through which we perceive that idea. ln chapter 4 Locke contends that we receive the idea of solidity through the sense of touch by means of the resistance we feel when we try to enter a space already occupied by another body: "The idea of solidity [ ... ] arises from the resistance which we find in body to the entrance of any other body into the place it possesses, till it bas left it,,3. We may thus initially characterize solidity as the absolutely unique presence of a body in that part of space in which it extends . No other material object can e ‫ ם‬ter into tbat space (i.e. penetrate it) or diminish it (i.e . compress the body ) 4 . Locke next turns to clarify his terrninological choice. First he makes clear that he does not use the word solidity in the manner of the mathematicians (i.e. as signifying volume ). More interesting, however, is the relation between the terms solidity and impenetrability . Locke does not reject the use of the latter as expressing the idea llnder discussion, but prefers the former option for three reasons. First, it accords with the "vulgar use" of the term solidity. Second, solidity is a positive term, while impenetrabi ‫ נ‬ity is negative. Finally and more importantly, Locke suggests that impenetrability is "[ ... ] more a co ‫ ם‬sequence of solidity, than solidity it se!f ,‫ כ‬. This seems to imply that solidity is a primitive property of body, while impenetrability is a derivative effect thereof. 1 will elaborate on this point later . For the meantime note that strictly speaking we sense the effect of solidity, not solidity itself. That is, we sense resistance or force of impenetrability, as is clear from Locke's claim that "[ ... ] the bodies which we daiJy handle, make us perceive, that whilst they remain between them, they do by an insllrmountable force, hinder the approach of the parts of our hands that press them,,6. We shall see that Locke will sirni ‫ נ‬arly argue that resistance depends on solidity. Thus one may reasonably object that while solidity is a primitive property of body, the idea we have of that property is an intellectually derived idea, not one we immediately receive through se ‫ ם‬se . Perhaps tbe most substantial point Locke makes with regard to solidity is that it is t h e essential property of matter : "[ Solidity] of all other, seems the idea most intimately con ‫ ם‬ected with, and essential to body, so as ‫ ם‬owhere else to be fou ‫ ם‬d or imagined, but o ‫ ם‬ly in matter: and though our senses take no notice of it, but in masses of 2 3 4 See II, II-ill; idditch, pp . 119-122 . II, r v § 1; Nidditcb, pp . 122-123 . Cf. Locke's statement, while differentiati ‫ ם‬g solidity and hard ‫ ם‬ess, that the former "[ ... ] consists in repletion, and so an urter exclu ion of other bodies out of the space ir j ossesses" ( E s s a y II, r v § 4 ; Nidditch, p . 125 ). E s s a y II, r v § 1; Nidditch, p . 123 . Ibid . E ssay E ssay - 1072 - zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR matter, of a bulk ufficient to cause a sensatiolJ in us; yet tbe rnind, having once got tbis idea from such grosser sensible bodies, traces it fartber; and considers it, as well as figure, in tbe rninutest particle of matter that can exist; and finds it inseparably inherent in body, wherever or ho\vever modified"'. Reduced t ‫ ס‬its very essentia1s, f ‫ ס‬r L ‫ ס‬cke materia1 b ‫ ס‬dy c ‫ ס‬nsists in substantiality and s ‫ ס‬lidity. What makes a substa ‫ ם‬ce materia1, is precisely the pr ‫ ס‬perty ‫ ס‬f s ‫ ס‬lidity. This serves and space . L ‫ ס‬cke t ‫ ס‬differentiate materia1 substa ‫ ם‬ce fr ‫ ס‬m b ‫ ס‬th spiritual substances Substa ‫ ם‬ce which has the p ‫ ס‬wer t ‫ ס‬thi ‫ם‬ is a s ‫ ס‬ul ‫ ס‬r spirit, whereas substance which has the 8 m ‫ ס‬dificatio ‫ ס ם‬f s ‫ ס‬lidity is matter . While tryi ‫ ם‬g t ‫ ס‬sh ‫ ס‬w thatWVUTSRQPONMLKJIHGFEDCB b o d y and extensi ‫ ם ס‬are ‫ ס ם‬t the s a e, be seems t ‫ ס‬use b ‫ ס‬dy and s ‫ ס‬lidity as i ‫ ם‬tel'cbangeable: "1 appea1 t ‫ ס‬every man's ‫ ס‬w ‫ם‬ th ‫ ס‬ughts, whether the idea ‫ ס‬f space be n ‫ ס‬t as distinct fr ‫ ס‬m that ‫ ס‬f s o l i d i t y , as it is fr ‫ ס‬m the idea ‫ ס‬f scarlet-c ‫ ס‬I‫ ס‬ur?,,9 As we shaU see, the essentiality ‫ ס‬f s ‫ ס‬lidity t ‫ ס‬matter is intimately li ‫ ם‬ed t ‫ ס‬its being a p r ary quality of body . L ‫ ס‬cke devotes secti ‫ ם ס‬s 2 and 3, and much of secti ‫ ס‬n 5, to differentiate s ‫ ס‬lj.dity from space and exte ‫ ם‬si ‫ ס‬n 10. He is eager to stress the obvious differel ‫ ן‬ce between l‫ ג‬s conception of ll body and the Cartesian identificatio ‫ ם‬of matter and space . In this discussi ‫ ס‬n he is careful not to confuse our i d e a of s ‫ ס‬lidity by which we c O I ‫ ן‬c e i v e b ‫ ס‬GFEDCBA dies with the p r o p e r t y (‫ ס‬r l2 quality) of s ‫ ס‬lidity and the way b ‫ ס‬dies a r e . His centra1 claim is that solidity and space are logica1ly distinct ideas, even if it happe ‫ ם‬s t ‫ ס‬be the case that a11parts of space are filled with s ‫ ס‬lid matter. He argues that we ca ‫ ם‬t h i n k of a moti ‫ ס‬n of a single body while others remain at rest, and so the place it has left gives us the idea of empty space with ‫ ס‬ut anything solid in it . Solidity is the idea ‫ ס‬f b ‫ ס‬dy by which we c ‫ ס‬nceive it to uniquely fil] its ‫ ס‬wn space. As a pr ‫ ס‬perty, it is that property of b ‫ ס‬dy by which it is exclusively present in its place. The resistance which a b ‫ ס‬dy exerts ‫ ס‬n c ‫ ס‬rporea] i ‫ ם‬vaders by means of its s ‫ ס‬lidity is what distinguishes s ‫ ס‬lidity fr ‫ ס‬m space, " ... which is capab]e neither of resistance n ‫ ס‬r l ‫ ת‬oti ‫ ס‬n " 13 . Similarly, the exte ‫ ם‬si ‫ ס‬n of b ‫ ס‬dy is distinct fr ‫ ס‬m the extension of space in that the f ‫ ס‬rmer co ‫ ם‬sists in the c ‫ ס‬hesion of s ‫ ס‬lid, separable, movable parts, while the latter in the continuity ‫ ס‬f "uns ‫ ס‬lid", inseparable, imm ‫ ס‬vable parts. Thus, the former is alterable, the latter is n ‫ ס‬t . , 11, x m § 11; Nidditich, p. ]72; Letter to Edward Stillingfleet, 7 January 1697; T h e W o r k s 10 vols., London 1823 (reprint Aa1en 1963 (hereafter WJL)), vol. 4, p. 33 (Leibniz quotes tbis passage in tbe preface to tbe N o u v e a u x e s s a i s (hereafter NE), A Vl, 6, 62); and "Elements of Natural Phi]osophy"; WJL r n , 303 . See the reference to tbe ]etter to Stillingf1eet above, and E s s a y 11, XXIII §§ 17, 22; Nidditich, pp . 306 , 307-308 . E s s a y 11, x m § 11; Nidditch, pp. 171-172 (italics added ). Locke discusses space in book 11 chapter 13 (Of tbe Simple Mode of Space). Sections 11-26 are again devoted to differentiating space and extension from body and solidity . Ibid. Cf. ‫ן ס‬ g 9 10 11 12 13 John E ssay Locke, Descartes argues tl1at space and material subs t ce are actually Ot ‫ן‬ e and the s a ne thing conceived in different ways: ''Nor in fact does space, or intemal place, differ from tbe corporeal substance contained in it, except in tbe way in which we are accustomed to conceive of tbem. For in fact tbe extension in length , breadth, and deptb which constitutes the space occupied by a body, is exactly the same as tbat which constitutes tbe body" ( P r i l ! c i p i a p h i l o s o p h i a e II §§ ]0-12; P r i n c i p l e s ‫ ן ס‬P h i l o s o p h y , trans. by V. R. Miller and R. P. Miller, Dordrecbt 1983, p . 43 ). Locke distinguishes between ideas on the one hand, and qualities of tbings on the otber, in book 11chapter 8 (especially in sections 2, 7, and 8). Yet he warns us in advance that he is not going to be strict about tbis usage of terms: "which ideas, if 1 speak of sometimes, as i ‫ ם‬the things tbemselves, 1 would he understood to mean tbose qualities in the ohjects which produce them in us" ( E s s a y 11, V § 8; idditch, p . 134 ). E s s a y ll, IV § 3; idditicb, p . 124 . - 1073 Confusion may arise due to the fact that certain materials yield more easily than others . We bend sponge more easily than wood, and our hands make their way without difficulty in water but not in steel. Thus we may thin.k that certain materials are more solid than others . But, Locke explains in section 4, this property which has to do with the degree of effort we have to exert in order to change the form of materia!s is WVUTSRQPONMLKJIHGFEDCBA h a r d n e s s , oot solidity. While the latter consists in absolute presence in certain place, the former consists in fum cohesion of the parts and is ascribed to materials with respect to the constitution of our body (hard is that which by pressing it we feel pain before it changes its figure, soft is that which we can easily change its figure without effort and feeling pain). But the softest matter is not a bit less solid than the bardest. A corpuscle of water, which contains no empty spaces and has nowhere to go, will be neither penetrated oor compressed and will as persistently retain its place as diamond will . Finally, Locke clairns in section 5 that impu.lse and resistance depend on solidity . Although he does n ‫ ס‬t so much argue for that claim, his thougbts on the matter may not be difficult to trace. If bodies were not solid, that is, if they were not to exclusively fill their space, it would be p ‫ ס‬ssible for some of them to coextensively be in one and the same place . The entrance of one into the territory of another would thus involve no resistance. As the former would not push the latter out of its place, there would a!so not be impulse and communication of m ‫ ס‬tion through collision . 2. Philalethes and Tbeophilus discuss solidity At the opening of his chapter Leibniz has Phila!ethes say that the s e n s a t i o n or j e e l i n g ("sentiment") of solidity arises from the resistance we feel in a body to the entrance of another into its place. Philalethes expects Theophilus's consent which is (partly) granted. After all it is not difficult for Leibniz to accept that we sense solidity by means of touching solid bodies. This, however, is not an accurate presentation of Locke's position. Locke is interested in the origin of the i d e a of solidity and his main point is that we receive that idea through the sense of touch, not that we sense or feel solidity by touch. Thus the initial agreement between Philalethes and Theophilus is somewhat feigned. Leibniz could silentJy pass over this point, as it represents a genera!, recurrent disagreement to which he has already responded. In book II Locke argues that our t a b u l a r a s a rnind receives all its ideas from experience through sensation and reflection. Leibniz has expressed his dissatisfaction concerning this point eve1' since his first reflections on the E s s a y from the rnid 1690S1 4 and 5 elaborates 00 it in the preface to the N o u v e a u x e s s a i s lGFEDCBA . Without getting too much into details, it is clear that "idea" denotes something completely different for Locke and for Leibniz. Locke conceives it is a meota! item actually present in the mind when one perceives and thinks, while f01' Leibniz it is a prerequisite, as it were, for cohe1'el1tSRQPON 14 15 See "Sur l'Essay de I'entendelnent hUlnain de Monsieur Lock"; GP V, 15-16; and "Echantillon Reflexions sur le I I . Livre"; GP V, 23. Cf. Leib ‫ ח‬jz's review of Pierre Coste's French rranslatio ‫ח‬ Locke's E s s a y , GP V , 37 . A VI, 6 , 47-53 . de of - 1074 16 thinking . Accordingly, outset of book ‫ ח‬: Leibniz makes the following general rel ‫ מ‬ark irnmediately at the " SRQPONMLKJIHGFEDCBA In order to keep away from an argument upon which we have aJready spent too long, let me say in advance , sir, that when you ay that ideas come from o ‫ ם‬e or other of those causes [i.e. sensatio ‫ ם‬or ref1ectio ‫] ם‬, 1 shaJI take that to mea WVUTSRQPONMLKJIHGFEDCBA ‫ ם‬the actuaJ perception of the ideas; for 1 believe 1 have how ‫ ם‬that in so far as they contain somethi ‫ ם‬g distinct they are i ‫ ם‬us before ,ve are aware ofGFEDCBA th e m "I ‫ ד‬. Thus the twist of Locke's claim here is l‫ ן‬nnecessary. Theophilus final1y comes to the point after a long iligression which consists of a detailed disCl‫ ן‬ssion of different kinds of resistances. He then makes the interesting point that in experiencing solidity vision may come to the aid of touch. He objects that a distinct idea of solidity basically comes from pure reason and not from sense alone, since the sensation of s ‫ ס‬lidity d ‫ ס‬es n ‫ ס‬t suffice t ‫ס‬ refute the opp ‫ ס‬sed idea that materials are not absolutely s ‫ ס‬lid but ‫ ס‬nly to a certain degree 80 that some of them can jointly occupy ‫ ס‬ne place 1 8 . Between his initial agreement with Philalethes and his ultimate rejection of the latter's offers a protracted po iti ‫ ס‬n concerning the ‫ ס‬rigin of the idea ‫ ס‬f soliility, Theophilus discussion of resistance and impenetrability. The major difficulty here is that Locke's points are n ‫ ס‬t directly addressed and several issues are rnixed together. M ‫ ס‬st importantly, there is n ‫ ס‬response t ‫ ס‬L ‫ ס‬cke's basic claim that s ‫ ס‬lidity is the g‫' ו‬ound ‫ ס‬f impenetrability, resistance , and impact. Theophilus ilistingu.ishes four causes and types of resistance in matter, some of them lie in the b ‫ ס‬dy itself, the ‫ ס‬thers in neighboring boilies. The first type is impenetrability . Its source is in the surr ‫ ס‬unding bodies and it c ‫ ס‬nsists in the reluctance of bodies to share the same place. In this c ‫ ס‬ntext it w ‫ ס‬uld have been enlightening to hear The ‫ ס‬phill ‫ ן‬s'S view on the relati ‫ ס‬n of impenetrability to solidity. Instead, be rushes to the next two sources of resistance, inertia and impetus. Both are located within the body: the forIner is effective wben the body is at rest, the latter when it is in motion (effectively, both together are tan t ount to Newton's principle ‫ ס‬f inertia). Regrettably, Theophilus does n ‫ ס‬t comment here on Locke's point concerning the indispensability ‫ ס‬f solidity t ‫ ס‬impact. As we shal1 see , Leibniz's views ‫ ס‬n this matter could have been stimulating t ‫ ס‬Locke. The fourth and last type ‫ ס‬f resistance ‫ ס‬f matter has its source in the surrounding b ‫ ס‬dies and consists in firmness or boniling of parts ‫ ס‬f matter ‫ ס‬ne t ‫ ס‬another, in much the same way as hardness in Locke . Leibniz's treatment of solidity with respect to space and extension is especially puzzling . Philalethes omits Locke's central claim in this c ‫ ס‬ntext and presents a different argument c ‫ ס‬ncerning extension than the one presented in the E s s a y . We have seen that L ‫ ס‬cke's iliscussion in sections 2, 3, and 5 challenges the Cartesian ident.ification of body and space and its implication that we have but ‫ ס‬ne idea under two names. Locke's main claim is that matter and space are logical1y ilistinct ideas regardless of the actual state of material bodies in space (i.e. whether or n ‫ ס‬t they are completely coextensive with space). Soliility has a pivotal role in this c ‫ ס‬ntext, as it is that which ilifferentiates matter from space: soliility is 16 ‫דן‬ 18 See "Quid sit idea"; A VI, 4, 1370-1371; "Med.itationes de cognitiolle, veritate et ideis"; A VT, 4 , 588590 . NE II, 1 § 2; A VI, 6, 111; quoted from N e \ v E s s a y s o n H u m a n U n d e r s t a n { l i n g , trans. by P. Remnant and J . Bennett, Cambridge 1996, p. III (All subsequent quotations fi'om tl‫ ך‬e N e w E s s a y s will be from this translatio ‫\ ם‬vithout speciaJ indication as its pagination follows that of the Academy Edition ). NE n , TV § 1; A VI, 6,124. See al 0 NE n , TV § 4; A VT, 6,126 . - 1075 - essential to matter, while space is devoid of all solidity and resistance. Philalethes passes over this discussion in sections 2 and 3 and jl ‫ ן‬mps directly to discuss extension in section SRQP 5. Even when he makes thjs point in passing in his second entrance in section 5, Theophilus hasti ‫ נ‬y evades discussion. He laconically agrees that extension and matter are distinct and rushes again to claim that he does not believe that there are two extensions. He does not pause to explicitly explain the crucial point for Locke, namely the ground of the distinction . In his first entrance PhiJalethes argues that the extension of body js different from that of space. Interestingly enough, he does not follow Locke's text but makes his case in an entirely different manner. As a matter of fact, Philalethes not so much argues for or bases his claim, but simply states it in connection with the unalterable volume of a body. He argues that body cannot be rarefied or compressed, and thus its volume or extension cannot cbange so that the " ... body wi ‫ נ‬l always be equ a to the same space,,19. Nevertbeless, he continues, its extension is distinct from the extension of the space. Now this somewhat lame suggestion is supposed to replace Locke's argu.ment that the two extensions are distinguished by means of solidity. The extension of body, according to Locke, consists in the cohesion of solid parts which can be torn apart and distanced from one another so that the extension of body may be altered. By contrast, the "unsolid" parts and regions of the spatial matrix are fixed to their place in tbe matrix so that the extensjon of space is irnmutable. Locke indeed believes that a material corpuscle whjch contains no interstices is incompressible and has a fixed volu.me, but he made no use of this in his distinction between matter and space and between their extensions. Thus TheophiJus flfSt responds to the point that Locke has never made and says that "Body could have its own extension without that implying that the extension was always determinate or equal to the same space,,20. Further, Philalethes's feeble alternative makes it easier for Theophilus to argue , this time against the re a Locke, that we need not postulate two distinct extensions, since the concrete extension of body is intelligible only in virtue of the abstract extension of space . He then has the occasion to plead Leibniz doctrine of space, according to which it is nothing but an order of things . Concerning solidity and hardness we may note that PhiJ a ethes quite fairly repI'esents Locke. Yet, whereas Locke and Philalethes are interested in hardness WVUTSRQPONMLKJIHGFED s o ja r a s it is d is tin c t j r o m s o l i d i t y , Theophilus shows little if any interest in this discussion and digresses into an exploration of the mechanism of cohesion of material parts. Remarkably, Theophilus entirely ignores Phil a ethes's claim here that solidity consists in absolute presence, thereby , again, leaving us still yearning for a clear characterization of solidity. It is further evident in Theophilus's terminological suggestions to contrast hard with soft and firm with f1uid , which serve more to introduce some of Leibniz's known views (in every body there is a degree of cohesion as well as f1ujdity, there are no unconquerably hard Epicurean atoms , etc.), than to converse with Locke. Theophilus does respond directly to two points: to Locke's assertion that we ascribe "soft" and "hard" with respect to our constitution and experience of things and to the report of the Florence experiment which demonstrates the soJidity of water. Concerning the former, Theophilus objects that if this were the case " ... there would not be many philosophers attributing hardness to their 'atoms",21. As with 19 20 21 NE II, IV § 5; A VI, 6, 126. Ibid. NE IL IV § 4; A VI, 6, 125. - 1076 solidity, the notion of hardness is strictly conceived by reason, while the senses only show that there is actually hardness in nature . In sum, we have seen that Philalethes is not a loyal representative of Locke. He sometimes omits basic clairns of Locke, while at other he simp]y distorts b.is arguments . Theophilus often evades discussion of central points only to digress to lengthy explorations of themes not directly relevant. Eventually, we do not have a clear respond from Leibniz to Locke' s characterization of solidity and b.is clairn concerning the essentiality of solidity to matter. We sti]llack Leibniz's answers to the questions in what matter consists and what solidity is in itself and in relation to key notions such as impenetrability, space, hardness , resistance, and irnpact. If Leibniz bad sent b.is chapter on solidity to Locke, it perhaps would have given some ground to the latter's acrid witticism: "It seems to me that we live very peacefully in good neighborship with the gentlemen in Ge ‫ ת‬any because they do not know our books, and we do not read theirs,,22. Although the peculiarities detected here appear elsewhere in the WVUTSRQPONMLKJIHGFEDCBA N o u v e a u x e s s a i s , their presence in the chapter on solidity is neither accidental nor merely due to the literary constraints of the dialogical form. Rather, their extent and degree here testify that they are symptoms of deeper and broader disagreements which concem the philosophies of nature of the two thinkers and block the possibility of a well-confined con t oversy over solidity. In the remainder of the paper 1 wish to illustrate this point by briefly examining three themes which have to do with solidity but are not thoroughly discussed in the chapter on solidity: the problem of the status of solidity as either an original, prirnary quality of matter, or a derivative property that is grounded in more fundamental forces; the connection between solidity and impact; and the question of the extension of solidity and its distinction from space . 3. Matter and solidity - the great divide Locke's famous distinction between prirnary and secondary qualities is presented only later in book II of the E s s a y . Thus an important feature of solidity, namely its being a primary quality of bodies, is not discussed in the chapter on solidity. Primary quality is an essential propert)' of bodies, one wb.ich is inseparable from each and every body and even from the insensible corpuscles of which they consist. Locke calls such properties "real" and " original". When we come in contact with bodies which are big enough to be perceived , their prirnary qualities produce simple ideas in our minds, by means of which we perceive the bodies as they are in themse]ves. Solidity is one such primary quality of bodies (the others include extension, figure, mobility, and number). Less known is that the distinction is not between two types of qualities, prirnary and secondary, but is in fact a tripartite distinction. In addition to primary qualities there ar'e also secol ‫ ב‬dary qualities, wb.ich are powers in the bodies to produce ideas in our minds that bear no resemblance to anything in the bodies themselves; and a third sort of qualities (which 1 will call "tertiary"), namely powers in the bodies to effect a change in the primar'y qualities of other bodies. Both result 23 from and depend on the modifications and arrangements of the primary qualities of bodies . 22 23 Related t ‫ ס‬Leib ‫ ם‬z SRQPONMLKJIHGFEDCBA i ‫ מ‬a letler fr ‫ ס‬m Th ‫ ס‬rnas Burnett, 23 July 1697; A 1, 14,364 . E s s a y n , v m §§ 9-10,23-26; Nidditich, p p . 134-135 , 140-143 . - 1077 - This means that at the most fundamental level matter consists i.n a group of static , inactive properties (note that it is not necessary for body to be in rn ‫ ס‬ti ‫ ס‬n, as rn ‫ ס‬bility only 24 ). This den ‫ ס‬tes that a b ‫ ס‬dy is n ‫ ס‬t flXed t ‫ ס‬one place and its p ‫ ס‬ssibility t ‫ ס‬be in rnotion SRQPONMLKJ acc ‫ ס‬unts for solidity as abs ‫ ס‬lute presence. An elementary material corpuscle is essentially endowed with the static pr ‫ ס‬perties of s ‫ ס‬lidity, extensi ‫ ס‬n, figure, and magnitude. It therefore has a certain volume, shape, and rnagnitude which adm..it of n ‫ ס‬degrees and cann ‫ ס‬t be changed. It cann ‫ ס‬t be penetrated, squeezed, or stretched in any way. Body fills space by solidity, which is a property, not by force. Whereas filling of space by f ‫ ס‬rce may adm..it degrees in acc ‫ ס‬rdance with the varied intensity of that force, there is no roorn for degrees and intensity in filling space by means ‫ ס‬f the pr ‫ ס‬perty ‫ ס‬f solidity. A space is either abs ‫ ס‬lutely filled by a solid body, or absolutely empty. The dynarnic aspect of bodies, on the other hand, comes only at the second level as dependent on their static c ‫ ס‬nstituti ‫ ס‬n. Tertiar)l qualities, which are "barely p ‫ ס‬wers", are derivative of the primary properties. A material b ‫ ס‬dy, for example, can be elastic in so far as it contains interstices ‫ ס‬r empty spaces which can becorne larger and sm a er. In this way the elasticity of the body is derived from the arrangernent ‫ ס‬f the corpuscles of which it is c ‫ ס‬mprised and their prirnary properties . Presumably, the forces of irnpenetrability and resistance depend in an anal ‫ ס‬gous way on the pr ‫ ס‬perty of solidity . Theophilus's response is rather mild. He d ‫ ס‬es not consider Locke's distinction in full but simply c ‫ ס‬rnments that "... when a power is intelligible and adrnits of being distinctly explained, it should be included am ‫ ס‬ng the prirnary qualities ... ,,25. Further, in the chapter on solidity he c ‫ ס‬ncurs that b ‫ ס‬dies are perfectly impenetrable. This seems to imply that Leibniz does not reject Locke's static c ‫ ס‬nstituti ‫ ס‬n ‫ ס‬f material b ‫ ס‬dies, but only suggests adding forces to his list of primary properties. But this is a false picture of Leibniz's c ‫ ס‬ncepti ‫ ס‬n ‫ ס‬f c WVUTSRQPONMLKJIHGFEDCBA ‫ ס‬rp ‫ ס‬real substances, which was developed at the same tirne he was c ‫ ם ס‬sidering L ‫ ס‬cke's E s s a y . Leibniz agrees with Locke against Descartes that there is in matter sornething beyond extension, but he g ‫ ס‬es further than that. He d ‫ ס‬es n ‫ ס‬t sirnply add the property ‫ ס‬f solidity to that ‫ ס‬f extension, but contend that both are n ‫ ס‬t prirnitive but rather derivative of rn ‫ ס‬re fundamental characterizati ‫ ס‬n ‫ ס‬f bodies. In writings such as S p e c i m e n d y n a m i c u m ‫ ס‬f 1695 he argues that corporeal substances essentially consist in forces and ‫ ס‬ffers a dynarnical concepti ‫ ס‬n ‫ ס‬f matter. Thus f ‫ ס‬r hirn extension and solidity are acc ‫ ס‬unted f ‫ ס‬r by means of f ‫ ס‬rces, and not the other way around as in L ‫ ס‬cke. There is elasticity in every bit ‫ ס‬f matter , and rnatter fills space by means ‫ ס‬f f ‫ ס‬rces and so can be squeezed and stretcbed in acc ‫ ס‬rdance with the interplay of forces applied t ‫ ס‬it. Leibniz's dynarnical c ‫ ס‬ncepti ‫ ס‬n was further developed by Kant in M o n a d o l o g i a p h y s i c a (1756) and R ‫ ס‬ger B ‫ ס‬scovich in T h e o r i a p h i l o s o p h i a e n a t u r a l i s (1758) and scientifically elaborated in the 19th century field theory . This conception is hardly visible in the chapter ‫ ס‬n s ‫ ס‬lidity, although certain hints are suggested in passing (e.g. the rejection ‫ ס‬f perfectly hard Epicurean at ‫ ס‬ms and the claim that in every b ‫ ס‬dy there is s ‫ ס‬me fluidity ). 24 2s In so far as Inotion il1volves force, Locke seelns to favor the idea that matter is at most endowed with passive force (the power to receive change) and 110tactive force (the power to generate cbange), since strictJy speaking " ... motion is rather a passion, than an action in [the body]" GFEDCBA (E s s a y Il, XXI §§ 2, 4; Nidd.itich, pp. 234, 235). NE Il, v m § )0; A VI, 6,130. - 1078 The next point to be considered, the connection between solidity and impact, is intimately linked to the former. Locke initially thought that bodies act on one anotl1er only by impact . Later, under the influence ‫ ס‬f Newton, he ln ‫ ס‬dified his view and argued that this is the only way their ‫ ס‬perati ‫ ס‬n is c ‫ ס‬nceivable to US 26 . In any case, it is clear that f ‫ ס‬r Locke the explanation ‫ ס‬f c ‫ ס‬rporeal nature essentially inv ‫ ס‬lves s ‫ ס‬lidity and ilnpact. Due t ‫ ס‬L ‫ ס‬cke's c ‫ ס‬ncepti ‫ ס‬n of s ‫ ס‬lidity, h ‫ ס‬wever, such a c ‫ ס‬mbinati ‫ ס‬n implies a basic difficu.lty which is best seen in light of Leibniz's criticisms of the c ‫ ס‬rpuscularian tenet according t ‫ ס‬which perfectly hard, n ‫ ס‬n-elastic b ‫ ס‬dies exist in nature . The corpuscularian position, Leibniz argues, faces two problems. First, it has no explanation for why bodies bounce when they collide. Second, it irnplies a vi ‫ ס‬lation of the plinciple ‫ ס‬f c ‫ ס‬ntinuity. When undef ‫ ס‬rmable, n ‫ ס‬n-elastic bodies bounce in collision their change of m ‫ ס‬tion is instantane ‫ ס‬us. This means that this change inv ‫ ס‬lves infinite accelerati ‫ ס‬n and theref ‫ ס‬re, in acc ‫ ס‬rd with Newt ‫ ס‬n's force law, infinite force. B ‫ ס‬th pr ‫ ס‬blems 27 can be eliminated, Leibniz explains in WVUTSRQPONMLKJIHGFEDCBA S p e c i m e n d y n a l n i c u m , if we grant that corpuscles are elastic in a certain degree . ‫ ח ן‬the pr ‫ ס‬cess ‫ ס‬f c ‫ ס‬llisi ‫ ס‬n between such bodies the f ‫ ס‬rce ‫ ס‬f c ‫ ס‬natus is gradually c ‫ ס‬nverted int ‫ ס‬a ‫ ח‬intemal pressure or elasticity as the bodies continually squeezed t ‫ ס‬ward ‫ ס‬ne a ‫ ס ח‬ther and thus compressed. Eventually the motion or conatus is exhausted as the bodies can n ‫ ס‬l ‫ ס‬nger be squeezed toward one another and c ‫ ס‬me t ‫ ס‬rest. At this point the elasticity stored in them begins t ‫ ס‬be effective and they gradually rest ‫ ס‬re their shape a ‫ ח‬d thereby push away ‫ ס‬ne another and reb ‫ ס‬und in the opp ‫ ס‬site directi ‫ ס‬n fr ‫ ס‬m which they came. Leibniz concludes that " ... alI reb ‫ ס‬und arises fr ‫ ס‬m elasticity ... " But elasticity presupposes, as was shown above, that bodies c ‫ ס‬ntain parts which can change their relative situatio ‫ ח‬. Hence e]astic corpuscles cann SRQPONMLKJIHGFEDCBA ‫ ס‬t be taken as undef ‫ ס‬rmable indivisible 28 entities . This conclusion has significa ‫ ח‬t conseque ‫ ח‬ces for Locke' s theory of matter, though he was not alone in this predicament. In their corresp ‫ ס‬ndence from the early 1690s Leibniz similarly urged Huygens to reconsider his corpuscularianism for the same reasons. Newt ‫ ס‬n noted in the P r i n c i p i a the essentiality of elasticity to impact, yet in the O p t i c k s confirrned the view that matter c ‫ ס‬nsists in solid corpuscles. These considerations, on the other hand , were compelling enough to lead the Newtonian Boscovich t ‫ ס‬suggest an ultimately dynarnical theory of the constitution of matter . Finally, the discussion of solidity and space likewise provides a doorway to considerati ‫ ס‬ns that g ‫ ס‬well beyond and cannot be sufficiently analyzed in the chapter on solidity. The c ‫ ס‬ntinuati ‫ ס‬n ‫ ס‬f this discussi ‫ ס‬n is given, as it were, in the c ‫ ס‬rrespondence between Leibniz and SamueI Clarke. We have seen that Leibniz ign ‫ ס‬res L ‫ ס‬cke's claim that s ‫ ס‬lidity is the differentia of matter as opposed to space. Leibniz grants L ‫ ס‬cke that space and matter are c ‫ ס‬nceptually distinct as against the Cartesian view, but senses that the real issue between them is ‫ ס‬nt ‫ ס‬I ‫ ס‬gical and so hastens to state his view that space is n ‫ ס‬thing but an 26 27 28 Cf. the modificatio ‫ ח‬of E s s a y II, v m § 11 from the t h . i I d (1695) to the fourth editio ‫ ( ח‬1700) and Locke's report of tbe modification in a Jetter to Stillingfleet, 4 May 1698; WJL r v , 467-468. Leibniz quotes this report in the preface to the N o u v e a ! 1 X e s s a i s (A Vl, 6, 60-61) but misses Locke's modification si ‫ ם‬ce Coste's translation retains the t h . i I d ed.ition versio ‫ ם‬of the releva ‫ ם‬t section . See S p e c i m e n . d y n a ‫ ז‬n i c u m ; GM VI, 248-249; G. W . L e i b n i z : P h i l o s o p h i c a l P a p e r s a n d L e t t e r s , trans. and ed. by L. E. Loe ‫ ז‬er, Dor d echt 1969, pp . 446-447 . This conclusio ‫ ם‬also fits Leibniz' s doc t e of co ‫ ם‬servation of v i s v i v a . If corpuscles have parts, then the seeming Joss of v i s v i v a in co1lisio ‫ ם‬s which are not perfectJy elastic can indeed be explained by its absorption in these parts . - 1079 - ordel' or an array of relations. Thus for Leibniz space is derivative of bod.ies, while for Locke, as for Newton, it is an ontological condition for the ex.istence of solid bodies. Now this poses the question for Locke, what kind of thing is space? He genel'ally speaks of spiritual and corporeal substances, na.mely substances capable of thinking on the one hand and solid substances on the other. But space can be neither, since it is neither a think:ing nor a solid entity. Further, in the context of 17th century metaphysics it is naturaJ to ask whether space is a substance or an accident. Yet either option entails absurd.ities, as Leibniz shows in the correspondence with Clarke 29 . Locke rejects the [1[st dichotomy and evades the latter . He answers that there is no basis for the claim that reaJity consists of think:ing and solid beings alone a.nd that he simply does not know whether space is a substance or an accidel1t due to the vagueness of these ideas 30 . Newton rejects the dichotolny of substance and accident in the case of space altogether. Space is neither substance nor accident, but that does not mean that it is merely ideaJ or nothing at aJl. It is rather a something which has its WVUTSR 31 sui g e n e r is mode of existence . Clarke, by contrast, embraces the dichotomy and consequently must deaJ with the absurdities irnplied in it32 . In conclusion, these considerations show the depth of the chasm between Locke and Leibniz on matter and solidity. At least to some extent they may explain why Leibniz beats about the bush and account for his reluctance to deaJ superficially with such substantial issues in the form of concise dialogical passages. Instead, he provides in the preface to the 33 N ouveaux e s s a is a clearer, broader ‫ ס‬verview of their differences by simply pl'esenting his views ‫ ס‬n the matter v i s - a - v i s L ‫ ס‬cke's. This by n ‫ ס‬means exbausts the discussi ‫ ס‬n but ‫ ס‬nly marks the essentiaJ points ‫ ס‬f disagreement and caJls f ‫ ס‬r a study ‫ ס‬f the subject in greater detail in ‫ ס‬ther chapters ‫ ס‬f the N o u v e a u x e s s a i s and in additi ‫ ס‬naJ texts as well . 29 30 31 32 33 See Leibniz's fourth letter §§ 8-12 and fifth letter §§ 36-46;GFEDCBA T h e L e ib /liz - C la r k e C o r r e s p o fld e flc e , H. G. Alex a der, Manchester 1956 (hereafter LC), pp . 37-38 , 66-69 . E s s a y SRQPONMLKJIHGFEDCBA n , XIll §§ 16-20; Nidditch, pp . 173-175 . 1. Newto ‫ ם‬: " De gravitatione et aequipondio fluidorun1", in: U f l p u b l i s h e d S c ie fllijic P a p e rs N e lv to fl, ed . a d tr a s. by A. R. Hal ‫ נ‬a d M. B. Hall, Cambridge 1962, pp . 131-132 . Clarke's fo u reply §§ 8-12; LC 47-48 . A VI , 6 , 59-60 . ed. by oj Is a a c