Cartesian causation: body–body interaction, motion, …...his doctrine of the creation of the...

Stud. Hist. Phil. Sci. 34 (2003) 737–762www.elsevier.com/locate/shpsa

Cartesian causation: body–body interaction,motion, and eternal truths

Tad M. SchmaltzDepartment of Philosophy, Duke University, Durham, NC 27708, USA

Received 20 November 2002; received in revised form 3 June 2003

Abstract

There is considerable debate among scholars over whether Descartes allowed for genuinebody–body interaction. I begin by considering Michael Della Rocca’s recent claim thatDescartes accepted such interaction, and that his doctrine of the creation of the eternal truthsindicates how this interaction could be acceptable to him. Though I agree that Descartes wasinclined to accept real bodily causes of motion, I differ from Della Rocca in emphasizing thathis ontology ultimately does not allow for them. This is not the end of the story however,since two of Descartes’s successors offered incompatible ways of developing his conflictedaccount of motion. I contrast the occasionalist view of Nicolas Malebranche that changes inmotion derive directly from divine volitions with the non-occasionalist claim of Pierre-SylvainRegis that such changes derive from a nature distinct from God. In light of Della Rocca’sinterpretation, it is noteworthy that the issue of eternal truths is relevant to both alternativeaccounts. Indeed, Regis took the doctrine that such truths are created to provide crucial supportfor his alternative to an occasionalist account of body–body interaction. What does not helpDella Rocca, however, is that Regis’s view of motion requires a fundamental revision ofDescartes’s ontology. 2003 Elsevier Ltd. All rights reserved.

Keywords: Descartes; Malebranche; Regis; Causation; Motion; Eternal Truths

E-mail address: [email protected] (T.M. Schmaltz).

0039-3681/$ - see front matter 2003 Elsevier Ltd. All rights reserved.doi:10.1016/j.shpsa.2003.09.004

738 T.M. Schmaltz / Stud. Hist. Phil. Sci. 34 (2003) 737–762

1. Introduction

Textbook discussions of Descartes’s contributions to early modern views of caus-ality tend to focus on the question of whether his insistence that mind and body aresubstances that differ radically in nature is compatible with the assertion of genuinemind–body interaction. A primary reason for this sort of emphasis is the assumptionthat later Cartesians were led by their acceptance of Descartes’s dualism to deny thepossibility of such interaction.1 However, there has always been an undercurrent ofinterest among historians of early modern philosophy and science in Descartes’sviews on body–body interaction, particularly with respect to the question of whetherhe allowed or can allow that bodies cause changes in the motions of other bodies.2This same question is prominent in a number of recent studies.3 One explanationfor the focus on body–body interaction—parallel to the explanation above of thefixation on mind–body interaction—is the appreciation that the Cartesian occasional-ists were motivated by issues not only in psychology but also in physics.I attempt here to contribute to the new work on body–body interaction in Descartes

by exploring the impact of his account of the bodily causation of motion. I beginwith a recent discussion in which Michael Della Rocca defends a non-occasionalistreading of this account. I am sympathetic to this reading insofar as I also find inDescartes suggestions of the standard scholastic position that God ‘concurs’ withbodies in bringing about effects in the natural world. Moreover, Della Rocca offersthe intriguing claim that Descartes can accommodate such a position by drawing onhis doctrine of the creation of the eternal truths. I argue that Della Rocca is overlyoptimistic in thinking that this doctrine provides substantial support for Descartes’sconcurrentism. Descartes’s ontology of the material world simply does not allow forthe attribution of bodily natures that serve to ground the causation of changes inmotion. But this is not the end of the story, since the French Cartesians NicolasMalebranche (1638–1715) and Pierre-Sylvain Regis (also Regis) (1632–1707)explicitly addressed the difficulties that bedevil Descartes’s account of motion.Though Malebranche and Regis offered conflicting solutions to these difficulties, itis significant, in light of Della Rocca’s discussion, that both their solutions broachissues concerning Descartes’s doctrine of created eternal truths.Malebranche was of course the main proponent of the occasionalist solution to

the difficulties with Descartes’s account of motion. I consider in particular Malebran-che’s rejection of concurrentism in favor of the claim that bodies serve as mereoccasions for the production of changes in motion by God’s ‘general volitions’.Furthermore, I emphasize that Malebranche concluded not only that bodies are not

1 For a classic example, see Copleston (1958), pp. 176–179, and for a more recent example, see Radner(1993) (though Radner also mentions issues concerning body–body interaction that I emphasize here).

2 Works characteristic of this undercurrent include Lennon (1974); Hatfield (1979); Gabbey (1980);and Gueroult (1980).

3 See, for instance, Garber (1992), pp. 293–305; Garber (1993); Des Chene (1996), pp. 313–341;Nadler (1997); and Della Rocca (1999). Below I focus in particular on the exchange between Garber andDella Rocca.

739T.M. Schmaltz / Stud. Hist. Phil. Sci. 34 (2003) 737–762

true causes, but also that the nature of extension does not determine God’s choiceof the laws that govern His production of motion. Here he distinguished such lawsfrom eternal truths concerning extension and its modes that he held, pace Descartes,to derive from God’s intellect rather than from His will.Malebranche’s accounts of the laws of motion and of eternal truths both are rel-

evant to the work of his contemporary, Regis.4 Regis is known to specialists as oneof the most prominent propagandists of Cartesian physics in France. What is oftenoverlooked is that he also offered a version of concurrentism as an alternative toMalebranche’s occasionalism. In particular, Regis argued that the production ofmotion is determined not only by God’s will but also by created natures external toGod. His account of the relevant natures starts from Descartes’s doctrine of createdeternal truths, but it deviates from Descartes’s own view of the material world andits relation to God. Nonetheless, Regis drew on his revisionary Cartesian ontologyto defend the position—which Descartes himself suggested—that explanations ofbodily interaction must ultimately appeal to the created natures that ground suchinteraction. In contrast, Malebranche accepted a more familiar form of Cartesianontology but also distanced himself from Descartes’s concurrentism insofar as hedenied that there are any created natures that determine the laws of motion requiredfor the explanation of natural change.In closing, I return to Della Rocca’s interpretation of Descartes, focusing in parti-

cular on the conflict between its implication that Descartes’s voluntarist account ofthe eternal truths is naturally linked to concurrentism and the recent claim byDesmond Clarke that Cartesian voluntarism instead yielded an occasionalist accountof causation. Though I side with Della Rocca on the basic point of disagreement, Itake the cases of Malebranche and Regis to reveal that Descartes’s views on theeternal truths do not suffice by themselves to reconcile the two very different concep-tions of causation that emerge from his profoundly conflicted account of motion.

2. Descartes

2.1. God’s causation of motion

In a familiar passage from article 36 in the second part of his Principles of philo-sophy, Descartes claimed that God is the ‘universal and primary cause of motion’insofar as He conserves the total quantity of motion and rest that He initially createdin the universe by means of His ‘ordinary concurrence’ (AT 8-1:61).5 Later,Descartes explained that God conserves the material world ‘by the same action andin accordance with the same laws as when He first created it’ (AT 8-1:66). Here hewas drawing on his argument in the Third Meditation that since the parts of thetemporal duration of an object are independent of each other, the same power that

4 On Regis, see Rodis-Lewis (1993).5 AT: Adam & Tannery (1996).


creates an object is needed to conserve that object at each moment of its existence(AT 7:49). In the Principles, the identification of God’s act of creation with His actof conservation serves to show that God brings about those transfers in motionresulting from collisions that preserve the total quantity of motion and rest Heinitially created.It might appear to be the case that God’s action is the only causal agent responsible

for these transfers. Indeed, Daniel Garber has claimed recently that ‘it seems to meas clear as anything that, for Descartes, God is the only cause of motion in theinanimate world of bodies, that bodies cannot themselves be genuine causes ofchange in the physical world of extended substance’.6 However, Della Rocca hascountered this occasionalist understanding of Descartes by highlighting Descartes’sown persistent suggestion that bodies are genuine causes, even in passages thatemphasize the role of God as the primary cause of motion. Thus, Della Rocca drawsattention to the claim in Principles II.40 that ‘the causes of all particular changes. . . are covered in this third law [which governs transfers of motion in collisions],at least those [causes] that are corporeal’ (AT 8-1:65).7 Moreover, in Principles II.43the force (vis) to act on or resist other bodies is said to consist in fact that everything‘tends, so far as in it lies [tendat quantum in se est], to persist in the same state’(AT 8-1:66). The force posited here derives from the first law of motion, accordingto which ‘each thing, to the extent that it is simple and undivided [quantenus estsimplex et indivisa], always remains in the same state, so far as in it lies [quantumin se est]’ (AT 8-1:62). To be sure, this first law is said to derive from the fact thatGod acts immutably as the primary cause of motion. As Della Rocca notes, however,there was by the seventeenth century an established tradition of using the phrasequantum in se est to indicate that which derives from the nature of a thing.8 Thus,there is reason to follow Della Rocca in taking Principles II.43 to indicate thatchanges in motion derive not only from God’s immutable action but also from a

6 Garber (1993), p. 12; emphasis in original. Elsewhere Garber’s defense of an occasionalist readingappeals to the fact that the positing of force in bodies conflicts with ‘Descartes’s commitment to theposition that everything in body must be conceived as a mode of extended substance’ (Garber, 1992, p.297); cf. Hatfield (1979), pp. 118f. I return to this ontological problem below.

7 In his translation of this passage, John Cottingham takes Descartes to say that the third law of motion‘covers all changes which are themselves corporeal’ (Descartes, 1985, p. 242). The passage, so translated,involves no commitment to bodily causes. However, the issue is somewhat unclear, since the Latin textspeaks only of covering ‘those which are themselves corporeal’ (eae quae ipsae corporeae sunt).Cottingham takes the demonstrative pronoun here to mutationes rather than to the causae particularesmutationum mentioned earlier in the passage. As Della Rocca observes however, it would be odd toemphasize that a law governing motion is restricted to bodily changes. It would make more sense toclaim that the law is restricted to changes deriving from bodily (as opposed to mental) causes (DellaRocca, 1999, p. 53). It is possible that one could reduce such bodily ‘causes’ to the passive bodily featuresthat merely provide the occasion for the production of motion. As I indicate below, however, there isinsufficient evidence that Descartes himself embraced this sort of occasionalist reduction.

8 Della Rocca (1999), p. 66, citing Cohen (1964). As Cohen indicates, the phrase quantum in se est,which was introduced in the work of Lucretius, was widely understood in the seventeenth century toindicate that which derives from the nature (ex natura sua), internal force (sua vi) or spontaneity (spontesua) of an object.


certain nature in bodies that explains their tendency to persist in their same state ofmotion or rest quantum in se est.9Further support for this reading is provided by the claim in Principles II.36, quoted

above, that God conserves motion by His ‘ordinary concurrence’ (concursumordinarium). On the standard scholastic view, God’s concurrence involves His ‘act-ing with’ secondary causes, that is, created causes that depend for their power onthe uncreated primary cause. To my knowledge, Descartes did not speak explicitlyof bodies as secondary causes of motion.10 Even so, his claim that God concurs inconserving motion may be read as indicating that bodies make some causal contri-bution to transfers of motion. For a scholastic such as Francisco Suarez, the mannerin which God concurs is determined by the nature of the creatures with which Heconcurs.11 It would make sense for Descartes to speak of ordinary concurrence inthe case of changes in motion if, as Della Rocca claims, he held that God concurswith an action that derives from the nature of bodies to persist in the same statequantum in se est.12

2.2. Bodily causation and created eternal truths

Della Rocca argues not merely that Descartes believed that God’s production ofmotion allows for a real causal contribution on the part of bodies, but also that there

9 Della Rocca (1999), pp. 58–62. Descartes’s argument for the second law of motion, which dictatesthat all motion is ‘in itself rectilinear’, does not appeal to the fact that bodies persist in the same statequantum in se est. However, Descartes did say that this law derives from the same sort of divine actionthat provides the foundation for the first law (AT 8-1:63f).10 Though the distinction between primary and secondary causes is related to the distinction Descartes

drew at one point between the causes of being (causae secundum esse) and the causes of becoming(causae secundum fieri) (AT 7:369). Moreover, he referred in Principles II.37 to ‘certain rules or lawsof nature’ as ‘secondary and particular causes of the various motions we see in particular bodies’ (AT8-1:62). For discussion of the controversy in the literature over the meaning of the latter claim, see Pessin(2003), which agrees with the claim here that Descartes offered a version of concurrentism that positsbodily causes but which does not emphasize the difficulties with his position indicated below.11 See Suarez’s claim that God’s concurrence is ‘in the manner of nature’ since God ‘accommodates

himself to the natures of the entities, and he gives to each a concurrence that is accommodated to thatpower’. Suarez further noted that ‘if one presupposes an efficacious willing on God’s part to concur hereand now with this particular cause in this particular action, then the action itself issues forth by necessityat a given time and place from both the secondary cause and the First Cause’ (Suarez, 2002, pp. 217f).For more the scholastic background to Descartes’s views on ordinary concurrence, see Des Chene (1996),pp. 319–324.12 Descartes tended to overlook the scholastic distinction between God’s conservation of the being of

a creature and His concurrence with the action of that creature. Thus, in Principles II.36 he referred tothe ‘ordinary concurrence’ by which God ‘conserves’ the same quantity of motion and rest (AT 8-1:61).Moreover, in the Third Meditation passage on which the reasoning here depends, Descartes spoke onlyof the conservation of his existence, and not of concurrence with his action (AT 7:49). Even so, heshowed some familiarity with the technical scholastic notion of concurrence when he referred in a 1642letter to Regius to the claim of the ‘theologians’ that ‘no creature can operate without the concurrenceof God’ (AT 3:372).


are ‘systematic and principled reasons’ that explain this belief.13 Della Rocca takessuch reasons to be indicated by an analogy between Descartes’s view of God’s caus-ation of motion and his doctrine of God’s creation of the eternal truths. As is wellknown, Descartes introduced the latter in 1630 when he told his correspondent, Mer-senne, that such truths ‘have been laid down by God and depend on Him no lessthan the rest of His creatures’ (AT 1:145). With respect to this doctrine, Della Roccaemphasizes in particular the implication in Descartes that the eternal truths are bothnecessary and created by God’s absolutely free will. There is, for instance, Descar-tes’s claim that ‘it is because [God] has willed that the three angles of a trianglenecessarily equal two right angles that this is now true and cannot be otherwise’(AT 7:432). Here, God’s will is the source of the necessity that belongs to the truthsconcerning a triangle. But likewise, according to Della Rocca, Descartes took God’simmutable activity to be the source of the causal powers that belong to bodies.14Della Rocca notes that these accounts of eternal truths and the bodily causation

of motion are problematic for similar reasons. Consider that God’s free will is sup-posed to ground the necessity of the eternal truths. The problem here is that the factthat these truths derive from such a will seems to show that the truths themselvesare not necessary. In the same way, God’s immutable activity is supposed to groundthe bodily causation of motion. Yet the fact that motion derives from this activityseems to show that it does not derive from anything in bodies.15Della Rocca’s proposal is that Descartes’s solution to this latter difficulty is anal-

ogous to his solution to the problem of the necessity of the eternal truths. In theparticular case of truths concerning triangularity, Descartes indicated that there is a‘true and immutable nature’ of a triangle from which the truths necessarily follow.16Even though this nature depends on God’s free will, the truths retain their necessaryconnection to the nature. Della Rocca argues that Descartes held in a similar waythat God creates changes in motion by creating natures that constrain bodies to persistin the same state of motion or rest quantum in se est. His conclusion is that Descar-tes’s doctrine of created eternal truths serves to ‘isolate certain aspects of his concep-tion of God, which may in part be behind his views on the causation of motion and

13 Della Rocca (1999), p. 62.14 Della Rocca (1999), pp. 62–70. Here Della Rocca rejects Frankfurt’s claim that for Descartes ‘the

eternal truths are inherently as contingent as any other propositions’ (Frankfurt, 1977, p. 42). For otherdiscussions that emphasize the necessity of Descartes’s eternal truths, see Beyssade (1979), pp. 108–113,124–128, and Curley (1984). Whereas Beyssade claims that the sort of necessity is the same in the caseof all eternal truths, Curley proposes on Descartes’s behalf a distinction between eternal truths concerningGod, which are necessarily necessary, and eternal truths concerning creatures, which are necessary thoughnot necessarily necessary.15 Della Rocca (1999), pp. 65f.16 See, for instance, his claim in the Fifth Meditation that the fact that ‘various properties can be

demonstrated of the triangle’ reveals that there is ‘some determinate nature, or essence, or form of thetriangle, immutable and eternal, which is not created by me [a me non efficta est] or dependent on mymind’ (AT 7:64).


which add crucial support to the [non-occasionalist] interpretation of his views oncausation I have outlined’.17The comparison of the causation of motion to the creation of the eternal truths

may initially seem to be quite plausible. It is significant, for instance, that in thecases of both motion and of the eternal truths, Descartes insisted that God acts asan efficient cause. Thus, just as he claimed that God established the eternal truths‘as their efficient and total cause’ (AT 1:152), so he held that ‘when dealing withnatural things’ we must consider God ‘as the efficient cause’ (AT 8-1:15). Neverthe-less, there is an important disanalogy between these two cases that is indicated byJanet Broughton’s comment that ‘what makes eternal truths true is God’s timelessdecree; what makes [a] law of motion true is God’s preservation of the world frommoment to moment by the same activity by which he created it’.18 Given his accept-ance of the traditional view that God has an atemporal existence, Descartes musthold all divine actions are timeless in some sense. 19 However, there still seems to bean important difference between the two cases Broughton mentions. When Descartesintroduced his views on the eternal truths, he emphasized that the truths themselvesare eternal and immutable in virtue of the fact that the divine will itself is eternaland immutable.20 Yet though he stressed the immutability of God’s action in creatingand conserving motion, Descartes also noted that the motion that derives from thisaction ‘is not something permanently fixed in given pieces of matter, but somethingthat is mutually transferred when collisions occur’ (AT 8-1:66). The upshot of God’stimeless creation of eternal truths is something that is itself immutable, whereas theupshot of His timeless creation of motion is something that is constantly changing.21Though Della Rocca does not discuss this difference, I will return to it later. Yet

he does mention a further problem with the Cartesian appeal to natures responsiblefor motion. In his terms, the problem is as follows: ‘[G]iven that an extended objectgenuinely has this tendency [to persist in the same state], how can its nature beconstituted by extension and also somehow involve this tendency?’22 Descartes’s

17 Della Rocca (1999), p. 68.18 Broughton (1987), p. 212.19 See Descartes’s claim to Arnauld that the fact that our thoughts have a successive existence serves

to show that the duration of our mind is not ‘entirely simultaneous [tota simul] like the duration of God’(AT 5:193). Whereas the effects of God’s act of creation/conservation are successive, then, the act itselfis timeless.20 Thus, Descartes offered Mersenne the following dialogue with a critic concerning the immutability

of created eternal truths: ‘One will say to you that if God has established these eternal truths, He canchange them as a king changes his laws; to which it is necessary to reply that yes, if his will can change.—But I understand them to be eternal and immutable.—And I judge the same concerning God.—But Hiswill is free.—Yes, but His power is incomprehensible’ (AT 1:145f).21 One could interpret Broughton as making this point when she says that ‘divine activity is required

to keep moving bodies transferring motion in the same way they have’, whereas ‘divine activity is notrequired to keep triangular bodies having the same number of sides they have’ (Broughton, 1987, p. 213).However, her emphasis is more on the fact that the necessity of the laws of motion differs in kind fromthe necessity of the eternal truths (see note 44).22 Della Rocca (1999), p. 69.


ontology of the material world does not seem to allow for the position that there issome nature or tendency in body over and above extension and its modifications.Della Rocca is concerned to argue against Garber that the fact that the nature of

body consists in extension alone does not prevent it from having counterfactualproperties that derive from its standing in certain relations to God. Thus, for instance,even though bodies can continue to exist only due to God’s constant act of conser-vation, enduring existence is still a property of bodies.23 However, there is animportant difference between the property of enduring existence, or duration, andthe counterfactual properties that Della Rocca has in mind.24 For Descartes, the claimthat matter endures amounts to the claim that extended substance and its modes areinstantiated. This follows from his view that there is only a ‘distinction of reason’,and not any distinction in reality, between duration and the substance that endures(AT 8-1:30). But surely the force to persist quantum in se est cannot consist simplyin the instantiation of extended substance and its modes. Descartes insisted in thePrinciples that the ‘force or action’ (vim vel actionem) that brings about motion isdistinct from motion as a bodily mode, that is, the transference of a body from thevicinity of contiguous bodies at rest (AT 8-1:53f). Moreover, in a 1649 letter toMore he denied that active ‘resistance’ to motion (actio sive renixus) can be identifiedwith the mode of rest (AT 5:403). The basic problem here is that the forces of motionand resistance involve a sort of activity that is irreducible to passive modes such asshape, size, motion, and rest that can be conceived completely through the natureof extension. Della Rocca’s appeal to duration fails to address this problem sinceduration itself does not require any sort of bodily feature beyond such passive modes.Whereas Descartes can ground the duration of a body in the nature of body as anextended thing, there is nothing in that nature which serves to ground the forcesresponsible for changes in motion.25Though Della Rocca has provided reason to think that Descartes wanted to allow

for the conclusion that bodies are true causes of motion, he failed to show that thedoctrine of the creation of the eternal truths serves to isolate a conception of Godthat provides room for such a conclusion. Descartes’s view that the nature of bodyconsists in extension alone simply cannot accommodate the bodily natures or forcesthat are supposed to be responsible for the production of motion.26 It might beobjected that given this result, the principle of charity forces us to an occasionalist

23 Ibid., pp. 59f. Della Rocca appeals to the example of durational existence in ibid., p. 75f n. 46. Cf.the remarks in Clarke (2000), p. 145.24 Thanks to Elmar Kremer and Eric Watkins for helpful discussion of the issues I raise here.25 This conclusion is perhaps a less qualified version of Garber’s observation that ‘there may not be

an altogether satisfactory view of the ontology of force in Descartes, one that is coherent and sensible,and is consistent with what he says about force in all of his writings, or in what he commits himself toin other contexts’ (Garber, 1992, p. 297). Incidentally, this observation may be in some tension withGarber’s remark elsewhere, quoted in note 6, that it is as clear to him as anything that Descartes tookGod to be the only cause of motion in the inanimate world.26 There is also some question whether Descartes’s ontology allows for the suggestion that God creates

eternal truths by producing eternal and immutable essences distinct from His own essence. I return tothis question in Section 4.


reading of Descartes. However, Descartes himself persistently spoke of the forcesas bodily modes responsible for changes in motion and rest.27 Moreover, I find noevidence that he thought through the complications his identification of body withpassive extension creates for a concurrentist account of the production of motion.28It was left to his occasionalist successors to replace such an account with the positionthat passive bodily features provide merely the occasion for changes in bodilymotion. Yet the conflict in Descartes is reflected in the fact that his views providedthe inspiration not only for Malebranche’s occasionalist account of the productionof motion but also for the concurrentist account in Regis of body–body interaction.

3. Malebranche

3.1. Occasionalism and general volitions

Malebranche did not evince any concern about illegitimately reading a lateroccasionalism back into Descartes. Indeed, in the fifteenth of his Elucidations to hisSearch after truth, Malebranche claimed that the opinion that bodies can move eachother cannot be attributed to Descartes given ‘what he expressly says in articles 36and 37 of the second part of his Principles of philosophy’ (OCM 3:238).29 Even so,this same elucidation argues for the unintelligibility of the notion of concurrencethat Descartes himself used in that portion of the Principles to describe God’s pro-duction of motion. Malebranche’s argument for unintelligibility is as follows:

To concur [Concourir] in contrary actions, is to give contrary concurrences, andby consequence to perform contrary actions. To concur with the action of creaturesthat resist each other is to act against oneself. To concur with useless motions isto act uselessly. But God does nothing uselessly; He produces no contrary actions;He does not struggle against Himself. Thus He does not concur with the actionof creatures, which often destroy each other and produce useless actions ormotions. (OCM 3:216; emphasis in original)

27 Besides the passages already cited, see his claim in a 1640 letter to Mersenne that ‘from the solefact that a body has started to move, it has in itself the force to continue to move; in the same way, fromthe sole fact that it is stopped in some place, it has the force to continue to stay there’ (AT 3:213).28 One could make a similar claim with respect to the account of the bodily production of sensation.

In the Sixth Meditation, Descartes concluded that the ‘active faculty’ that produces the objective realityof our sensory states exists in bodily substance, without considering whether such a faculty can be con-ceived in terms of extension alone (AT 7:79f). This argument seems to assume that the action of bodyon mind is permissible because it does not violate the abstract principle, introduced earlier in the Medi-tations, that the cause of the objective reality of an idea must contain a level of formal reality that atleast matches this objective reality (AT 7:40f). See Wilson (1999), which argues for the compatibility ofthe action of body on mind with this principle but also emphasizes the problematic nature of his conceptionof this action.29 OCM: Robinet (1958–1984).


In the case of a moving body colliding with a body at rest, God does not have oneconcurrence with the tendency of the moving body to remain in motion and a con-flicting concurrence with the tendency of the resting body to remain at rest. Rather,by a single action He directly causes the transfer of motion that is in accord withthe natural laws that He has instituted.In the Fifteenth Elucidation, Malebranche described his own alternative to concur-

rentism in terms of two laws of motion instituted by God, the first of which dictatesthat unimpeded motion is rectilinear and the second of which dictates that transfersof motion in collisions occur in proportion to the sizes of the colliding bodies andin a way that conserves the total quantity of speed. The first law of motion is relatedto Descartes’s second law, and Malebranche’s second law to Descartes’s third law.30Significantly enough though, Malebranche has nothing corresponding to Descartes’sfirst law, which dictates that bodies have a tendency to persist in the same statequantum in se est. Instead of this bodily tendency, Malebranche appealed to the factthat God

positively wills through the first of the natural laws [concerning rectilinearmotion], and consequently produces, the collision of bodies; and that He thenmakes use of this collision, which obliges Him to vary His action due to theimpenetrability of bodies, as the occasion to establish the second law of nature,which regulates the communication of motions; and thus the actual collision isthe natural or occasional cause of the actual communication of motions, by whichGod without changing His conduct produces an infinity of admirable works.(OCM 3:216)

Since the material world is a plenum, the rectilinear motion required by the firstlaw will bring the moving body into contact with other bodies. Furthermore, Maleb-ranche held, with Descartes, that impenetrability is a property that derives necessarilyfrom the nature of body.31 This nature dictates that a moving body cannot simplyinterpenetrate other bodies and continue on, but must bring about or suffer somechange. In Malebranche’s terms, the claim here is that the nature of body requiresthat God ‘vary His action’ in the case of collisions. The second law then dictatesthat all such variation involve the conservation of the total quantity of the speedsof the bodily motions.

30 However, the fact that Malebranche’s second law requires the conservation only of the quantity ofspeed serves to distinguish it from Descartes’s third law, which requires the conservation of quantity ofmotion (size times speed). Malebranche also rejected the force of a resting body to repel motion thatDescartes took to be responsible for certain changes governed by his third law. Compare Descartes’sview of this force in the Principles, at AT 8-1:68, and Malebranche’s critique of this view in the Search,at OCM 2:420–449.31 Descartes argued in 1649 correspondence with More that impenetrability must ‘pertain to the essence

of extension’ since it is ‘impossible to conceive of one part of an extended thing penetrating anotherequal part without thereby understanding that half of the total extension is taken away or annihilated’(AT 5:341f). Cf. Malebranche’s claim in the Search that impenetrability is an inseparable bodily propertythat follows from the essence of matter (OCM 1:459f).


The impact of bodies therefore is in Malebranche’s terms an ‘occasional cause’that merely prompts God’s production of natural changes in motion that follow fromthe two laws of nature.32 For Malebranche, the ‘general volitions’ in God that serveto establish these laws are the real causes of such changes.33 The impenetrability ofbodies ‘obliges’ God to impose the second law of motion, and the distribution oftheir motions serves to determine the particular effects of the general volition associa-ted with this law. Since the bodies themselves are merely passive bits of matterhowever, they can have no causal efficacy. As Malebranche put the point, bodiesmust be passive since ‘the properties of extension can consist only in relations ofdistance’ (OCM 12:150).There is admittedly some question concerning the precise manner in which Maleb-

ranche related the laws of motion to the corresponding general volitions in God.Malebranche’s Cartesian critic Antoine Arnauld read him as identifying the lawswith the volitions, and then objected that such an identification illicitly conflatesacting by laws with acting according to laws.34 However, Steven Nadler has arguedrecently that this whole line of objection involves a misunderstanding of Malebran-che’s occasionalism. For Nadler, ‘Malebranche’s God must be directly and immedi-ately responsible for each and every particular effect in nature’.33 His argument forthis claim emphasizes the position, which is prominent in Malebranche’s discussionof occasionalism in the Dialogues on metaphysics (1688), that God brings abouteffects in nature by means of His continuous creation of the universe (OCM 12:157).Thus, God moves a body by willing that it exist successively in different places. AsNadler sees it, Malebranche held that God wills the existence of the body in a placeat any particular moment by means of ‘a discrete and temporalized volition with aparticular content (e.g., “Let this body move now thus”)’. This volition is generalsimply in the sense that it is in accord with a general law.36To be sure, Malebranche’s claim that God acts by general volitions ‘in conse-

quence of the general laws that He has established’ (OCM 5:147) appears to suggestthat general volitions are merely in accord with general laws and not identical tothem. Moreover, the stress in the Dialogues on continuous creation may seem toindicate that God causes effects by means of ‘an infinite number of discrete tem-poralized acts’, as Nadler puts it.37 Yet Malebranche emphasized in this same textthat ‘the conservation of creatures is, on the part of God, only a continued creation,

32 As indicated below, however, Malebranche held that occasional causes not merely prompt but also‘determine’ God’s action in a non-causal manner (to be explicated).33 According to Malebranche, God’s production of these changes contrasts with his production of mir-

aculous events. God is said to produce the latter by means of ‘particular volitions’ that are restricted toparticular circumstances and thus that do not establish general law-like relations between occasional causesand their effects.34 Arnauld (1967), Vol. 39, p. 175. On Arnauld’s discussion here, see Black (1997), pp. 33–37. Cf.

Jolley (2002), pp. 245–247.33 Nadler (1993), p. 41.36 Ibid., p. 43. Cf. the development of Nadler’s interpretation in Pessin (2001).37 Nadler (1993), p. 43. By ‘temporalized acts’, Nadler means acts that though not themselves temporal,

are indexed to particular times (e.g., ‘Let body A exist at place P at time t5’).


simply the same volition that subsists and operates unceasingly’ (OCM 12:160). Herehe was simply following Descartes’s claim that conservation is distinct only by rea-son from creation, a claim, as we have seen, that underlies the view in the Principlesthat God conserves motion ‘by the same action’ with which He created it. But ifMalebranche accepted Descartes’s point that it is the very same volition that createsand conserves motion, as the passage from the Dialogues seems to indicate, thenpace Nadler, he could not have held that God brings about motion by means of aseries of distinct law-like volitions.38There are further problems for Nadler’s interpretation introduced by Malebran-

che’s insistence to Arnauld that ‘God must act through laws or general volitions,the efficacy of which is determined by the action of natural or occasional causes’(OCM 8:667). One obvious problem is that the passage suggests the identificationof laws with God’s general volitions (loix ou des volontez generales). Yet there isanother, and in some respects more significant, difficulty that derives from the claimthat natural or occasional causes ‘determine’ the efficacy of laws or general volitions.If the general volitions had a particular content (e.g. following Nadler, ‘Let this bodymove now thus’), the efficacy of the volitions would seem to be fixed by this contentalone. There would be nothing left for the occasional causes to determine. However,if the content of the general volitions were exhausted by general laws (e.g. ‘Letmotion be communicated after collision in a manner that is proportional to the sizesof the colliding bodies and that conserves the total quantity of speed’),39 these vol-itions by themselves would not determine any particular effect. What would berequired in addition are particular bodies with the particular sizes and states of motionand rest that, together with the general laws or volitions, yield the determinate results.As we will see, Malebranche’s claim that particular occasional causes are required

to determine the efficacy of general laws has a counterpart in Regis’s version ofconcurrentism. What distinguishes Malebranche from the concurrentist is his insist-ence that the causal efficacy deriving from this determination can be provided onlyby God’s general laws/volitions. In the case of body–body interaction, then, thesomewhat clouded picture in Descartes of God’s concurrence with bodily forces isreplaced by the much clearer picture in Malebranche of the determination of God’sgeneral volitions by various modifications of inert parts of extension.40

38 For a similar objection to Nadler’s position, see Black (1997), p. 39. Black offers the related objectionthat Nadler cannot accommodate the position in Malebranche (e.g., at OCM 5:31) that God reduces asmuch as possible the number of volitions required to bring about natural effects (Black, 1997, p. 40).39 Of course, the full content would specify the exact proportions and the precise ways in which quantity

of speed is conserved. Since the details are not relevant here, I provide a simplified description of therelevant general volition.40 There is still some question whether Malebranche can hold that the laws can be efficacious given

that they must be identified with the propositional content of God’s volitions rather than with the volitionsthemselves. For a discussion of this difficulty, see Jolley (2002), pp. 254–257. One possibility, which Icannot explore here, is that Malebranche held that only the volition and its content taken together canbe said to produce the effects when certain determining conditions are present.


3.2. Eternal truths and laws of motion

I have noted Malebranche’s claim that his occasionalist account of body–bodyinteraction is in line with Descartes’s account in the Principles. However, his accountof motion broaches an explicit and fundamental disagreement with Descartes’s doc-trine of the creation of the eternal truths. The relevant disagreement is connected towhat, from Malebranche’s perspective, was an unfortunate reference in the initialedition of the Search (1674) to ‘necessary truths, immutable by their nature andbecause they have been determined by the will of God, which is not subject tochange’ (OCM 1:63a). In a 1675 text, Malebranche’s first critic, Simon Foucher,took this passage to endorse Descartes’s view that all necessary truths derive fromGod’s will.41 Prompted by Foucher’s reading, Malebranche later changed the passageto emphasize the distinction between necessary truths that ‘are by their nature immu-table’ and necessary truths that ‘have been fixed by the will of God’ (OCM 1:63).Thus, for instance, the truth that bodies are impenetrable is immutable ‘by its ownnature’ since it derives necessarily from the nature of extension. In contrast, truthsconcerning the communication of motion must be ‘fixed by the will of God’ sincethey derive not from the nature of extension, but rather from the general volitionthat actually causes changes in motion when determined by inefficaciousoccasional causes.Malebranche later emphasized, in the Tenth Elucidation (1678), that the necessity

of truths that are ‘immutable by themselves’ does not require ‘that God as sovereignlegislator has established these truths, as Descartes has asserted’ (OCM 3:136). Themain argument against Descartes in this text is that if these truths derive from God’sfree will, ‘it seems evident to me that there would no longer be any true scienceand that we might be mistaken in claiming that the arithmetic or geometry of theChinese is like our own’. Descartes himself suggested that the immutability of theeternal truths is guaranteed by the immutability of the divine will.42 However, Maleb-ranche challenged this line of response in asking:

Do we clearly see that God could not have willed certain things for a certaintime, for a certain place, for certain people, or for certain kinds of being—given,as some would have it, that He was entirely free and indifferent in His willing?As for me, I can conceive no necessity in indifference, nor can I reconcile twothings that are so opposite. (OCM 3:132)43

The only way to guard against this kind of skepticism, according to Malebranche,is to hold that eternal truths are grounded not in divine volitions but in uncreatedideas in God’s intellect that serve as immutable archetypes for His creation of theworld.

41 Foucher (1969), pp. 25–32. Cf. note 41.42 See the passage quoted in note 20.43 Somewhat ironically, Foucher offered a similar objection to the account of necessary truths that he

found in the initial edition of the Search; see Foucher (1969), p. 30.


The argument against Descartes in the passage above may appear to be compro-mised by Malebranche’s admission in the Search that there are certain necessarytruths that have been ‘fixed by the will of God, which is not subject to change’. Inparticular, the immutability of truths concerning the communication of motion isguaranteed by the fact that they derive from God’s immutable general volitions.There seems to be no concern at this point that the science of motion of the Chinesemay not be like our own. But why then couldn’t the immutability of the divine willsuffice to eliminate doubts about the similarity of our arithmetic and geometry tothat of the Chinese?In response, Malebranche could emphasize that God’s choice of general volitions

is constrained by considerations beyond His volitional control. Thus, in the passagefrom the Fifteenth Elucidation cited above, he indicated that God must choose thosevolitions that produce ‘an infinity of admirable effects’ in the most economical way.It is the need for economy, rather than the immutability of the divine will, thataccounts for the generality of the volitions responsible for motion. In contrast,Descartes’s acceptance of the doctrine of the creation of the eternal truths led himto assert that there is no ‘prior order, or nature, or ratione ratiocinate, as it is called,such that this idea of the good impelled God to choose one thing rather than another’(AT 7:432). There would seem to be nothing here to constrain God to produce motionby general volitions rather than by volitions that produce effects that hold ‘only fora certain place, for certain people, or for certain kinds of being’.It might be thought that Descartes could respond by appealing to his position in the

Principles that God’s production of motion is constrained by His perfection insofar assuch perfection requires ‘not only that He be immutable in Himself, but also thatHe operate in that manner that is most constant and immutable’ (AT 8-1:61). Onthe basis of this position, Blake Dutton has claimed recently that Descartes took thelaws of motion to have ‘a higher order of necessity’ than that of the eternal truths.In the case of the eternal truths, God is indifferent with respect to the choice ofwhich truths to create. But though Descartes allowed that God is indifferent withrespect to the decision of whether to create the laws of motion, the view that Duttonattributes to Descartes is that divine indifference does not extend to the choice ofwhich laws to create.44Such a view seems to me to conflict with Descartes’s emphatic claim in the pass-

age just cited that there is no order or nature that determines God’s choice of whatto create. If God’s perfection compelled Him to create/conserve motion in a particularmanner, surely that would count as a determination of His choice by some priororder or nature.45 A further difficulty is indicated by Broughton’s claim that ‘if the

44 Dutton (1996), pp. 208f. This claim contrasts with the thesis in Broughton (1987) that the laws ofmotion have a ‘physical necessity’ that is weaker than the ‘mathematical necessity’ of the eternal truths.45 Dutton grants that Descartes cannot take divine immutability alone to determine the laws of motion,

since the content of these laws depends essentially on eternal truths concerning the nature of extension(Dutton, 1996, pp. 209–212). However, he insists that ‘nowhere does Descartes sever the intelligibleconnection that the laws have with the divine nature, as he does with the eternal truths’ (ibid., p. 212).The problem I raise is that the admission of such a connection seems to conflict directly with Descartes’sown denial that there is any prior order or reason that leads God to create in one way rather than in another.


laws of motion are not about an essence, then they are not necessary in the waythat, for instance, mathematical truths are’.46 In Descartes’s view, as we have seen,mathematical truths derive from the ‘true and immutable nature’ of extension. It isbecause the truths derive from this immutable nature that they necessarily have thecontent that they do. However, the laws of motion cannot be founded in a similarway on the nature of motion. In the Principles, this nature dictates simply that motionis a transference (translatio) of one piece of matter from other pieces contiguouswith it that are regarded as being at rest (AT 8-1:53f). Though the nature of motion,so defined, can establish certain truths, for instance, that there is no motion in undiv-ided matter, this nature does not serve to determine the precise manner in which thegeneral and particular causes produce changes in motion.47 There would be a wayaround this problem if, as Della Rocca claims, Descartes held that God created aparticular nature in bodies that determines the way in which motion is redistributedafter collisions. However, the discussion above makes clear the difficulties thatDescartes’s ontological commitments create for the attribution of such a nature tobodies.48The point that laws of motion differ from other eternal truths would not have

bothered Malebranche, since he granted that these laws are underdetermined by thenatures that condition God’s creation of the material world. Indeed, he emphasizedat one point that though truths concerning these natures have a necessity that isindependent of God’s will, the truth concerning the communication of motion incollision ‘is arbitrary and depends on the volitions of the Creator’ (OCM 17-1:45).In saying that this truth is arbitrary, Malebranche did not mean to deny that thereare considerations that guide God’s production of motion. I have noted, for instance,his claim that the generality of the laws of motion follows from the need for economyin God’s actions. Even so, Malebranche held that unlike truths concerning extension,the truth concerning the communication of motion is ‘arbitrary’ in the sense that itis not determined by any nature reflected in uncreated ideas in the divine intellect.49Della Rocca briefly suggests at one point that just as Descartes’s claim that bodies

are causes of motion is connected to his claim that God is the cause of eternal truths,so Malebranche’s denial of the former claim may be ‘importantly connected’ to his

46 Broughton (1987), p. 218.47 For this point, see ibid., pp. 211f.48 Broughton claims that though Descartes did connect laws of motion to other eternal truths in Le

Monde (1633) and the Discourse (1637), he later denied such a connection in the Principles (1644)because ‘he found it very important to deny that moving bodies have built into them inertial powers,tendencies to move in a straight line, or forces to transfer their motion in collision’ (ibid., p. 218). I havealready argued with Della Rocca that the Principles does posit such powers, tendencies, or forces, andthus would not be inclined to distinguish Descartes’s earlier and later views in the manner that Broughtondoes. I also do not follow Broughton’s claim that her conclusion in the foregoing passage is ‘compatiblewith the claim that in the Principles the term “force” refers to real inherent qualities of bodies’ (ibid.,pp. 220f n. 38, citing Gueroult, 1980, and Gabbey, 1980).49 This point helps to explain why Malebranche held that God can produce miraculous exceptions to

the laws of motion but not to truths deriving from the nature of body (cf. note 33).


denial of the latter claim.50 I have noted, and will return below, to problems concern-ing the purported connection between these claims in Descartes. However, I thinkthat there is some, albeit indirect, connection between the demurrals in Malebranche.Though he held that the Cartesian nature of body determines truths, such as thoseconcerning impenetrability, that hold independently of the divine will, Malebrancheemphatically denied that this nature suffices to determine the effects that follow fromthe laws of motion. Such a denial reinforces his position that God’s general volitionsare responsible for such effects. What is at issue here is not so much whether naturesare created, but whether there is a nature from which the laws of motion derive.Malebranche’s claim that all eternal truths concerning body derive from the natureof extension and his insistence that that nature does not serve to fix the laws ofmotion thus prepare the way for his occasionalist account of body–body interaction.In Regis, by contrast, there is an attempt to defend a concurrentist account of such

interaction by claiming that the laws of motion derive from a created nature that isakin to the nature responsible for eternal truths concerning extension. He thereforeprovided the sort of link between motion and the eternal truths that Della Roccaposits in the case of Descartes.51 However, it is no help to Della Rocca that the linkin Regis requires the rejection of central features of Descartes’s account of God’scausation of motion.

4. Regis

4.1. Motion and concurrence

In his System of philosophy (1690), Regis spoke of God as ‘the first and totalcause of all motion that is in the world’.52 On the basis of claims such as this, onecommentator has ranked Regis among the occasionalists.53 However, even in theSystem Regis insisted that particular bodies are ‘second causes’ of motion.54 Theresistance to occasionalism is even more prominent in his final work, the Use ofreason and faith (1704), which devotes a chapter to the refutation of the claim thatsince ‘there is no power in the universe other than that of God’, it must be the casethat the so-called secondary causes are ‘only occasional causes that simply determinethe author of nature to act in such and such a way, in such and such an encounter’

50 Della Rocca (1999), p. 78 n. 74.51 Though Regis did not straightforwardly identify this nature with the tendency to persist quantum in

se est that Della Rocca emphasizes; see note 63.52 Regis (1970), 1, p. 305.53 Hatfield (1979), p. 136 n. 87.54 See Regis (1970), 1, pp. 310–313. Regis indicated at the end of this passage that God as the primary

cause of motion ‘does not act immediately to move or leave at rest particular bodies’, and thus that bodiescan serve as ‘second causes of the motion and rest of particular bodies’ (ibid., p. 313). Clarke recognizesthe opposition to occasionalism in the System, though he argues that this text concedes too much toMalebranche to provide a viable alternative to an occasionalist account of the production of motion(Clarke, 1989, pp. 125–129).


(URF, 409f).55 The argument against occasionalism in this chapter draws on a diag-nosis of why the occasionalists have rejected the claim that bodies are secondarycauses. Regis urged in particular that there are two reasons that explain this rejection.The first is that the occasionalists ‘take the will of God for motion itself’, from whichthey conclude that ‘there is no other force in the world than the will of God’, whereasthe second is that ‘they confuse motion with manners of motion’, and therefore holdthat ‘as God produces motion, He produces as well the manner of motion’ (URF,416). In response to the first consideration, Regis insisted that God’s will is distinctfrom the motion it produces. He responded to the second consideration by notingthat the motion that God produces must be distinguished from the various ‘manners’or specifications of motion with respect to speed and determination that derivedirectly not from God’s will but from bodily secondary causes.Regis’s first charge that the occasionalists confuse motion with the divine will

seems initially to be grossly unfair to Malebranche. After all, Malebranche insistedon the distinction between the general volition by which God produces motion andthe particular motions in bodies that serve as the occasional causes for this pro-duction. Moreover, the charge that the occasionalists confuse motion with God’s willsits uneasily with the additional charge that they confuse motion with manners ofmotion. Taken together, the two charges imply that the occasionalists have confusedGod’s will with particular bodily motions, a confusion that certainly cannot be foundin Malebranche.However, we can understand Regis’s basic objection here to be that the occasional-

ists have failed to recognize that there is a kind of motion that is distinct both fromefficacious volitions in God and from particular manners of motion in bodies. In theUse of reason, Regis began by distinguishing between motion considered in the firstmover, which is indeed identical to the relevant volitions in God, and motion con-sidered in the object moved, which is ‘nothing other than the different manners inwhich bodies apply themselves to each other’. He went on to note a further distinc-tion in the object moved between ‘formal motion’ and the manners of motion thatmodify this formal motion (URF, 295). His response to the occasionalists indicatesthat the fact that the formal motion is a product distinct from the divine will allowsfor the position that the modifications of this motion are produced by bodily second-ary causes.Admittedly, Regis seems at times to downplay the causal significance of formal

motion. For instance, he indicated that this sort of motion plays no direct role incausal interactions when he noted that ‘motion considered in itself can producenothing; it needs to be modified to be efficacious’ (URF, 412). Moreover, he seemsto have bypassed formal motion entirely when he argued that God cannot directlyproduce particular changes since ‘God being immutable, he can immediately producenothing successive’. Here it supposedly follows directly from the fact that particularmanners of motion are successive that God cannot be the immediate cause of them.

55 URF: Armogathe (1996).


In the case of body–body interaction, the immediate causes are rather successivemanners of motion (URF, 412).56On the interpretation offered above, however, Malebranche could concede that

God’s immutable general volitions cannot bring about changes in motion by them-selves. Such volitions require other particular conditions that serve to determinethem. He could nonetheless protest that the fact that these volitions do not immedi-ately cause particular changes does not suffice to establish Regis’s conclusion thata determining condition is ‘a very real and very positive physical cause’ (URF, 412).That is to say, the determining conditions may not be real and positive causes, butoccasional causes that serve merely to direct in a particular way an efficacy that canderive only from God’s volitions.The distinguishing feature of Regis’s position, however, is his claim that manners

of motion determine God’s action by modifying it. The occasionalist identificationof this action with God’s own general volition would yield the unpalatable conse-quence that manners of motion modify God. Regis can avoid this consequence sincehe takes this action to produce a formal motion distinct from Him that the mannersof motion subsequently modify. Thus, the modification of God’s action need notinvolve any modification of God.Regis’s claim that manners of motion modify formal motion seems to suggest that

formal motion is substance-like. Indeed, Regis spoke explicitly of God’s creation ofthe ‘substance of formal motion’. He admitted that this sort of talk is odd, since‘one cannot conceive that formal motion which is a mode can be considered as asubstance’. However, he responded that

as substances are said to be permanent beings only since they are producedimmediately by the will of God, which is immutable, for the same reason formalmotion can be considered as a substance because it proceeds immediately fromthe same will. It is for this reason that formal motion cannot ever change eitherwith respect to its nature or with respect to its quantity. (URF, 296f)

The claim that formal motion is a substance thus indicates merely that it is a ‘perma-nent being’ that derives immediately from God’s will. Given his view of formalmotion, Regis was committed by his principle that all immediate effects of this willlack a successive existence to the conclusion that this motion lacks this kind ofexistence as well. Such a commitment serves to explain his claim that formal motionhas ‘only an indivisible point of existence’, in contrast to the manners of motionthat modify it, which are ‘successive and changing’ (URF, 412).Regis’s remarks may initially seem to suggest that formal motion is simply the

56 Cf. the passage from the earlier System cited in note 52. The force of Regis’s principle that Godcannot immediately produce anything successive is admittedly unclear. At times, he indicated that thisprinciple is restricted to the ‘order of nature’, and thus allows for God’s miraculous production of modesin the ‘order of grace’ (see, for instance, URF, 274). However, he also appealed to this principle insupport of the conclusion that God cannot annihilate the substances He creates even by His ‘absolutepower’ (URF, 325–328). For further discussion of this tension in Regis, see Schmaltz (forthcoming).


total quantity of motion. But given this suggestion, it is difficult to see how formalmotion could be said to have an ‘indivisible point of existence’. The quantity ofmotion would appear to have an enduring temporal duration that is divisible intoparts. However, Regis’s account of extended substance in the Use of reason indicatesthat formal motion is distinct from the quantity of motion. In particular, Regisemphasized the distinction between extended substance as ‘the essence of body’ andthe ‘quantity’ (quantite) of matter. The primary difference is that whereas materialquantity is divisible into parts, extended substance as the essence of body cannot beso divisible. The argument for indivisibility begins with the assumption that extendedsubstance is simply the nature that all particular bodies share as modes of this sub-stance. Since this nature is immutable, and since any division brings about a changein what is divided, extended substance itself cannot be divided (URF, 282f). Allsorts of divisibility are ruled out here, including a divisible temporal existence.In light of this argument for indivisibility, we can take Regis’s claim that particular

bodies are modifications of extended substance to indicate that they are temporalinstantiations of the indivisible and atemporal nature of extension. In the same way,his claim that manners of motion modify a single formal motion indicates that thesemodifications are temporal instantiations of the indivisible and atemporal nature ofmotion. It is this nature that explains the continuing conservation of the quantity ofmotion in all temporal changes among the manners of motion.Certainly, this unusual account of the nature of motion cannot be found in

Descartes. There is even one point at which Regis’s claim that formal motion lacksthe successiveness of manners of motion conflicts directly with Descartes’s accountof God’s production of motion. Regis himself drew attention to this point of conflictwhen he challenged the position of ‘a very considerable philosopher’—indicated ina marginal note to be Descartes—that God needs to conserve substances in existenceat each instant. As we have seen, the general principle here that created objectsrequire a cause at each moment of their existence is essential to the account in thePrinciples of God’s conservation of motion. However, Regis rejected such a principleby arguing that ‘since the existence of substances is simple and indivisible, it is notnecessary to look there for the successive conservation that is found in the existenceof modal things’ (URF, 322). In the case of motion, the upshot is that God’s act ofcreation results in the production of the indivisible ‘substance’ of formal motionrather than, as in the case of Descartes, a modal quantity with a successive existencethat is divisible into parts.Even so, Regis’s appealed explicitly to the notion of concurrence that is so promi-

nent in Descartes’s own account of motion. Regis’s discussion is in fact quite attunedto the subtleties of scholastic discussions of concurrence, as shown by his distinctionin the Use of reason between God’s concurrence as a ‘physical premotion’(premotion physique) and that concurrence as a ‘simultaneous concourse’ (concourssimultanee) (URF, 383).57 Regis held that God concurs in the latter way when ‘He

57 The reference here is to a dispute between scholastics over whether God concurs with effects bymoving the agent to act (physical premotion), as the followers of the Dominican Domingo Banez (1528–1604) held, or by acting directly on the effect (simultaneous concurrence), as the followers of the Jesuit


produces the motion that bodies modify at a particular time; thus God and bodyconcur at that time, God in producing the motion, and these bodies in modifying it’(URF, 384f).58 The view here is that God simultaneously concurs by creating formalmotion, whereas bodies concur by producing the particular modifications of thatmotion. In a sense, Regis can agree with Descartes that God’s act of creation is notdistinct from his act of concurrence or conservation. But there is still the differenceindicated above, namely, that Descartes’s God creates a modal quantity that has asuccessive existence, whereas Regis’s God creates a substance-like entity that has anon-successive existence.

4.2. Created natures and formal motion

I have noted Broughton’s observation that the divine activity that Descartes positedin the case of God’s creation of the eternal truths differs in nature from the activitythat he posited in the case of God’s production of motion. God’s creation of theeternal truths yields something that is itself eternal and immutable, whereas Hisproduction of motion yields a modal quantity that is constantly being redistributedat each moment. A related point is that the eternal truths that God creates seem tobear a different relation to the material world than the quantity of motion that Heproduces. Though Descartes held that God’s production of motion requires the con-tinuing conservation of a changing material world, his remarks in the Fifth Medi-tation make clear that the ‘true and immutable natures’ of various shapes do notdepend on the existence of those shapes, or indeed on the existence of the materialworld itself (AT 7:64). This sort of nature does not appear to be involved in God’sconservation of motion by means of His initial act of creating it.Admittedly, Descartes’s view of the ontology of true and immutable natures is

not entirely clear. He cannot identify immutable bodily natures with any feature ofthe created material world for instance, since he allowed for the possibility that suchnatures exist merely ‘objectively’ in our thoughts concerning that world. This sug-gests the position, to which Descartes himself seems to have been inclined, that thenatures exist objectively in our mind in the sense that they are encoded in innatemental structures that explain our perception of the relevant eternal truths concerningbody.59 However, there is some question whether such a position can do full justice

Luis de Molina (1535–1600) held. For discussion of this dispute and the issues connected to it, seeFreddoso (1988).58 In response to the scholastic dispute indicated in note 57, Regis held that God can be said to concur

in the case of body–body interaction by means of physical premotion as well as by means of simultaneousconcourse, since He is the cause of the formal motion ‘that contains [renferme] all the qualities that oneis accustomed to attribute to physical premotion’ (URF, 384).59 Cf. the conclusion in Nolan (1997), p. 186, that ‘Cartesian true and immutable natures are innate

ideas considered with regard to their objective being’. This conclusion of course takes into account thedistinction in Descartes between the objective being that objects have in the mind and the formal beingthat they have in reality (see, for instance, AT 7:161). My additional reference to mental structures thatexplain our perception reflects Descartes’s claim that certain ideas are innate in us in the sense in whichdiseases are innate, namely, in the sense that we ‘are born with a certain disposition or faculty to contractthem’ (AT 8-2:358).


to his indication in his 1630 correspondence with Mersenne that God has producedthese natures ‘from all eternity’ (AT 1:152).60 It might be suggested that Descartesheld that eternal truths are eternal only in the sense that they are immutable. Sucha suggestion would be in line with the identification of these truths with enduringmental structures. On such a reading however, Descartes could not appeal to theeternity of the truths to explain their immutability. Indeed, it would seem that theimmutability of the eternal truths could not follow even from the eternity of thedivine will that creates them. That this does not follow is indicated by Malebranche’sobjection above that an eternal will could nonetheless establish certain truths ‘for acertain time, for a certain place, for certain people, or for certain kinds of being’.Just as God’s eternal will can create mutable features of the material world, so, itseems, it could make the natures manifested in this world to be mutable. In our case,the worry is that this same eternal will could produce mutable natures by creatingmental structures that vary over time. It appears that the best way around this objec-tion would be to identify the natures rather with something that is eternal in thesame way that God’s will is eternal, and so, like God’s will, never varies. But ifDescartes took this route, he would need to find something other than temporalmental structures to identify with the eternal natures.61Malebranche had no problem here since he identified these natures with eternal

features of God Himself. However, it was not open to Descartes to identify thenatures with God, given his insistence to Mersenne that eternal truths ‘are no morenecessarily attached to [God’s] essence than are other creatures’ (AT 1:152). Suchan identification also was not open to Regis, since he concluded in the Use of reason,following Descartes, that ‘all immutable truths that are the consequences of the natureof created things depend on the will of God as on their true and unique immediateefficient cause’ (URF, 275). Earlier in this text, Regis had contrasted this conclusionwith the argument of ‘the disciples of Plato’—among whom he counted Malebran-che—that since God knew creatures before He created them, ‘he can discover theirnature only in His essence’ (URF, 207).62 His rejoinder is that since ‘knowledgedoes not precede will’ in the case of God, God can know the nature of creaturesonly after actually producing them (URF, 210). In line with Descartes’s denial thatcreated natures are ‘necessarily attached’ to God’s essence, Regis insisted that whatGod creates cannot be a mere possibility that exists in His power, but must actuallyexist external to Him (URF, 185f).Regis added to Descartes’s position not only a response to Malebranche’s Platon-

ism, but also an ontology that allows for the distinction of created natures not onlyfrom God but also from temporal features of the created world. Regis accepted thetraditional Cartesian view that the nature or essence of body consists in extension,

60 Descartes spoke explicitly here only of God’s creation of truths from eternity, though in the sameletter he noted that the ‘essence of created things . . . is nothing other than the eternal truths’ (AT 1:152).61 For a discussion of a related problem with Descartes’s account of the eternity of the eternal truths,

see Bennett (1994), pp. 664f.62 For more on Regis’s opposition to the Platonism of Malebranche and his followers, see Schmaltz

(2002), §5.4.


but as we have seen, he made the novel proposal that this nature or essence, as anindivisible extended substance, must be distinguished from its divisible modes. Regisfurther identified possibilities concerning these modes with extended substance ‘con-sidered as capable of receiving certain modes’ (URF, 189). In Regis’s view, Godcreates possibilities concerning the modes of extension by creating extension itselfor, what is the same, the nature of extension. Apart from God’s free and indifferentact of creating extended substance, there are no possibilities regarding these modes.Since this act of creation produces something that has only ‘an indivisible point ofexistence’, however, the modal possibilities that derive from the nature of extensionare not themselves subject to change.One primary advantage that Regis’s account of the creation of the eternal truths

has vis-a-vis the account in Descartes is that it is clearly related to the issue ofGod’s creation of motion. For just as Regis held that God’s creation of eternal truthsconcerning extension consists in His creation of extended substance, so he claimedthat God’s creation of motion consists in his creation of a substance-like formalmotion. In both cases, the divine act of creation consists in the production of some-thing that is itself atemporal, and thus immutable. In Regis’s view, moreover, thesource of necessary truths concerning both extension and the causation of motionderive from natures that are distinct from God. Just as necessary truths concerningextension derive immediately from created extended substance, so necessary truthsconcerning the causation of motion derive immediately from a created formal motion.In response to Della Rocca, then, it can be said it was that Regis, more thanDescartes, who offered a version of the doctrine of the creation of eternal truths thatserves to isolate a conception of God that is linked to an anti-occasionalist accountof motion.63

5. Conclusion

We began with the thesis in Della Rocca that Descartes’s doctrine of God’s freecreation of the eternal truths adds ‘crucial support’ for a concurrentist interpretationof his views on body–body interaction.64 For some, however, the Cartesian emphasison the complete dependence of creatures on God instead supports an occasionalistaccount of causation. Thus, Desmond Clarke has claimed recently that for the Car-tesian occasionalists,

63 In the Use of reason, Regis does not seem to derive the principle that ‘each thing persists insofaras it can in remaining in the state it is in’, which grounds the first law of motion (URF, 299), from formalmotion. Indeed, in the earlier System he treated this principle as a general constraint on causation, andnot something tied to motion in particular (Regis, 1970, Vol. 1, p. 332, which appeals to a basic metaphys-ical axiom in ibid., Vol. 1, pp. 69f.) Even so, Regis held that this principle is a necessary truth, onewhich, like all necessary truths, ‘follow[s] from the nature of things’ (URF, 121; cf. Regis, 1970, Vol.1, p. 178). Though Regis is not explicit on the matter, it would seem that formal motion is the naturefrom which persistence in motion is supposed to follow.64 Della Rocca (1999), p. 49.


whenever causal powers are found in finite causes, they are present there onlybecause God decided to add them to the relevant substances and to control theiroperations by the laws of nature. . . . In this sense, occasionalism is a consequenceof Cartesian voluntarism. (Clarke, 2000, p. 145)

To be sure, Clarke’s analysis concerns the later development of Descartes’s viewsrather than his views themselves. In this sense, then, he does not directly contradictDella Rocca’s interpretation of Descartes.65 Even so, Clarke’s claim that voluntarismand occasionalism were naturally linked in Descartes’s followers at least brings intoquestion Della Rocca’s view that Descartes’s voluntarist account of the eternal truthsserves to reinforce his concurrentism.Our own investigation of later Cartesianism tends to support Della Rocca’s pos-

ition over Clarke’s. After all, Regis explicitly denied that occasionalism is a conse-quence of the voluntarist position that the bodily natures responsible for causationderive from God’s free will. Indeed, he insisted that this sort of voluntarism actuallysupports a concurrentist alternative to occasionalism. In Malebranche, moreover,occasionalism is connected explicitly with the rejection of the voluntarist doctrinein Descartes of the creation of the eternal truths. So the historical evidence doesseem to confirm Della Rocca’s hypothesis of the connection in Cartesianism betweenconcurrentism and voluntarism on the one hand, and between occasionalism andanti-voluntarism on the other.Nevertheless, Clarke’s remarks serve to highlight a limitation that I have already

emphasized in Della Rocca’s defense of Descartes’s concurrentism. Prior to the pass-age cited above, Clarke noted the occasionalist rejection of the view that thecapacities of minds and bodies to affect each other are essential properties of thosecreated objects. To be sure, there is no reason to accept the suggestion in Clarkethat a Cartesian occasionalist such as Malebranche accepted causal powers in createdobjects that are not essential to them.66 However, there is something to Clarke’sview that Cartesian occasionalism involves denying that causality derives in anyessential way from those objects. Thus, as we have seen, whereas Malebranche

65 Indeed, Della Rocca’s view seems to be in line with the suggestion in Clarke that Descartes positedbodily powers as ‘modal dispositions’ that derive from their relation of bodies to God; cf. Della Rocca(1999), pp. 60–62 and Clarke (2000), pp. 143, 145. As I indicate below however, a crucial differencebetween their views concerns the question of whether Descartes held that these powers derive frombodily natures.66 I take this suggestion to be related to the insistence in Clarke (1995), directed against the interpretation

of Malebranche’s occasionalism in Nadler (1993), that Malebranche’s views do not differ substantiallyfrom Leibniz’s theory of pre-established harmony (cf. Clarke, 1989, p. 121). As Nadler correctly indicatesin his response to Clarke, Leibniz’s invocation of harmonized natures ‘is inconsistent with the centralclaim of Malebranche’s occasionalism, namely, that finite beings are devoid of all powers and natures’(Nadler, 1995, p. 507). More precisely, this indication is correct insofar as the claim is taken to be thatfinite beings lack natures that serve to determine causal relations. Malebranche allowed that bodies havea nature that entails impenetrability, as we have seen, but he insisted that neither this property nor anythingelse that follows directly from the nature of body as an extended thing suffice to explain causal relationsinvolving the laws of motion. For more on how this point serves to distinguish Malebranche’s occasional-ism from Leibniz’s pre-established harmony, see Rutherford (1993).


admitted that truths concerning impenetrability follow from the nature of extension,he insisted that truths concerning the communication of motion are arbitrary in thesense that they are fixed by no bodily nature. Given that Malebranche borrowed hisrather “thin” conception of body in terms of passive extension from Descartes him-self, it is difficult to see how an appeal to the doctrine of the creation of the eternaltruths could save Descartes from Malebranche’s conclusion that truths concerningmotion are arbitrary in this sense. What allowed Regis to avoid such a conclusionwas not so much his appeal to this doctrine, but rather his view that there are bodilynatures that determine truths concerning motion. His acceptance of Descartes’s cre-ation doctrine did allow him to reconcile the claim that such truths derive necessarilyfrom a bodily nature with the claim—which Descartes suggested and Malebrancheemphasized—that the laws of motion themselves depend on God’s free will. In orderfor this reconciliation to work though, Regis needed to reconfigure Descartes’s doc-trine. In particular, he needed to posit a formal motion that temporal manners ofmotion determine but that, like the nature of extension, has an atemporal existencethat follows directly from God’s free act of creation. The fact that we are so farremoved from Descartes’s own ontology reveals the depth of the difficulties thatconfront any attempt to defend his concurrentist account of body–body interactionby appealing to his view of the creation of the eternal truths.

Acknowledgements

Many thanks to audiences at the Australian conference, ‘The Origins of Mod-ernity’, at the University of New South Wales and the meeting of the Central CanadaSeminar for the Study of Early Modern Philosophy at the University of Toronto forstimulating discussion of earlier versions of this essay. Thanks also to Des Clarke,Michael Della Rocca, Andrew Janiak, Nick Jolley, Elmar Kremer, Steve Nadler,Andy Pessin, Eric Watkins, and an anonymous referee from Studies for helpful com-ments on the manuscript.

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