DESCARTES ON CAUSATION

DANIEL E. FLAGE and CLARENCE A. BONN EN

The fonn is properly a cause not of the generation but of the thing generated.

Suarez, Metaphysical Disputations, 17.1.2

IN THE THIRD MEDITATION, Descartes suggests that God, and only God, is self-caused. 1 This claim results in objections, first from Caterus and then from Arnauld, that an efficient cause must be dis­tinct from its effect, and therefore the notion of self-causation is unin­telligible.2 In the course of his reply to Arnauld, Descartes distin­guishes between a formal cause and an efficient cause, contends that God's essence is properly the formal cause of God's existence, and at­tempts to find a cause midway between a formal cause and an effi­cient cause.

In this paper, we examine Descartes' discussion of the distinction between formal and efficient causes in the reply to Arnauld. We show that Descartes' account of the formal/efficient causation distinction is consistent with prominent accounts of that distinction from Aristotle to Suarez: an explanation by formal cause is an explanation based on the essence of a thing, while an explanation by efficient cause is an ex­planation based on agency. We then ask whether Descartes' concern with formal causation is limited to God's self-causation. To answer that question, we examine the ontological and epistemic status of Descartes' natural laws. We argue that Cartesian natural laws are

Correspondence to: Department of Philosophy and Religion, James Madison University, Harrisonburg, VA 22807.

IRene Descartes, Oeuvres de Descartes (hereafter, "AT"), ed. Charles Adam and Paul Tannery, republished by Nouvelle Presentation, ed. B. Rochot, P. Costabel, and J. Beaude, 11 vols. (Paris: J. Vrin, 1964-76), 7:49-50; The Philosophical Writings of Descartes (CSM) , trans. John Cottingham, Robert Stoothoff, and Dugald Murdoch, with the correspondence translated in part by Anthony Kenny, 3 vols. (Cambridge: Cambridge University Press, 1984, 1985, and 1991),2:34.

2AT, 7:95, CSM 2:68; AT, 7:207-13, CSM, 2:146-50.

The Review of Metaphysics 50 (June 1997): 841-872. Copyright © 1997 by The Review of Metaphysics

842 DANIEL E. FLAGE AND CLARENCE A. BONNEN

ontologically and epistemically indistinguishable from eternal truths: they constitute the form of the world. If we are correct, it follows that, apart from God's action in creating and sustaining the world and acts of the human will, all Cartesian causes are formal. Such a posi­tion makes intelligible Descartes' remarks on the union of mind and body.3

I

In the Third Meditation, Descartes considers the possibility that he, a thinking thing with an idea of God qua supremely perfect being, is caused by something distinct from himself. Either he is caused by God, or he is caused by something less perfect than God, and if the lat­ter, he can raise the same question regarding the cause of that being. Ashe wrote:

In respect of this cause one may again inquire whether it derives its ex­istence from itself or from another cause. If from itself, then it is clear from what has been said that it is itself God, since if it has the power of existing through its own might, then undoubtedly it also has the power of actually possessing all the perfections of which it has an idea-that is, all the perfections which I conceive to be in God. If, on the other hand, it derives its existence from another cause, then the same ques­tion may be repeated concerning this further cause, namely whether it derives its existence from itself or from another cause, until eventually the ultimate cause is reached, and this will be God.4

The argument is a variation on the cosmological argument, and as Descartes tells Caterus in his reply, he takes this self-causing God to effectively alleviate any possibility of an infinite causal regress. 5

Descartes' commentators found the argument puzzling. Caterus asked what Descartes meant by "from itself." Caterus distinguished between a positive and a negative sense of that expression. In the positive sense, it means "from itself as from a cause," and in this sense a cause from itself "bestows its own existence on itself; so if by an act

3 Some philosophers might argue that the Cartesian texts are so under­determined with respect to a theory of causation that any project to delin­eate such a theory is a form of wishful thinking. We find this contention a bit premature and leave it to our readers to judge whether we have succeeded in demonstrating that a Cartesian theory of causation can be gleaned from Des­cartes' writings.

4 AT, 7:49-50, CSM, 2:34. 5 AT, 7:108-9, CSM,2:78.

DESCARTES ON CAUSATION 843

of premeditated choice it were to give itself what it desired, it would undoubtedly give itself all things, and so would be God."6 However, Caterus considered the negative sense of "from itself," that is, "not from another," as what is more commonly understood by that phrase. So, he naturally concludes, "it does not derive existence from itself as a cause, nor did it exist prior to itself so that it could choose in ad­vance what it should subsequently be."7

Caterus further relates this negative sense of "from itself" to the essence or form of a thing by focusing on the question of limitation. Claiming Descartes had not proved that the essence of God is infinite, Caterus gives an example to show that the internal (formal, essential) principles of things place limitations on things. He writes: "That which is hot, for example, ... wlll be hot as opposed to cold in virtue of its internal constitutive principles, and this will be true even if you imagine that its being what it is does not depend on anything else. "8 If there are essential properties, these properties place limitations on things regardless of whether those things are caused by another. Thus, unless Descartes shows that God has no essential limitations, the negative sense of "from itself" fails to prevent the potential re­gress.

In his reply, Descartes modified the standard meaning of "effi­cient cause" in applying it to a divine cause, an attempt that continues in his replies to Arnauld. Among the fairly standard conceptual con­straints on the notion of efficient causality were the claims that (l) whatever will count as an efficient cause must be prior in nature to its effect, and (2) the cause and the effect must be distinct entities (it is an extrinsic cause).9 Descartes rejects both of these in the case of God's self-causation. He cites three reasons for rejecting these stan­dard constraints: (a) "it would make the question trivial, since every­one knows that something cannot be prior to, and distinct from, itself";lo (b) the cause qua cause exists only at the time it is effective;

6 AT, 7:95, CSM, 2:68. 7 AT, 7:95, CSM, 2:68-9. 8 AT, 7:95, CSM, 2:69. 9 See Francisco Suarez, On Efficient Causality: Metaphysical Disputa­

tions 17, 18, and 19, trans. Alfred Freddoso (New Haven: Yale University Press, 1994), Disputation 18, §7, pp. 131-77, and Disputation 17, Introductory Remarks, 3. For careful discussion of Aristotle's, Aquinas's, and Suarez's cri­teria for deeming a cause an efficient cause, see J. E. K. Secada, "Descartes on Time and Causality," Philosophical Review 99 (1990): 45-72, esp. 49-51.

10 AT, 7:108, CSM,2:78.

844 DANIEL E. FLAGE AND CLARENCE A. BONNEN

and (c) the assumption of self-causation is the only means of heading off an inflnite causal regress. 11

Descartes continues by attempting to explain how God can be self-preserving, that is, the positive sense in which God's existence is from itself. He argues for this extended positive sense of "efflcient causation," by trying to expand the domain to which the notion of an efflcient cause can apply. He suggests that if he preserved his own be­ing, he would have no problem referring to himself as his own effl­cient cause. On the basis of such an appeal to authority, he then turns to the case of God. He warns us against applying the notion of effl­cient causation to God's causal powers when he tells us, " ... all that is implied [by divine self-preservation] is that the essence of God is such that he must always exist."

In the next paragraph, Descartes claims that God's self-preserv­ing causality is analogous to, but presumably not the same as, effl­cient causality. There Descartes writes: "There are some who attend only to the literal and strict meaning of the phrase 'efflcient cause' and thus think it is impossible for anything to be the cause of itself. They do not see that there is any place for another kind of cause analogous to an efflcient cause .... "12 This is followed by a discussion of "the im­mense and incomprehensible power that is contained within the idea of God."13 If we attend to this, "we will have recognized that this power is so exceedingly great that it is plainly the cause of his con­tinuing existence, and nothing but this can be the cause."14 It is the immense power of God, Descartes says, that constitutes the positive sense in which one can claim that God's existence is "from himself" as an efflcient cause or as something analogous to an efflcient cause.

This is not Descartes at his best. Although here he explicitly claims that there is a positive sense in which God is the efflcient cause of himself-or, at least, something closely analogous to the efflcient cause of himself-in the Comments on a Certain Broadsheet, he writes: "I must advise the author of these pamphlets that I have never written that God should be called 'the efflcient cause of himself not just in a negative but also in a positive sense,' as he is rash enough to allege on page eight of the second booklet."15 Why the about face? In the First Replies, Descartes has blurred the distinction between an ef-

11 AT, 7:108-9, CSM,2:78. 12 AT, 7:109, CSM,2:79. 13 AT, 7:110, CSM, 2:79. 14 AT, 7:110, CSM, 2:79-80. 15 AT, 8B:368, CSM, 2:310.

DESCARTES ON CAUSATION 845

ficient and a formal cause. 16 In claiming, "all that is implied is that the essence of God is such that he must always exist,"17 Descartes is ap­pealing to a formal cause, not an effiCient cause. 18 This point did not go unnoticed by Arnauld, whose criticisms focus primarily on the po­sition advanced in the replies to Caterus. However, before we turn to Arnauld's objections, we digress briefly and examine the traditional distinction between an efficient and a formal cause.

II

The Aristotelian doctrine of the four causes was presupposed by Descartes and his critics. These causes provided the four ways of an­swering the question "Why?" That Descartes rejected the doctrine of final causality, that is, a natural end or purpose, is widely acknowl­edged. 19 Descartes also had little interest in material causality, that is, questions concerning the stuff of which something is made.20 His offi­cial interest is in efficient causality, that is, the cause of existence or change, although in the Fourth Replies he raises questions regarding formal causality, that is, explanation based on the essence of a thing. To place the Descartes-Arnauld exchange into context, we look briefly at historical discussions of efficient causality and formal causality.

Aristotle defined an efficient cause as "that from which the change or the resting from change first begins; e.g. the advisor is a cause of the action, and the father a cause of the child, and in general

16 One might think that "blur" is too weak a word here. It appears that Descartes is attempting to make an exception to the standard criteria for effi­cient causality in the case of God's causing himself. However, this would make nonsense of the argument in Meditation 3, since it would introduce an equivocation on the notion of an efficient cause. Taken in this strict sense, such a move might provide evidence for elements of the dissimulation thesis, that is, the thesis that the Descartes of the Meditations intentionally misrep­resented important elements of his philosophy. See Louis E. Loeb, "Is There Radical Dissimulation in Descartes' Meditations?" in Essays on Descartes's Meditations, ed. Amelie Oksenberg Rorty (Berkeley: University of California Press, 1986),243-70, for a discussion of the dissimulation thesis. To examine the thesis is beyond the scope of this paper.

17 AT, 7:109, CSM, 2:79. 18 Such a move would confiate Descartes' cosmological argument with

his ontological argument, and we believe he had methodological reasons for not wanting to do so. To examine those reasons, however, is beyond the scope of the present paper.

19 See AT, 7:55, 5:158; CSM, 2:38-9, 3:341; Principles 1:28, AT, 8A:15-16, CSM, 1:202-3.

20 See AT, 7:242, 366; CSM, 2:169, 252.

846 DANIEL E. FLAGE AND CLARENCE A. BONNEN

a maker a cause of the thing made and the change-producing of the changing."21 In the Aristotelian metaphysics of agent and patient, the efficient cause was the agent to the material cause's patient. This is the standard nomenclature throughout the medieval period and into Descartes' time.22 Descartes was well within the tradition in suggest­ing that an efficient cause is that "without which finite things cannot exist, "23 as he was in claiming that at least God and human wills are ef­ficient causes24 and that there is only a distinction of reason between creation and conservation.25

Aristotle defines a formal cause as follows: "The form or pattern, i.e., the defmition of the essence, and the classes which include this (e.g. the ratio 2: 1 and number in general are causes of the octave), and the parts included in the definition. "26 In the passage Descartes cites from the Posterior Analytics,27 Aristotle says this:

Why is the angle in a semicircle a right angle?-or from what assump­tion does it follow that it is a right angle? Thus, let A be right angle, B the half of two right angles, C the angle in a semicircle. Then B is the cause in virtue of which A, the right angle, is attributable to C, the angle

2l Aristotle, Metaphysics, 5.2, 1013a29-33, trans. W. D. Ross, in The Ba­sic Works of Aristotle, ed. Richard McKeon (New York: Random House, 1941), 752. See also Posterior Analytics, 2.11, 93a36-94b8, trans. G. R. G. Mure, Basic Works, 171; and Physics, 2.3, 194b29-32, trans. R. P. Hardie and R. K. Gaye, Basic Works, 241.

22 See Thomas Aquinas, Commentary on the Posterior Analytics of Ar­istotle, trans. F. R. Larcher (Albany, NY: Magi Books, 1970), 198-9; Peter of Spain, Topics, in The Cambridge Translations of Medieval Philosophical Texts, vol. 1, Logic and the Philosophy of Language, ed. Norman Kretzmann and Eleonore Stump (Cambridge: Cambridge University Press, 1988), 236; William of Sherwood's Introduction to Logic, trans. Norman Kretzmann (Minneapolis: University of Minnesota Press, 1966), 86-7; Suarez, On Effi­cient Causality; and Antoine Arnauld, The Art of Thinking: Port-Royal Logic, trans. James Dickoff and Patricia James, Library of Liberal Arts (Indi­anapolis: Bobbs-Merrill, 1964), 243.

23 AT, 7:236, CSM, 2:165. 24 See Descartes' Passions of the Soul (hereafter, "POS") , §§34-36, AT,

11:354-7, CSM, 1:341-2. See also Suarez, On Efficient Causality, Disputa­tion 18, §2, n. 40, p. 88; Disputation 19, §2, nn. 12-23, pp. 290-300. See also Daniel Garber, "Descartes and Occasionalism," in Causation in Early Mod­ern Philosophy: Cartesianism, Occasionalism, and Preestablished Har­mony, ed. Steven Nadler (University Park: Pennsylvania State University Press, 1993), 9-26.

25 See Boethius of Dacia, "The Sophisma 'Every Man is of Necessity an Animal'," in The Cambridge Translations of Medieval Philosophical Texts, vol. 1, 499; and Suarez, On Efficient Causality, Disputation 18, §3, n. 12, pp. 98-9.

26 Aristotle, Metaphysics, 5.2, 1013a27-9, in Basic Works, 752. 27 AT, 7:242, CSM,2:169.

DESCARTES ON CAUSATION 847

of a semicircle, since B = A and the other, viz. C, = B, for C is half the two right angles. Therefore it is the assumption of B, the half of two right angles, from which it follows that A is attributable to C, i.e. that the angle in a semicircle is a right angle. Moreover, B is identical with (b) the defining form of A, since it is what A's defmition signifies. More­over, the formal cause has already been shown to be the middle.28

A fonnal cause is explanatory. Unlike an efficient cause, which ex­plains why or how something comes to be, a fonnal cause explains why something is what it is. As Suarez puts it, "the fonn is properly a cause not of the generation but of the thing generated. "29 As Aristo­tle's example shows, appeals to a fonnal cause explain why something is the case. Such explanations are deductive: the essential defmition (as major premise) plus a statement of conditions (minor premise) en­tail a description of the phenomenon to be explained. In a geometric case, the fonnal cause explains the phenomenon by reducing it to (de­ducing it from) Euclid's fundamental elements; in the case of a natural phenomenon, it is to give a deductive-nomological explanation where one takes the natural law to be "essential. "30 Insofar as it is based on the essence of a thing, it is an intrinsic cause, while an efficient cause is extrinsic.31 Again, prior to Descartes a fonnal cause was commonly understood as an explanation from the essence of a thing,32 and Des­cartes also understood it in that way.33

Given this distinction, we may now turn to Arnauld's objections and Descartes' replies.

III

Arnauld was not satisfied with Descartes' reply to Caterus and proceeded to push the objection further. After summarizing the reply to Caterus, Arnauld raises questions regarding the fonnal criteria for

28 Aristotle, Posterior Analytics, 2.11, 94a27-35, in Basic Works, 171. See also Posterior Analytics, 2.8, 93a3-14, in Basic Works, 167; Aquinas, Commentary on the Posterior Analytics, 198.

29 Suarez, On Efficient Causality, Disputation 17, §1, n. 2, p. 5. 30 It is comparable to doing a formal proof in logic. While one is typically

asked to show that the conclusion follows from the premises and a certain set of rules, the same procedure can be seen as explaining why the conclu­sion follows from the premises and a set of rules.

31 Suarez, On Efficient Causality, Disputation 17, Introduction, 3. 32 Peter of Spain, Topics, 237; Arnauld, The Art of Thinking, 244; see

also WiUiam of Sherwood's Introduction to Logic, 86-7. 33 AT, 7:236, CSM,2:165.

848 DANIEL E. FLAGE AND CLARENCE A. BONNEN

being an efficient cause, notably, the contention that an efficient cause must be a distinct thing from its effect. Quoting Descartes' con­tention that the natural light reveals that an efficient cause qua cause exists only at the time that it produces its effect,34 Arnauld raises a se­ries of objections focusing on the distinction between an efficient cause and its effect: (1) The natural light seems to require that the cause is distinct from the effect, or, at least, Descartes provided no reasons to believe otherwise.35 (2) The causal relation is irreflexive: nothing can receive existence from itself.36 (3) The causal relation is dyadic and asymmetrical: "there is a mutual relation between cause and effect. But a relation must involve two terms. "37

Next Arnauld launches an attack on Descartes' claim that God, in particular, is the efficient cause of himself in a positive sense: (1) The conservation thesis cannot be applied to God, for it requires that the existence of a thing be divisible into temporally distinct units, and temporal predicates are inapplicable to God.38 (2) Insofar as God is eternal, "it is pointless to ask why this being should continue to ex­ist,"39 indeed, the question why God should continue to exist is ab­surd.4o (3) If God derived existence from himself, he would have to be conceived as existing before he existed.41 (4) The notion ofpreserva­tion presupposes original creation, and "the very terms 'continuation' and 'preservation' imply some potentiality, whereas an infinite being is pure actuality, without potentiality."42

Yet the most telling objection rests on the distinction between ef­ficient and formal causes. After remarking that "[w]e look for the effi­cient cause of something only in respect of its existence, not in re­spect of its essence,"43 Arnauld explains that mathematicians do not look for the existence of the objects of their studies.44 Then he pro­ceeds to show that Descartes had blurred the distinction between for­mal and efficient cause. In Arnauld's words:

But it belongs to the essence of an infinite being that it exists, or, if you will, that it continues in existence, no less than it belongs to the essence

34 AT, 7:209, CSM, 2:147; quoted from AT, 7:108, CSM, 2:78. 35 AT, 7:209, CSM,2:147. 36 AT, 2:209-10, CSM, 2:147, 147-8. 37 AT, 7:210, CSM, 2:147. 38 AT, 7:211, CSM, 2:148. 39 AT, 7:211, CSM,2:148. 40 AT, 7:211, CSM,2:148-9. 41 AT, 7:211-12, CSM, 2:149. 42AT, 7:212, CSM, 2:149.

DESCARTES ON CAUSATION 849

of a triangle to have its three angles equal to two right angles. Now if anyone asks why a triangle has its three angles equal to two right angles, we should not answer in terms of an efficient cause, but should simply say that this is the eternal and immutable nature of a triangle. And simi­larly, if anyone asks why God exists, or continues in existence, we should not try to find either in God or outside him any efficient cause, or quasi-efficient cause (I am arguing about the reality, not the name); in­stead, we should confine our answer to saying that the reason lies in the nature of a supremely perfect being.

The author says that the light of nature establishes that if anything ex­ists we may always ask why it exists-that is, we may inquire into its ef­ficient cause, or if it does not have one, we may demand why it does not have one. To this 1 answer that if someone asks why God exists, we should not answer in terms of an efficient cause, but should explain that he exists simply because he is God, or an infinite being. And if someone asks for an efficient cause of God, we should reply that he does not need an efficient cause. And if the questioner goes on to ask why he does not need an efficient cause, we should answer that this is because he is an infinite being, whose existence is his essence. For the only things that require an efficient cause are those in which actual existence may be distinguished from essence.45

Arnauld's point is this: If existence is essential to God, then God's es­sence is a fonnal cause of his existence, that is, the essence of God ex­plains why it is impossible to push the causal regress in a version of the cosmological argument to the point of asking, "And what is the cause of God?" That question is unintelligible. So in appealing to effi­cient causation with respect to God, Descartes had misstated the proof. Rather than repeatedly asking whether or not the cause of one's being is self-caused and pushing the inquiry until such a point as

, . one finds a self-caused being, Descartes should have asked whether the cause of one's being is itself caused or is God. The chain would have ended at the point that God was identified as an efficient cause of one of the causes of one's being, since the essence of God entails existence: A fonnal cause would have ended the chain of efficient

43 AT, 7:212, CSM, 7: 149. This is a position Descartes rejects, as we shall see below when examining elements of his voluntarism. Further, the conten­tion that essences are uncreated was not universally accepted. See Suarez, On the Essence of Finite Being as such, on the Existence of that Essence and Their Distinction, trans. Norman J. Wells (Milwaukee: Marquette Uni­versity Press, 1983), Disputation 31, §2, 57-66. This is not to say that Des­cartes' views were in complete compliance with Suarez's. On the differences, see Gary Hatfield, "Reason, Nature, and God in Descartes," in Essays on the Philosophy and Science of Rene Descartes, ed. Stephen Voss (New York: Ox­ford University Press, 1993),269-75.

44 AT, 7:212, CSM, 2:149. 45 AT, 2:212-13, CSM,2:149-50.

850 DANIEL E. FLAGE AND CLARENCE A. BONNEN

causes. If one accepts the distinction between formal causes and effi­cient causes, we believe that Arnauld's criticism is exactly right. 46

In his reply, Descartes attempts to defend a broadened notion of efficient causality, one that would justify deeming God self-caused in a positive sense. He stresses that "in saying that God 'in a sense' stands in the same relation as an efficient cause, I made it clear that I did not suppose he was the same as an efficient cause,"47 and that his guiding principle was that "'if anything exists we may always inquire into its efficient cause' ... 'or, if it does not have one, we may demand why it does not need one'. These words make it quite clear that I did believe in the existence of something that does not need an efficient cause. And what could that be, but God?"48 In claiming that God was "his own cause," Descartes says he did not "mean an efficient cause; it simply means that the inexhaustible power of God is the cause or rea­son for his not needing a cause."49 It is because God's positive es­sence qua "inexhaustible power or immensity of the divine essence is as positive as can be, I said that the reason or cause why God needs no cause is a positive reason or cause."50

Descartes next introduces the distinction between a formal and an efficient cause. He writes:

Similarly, in every passage where I made a comparison between the for­mal cause (or reason derived from God's essence, in virtue of which he needs no cause in order to exist or to be preserved) and the efficient cause (without which finite things cannot exist), I always took care to make it explicitly clear that the two kinds of cause are different. And I never said that God preserves himself by some positive force, in the way in which created things are preserved by him; I simply said that the immensity of his power or essence, in virtue of which he does not need a preserver, is a positive thing.51

The paragraph is interesting in a number of ways. First, as we have seen, Descartes' distinction between a formal and an efficient cause is well within the Aristotelian tradition. Second, we have been tmable to find any place other than the Fourth Replies where Descartes takes "care to make it explicitly clear that the two kinds of cause are differ­ent." Finally, even here he is concerned, not with the claim that God's existence follows immediately from his essence, but with the conten-

46 See note 18. 47 AT, 7:235, CSM, 2:164-5. 48 AT, 7:235-6, CSM, 2:165. 49 AT, 7:236, CSM, 2:165. 50 AT, 7:236, CSM,2:165. 51 AT, 7:236-7; CSM, 2:165.

DESCARTES ON CAUSATION 851

tion that the essential power of God somehow accounts for God's ex­istence and that God does not preserve himself in the same way that he preserves other things. Thus, Descartes grants Arnauld that God is not properly the efficient cause of himself, bqt insofar as the power of God is a positive element of God's essence, God is not the cause of himself in a purely negative sense.

As he continues, Descartes attempts to detail the extended sense in which he is wont to use the expression "efficient cause" with re­spect to God's self-causation. Suggesting that virtually everyone grants that considering efficient causes as "the primary and principal way, if not the only way, that we have of proving the existence of God, "52 Descartes suggests that it is correct to inquire into the efficient causes of God himself, "even though we have not given an explicit ac­count of what it means to say that something derives its existence 'from itself'."53 However, as he continues, he suggests that, properly speaking, this blurs the distinction between a formal and an efficient cause of God. In his words:

Those who follow the sole guidance of the natural light will in this con­text spontaneously form a concept of cause that is common to both an efficient and a formal cause: that is to say, what derives its existence 'from another' will be taken to derive its existence from that thing as an efficient cause, while what derives its existence 'from itself' will be taken to derive its existence from itself as a formal cause-that is, be­cause it has the kind of essence which entails that it does not require an efficient cause. Accordingly, I did not explain this point in my Medita­tions, but left it out, assuming it was self-evident.54

Here Descartes suggests a notion of cause that is common to both an efficient and a formal cause, although his discussion suggests that this common element is little more than a blurring of the distinction: prop­erly speaking, deriving existence "from itself"-from its own es­sence-is an instance of a formal causality. Indeed, while arguing for an extended notion of "efficient cause," Descartes later grants that he can reconcile his differences with Arnauld by deeming God the formal cause of his own existence. He writes:

But to reconcile our two positions, the answer to the question why God exists should be given not in terms of an efficient cause in the strict sense, but simply in terms of the essence or formal cause of the thing. And precisely because in the case of God there is no distinction between existence and essence, the formal cause will be strongly analogous to an

52AT, 7:238, CSM,2:166. 53 AT, 7:238, CSM, 2:166. 54AT, 7:238--9, CSM, 2:166-7.

852 DANIEL E. FLAGE AND CLARENCE A. BONNEN

efficient cause, and hence can be called something close to an efficient cause.55

The question is, then, what is this analogy between God's self­causation and an efficient cause? How can Descartes extend the no­tion of an efficient cause to include God's self-causation? Contending that the causal argument must fail unless efficient causality extends to God's own existence,56 Descartes defends the extended meaning of "efficient cause" by means of several geometrical analogies. In his words:

To give a proper reply to this, I think it is necessary to show that, in be­tween 'efficient cause' in the strict sense and 'no cause at all', there is a third possibility, namely 'the positive essence of a thing', to which the concept of an efficient cause can be extended. In the same way in ge­ometry the concept of the arc of an indefinitely large circle is customar­ily extended to the concept of a straight line; or the concept of a rectilin­ear polygon with an indefinite number of sides is extended to that of a circle. I thought I explained this in the best way available to me when I said that in this context the meaning of 'efficient cause' must not be re­stricted to causes which are prior in time to their effects or different from them. For, first, this would make the question trivial, since every­one knows that something cannot be prior to, or distinct from, itself; and secondly, the restriction 'prior in time' can be deleted from the con­cept while leaving the notion of an efficient cause intact. 57

What is this analogy supposed to show? Consider the case of a regular rectilinear polygon with an indefinite number of sides. Such a polygon can be construed as a circle. Why? Descartes seems to be­lieve that each side of a rectilinear polygon with an indefinite number of sides would have a side with the length of one point. Hence, the distinction between a polygon and a circle would collapse. Similarly, Descartes seems to claim that when one is concerned with a being whose essence is infinite power,58 the distinction between a formal and an efficient cause collapses. Why? An efficient cause is an agent; it is the cause of the generation of a thing or state of affairs. A formal cause is the essence of a thing. If the essence of a thing is infinite power, then there can be no limits on its causal efficacy. Its essence as a formal cause entails existence in the sense that there could be no

55 AT, 7:243, CSM, 2:170. 56 AT, 7:239, CSM, 2:167. 57 AT, 7:239-40, CSM, 2:167; see also AT, 7:245, CSM, 2:170-1. 58 We shift from the Cartesian term "indefinite" to "infinite" because

Descartes holds that God's causal efficacy is truly infinite. See the following note.

DESCARTES ON CAUSATION 853

efficient cause that would prevent its existence. We believe that it is in this peculiar way that Descartes attempts to collapse the formal/ef­ficient cause distinction in the case of God. Just as the distinction be­tween a regular rectilinear polygon and a circle collapses when the number of sides of the polygon becomes indefinitely large, so the dis­tinction between efficient and formal causality collapses when pushed to infinity. 59 Such seems to be the point of the analogy. 50

59 We should note that our explanation is consonant with Descartes' lim­itation on the use of "infinite" and "infinity." See First Replies, AT, 7:113-44, CSM, 2:81-2; Fifth Replies, AT, 7:286-7, CSM, 2:199-200; and Principles, 1:26-7, AT, 8A:14-15, CSM, 201-2. Quite clearly Descartes gets quite a bit of mileage from his notion of infinity in Meditation 3. His analogy here is trou­blesome. In the passages just cited, Descartes admonishes others not to be­lieve that they have an adequate enough notion of infinity to apply it to geo­metrical or physical objects. It should be noted in the passage quoted above that Descartes lives by his own rules by choosing the phrases "indefinitely large circle" and "indefinite number of sides" for his own analogy. However, by doing so, he significantly weakens his analogy. One would have hoped for a strict similarity between these two geometrical analogues and the nature of divine causality. However, God is the only truly infinite being in Cartesian re­ality.

60 Jonathan Bennett has suggested an alternative interpretation of this analogy during his 1995 NEH Seminar and in personal correspondence with us. He suggests that Descartes is thinning the notion of efficient causality as it applies to God. What is thinned from the notion is the idea that an efficient cause of something cannot be the cause of itself. Yet, Bennett believes that an element of efficient causation remains, namely, that element which helps stop the question, "Why does .r exist?" Furthennore, Bennett believes that this interpretation makes Descartes' geometric analogy more cogent. We be­lieve there are two problems with Bennett's interpretation. First, he cannot preserve Descartes' distinction between the infinite and the indefinite. The usefulness of the analogue, which is a rectilinear figure the number of whose sides is indefinitely large, turns on its sides actually being infinite in number. Bennett argues that the theoretical advantage to discussing circle arcs in rec­tilinear ternlS is that one need not always specify that the circle has a finite radius; however, Descartes would maintain that it could not have an infinite radius. In short, the analogue fails to supply explanatory insight at precisely the point where one would expect it. (See previous note as to how our inter­pretation preserves this Cartesian distinction.) Second, Bennett's interpreta­tion faces the following dilemma: either the "thin" notion applies only in the case of God or it does not. If Bennett believes the fonner, then there is an equivocation on "efficient cause" in the Third Meditation (see note 18). If he believes the latter, then lawful explanation becomes impossible. If the "thin­ning" notion is intended to stop the question, "Why does x exist?" then in principle anything could cause itself rather than be caused by something else, at least from time to time. For example, this arbitrariness would defeat Lewis Carroll's literary effect on the reader when the Cheshire Cat disap­pears except for its smile, that is, decides to cause only its smile-at least for awhile.

854 DANIEL E. FLAGE AND CLARENCE A. BONNEN

We are not convinced that this analogy is intelligible. At best it shows that God's self-causality is sui generis, and given Descartes' re­marks on the limitations of the human understanding with respect to the divine, this might not speak against it.6! Our interest, however, is in the introduction of the notion of a formal cause. As we argue in the last two sections of this paper, construing much of Cartesian explana­tion in terms of formal causality is consistent with both the textual ev­idence regarding the status of natural laws and the integration of Des­cartes' grand explanatory scheme. Yet Descartes seems hesitant to discuss his program in terms of formal causation; the only place he explicitly alludes to formal causes is in the replies to Arnauld. In the remainder of this section, we give reasons why Descartes might have been hesitant to construe his explanatory program in terms of formal causes.

A formal cause is an explanation based on essential properties. Descartes was no opponent to essence-talk. Indeed, he held that "ac­cording to the laws of true logic, we must never ask about the exist­ence of anything until we first understand its essence."62 Further, he clearly held that mathematical explanations (geometric proofs) are explanations based on formal (essential) causes. Why, then, did he seemingly spurn explanations based on formal causes? Our suspicion is that it has to do with the word "form."

Famously, Descartes rejected the Aristotelian doctrine of forms. His evidence against the doctrine came, in part, from showing that a particular phenomenon could be explained without reference to forms. In the Optics, he indicates that his explanation of color aoes not require intentional forms.63 In the Meteorology, he stresses that his account of the nature of terrestrial bodies does not "deny any fur­ther items which they imagine in bodies over and above what I have described, such as 'substantial forms', their 'real qualities', and so on. It simply seems to me that my arguments must be all the more accept­able in so far as I can make them depend on fewer things."64 As he tells Regius in January 1642, by not denying the existence of substan­tial forms, while showing that a phenomenon can be explained with­out positing their existence, one effectively shows that the doctrine of forms is useless and may fruitfully be rejected.65 Given his rejection

61 See, for example, AT, 7:220, CSM, 2:155. 62 AT, 7:107-8; CSM, 2:78. 63 AT, 6:85, CSM, 1:155-6; see also AT, 6:112, CSM, 1:165. 64 AT, 6:239, CSM, 2: 173n2. 65 AT, 3:491-2, CSM, 3:205.

DESCARTES ON CAUSATION 855

of the doctrine of forms, we believe Descartes held it would be ver­bally misleading to suggest his explanations are based on formal causes.

Furthermore, while Descartes' account of formal causes alludes to essences, and Cartesian essences are assayed as something other than Aristotelian forms,66 it was not uncommon to conflate "formal cause" or "formal explanation" with "caused by (or explained on the grounds of) an Aristotelian form." Notice how the sixteenth-century philosopher Peter Ramus defined formal causality:

The formall cause is that by the which the thing hathe his name and beyng. And therfore euery thing is distingued from another by its forme.

The forme also is engendred togeather, with the thing it self: as, a rea­sonable soule is the forme of man, for by it Man is man, and is dis­tingued from other thinges. The Geometricall figures haue their forme, some beyng triangles, and some quadrangles. So hathe naturall thinges: as the heauen, the earthe, trees, fyshe and suche others. So that euery thing is to be expounded as the nature of it is, if we maye attayne to the knowledge therof, as in artificiall thinges is more easie to be founde. 67

66 We examine this is greater detail below. 67 The Logike of the Most Excellent Philosopher P. Ramus Martyr, trans.

Roland MacIlmaine (1574), ed. Catherine M. Dunn (Northridge, CA: San Fernando Valley State College, 1969), 15. See also William of Sherwood's In­troduction to Logic, 85-6; Thomas Wilson, The Rule of Reason (1553), ed. Ri­chard S. Sprague (Northridge, CA: San Fernando Valley State College, 1972), 111-12; John Poinsot (John of St. Thomas), Tractatus de Signis (1632), trans. John N. Deely (Berkeley: University of California Press, 1985),382.

By a hundred years after Descartes, the formal/efficient causality dis­tinction seems distinctly to have fallen out of favor. Thus it is that Hume, giv­ing the results of his analysis of causation, could write: "We may learn from the foregoing doctrine, that all causes are of the same kind, and that in partic­ular there is no foundation for that distinction, which we sometimes make betwixt efficient causes, and causes sine qua non; or betwixt efficient causes, and fonnal, and material, and exemplary, and final causes. For as our idea of efficiency is deriv'd from the constant conjunction of two objects, wherever this is observ'd, the cause is efficient; and where it is not, there can never be a cause of any kind"; David Hume, A Treatise of Human Nature, ed. L. A. Selby-Bigge, 2d ed., rev. P. H. Nidditch (Oxford: Clarendon Press, 1978), 171. Hume's conclusion is unacceptable. Insofar as he held that the truths of arithmetic and algebra, although perhaps not geometry, are known on the ba­sis of relations of ideas, they are subject to demonstration; see Treatise, 71. Corresponding to every arithmetic or algebraic demonstration, however, there is an explanation from formal causes. It is thus false that "where it is not [for efficient causality], there can never be a cause of any kind." None­theless, as history shows, Hume was on the winning side in the intellectual war over the number and kind of causes. Hence, insofar as Descartes' at­tempt to extend the notion of an efficient cause to God's self-causality, Des­cartes was on the winning side in the war, even though we must grant that Ar­nauld won the battle.

856 DANIEL E. FLAGE AND CLARENCE A. BONNEN

Notice that obtaining an Aristotelian form somehow explains why something is what it is. Our suspicion is that even though Descartes understood formal causes in terms of deductions from Cartesian es­sences, he recognized that the very expression "formal cause" invites theoretical confusion-it contains unwanted Aristotelian connota­tions, probably including the sanctioning of fmal causes-and he therefore avoided the terminology. What we hope to show in the next two sections is that while he avoided the terminology, many of his ex­planations are best construed as explanations from formal causes (es­sences).

IV

So far we have examined Descartes' discussions of the self-cau­sality of God. In the replies to both Caterus and Arnauld, Descartes attempted to defend ascribing to God a form of self-causality midway between formal and efficient causality. We are not convinced that he was successful. Nonetheless, since Descartes himself acknowledged that taking God to be only a formal, and not an efficient, cause of him­self alleviates his differences with Arnauld,68 we explore the possibil­ity that either the formal/efficient causality distinction was blurred in other contexts or that Descartes came to acknowledge that a large part of his explanatory structure rests on formal causes. In this sec­tion, we argue that Cartesian natural laws can be construed as es­sences. In the next section, we argue that such a construal of natural laws helps clarify Descartes' account of mind-body interaction.

Outside the replies to Arnauld, Descartes does not explicitly con­cern himself with formal causality. Throughout his writings, how­ever, he provides explanations on the basis of natural laws and ap­peals to various eternal truths known by the natural light. Several questions should be asked regarding natural laws and eternal truths: What is their ontological and epistemic status? Insofar as God is the efficient cause of essences, eternal truths, and natural laws,69 are these ontologically on a par? What are the epistemic relations among them? If essences, eternal truths, and natural laws are ontologically

68 AT, 7:243, CSM, 2:170. 69 Descartes' divine voluntarism regarding essences and eternal truths is

not without precedents. See Suarez, On the Essence of Finite Being, Dispu­tation 31, §2, pp. 57-64.

DESCARTES ON CAUSATION 857

on a par-if the laws of physics, along with the laws of geometry, con­stitute the essence of the material world-it is reasonable to construe Cartesian explanations as explanations based on formal causes. In this section, we begin with a short argument to show that a deductive­nomological explanation is more reasonably construed as an explana­tion from formal causes than from efficient causes, that, as Suarez puts it, "the form [natural law] is properly not a cause of the genera­tion but of the thing that is generated."70 Then we show that the tex­tual evidence in Descartes' works tends to support the contentions that natural laws constitute the essence of the physical world, that they are eternal truths, and therefore that a Cartesian deductive-no­mological explanation meets the criteria for being an explanation based on formal, not efficient, causes.

Consider the form of a deductive-nomological explanation: given a natural law and a set of antecedent conditions, one deduces a de­scription of a phenomenon to be explained. For example, if we wanted to explain why the water on the stove is boiling, we might pro­pose the following explanation:

All water heated to 212°F boils. (law) The water on the stove is water heated to 212°F. (antecedent condition)

Therefore, the water on the stove boils. (phenomenon to be explained)

What does this explain? It explains why the water on the stove is boil­ing water rather than gaseous water or frozen water. It explains why the thing generated has the characteristic it has. It does not explain how there came to be boiling water on the stove. That would require a different kind of story:

John went into the kitchen. He filled a pan with water. He placed the pan on the stove and turned on the gas. The heat from the burning gas was transferred to the molecules of water, causing them to move rap­idly. At a certain point the movement of the molecules became so rapid that it manifested itself in the macroscopic property we call "boiling wa­ter."

Here John is an agent of change; he is the transient efficient cause of the boiling of the water. The deductive-nomological explanation, on the other hand, has the characteristics of an explanation based onjor­mal causes. To see this, we must consider the similarities between the characteristics of a natural law and a metaphysical essence.

70 Suarez, On Efficient Causality, Disputation 17, §1, n. 2, p. 5.

858 DANIEL E. FLAGE AND CLARENCE A. SONNEN

Natural laws71 state the necessary and sufficient conditions for the occurrence of a state of affairs. 72 A complete description of the essence of a thing of a kind would allow one to deduce the various states of a thing of a kind under various conditions. Both natural laws and essential descriptions are sempiternal: they hold at all times. Both natural laws and essential descriptions are partial descriptions of the structure of the world. In a well-developed system, both natu­rallaws and essential descriptions can, and do, stand in deductive hi­erarchical relations to one another. Due to these similarities, we be­lieve it is reasonable to suggest that the distinction between a natural law and an essential description is merely verbal and that deductive­nomological explanations are explanations from formal causes.73

Here someone is certain to object that, even granting these simi­larities, there are absolutely fundamental differences between natural laws and essential descriptions. Natural laws are contingent truths; essential descriptions are necessary truths. One can imagine denying a natural law; one cannot imagine denying an essential description. In­deed, the denial of an essential description is self-contradictory. Hence, even if formal similarities exist between deductive-nomologi­cal explanations and explanations based on formal causes, their fun­damental difference rests on the status of natural laws with regard to essential descriptions. While explanations based upon essential de­scriptions are explanations from formal causes, deductive-nomologi­cal explanations cannot be, since natural laws are contingent.

71 There is an ambiguity in the expression "natural law. " It is sometimes taken to be certain uniformities in nature; at other times it is taken to be statements describing those uniformities. Weare using it within this para­graph and the next in the second way, although nothing in our interpretation of Descartes' treatment of natural laws hangs on how we use the expression.

72 Philosophers of science often distinguish two kinds of natural law: laws of simultaneity and transtemporallaws. An examination of Descartes' examples of natural laws suggest that they are all laws of simultaneity, though such a construal might be more temporal than Descartes requires; see AT, 9:38--48, CSM, 1:92-8; Principles, 2:37-52. Descartes has a problem with time. Principles 1:57 suggests that he understands time as a theoretical construct; Descartes maintains motion as primary in his physics and time as measured on the basis of arbitrarily chosen motions. A thorough examina­tion of this issue is beyond the scope of the present paper.

73 If we are right on this point, of course, it is ironic that the logical posi­tivists were both the foremost proponents of the deductive-nomological ac­count of explanation and purported champions of a nonrnetaphysical philos­ophy of science. See also B. A. Brody, "Towards an Aristotelian Theory of Scientific Explanation," Philosophy of Science 39 (1972): 20-31.

DESCARTES ON CAUSATION 859

This objection merely assumes that all natural laws are nonessen­tial. There are three considerations that tend to show that Descartes considered natural laws to be a species of eternal truths. First, Des­cartes held that God created eternal truths along with all other things. Second, he held that God so constructed the natural realm that the natural laws follow deductively from God's nature and the other eter­nal truths. It is for this reason that Descartes would deny Hume's claim that it is clearly conceivable, and therefore possible, that "the course of nature may change. "74 Finally, the terminology Descartes uses to describe a person's psychological disposition to accept a natu­rallaw is the same terminology he uses to describe one's psychologi­cal disposition to accept an eternal truth. Let us turn to the fIrst of these three considerations.

74 David Hume, An Enquiry concerning Human Understanding, in En­quiries concerning the Human Understanding and concerning the Princi­ples of Morals, ed. 1. A. Selby-Bigge, 3d ed., rev. P. H. Nidditch (Oxford: Clar­endon Press, 1975),35 and 37-8. Jonathan Bennett in "Descartes' Theory of Modality," Philosophical Review 103 (1994): 639-67, argues that the domain of the conceivable and the possible are one and the same for Descartes. He is uneasy about our argument here. He objects that natural laws are not eternal truths because their falsehood is conceivable. This he takes as one upshot of his paper. We grant Bennett the thesis of his paper, but deny this conclusion. To see why, consider two cases. First, one may confront a necessary truth without recognizing it as such. Hobbes relates with delight his astonishment at finding a seemingly false, indeed, necessarily false, theorem in Euclid's EL­ements. Only after tracing its deductive ancestry back to Euclid's most basic elements did he recognize that the theorem was not only true, but necessarily so. Hobbes has discovered a feature of nonbasic eternal truths, namely, that those truths derived from the more basic need not be self-evident on first consideration. Second, nor does the apparent conceivability of a state of af­fairs demonstrate that it is possible. Consider a perpetual motion machine consisting of an electric motor and a generator. The generator produces enough electricity to power the motor, which turns the generator. So far no obvious trouble arises. Upon closer and more careful scrutiny, however, one finds reasons that, while the machine may be possible, it cannot be a perpet­ual motion machine. Physics tells us that both the motor and generator are subject to friction. Therefore, the system will slowly lose energy that will need to be replaced if the machine were to run perpetually. When all the laws of physics are brought to bear on this system, we discover that what we had taken as a clear and possible idea was not. These two cases show that if the eternal truths are arranged in a hierarchical structure, then one clearly conceives an eternal truth lower in the hierarchy only when one understands its relationships to the more fundamental eternal truths. Thus, if Descartes construed natural laws as lower level eternal truths, then he can at once re­ject Hume's maxim and embrace Bennett's account of Cartesian modalities.

860 DANIEL E. FLAGE AND CLARENCE A. SONNEN

Descartes claimed that God is the efficient cause of all things, and in saying this, he included the eternal truths. Note what he wrote to Mersenne:

As for the eternal truths, I say once more that they are true or possible only because God knows them as true or possible. They are not known as true by God in any way that would imply that they are true indepen­dently of him. If men really understood the sense of their words they could never say without blasphemy that the truth of anything is prior to the knowledge God has of it. In God willing and knowing are a single thing in such a way that by the very fact of willing something he knows it and it is only for this reason that such a thing is true. So we must not say that if God did not exist nevertheless these truths would be true; for the existence of God is the first and most eternal of all possible truths and the one from which alone all others proceed.75

You ask me by what kind of causality God established the eternal truths. I reply: by the same kind of causality as he created all things, that is to say, as their total and efficient cause. For it is certain that he is the author of the essence of created things no less than of their exist­ence; and this essence is nothing other than the eternal truths. 76

Descartes seems never to have relinquished the claim that God is the total and efficient cause of all things, including eternal truths. 77

Insofar as God is the cause of all things, including the essences of things, it seems prima facie plausible to suggest that the natural laws are eternal truths insofar as they constitute the essence of the mate­rial world.

One might object, however, that insofar as Descartes is con­cerned with the essence of the material world, he is concerned-as he makes clear in Meditation 5-with the principles of geometry. Even if one grants that the principles of geometry are eternal truths, this does not entail that the laws of motion are. In reply several points should be noticed. First, Descartes occasionally suggests that "my entire physics is nothing but geometry. "78 While one might suggest that this is something of an overstatement, we shall see that Descartes consid­ered it only a slight exaggeration. Second, in section 5 of the Dis­course on Method, his summary of The World, Descartes writes:

Further, I showed what the laws of nature were, and without basing my arguments on any principle other than the infmite perfections of God, I

75 AT, 1:149-50, CSM, 3:24. 76 AT, 1:151-2, CSM, 3:25; see also AT, 1:145, 152-3,2:138; CSM, 3:23, 25-

6,103. 77 See AT, 7:432, CSM,2:291. 78AT, 2:268, CSM, 3:119; see also AT, 1:476,3:39; CSM, 3:77,145.

DESCARTES ON CAUSATION 861

tried to demonstrate all those laws about which we could have any doubt, and to show that they are such that, even if God created many worlds, there could not be any in which they failed to be observed.79

The suggestion that the principles of motion are true in all possi­ble worlds suggests that they are eternal truths. Finally, the fact that Descartes deemed his physics mechanical, that, except in those cases in which the material realm is impinged upon by a mind qua efficient cause, all events are explainable on the basis of a small collection of laws,8o indicates that he held that they are universally true. Insofar as God is the cause of all things, including eternal truths, one would need a reason why the laws of physics are intrinsically different from other eternal truths. As we shall see, the laws of physics are different from other eternal truths, but not in a way that makes them less eternal or necessary.

How do the laws of physics differ from other eternal truths? They are less basic, since one derives the laws of physics from the truths of metaphysics and the more basic eternal truths. This brings us to our second consideration, namely, that Descartes understood his philoso­phy as constituting a deductively related whole. Again, this is a recur­rent theme in the letters:

I must tell you that the little book on metaphysics which I sent you [the Meditations 1 contains all the principles of my physics.81

I may tell you, between ourselves, that these six Meditations contain all the foundations of my physics.82

In his writings, he makes the same point. In The World, he justifies his first two laws of motion as follows:

So it is that these two rules follow manifestly from the mere fact that God is immutable and that, acting always in the same way, he always produced the same effect.83

79 AT, 6:43, CSM, 1:132. 80 That he held this should be clear from the fact that, in The World, he

introduced the assumption that God will never perform miracles and that "rational souls ... will not disrupt in any way the ordinary course of nature"; AT, 6:48, CSM, 1:97. Note further that, assuming similar principles, the Des­cartes of the Principles claimed that all phenomena in the physical world could be explained. See Principles, 3:47, AT, 8A:I02-3, CSM, 1:257-8.

81 AT, 3:233, CSM,3:157. 82 AT, 3:298, CSM, 3:173. See also the Conversation with Burman, AT,

5:165, CSM,3:346-7. 83 AT, 11:43, CSM, 1:96.

862 DANIEL E. FLAGE AND CLARENCE A. SONNEN

A bit later we find this:

But I shall be content with telling you that apart from the three laws I have expounded, I do not wish to suppose any others but those which follow inevitably from the eternal truths on which mathematicians have usually based their most certain and most evident demonstrations-the truths, I say, according to which God himself has taught us that he has arranged all things in number, weight and measure. The knowledge of these truths is so natural to our souls that we cannot but judge them in­fallible when we conceive them distinctly, nor doubt that if God had created many worlds, they would be as true in each of them as in this one. Thus those who are able to examine sufficiently the consequences of these truths and of our rules will be able to recognize effects by their causes. To express myself in scholastic terms, they will be able to have a priori demonstrations of everything that can be produced in this new world.84

Similarly, his call in the Meditations for new foundations for the sci­ences85 can be seen as such a clarion call. Again, in his letter to Mersenne of 11 March 1640, he is concerned with the reduction of the laws of physics to the more basic laws of mathematics. He wrote:

. . . I would think I knew nothing in physics if I could say only how things could be, without demonstrating that they could not be other­wise. This is perfectly possible once one has reduced physics to the laws of mathematics.86

Further, the penultimate section of the Principles shows that Des­cartes attributed absolute certainty to his physics insofar as the less fundamental elements were deduced from the more fundamental. In his words:

This [absolute 1 certainty is based on a metaphysical foundation, namely that God is supremely good and in no way a deceiver .... Mathematical demonstrations have this kind of certainty, as does the knowledge that material things exist; and the same goes for all evident reasoning about material things. And perhaps even these results of mine will be allowed into the class of absolute certainties, if people consider how they have been deduced in an unbroken chain from the first and simplest princi­ples of human knowledge .... Once this is accepted, then it seems that all the other phenomena, or at least the general features of the universe and the earth which I have described, can hardly be intelligibly ex­plained except in the way I have suggested.87

84AT, 11:47, CSM, 1:97. 85AT, 7:17, CSM,2:12. 86 AT, 3:39, CSM, 3:145; see also AT, 1:140-1; CSM,3:22. 87 Principles, 4:206, AT, 8A:328-9, CSM, 1:290-1.

DESCARTES ON CAUSATION 863

If the laws of physics are "deduced in an unbroken chain from the first and simplest principles of human knowledge," and if those principles are eternal truths, then the laws of physics must also be eternal truths, although insofar as they are more complex and derivative truths, they might not be as immediately obvious as their more basic counter­parts.88

We support the view that Cartesian natural laws are essential truths with our third and final consideration: Descartes uses the same tern1inology to describe one's psychological dispositions to accept natural laws, on the one hand, and eternal truths, on the other. He claims that eternal truths are self-evident:

But when we recognize that it is impossible for anything to come from nothing, the proposition Nothing comes from nothing is regarded not as a really existing thing, but as an eternal truth which resides within our mind .... It would not be easy to draw up a list of all of them; but none­theless we cannot fail to know them when the occasion for thinking about them arises, provided that we are not blinded by preconceived no­tions.89

Does Descartes ascribe such certainty to the laws of physics? Yes. In the Discourse, one finds this:

What is more, I have noticed certain laws which God has so established in nature, and of which he has implanted such notions in our minds, that after adequate reflection we cannot doubt that they are exactly ob­served in everything which exists or occurs in the world.9o

In his letter to More of 5 February 1649, he writes:

Moreover, I do not agree with what you very generously concede, namely that the rest of my opinions could stand even if what I have writ­ten about the extension of matter were refuted. For it is one of the most important, and I believe the most certain, foundations of my physics; and I confess that no reasons satisfy me even in physics unless they in­volve that necessity which you call logical or analytic, provided you ex­cept things which can be known by experience alone, such as that there is only one sun and only one moon around the around the earth.91

88 Our discussion assumes that the distinction between God's action(s) and God's character (immutability) collapses. Following traditional theol­ogy, speaking of change in God's case can only be metaphorical. God's acts are not in time. Thus, all God's acts are "at the same time" because they are not at any time at all. Descartes accepted the traditional theology in part be­cause he sought to avoid theological controversy. We believe that his theory of time also supports a traditional theology. See note 72.

89 Principles, 1:49, AT, 8A:23-4, CSM, 1:209. 90 AT, 6:41, CSM, 1:131. 91 AT, 5:275, CSM, 3:364-5.

864 DANIEL E. FLAGE AND CLARENCE A. BONNEN

These passages tend to show that the laws of physics are known with the same certainty as, and therefore should be deemed a species of, eternal truths. Yet even if Descartes had not alluded to the psycholog­ical force with which the laws of physics strike upon the mind, his contention that these laws are deductively entailed by more basic eternal truths shows that the laws of Cartesian physics, and all other natural laws, must be deemed eternal truths. As eternal truths, they provide a partial specification of the essence of the world. For that reason, explanations based on appeals to natural laws are explana­tions based on formal causes.

v

Two objections might be raised at this point. First, someone might object that our concern with formal causality ignores questions regarding efficient causality. Descartes deemed God and human minds efficient causes of states of affairs. If we do not delineate the relationship between formal and efficient causality, the critic will claim that our case lacks credibility. Second, the only place Descartes explicitly alludes to formal causes is in his reply to Arnauld, and there he seems inclined to avoid them. Unless one can show that constru­ing causal issues as questions of formal causation elucidates an other­wise opaque issue, one has little reason to believe Descartes em-' braced formal causality so thoroughly as we claim.

To answer the first objection, we must look briefly at some of Descartes' remarks on efficient causality. These concern questions of the will, the aspect in which human beings most resemble God.92 Des­cartes wrote that even though one does not speak univocally in com­paring the divine will and the human will, "the only idea I can find in my mind to represent the way in which God or an angel can move matter is the one which shows me the way in which I am conscious I can move my own body by my thought."93 What is the will? "[T]he will simply consists in our ability to do or not do something (that is, to affirm or deny, to pursue or avoid); or rather, it consists simply in the fact that when the intellect puts something forward for affirmation or

92 AT, 7:57, CSM, 2:40. 93 AT, 5:347, CSM, 3:375.

DESCARTES ON CAUSATION 865

denial or for pursuit or avoidance, our inclinations are such that we do not feel we are determined by any external force."94

This defmition is somewhat curious. The will is an ability: the power to do or refrain from various activities. What does this mean? Presumably, one can find out what these powers or abilities are only by practice. Can one effect a movement of one's arm by an act of will? Yes. One wills it to move and it moves, although, starting with a move­ment of the pineal gland,95 there are numerous intermediate effects between the act of volition and the movement of the arm. An act of will is an agent's action; as such, an act of will has no further explana­tion. Yet what is this? In characterizing will as an ability or a power, what does this mean? Descartes offers no characterization of the no­tions of power or ability. It is basic; it is ineffable. To put any concep­tual meat on the bones of power, one must analyze the power or the ability to do something. That analysis comes in the form of a law: if act of will Am occurs, then a mental state 8m occurs, or a physical state 8b occurs. To say that God is omnipotent is to say that for any x, if God wills that x, then x. The human will has limits: we discover these limits by experience. Yet the fact that acts of will escape further ex­planation does not entail that there is no lawful correlation between certain acts of the will and certain states of the pineal gland. As Des­cartes told Princess Elizabeth in his letter of 6 October 1645: "I must say at once that all the reasons that prove that God exists and is the first and immutable cause of all effects that do not depend on human free will prove similarly, I think, that he is also the cause of all the ef­fects that do so depend."96 God established laws correlating acts of the will with states of the pineal gland. In this way the notion of power obtains cognitive content. One explains and understands the efficacy of the will only in terms of natural laws. So considerations of efficient causality do not militate against the contention that Cartesian explanation should be construed in terms of formal causality; rather, they tend to support it.

The lawful connection between states of the will and states of the pineal gland also implies that formal causality helps us Understand Descartes' account of the connection between mind and body: Mind and body are lawfully connected. This answers the second objection.

94 AT, 7:57, CSM, 2:40; see also POS, §41. 95 POS, §41, AT, 11:359-60, CSM, 1:343. 96 AT, 4:314, CSM,3:272.

866 DANIEL E. FLAGE AND CLARENCE A. BONNEN

If Descartes holds that the world is governed by natural laws and these laws are eternal truths, then lawful explanations of body to body relations are based on formal causes. Insofar as God is the effi­cient cause of all natural laws, God could establish a series of lawful (essential) relations between bodily states and mental states. Des­cartes' discussion of phantom pains in the Sixth Meditation makes lit­tle sense unless one assumes that there is some kind of lawful connec­tion such that if the pineal gland is in a certain state Sb, the mind is in a state Sm.97 Similarly, such a lawful relationship is suggested in the Comments on a Certain Broadsheet when, after alluding to his Op­tics, Descartes proposes that innate ideas are dispositions to form oc­current ideas with a particular content, that "[t]he ideas of pain, co­lours, sounds and the like must be all the more innate if, on the occasion of certain corporeal motions, our mind is to be capable of representing them to itself, for there is no similarity between these ideas and the corporeal motions. "98 If we look at his letter to Eliza­beth of 21 May 1643, we shall see that Descartes' remarks support our contention that the connections between mind and body are lawful connections construed as eternal truths.

In responding to Elizabeth's question "how the soul of man (since it is but a thinking substance) can determine the spirits of the body to produce voluntary actions, "99 Descartes indicates that he had said lit­tle about how the body and soul act upon one another, his primary

97 See AT, 7:83-8, CSM, 2:58-61. 98 AT, 8B:359, CSM, 1:304. In the Optics one fmds: "Instead we must

hold that it is the movements composing this picture which, acting directly upon our soul in so far as it is united with our body, are ordained by nature to make it have such sensations"; AT, 6:130, CSM, 1:167. We believe that the doctrine of innate ideas suggests that the mind is structured in such a way that there are natural patterns of thought. While the will might be the motive force that begins a chain of thought, affirms and denies propositions, and pushes the process of analysis onward, innate ideas as dispositions to form occurrent ideas with a certain content are lawfully organized. For example, if one begins with an idea of God as a magnified idea of oneself and inquires into the adequacy of that idea, this will lead to an idea of God as being that is infinite, omnipotent, omniscient, and so forth, and ultimately to an idea of a supremely perfect being. See Daniel E. Flage and Clarence A. Bonnen, "Des­cartes' Factitious Ideas of God," Modern Schoolman 66 (1989): 197-208; and Daniel E. Flage and Clarence A. Bonnen, "Innate Ideas and Cartesian Dispo­sitions," International Studies in Philosophy 24 (1992): 65-80. If we are correct, this explains Descartes' confidence that anyone following his method will reach the same conclusions he reached.

99 In John J. Blom, Descartes: His Moral Philosophy and Psychology (New York: New York University Press, 1978), 106.

DESCARTES ON CAUSATION 867

aim having been to demonstrate their distinctness. lOo To explain how we understand both the distinctness and the union of mind and body, he alluded to primitive notions. He wrote:

First I consider that there are in us certain primitive notions which are as it were the patterns on the basis of which we fonn all our concep­tions. There are very few such notions. First, there are the most gen­eral-those of being, number, duration, etc.-which apply to everything we can conceive. Then, as regards body in particular, we have only the notion of extension, which entails the notions of shape and motion; and as regards the soul on its own, we have only the notion of thought, which includes the perceptions of the intellect and the inclinations of the will. Lastly, as regards the soul and the body together, we have only the notion of their union, on which depends our notion of the soul's power to move the body, and the body's power to act on the soul and cause its sensations and passions. lOl

Descartes claims we have certain primitive notions in our mind. These primitive notions are of four sorts. There are the most general notions, notions that apply to anything at all. More interestingly, there are the primitive notions (1) of extension, "which entails shape and movement," (2) of thought, and (3) of the union of body and mind, on which depends all knowledge of the powers minds have regarding body and bodies have regarding mind. What are these primitive no­tions? They are the eternal truths, the common notions of Principles, part 1, §§48-50, or, more properly, they are the most basic eternal truths, those from which all other eternal truths (natural laws) can be deduced. As eternal truths, these primitive notions express the es­sence of mind, body, and the mind-body union. Indeed, all of knowl­edge follows from them. As Descartes continues:

I observe next that all human knowledge consists solely in clearly distin­guishing these notions and attaching each of them only to the things to which it pertains. For if we try to solve a problem by means of a notion that does not pertain to it, we cannot help going wrong. Similarly we go wrong if we try to explain one of these notions by another, for since they are primitive notions, each of them can be understood only through it­self.102

It is to our own soul that we must look for these simple notions. It pos­sesses them all by nature, but it does not always sufficiently distinguish them from each other, or assign them to the object to which they ought to be assigned. 103

100 AT, 3:665, CSM, 3:218. 101 AT, 3:665, CSM, 3:218; see also AT, 3:690-1; CSM, 3:226. 102 AT, 7:665-6, CSM, 2:218, emphasis added. 103 AT, 7:666-7, CSM, 2:219.

868 DANIEL E. FLAGE AND CLARENCE A. BONNEN

Notice that Descartes says exactly what he should say if all Cartesian explanation is from formal causes (essences). The primitive notions constitute the essences of mind, body, and the mind-body union. They are distinct essences: each is known through itself. As eternal truths they reside in the soul and "have no existence outside our thought. "104 Error occurs when these essential truths are applied to the wrong domain.

Notice further that this account makes intelligible Descartes' analogy between the mind-body connection and heaviness construed as a real quality. Descartes writes:

So I think that we have hitherto confused the notion of the soul's power to act on the body with the power one body has to act on another. We have attributed both powers not to the soul, for we did not yet know it, but to the various qualities of bodies such as heaviness, heat, etc. We imagined these qualities to be real, that is to say to have an existence distinct from that of bodies, and so to be substances, although we called them qualities. In order to conceive them we sometimes used notions we have for the purpose of knowing bodies, and sometimes used no­tions we have for the purpose of knowing the soul, depending on whether we were attributing to them something material or something immaterial. For instance, when we suppose that heaviness is a real quality, of which all we know is that it has the power to move the body that possesses it towards the centre of the earth, we have no difficulty in conceiving how it moves this body or how it is joined to it. We never think that this motion is produced by a real contact between two sur­faces, since we find, from our own inner experience, that we possess a notion that is ready-made for forming the conception in heaviness, which-as I hope to show in my Physics-is not anything really distinct from body. For I believe that it was given us for the purpose of conceiv­ing the manner in which the soul moves the body.105

In alluding to real qualities or substantial forms, Descartes attempts to elucidate the relationship between body and soul on the basis of a the­oretical concept he rejects. 106 How can this be helpful? Natural laws qua eternal truths fulfill some of the functions in Descartes' philoso­phy that Aristotelian forms fulfill in scholastic philosophy. They spec­ify the essential connections among things. Just as a scholastic form is the essence of a thing of a kind, natural laws (primitive notions, eternal truths) provide the essential connection between mind and

104 Principles, 1:48. 105 AT, 3:667-8, CSM, 3:218-19; see also AT, 3:693-4, 7:441-2; CSM,

3:227-8,2:297-8. 106 Daniel Garber presents an extended account of Descartes' views on

substantial forms in his Descartes' Metaphysical Physics (Chicago: Univer­sity of Chicago Press, 1992),95-103.

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body. So Descartes' allusions to primitive notions supports our ac­count of the mind-body relationship, and our account tends to be con­firmed insofar as it makes intelligible the analogy to heaviness con­strued as a real quality.

Yet certainly someone will raise an objection. The union between mind and body is either a substantial union or it is not. 107 If the human mind and body join to form a single substance, then one must raise all the questions that are germane to the doctrine of substance; for exam­ple, what is its principal attribute? Descartes does not tell us what the principal attribute of the mind-body union is, which provides prima facie evidence that Descartes did not hold that there is a substantial union between body and soul. On the other hand, if there is not a sub­stantial unity between body and soul, the suggestion that there is an essential relation between them is far too strong. Indeed, if there are essential connections between mind and body, it is unclear how Des­cartes could claim that the soul is immortal,108 since to claim an essen­tial connection is to claim that what are putatively two things are, at bottom, one. Thus, the critic would claim, either Descartes made an elementary error or our interpretation is wrong. Given that the latter seems far more probable than the former, the critic would reject our interpretation.

This objection is misguided, for it assumes that there are essential truths only with respect to substances. Descartes rejects such a view. His doctrine of true and immutable natures entails that there are es­sential and eternal truths with respect to nonsubstantial entities, such as triangles. 109 Essential truths are truths about kinds of things. So, one might reasonably interpret Descartes' remarks on primitive no­tionsllO as claiming that there are essential truths pertaining to this

107 In "The Unity of Descartes' Man," Philosophical Review 95 (1986): 339-70, Paul Hoffman argues that the union between mind and body is sub­stantial. In "Descartes: The End of Anthropology," in Reason, WiU and Sen­sation: Studies in Descartes's Metaphysics, ed. J. Cottingham (Oxford: Ox­ford University Press, 1994),273-306, Stephen Voss argues that Descartes did not have a settled view on the nature of human beings. While the Descartes of the Meditations might have held that there is a substantial unity between the human soul and the human body, the Descartes of the Principles and later did not clearly hold that the notion of a human being is significant, at least in any sense in which the mind and body ontologically constitute one entity.

108 AT, 7:14, CSM, 2:10. 109 AT, 7:64, CSM, 2:44-5. 110 AT, 3:665, CSM, 3:218.

870 DANIEL E. FLAGE AND CLARENCE A. BONNEN

mind insofar as it is an entity of the mental kind, to this body insofar as it is an entity of the bodily kind, and to this mind-body complex in­sofar as it is an entity of the mind-body kind. One might cringe at this hyphenate, but it is perfectly justified. Descartes tells us that the no­tion of the mind-body union is primitive. If so, then the mind-body union constitutes a basic kind. Moreover, Descartes explicitly tells Arnauld in the Fourth Replies that "although mind is part of the es­sence of man, being united to a human body is not strictly speaking part of the essence ofmind."l1l Whether the mind-body complex con­stitutes a substantial union is a distinct question from whether there are essential properties of the mind-body complex insofar as it is an entity of the mind-body-complex kind. Since Descartes himself seems not to have been of a mind on the first question, there is little reason to pursue it. 112 Whether a mind, insofar as it is an entity of the mental kind, could exist apart from the body to which it is united is a distinct question from whether a mind, insofar as it is an entity of the element­of-a-mind-body-complex kind, could exist apart from the kind of com­plex of which it is an element. Descartes answers the first question in the affirmative. 113 We fmd Descartes' negative response to the second question in the Fourth Replies:

Thus a hand is an incomplete substance when it is referred to the whole body of which it is a part; but it is a complete substance when it is con­sidered on its own. And in just the same way the mind and the body are incomplete substances when they are referred to a human being which together they make up. But if they are considered on their own, they are complete. 114

Though Descartes avoids such bothersome hyphenates as our "ele­ment-of-a-mind-body-complex," a mind and body do conjoin to form an instance of the mind-body kind. They are properly parts of that whole. Moreover, given Descartes' commitment to the mind-body kind, relative to the mind-body kind neither mind nor body can be conceived independently of one another. One can conceive of a mind separate from a body, but only when one so conceives of a mind as a thing of the mental kind. 115

We conclude, therefore, that Descartes' answer to the problem of the connection between mind and body is that they are joined by nat­ural laws, that these laws are eternal truths, and that questions of

III AT, 7:219, CSM, 2:115, emphasis added. 112 See Voss, "Descartes: The End of Anthropology." 113 See AT, 7:444-5, CSM, 2:299. 114 AT, 7:222, CSM,2:157.

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causal relations in Descartes are questions of formal causality. We have supported this conclusion by tracing the implications of

115 Some will argue that even if we have shown that one can read Des­cartes' discussions of mind-body interaction in terms of formal causes, we have not solved the problem of mind-body or even body-body interaction in Descartes, since the problem of interaction presupposes the notion of effi­cient causality. Insofar as Descartes claimed that there is only a conceptual distinction between creation and preservation (AT, 7:49, 109, 110; CSM, 2:33, 79), we must at least explain how God continually recreates these laws, that is, how God acts in such a way that the relations between created entities ap­pear to be lawful. Does not our account, we would be asked, follow Garber's views (Descartes' Metaphysical Physics, 299-305, "Descartes and Occasion­alism") and tum Descartes into at least a quasi-occasionalist? No. First, if one takes seriously Descartes' claim that the best model we have for divine will is human will (AT, 5:347, CSM, 3:375), and if one recognizes Cartesian be­liefs are subject to the will, then a belief is the result of an act of the will, and any given belief will be retained until such a time as it is rescinded by some other act. If one applies this will-it-and-forget-it-forever theory of belief in the divine case, there is no reason to assume that God is continually acting behind the scenes to make sure all the laws are followed. This also fits nicely with the notion that God is immutable. Second, the question, "What is God doing?" is properly a theological question, and Descartes regularly indicates that theological questions, properly so called, are beyond the scope of his in­vestigations. Third, Descartes claims he did not explain the nature of the unity between body and soul. Notice what he wrote to Clerselier: "These questions [how can the soul move the body if it is in no way material, and how can it receive the forms (especes) of corporeal objects?] presuppose amongst other things an explanation of the union between the soul and the body, which I have not yet dealt with at all. But I will say, for your benefit at least, that the whole problem contained in such questions arises simply from a supposition that is false and cannot in any way be proved, namely that, if the soul and body are two substances whose nature is different, this prevents them from being able to act on each other. Yet those who admit of real acci­dents like heat, weight and so on, have no doubt that these accidents act on the body; but there is much more of a difference between them and it, i.e., be­tween accidents and a substance, than there is between two substances"; AT, 9A:213, CSM, 2:275-6. Finally, occasionalism seems to be inconsistent with Descartes' theory of substance. Insofar as he draws a distinction between in­fmite substance, fmite substance, and modes on the basis of independence (AT, 7:165-6, CSM, 2:117, Principles, 1:51), to suggest that God literally recre­ates the world at every moment would seem to collapse the distinction be­tween finite substance and mode. If both a finite substance and the modes that clothe it depend solely on a God that recreates them every moment, nei­ther is more independent than the other: the substance-mode complex is re­duced to a series of temporal slices and a finite substance, as such, would be nothing more than an abstraction from such a series of temporal slices. On such a view, the temporal slices, as such, would possess a greater degree of independence (reality) than the finite substances abstracted from them. Of course Descartes' official ontology provides no slot for a temporal slice as such. For these reasons, while granting that we have little understanding of the Cartesian God as an efficient cause, we would reject occasionalism as a plausible option.

872 DANIEL E. FLAGE AND CLARENCE A. BONNEN

Descartes' reply to an objection raised by Caterus and pursued by Ar­nauld, namely, that Descartes must abandon the explanation of divine self-causation in terms of efficient causality. While Descartes' re­sponse to Arnauld-that God's self-causation is a kind of causality midway between efficient and formal causality-reflects his resis­tance to scholasticism, his language masks his ultimate adoption of formal causality as the explanation of divine self-causation. After supplying evidence that Cartesian natural laws are a species of eternal truth, we argued that causal relations in Cartesian natural philosophy are formal causes. Once one recognizes that Descartes' implicit em­brace of formal causality is not ad hoc, the problematic appearance of the mind-body relation pales to nothing more than an instance of the same kind of causal relation found in his science.116

James Madison University and Austin, Texas

116 Earlier versions of this paper were presented to the Virginia Philo­sophical Association in October 1994 and at Jonathan Bennett's 1995 Sum­mer Seminar for College Teachers. Weare indebted to the late William Will­iams, Jonathan Bennett, Charles Huenemann, Lisa Hall, Steven Voss, Eric Palmer, Kent Baldner, Joseph Campbell, Rocco Gennaro, Eric Sotnak, Sus­anna Goodin, Matthew Stuart, and Sam Levey for their helpful comments.