Descartes on the causal powers of bodies without substantial forms

Descartes on the causal powers of bodies without substantial forms

Kara Richardson

Draft for UNYWEMP, Sunday Oct. 4, 2009

One major difference between Descartes and his Aristotelian

predecessors is his rejection of substantial forms.1 According to some of his

interpreters, this rejection deprives bodies of causal powers. Daniel Garber

puts the point this way:

For the schoolmen, the world God sustains is a world of matter and substantial forms. These forms are active principles that constitute an important class of the mediating causes of change that the schools recognized. But in a physical world whose only constituents are extended bodies, a world without forms (at least if we set aside human souls), then this class of mediating causes is not available to press into service. What Descartes chooses in their place is God, who will act not only as the general conservator of the world, but as the direct cause of motion and change in that world.2

1 The claim that Descartes rejects substantial forms must be qualified in two ways. First, Descartes sometimes refers to the mind as the form of the human body or as the form of the human being, e.g., at CSM II 246/ AT VII 356, CSM III 207 /AT III 503 and CSM III 208/ AT III 505). Scholars disagree about whether his use of Aristotelian language in this regard indicates that he endorsed a hylemorphic account of the unity of a human being. Hoffman (1986) argues in favour of this view; Rozemond (1998), ch. 5 argues against it. Second, Marleen Rozemond has shown that Descartes’ notion of a principal attribute is a successor to substantial form in the sense that “the principal attributes of extension and thought determine the kinds of modes found in bodies in general and in minds” (Rozemond (1998), p. 117). In this way, it play a role similar to that of a substantial form which determines the proper accidents of a substance, e.g., the substantial form of water determines its proper accidents, sc., coldness and moisture. 2 Garber (1992), pp. 274-5. Garber makes the same point in several other works; see Garber .Gary Hatfield also makes this point; see Hatfield (1979), p. 113. Michael Della Rocca thinks that Descartes’ denial of substantial forms conflicts with his attribution of causal powers to bodies, but defends Descartes; see Della Rocca (1999).

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The view that Descartes’ rejection of Scholastic substantial forms deprives

bodies of causal powers depends in part on the claim that these forms are

active principles. But this claim is ambiguous. Is the substantial form of a

substance a direct source of motion and change? In other words, does a

substantial form make an efficient causal contribution to substantial

activity? Or does it contribute to activity indirectly, by determining the

characteristic features and behaviors of a member of some natural kind? In

other words, does the explanatory value of a substantial form stem solely

from its role as the formal cause of a material substance? Both of these

accounts of the relationship between substantial forms and substantial

activity appear in secondary literature on causation in Late Scholastic and

Early Modern philosophy, but they are not distinguished.3 One aim of this

3 In a recent article, Robert Pasnau argues that emphasis on the concrete, causal roles of substantial forms (as opposed to their abstract, metaphysical roles) is distinctive of the Scholastic notion of substantial form. See Pasnau (2004), pp. 35-39. He discusses some cases in which substantial forms were held to play direct efficient causal roles; e.g., he mentions Ockham’s and Suarez’s view that the substantial form of water is the cause of heated water’s reversion to coldness (Pasnau (2004), pp. 37-38). Nevertheless, he summarizes the concrete, causal side of the Scholastic doctrine of substantial form as follows: “[i]n all these texts, the dominant conception of form is decidedly concrete rather than metaphysical. Substantial forms are understood as causal agents that would figure centrally in any complete scientific account of the natural world. They explain why water is cold, why gold is heavy, why horses have four legs and human beings two, and why horses merely whinny whereas human beings talk” (Pasnau (2004), p. 39). This summary suggests the view that substantial forms contribute to substantial activity indirectly, by determining the characteristic features and behaviors of a member of some natural kind.

Garber identifies substantial forms as “active principles” and as “mediating causes” in the above cited passage from Descartes’ Metaphysical Physics, which suggests that they play efficient causal roles. But earlier in the book, he provides an account of the relationship between substantial forms and substantial activity which mentions only their indirect

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paper is to show that the Scholastics themselves disagreed about the

contribution of substantial forms to substantial activity. A second aim is to

show that their disagreements inform Descartes’ view of the causal powers

of bodies.

This paper has three parts. I focus first on Scholastic debates about

the contribution of substantial forms to substantial activity as reported by

Suarez in his Metaphysical Disputations. Suarez himself defends a robust

account of the efficient causality of substantial forms. He argues that

substantial forms contribute directly to substantial activity in several cases.

And he contrasts his view with that of “Thomist” Aristotelians who hold that

the influence of substantial forms on substantial activity is limited to their

roles as formal causes. For the latter Aristotelians, substances act directly

through their accidents, not their substantial forms.

In the second part of the paper, I show that Descartes responds to the

Scholastic debates about the relationship between substantial forms and

substantial activity in his letter to Regius of January 1642. I argue that he

role: “substantial form is that from which the characteristic behavior of the various sorts of substances derives, and thus that in terms of which their behavior is to be explained” (Garber (1992), p. 95). The latter kind of account is fairly common. For example, Steven Nadler claims that “[t]he substantial form of the substance is that from which its essential properties and characteristic behaviours derive. All motion and change, all causal and other powers are to be explained by reference to the specific form inhering in (and individuating) a parcel of matter” (Nadler (1993), pp. 2-3). A similar account is offered by Rozemond (1998), pp. 104-5. A few scholars fairly clearly identify substantial forms as efficient causes. For example, Cees Leijenhorst writes that “according to the Aristotelians, forms are intrinsic principles of motion. The substantial form of an “earthly” body explains why and how it strives to the centre of the earth” (Leijenhorst (2002), p. 138). A similar account is offered in Van Ruler (1995), pp. 134-6.

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there sides with those Aristotelians who hold that the actions of substances

depend directly on their accidents alone, and I argue that this letter reveals

Descartes’ own view of the causal powers of bodies without substantial

forms. Rather than replacing substantial forms with God to explain activity

in the created world, Descartes reforms the ground for activity in the

created world, by replacing Aristotelian active qualities with Cartesian

ones. In the final part of the paper, I consider an important objection to my

interpretation, sc. that it conflicts with Descartes’ view that the nature of

body is extension.

1. Suarez on substantial forms as efficient causes

Scholastic substantial forms have their roots in Aristotle who claims

that among the causes of something are its form, i.e., the definition of its

essence (Physics 194b 27-28). To know the form of a thing is to know what

kind of thing it is. This contribution to knowledge is quite different from the

one made by an efficient cause, i.e., by “the primary source of the change or

rest” (Physics 2.3 194b 30-32). To know the efficient cause of a thing is to

know the mover or shaper who makes it happen or brings it to be.

Nevertheless the two types of cause intersect: what kind of thing X is

determines for the most part what changes X can bring out or suffer.

Efficient causal powers are rooted in the substantial forms of agents, and

their exercise depends on passive powers which are so rooted in patients.

For example, the rational soul – the substantial form of human being –

determines our powers to nourish ourselves and grow, to reproduce, sense,

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move about, imagine and understand. These powers are either active or

passive, and Scholastic philosophers disagreed about which were which: for

example, Aquinas held sensation to be a passive power acted on by the

object of sense, e.g., sight is a passive power acted on by colour, whereas

Suarez held it to be an active power on the ground that sensation requires

attention on our part. But they agreed on the general point that the

substantial form of a substance determines what it can do or suffer. Viewed

from this perspective, substantial forms play a role in natural action, but

this role is indirect.

The view that substantial forms play direct efficient causal roles was

controversial in the Middle Ages. Suarez holds that they do in at least two

kinds of ways.4 First, he argues that a substantial form is the efficient cause

of accidents appropriate to it, e.g., an animal soul is the efficient cause of

the powers of sensation and locomotion, which are accidents appropriate to

an animal soul.5 Likewise, the substantial form of water is the efficient

4 My account focuses on Suárez’ discussion of efficient causality in Disputationes Metaphysicae (DM) 17-19 and on his discussion of formal causality in Disputationes Metaphysicae 15. Disputations 17-19 are available in English translation by Alfred Freddoso: Suárez, Francisco. On Efficient Causality: Metaphysical Disputations 17, 18, and 19, trans. Freddoso. New Haven: Yale University Press, 1994. Disputation 15 is translated into English by John Kronen and Jeremiah Reedy: Suárez, Francisco. On the Formal Cause of Substance: Metaphysical Disputation XV, trans. Kronen and Reedy. Milwaukee: Marquette University Press, 2000. Unless otherwise noted, quotations of Suárez in English are taken from these translations. 5 DM 15.1, DM 18.3. In DM 15.1, Suarez uses the example of water to support the claim that we must posit substantial forms. He says “if water, for example, is heated, and later the external cause of the heat is removed, the water returns to its original coldness because of an intrinsic force, as experience attests. This is a sign, therefore, that there is in water a certain

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cause of the reversion of heated water to coldness, which is an accident

appropriate to the watery form. Second, substantial forms make direct

efficient causal contributions to substantial activity. For example, the soul

has a direct influence on vital actions, including relatively lowly ones such

as digestion, as well as nobler acts such as sensation and, in the human

case, intellection.6 And substantial forms are direct efficient causes of the

generation of new corporeal substances. In all of these cases, Suárez

defends the view that substantial forms play genuine efficient causal roles

against “Thomist” Aristotelians, who attribute to substantial forms roles

that fall short of genuine efficient causality. I will focus primarily on the

last of these cases – sc., the causal role of substantial forms in generation –

because Suárez’ discussion of it is especially instructive with respect to the

difference between his own robust view of the efficient causality of

substantial forms and the different view of his opponents.

In Disputationes Metaphysicae 18.2, Suarez aims to determine the

principle by which one substance generates another, i.e., he aims to

determine which of X’s metaphysical constituents – sc., form, matter and

inner principle from which an increase of cold flows anew after all external obstacles have been removed. That principle which returns water to its original temperature, however, cannot be anything other than the substantial form” (DM 15.1, Kronen (trans.), p. 22). Suarez continues by refuting alternative explanations of this phenomenon, which do not employ the claim that the principle which returns water to its original temperature is the substantial form (DM 15.1, Kronen (trans.), pp. 22-25). He cites the example of water in DM 18.3 as support for the claim that “the substantial form has a certain power for having its proper accidents emanate from it” (DM 18.3, Freddoso (trans.), p. 93).6 DM 18.5.

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accidents – is that in virtue of which X generates Y.7 Suarez rules out

matter immediately, since matter itself is nonactive. He then argues that no

accident is a principal principle of a substance:

a principal cause must be either more noble than, or at least no less noble than, the effect. For since no one gives what he does not have, how can an imperfect form have within itself or communicate to its suppositum a principal power for effecting a more perfect form, a form which it is unable to contain either formally or eminently? But an accidental form is more imperfect than a substantial form. Therefore, an accidental form cannot be a principal principle for educing a substantial form.8

The argument depends on a causal principle familiar to readers of

Descartes’ Third Meditation: the effect cannot be more perfect than the

cause. It also relies on an ontological hierarchy in which substantial forms –

e.g., George the monkey’s soul – are more perfect than accidental ones, e.g.,

George’s height, weight etc. Finally, it assumes that in generation, a new

substantial form is educed from the potentiality of matter by some agent or

agents. The causal principle, coupled with the ontological hierarchy, yields

a fairly simple argument against the view that the generation of a new thing

could be the work of accidents alone: since accidents are less perfect than

7 More precisely, he discusses the principle by which one created substance generates another. Suarez is here concerned with the causal powers of creatures in cases of substantial generation. He aims to defend the view that new substances are educed from the potency of matter through natural processes. His main target is Avicenna’s view that new substantial forms are bestowed by a separate intelligence (DM 18.1, pp. 597-98, Freddoso (trans.), pp. 48-49). He attributes a view of this sort to Plato, Philoponus and Themistius as well. Philoponus is said to identify the form-giver as “the Universal Craftsman of nature”; Themistius is said to identify it as “the world soul” (DM 18.2, p. 602, Freddoso (trans.), p. 60). 8 DM 18.2, p. 599; Freddoso (trans.), p. 52.

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substantial forms, they cannot by themselves effect substantial forms.9

Note that Suarez holds the conclusion of the argument – sc., that no

accident is a principal cause of a substance – to be uncontroversial: he says

that “[o]n this almost everyone agrees”.10 This could be due to the influence

of the argument itself, which is not original to Suarez. It appears at least as

9 Suarez’ claim that no accident is a principal efficient cause of a substance is compatible with his later claim that accidents are instrumental causes in cases of substantial generation. In brief, he holds that accidents play genuine efficient causal roles in generation as instruments of the principal principle of generation, i.e., the substantial form of the generator. Suarez distinguishes a principal efficient cause from an instrumental efficient cause in DM 17.2. He defines a principal cause as “a cause which through a principal power – that is, a power that is more noble than, or at least as noble as, the effect – influences the action whereby such an effect is produced (DM 17.2, p. 591; Freddoso (trans.), p. 30). A principal cause operates “through its own power, not only because it has an intrinsic and innate power to act but also because it has a power that is per se proportionate to the effect and does not stand in need of any elevation” (Ibid.). An instrument “is said to operate ‘in the power’ of the principal agent” not because it doesn’t require its own intrinsic power, but rather because its intrinsic power “is not proportionate or sufficient, and the instrument has the ability to operate only according to the measure of the principal agent’s power and elevation” (DM 17.2, p. 591; Freddoso (trans.), p. 31). To illustrate the distinction Suarez uses the stock example of a saw, which is an instrumental cause of an artifact produced by a craftsperson who uses the saw as her tool. One problem with the example is that it is easy to overlook the fact that genuine causal power is attributed to instruments, e.g., the power to cut is attributed to the saw. The saw is an instrumental cause only with respect to the production of the artifact produced by the craftsperson; it is more like a principal cause with respect to cutting. Suarez puts the point as follows: “[a] saw, for instance, is an instrument for making a given artifact. By striking the middle parts [of the wood] and moving them locally, this instrument proximately effects only a division [of the wood] and is related to this effect more as a principal cause. But what results from this in the form of the artifact, to which the saw is related as an instrumental cause. For it does not attain to this form immediately by its own action; rather, the form merely results from the prior effect”(MD 17.2, p. 587; Freddoso (trans.), p. 30). 10 DM 18.2, p. 599, Freddoso (trans.), p. 52. He continues as follows: “[f]or even though John Major, Sentences 4, dist. 12, is commonly cited in favor of the contrary opinion, he does not deny this point; nor does anyone else I

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early as Aquinas’ De Potentia, where it is presented as an objection to his

claim that corporeal agents can generate new corporeal substances.11

Since Suarez has ruled out both matter and accidents as candidates

for the role of the principal principles by which one created substance

produces another, he concludes that this role must be played by the

substance’s substantial form. He holds this conclusion to be

uncontroversial as well, in part because “once an enumerative induction has

been made, nothing else remains” and also because it too “seems to be

accepted by the common consensus of everyone”.12 But Suarez’ report of

have looked at (Ibid.). 11 In De Potentia 3.8, Aquinas raises and responds to the following objection to his claim that natural agents generate their progeny. The objection employs the claim that the active principles of natural agents are accidents, e.g., fire acts by heat, which is an accident. The objector argues that since an effect cannot excel its cause, and since a substantial form excels an accident, an accident cannot be the active cause of a substantial form (Aquinas. De Potentia 3.8, Marietti 9th rev. ed., vol. 2, p. 60; Dominican Fathers (trans.), Book 1, p. 138). Aquinas argues in response that since “[a]n accidental form acts by virtue of the substantial form whose instrument it is…it is not unreasonable if the action of an accidental form terminate in a substantial form” (Ibid.). In other words, when fire is generated by fire, the heat of the generating fire acts in virtue of its substantial form and for this reason is up to the task of bringing about a new substance. In DM 18.2, Suarez argues that this response succeeds only if substantial forms are genuine efficient causes of generation. Aquinas’ claim in De Potentia 3.8 that an accidental form acts by virtue of the substantial form (in virtute formae substantialis) is ambiguous with respect to this issue. We will see that Suarez attributes to Thomists in general the denial that substantial forms are genuine efficient causes. 12 DM 18.2, p. 599; Freddoso (trans.), p. 52. The reason Suarez cites for this consensus is the principle that operation follows upon esse: since this is so and “since the substantial form is the principal act of the suppositum and that which principally gives it esse, it must also be the principal principle of operating” (Ibid.). Freddoso notes that the principle that operation follows upon esse is a “scholastic adage” (Ibid., n. 6). Is this the same principle which grounds Aquinas’ argument for the subsistence of the human soul in Summa Theologiae 1.75.2? Aquinas argues there that only what subsists

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consensus in these matters elides an important dispute about “the way in

which the substantial form is a principal principle” in generation.13 This

dispute has to do with whether the substantial form has an immediate

influence in generation or whether it has “only a remote and, as it were,

originating influence”.14

Suarez himself argues that the substantial form has an immediate

influence in generation. He attributes the alternative view – sc., that the

substantial form has a merely remote and originating influence – to the

Thomists, but he also says that it “seems to be the common position of the

Peripatetics” and cites Aristotle, Alexander of Aphrodisias and Averroes as

its proponents.15 One argument for the alternative view relies on the claim

that “a substantial form is not per se immediately active but is instead

active through a power, which is a quality distinct from it”.16 This claim is

evident by induction: “we see that any substance whatsoever uses accidents

for all its other actions”.17 And it derives support from the following

argument: “a substantial form is of itself determined only to giving esse as a

formal cause, whereas with respect to its actions it is an indeterminate

per se can operate per se on the ground that “as a thing operates, in that way it is” (Aquinas. Summa Theologiae 1.75.2, p. , Pegis (trans.), p. 685). Since the human intellect performs an operation per se – sc., understanding – it follows that the human intellective soul subsists per se. 13 DM 18.2, p. 599; Freddoso (trans.), p. 53.14 DM 18.2, p. 599; Freddoso (trans.), p. 53.15 DM 18.2, p. 601, Freddoso (trans.), p. 58.16 DM 18.2, p. 601, Freddoso (trans.), p. 59.17 DM 18.2, p. 602, Freddoso (trans.), p. 54.

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principle, since it is almost always able to effect several actions to which it

is determined by its accidents”.18

In these arguments, the contribution of a substantial form to the

actions of a substance is restricted to its role as a formal cause which gives

being to the composite. The substance’s actions are achieved by means of

its accidents. Experience confirms the latter claim, but it can also be

deduced from the fact that the form itself is not determined to any one

action. For example, a maple tree has the powers to nourish itself and to

grow, to produce seed and to produce sap. Its substantial form makes it be

by making it be something, namely, a maple tree. And the various powers

of the maple tree are powers which it has in virtue of what it is. But since

the substantial form confers upon this substance a variety of powers, the

substantial form is not itself determined to any one action (apart from the

act of giving being). Rather, the accidents of the maple tree are determined

to specific actions. So, properly speaking, the accidents of the maple tree,

not its substantial form, are the immediate principles of its activities.

Suarez’s argument against the alternative view depends in part on the

claim that his opponents attribute to the substantial form an influence

which falls short of genuine efficient causality. He argues for this claim as

follows:

Nor is it sufficient to reply that efficient causality is attributed to [substantial] forms because the qualities through which alone they exercise all their actions emanate from them. For, as we explained above, this is not proper and per se efficient causality but rather only remote and originating

18 DM 18.2, p. 601, Freddoso (trans.), p. 59.

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efficient causality, since an action that arises immediately from an accidental form alone likewise depends per se and essentially on it alone as on a proximate principle. (I am here leaving to one side the concurrence of a universal cause.) An indication of this is that if God conserves, say, the heat [without the fire], then every action that proceeds proximately just from the heat can be conserved, too – as the authors of the contrary position also acknowledge. Therefore, this is an indication that the substantial form is not a per se principle of any such action.19

Suarez’s claim that “remote and originating efficient causality” is not

genuine efficient causality is persuasive. But it is not immediately clear that

this argument serves as support for his view that substantial forms play

genuine efficient causal roles. Couldn’t his opponents simply embrace the

denial that substantial forms are efficient causes? After all, it seems

obvious that heat conserved apart from the fiery form will scorch, melt,

blacken and so on just as well as heat conserved with the fiery form. In that

case, there is no need to attribute an efficient causal role to substantial

forms. Suarez discounts this response due to the problem at hand, sc., that

if substances act by their accidents alone, then they are without any

principle sufficient for generation: remember, the lower can’t effect the

higher. The claim that substantial forms are genuine efficient causes

safeguards the view that generation occurs through natural processes.20

Whether or not Suarez can succeed against his Thomist and

Peripatetic opponents need not be determined here. I want instead to focus

19 DM 18.2, Freddoso (trans.), p. 71.20 But the claim isn’t necessarily ad hoc. As mentioned earlier, Suarez holds that substantial forms play efficient causal roles in a variety of cases. The scope of their efficient causal contributions is probably a source of Suarez’s confidence in his own view. I do not mean to suggest that I think that Suarez’s identification of substantial forms as efficient causes is justified. This issue requires a more detailed treatment than I can offer here.

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on a view of the causal powers of bodies which his argument against these

opponents suggests. Suarez claims that qualities or accidents conserved

(by God) apart from substantial forms will do whatever they do when

conserved with these forms. Suarez illustrates his point with the example of

heat, a single quality. But there is no reason why God couldn’t conserve

collections of qualities or accidents apart from the substantial forms which

are supposed to give rise to these collections in nature.21 Say God

conserves the tart, white flesh of the apple apart from its form. It is clear,

Suarez thinks, that these qualities would act on our senses in just the way

they do when conserved with the form of apple.22 This account of the

actions of qualities or accidents conserved by God apart from substantial

21 God conserves collections of accidents apart from substantial forms in the mystery of the Eucharist, i.e., he conserves the accidents of wine and bread apart from their substantial forms. Thus, one of the questions Suarez must determine in DM 18.2 is whether the separated accidents of wine and bread act apart their substantial forms. He thinks that it is obvious that they do; however, he denies that the separated accidents of wine have sufficient power to convert a drop of water into wine. Such a conversion is a substantial generation and requires the aid of a higher power (DM 18.2.29, Freddoso (trans.), p. 77). 22 What, then, is the difference between a collection of qualities and a collection of qualities plus a substantial form? According to Suarez, one difference is that a collection of qualities lacks the unity which is required to constitute a natural thing (DM 15.1.7). Another is that the substantial form which unites the collection may also be needed for cooperative efforts amongst members of collection. For example, Suarez argues that the various powers of my human soul, e.g., sight, imagination and understanding, cannot interact with one another directly. Their apparent interaction requires that they are “connected in some common principle” – sc., my soul – which is the substantial form of my body (DM 18.5.3, Freddoso (trans.), p. 123). This aspect of the efficient causality of substantial forms is the focus of Marleen Rozemond’s “Suarez and the Unity of Consciousness” (2008). So Suarez identifies interesting and important differences between aggregates and aggregates unified by substantial forms.

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forms suggests that bodies without substantial forms could have causal

powers, and that the ground for these powers would be qualities or

collections of qualities. In the next Section, I will argue that Descartes

adopts a similar view.

2. Descartes on substantial forms and activity

Descartes most often attacks the Scholastic doctrine of substantial

forms by arguing that we do not need to posit them in order to explain

natural phenomena. We see this strategy at work in his account of how

flame burns wood in his early physical treatise, The World. There he says:

When flame burns wood or some other similar material, we can see with the naked eye that it sets the minute parts of the wood in motion and separates them from one another, thus transforming the finer parts into fire, air and smoke, and leaving the coarser parts as ashes. Others may, if they wish, imagine the form of fire, the quality of heat, and the process of burning to be completely different things in the wood. For my part, I am afraid of mistakenly supposing there is anything more in the wood than what I see must necessarily be in it, and so I am content to limit my conception to the motion of its parts.23

The conclusion of this attack is of course compatible with the existence of

substantial forms, and Descartes does not claim that there are no

substantial forms.24 One of the reasons Descartes cites for his adoption of

this strategy is political: he thinks that to deny substantial forms is to court

controversy. So he admonishes his disciple Regius for openly rejecting

them:

Do you not remember that on page 164 of my Meteorology, I said quite expressly that I did not at all reject or deny [substantial forms] but simply 23 CSM I 83/AT XI 7.24 Garber, Rozemond

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found them unnecessary in setting out my explanations? If you had taken this course, everybody in your audience would have rejected them as soon as they saw they were useless, and in the mean time you would not have become so unpopular with your colleagues.25

Given the uproar at the University of Utrecht which followed Regius’

decision openly to reject substantial forms, the political reason for

Descartes’ less confrontational approach appears to have been well-

founded. Nevertheless, Descartes comes to the aid of his beleaguered

student in his letter of January 1642 which marshals arguments Regius can

use against his Aristotelian opponents.

In one of these arguments against substantial forms, Descartes

exploits the terms of Scholastic debates about the causal roles of substantial

forms. He says,

[i]t would certainly be absurd for those who believe in substantial forms to say that these forms are themselves the immediate principle of their actions; but it cannot be absurd to say this if one does not regard such forms as distinct from active qualities. Now we do not deny active qualities, but we say only that they should not be regarded as having any degree of reality greater than that of modes; for to regard them so is to conceive of them as substances. Nor do we deny dispositions, but we divide them into two kinds. Some are purely material and depend only the configuration or other arrangement of the parts. Others are immaterial or spiritual, like the states of faith, grace and so on which theologians talk of; these do not depend on anything bodily, but are spiritual modes inhering in the mind, just as movement and shape are corporeal modes inhering in the body.26

Here Descartes rejects as absurd the view that Scholastic substantial forms

are immediate principles of their action, and claims that the absurdity of

this view is avoided by those who conflate substantial forms with active

qualities. Thus there is absurdity in holding that active qualities are

25 CSM III 205/AT III 492.26 CSM III 208/AT III 503-4.

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immediate principles of their actions. And Descartes himself embraces

active qualities and dispositions. While the terms “active quality” and

“disposition” are Aristotelian in origin, Descartes does not mean to suggest

that he agrees with his predecessors about the character or nature of these

things. For example, while Aristotelians of all stripes consider heat an

active quality, Descartes considers it an obscure sense impression which

arises in part from the size and speed of bits of matter and in part from an

idea in the mind. But he does mean to suggest that he holds that created

substances have active powers, so long as these are understood to be

modes.

By rejecting the view that substantial forms are immediate principles

of action, and by identifying active qualities as the direct principles of

substantial activity, Descartes affirms one of the Scholastic views mentioned

above, namely, that substances act through their accidents alone. For in

Scholastic ontology, active qualities are accidents. Descartes’ letter to

Regius indicates that he considers his denial of substantial forms to be

compatible with the claim that bodies have causal powers. So this letter

tells against Garber’s claim that Descartes replaces substantial forms with

God as the direct source of motion and change in the created world. And it

illuminates Descartes’ view of the ground of activity in bodies without

substantial forms. His view echoes a Scholastic model, which Suarez

illustrates in his example of the action of the active quality heat when

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conserved apart from the fiery form. On this model, activity in the created

world depends on accidents alone.

Descartes employs the model on several occasions. One prominent

example is his account of how fire burns wood in Le Monde. There he

argues that in the absence of the form of fire and the quality of heat, that is,

in the absence of those entities which ground Scholastic causal powers, the

changes we observe when wood burns could be caused by “some power

which puts its finer parts into violent motion and separates them from the

coarser parts”.27 He then explains what constitutes this power in the body

of the flame:

Now since it does no seem possible to conceive how one body could move another except through its own movement, I conclude that the body of the flame which acts upon the wood is composed of minute parts, which move about independently of one another with a very rapid and very violent motion. As they move about in this way they push against the parts of the bodies they are touching and move those which do not offer them too much resistance. I say that the flame’s parts move about individually, for although many of them often work together to bring about a single effect, we see nevertheless that each of them acts on its own upon the bodies they touch. I say, too, that their motion is very rapid and very violent, for they are so minute that we cannot distinguish them by sight, and so they would not have the force they have to act upon the other bodies if the rapidity of their movement did not compensate for their lack of size.28

Flame, according to Descartes, is a body composed of very tiny, very rapidly

moving parts. The size and speed of its parts constitutes its power to burn.

In Principles IV, ss. 187, Descartes boasts that he has penetrated

seeming mysteries such as “the properties [proprietates] of magnets and of

27 CSM I 83/AT XI 7-8.28 CSM I 83/AT XI 8.

17

fire”, and “how a huge flame can be kindled from a tiny spark in a moment”

without appeal to the “occult qualities” of his predecessors:

In this book I have deduced the causes – which I believe to be quite evident – of these and many other phenomena from principles which are known to all and admitted by all, namely the shape, size, position and motion of particles of matter. And anyone who considers all this will readily be convinced that there are no powers in stones and plants that are so mysterious, and no marvels attributed to sympathetic and antipathetic influences that are so astonishing, that they cannot be explained in this way. In short, there is nothing in the whole of nature (nothing, that is, which should be referred to purely corporeal causes, i.e. those devoid of thought and mind) which is incapable of being deductively explained on the basis of these selfsame principles; and hence it is quite unnecessary to add any further principles to the list.29

Here Descartes replaces Aristotelian occult qualities with mechanistic

properties. Occult qualities were posited by Aristotelians to explain

phenomena seemingly irreducible to mixtures of the four elements (earth,

air, fire, water). Famous examples: magnetism, effects of drugs, e.g.,

opium. Descartes’ boast is perhaps not only about the fact that his

explanatory principles known and admitted by all but also that his most

basic principles, unlike the Aristotelian elements, encompass all natural

phenomena caused by bodies, i.e., he doesn’t have to posit hidden powers in

certain cases.

The merits of Descartes’ project of reforming the ground for corporeal

causal powers by replacing Aristotelian forms and qualities with the

mechanistic properties is not addressed here. Others have noted that

Descartes’ own explanations are often flawed, unsatisfying. I aim only to

show that Descartes does not consider bodies devoid of forms to be bodies

29 CSM I 279/AT VIIIA 314-15.

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without activity, and that his basic model for corporeal causal powers

derives from a Scholastic view that bodies act directly through their

accidents. I also think that the model supports Descartes’ very frequent

claims that bodies are causes by identifying the ground of their activity. 30

But the occasionalist interpretation of body-body causation in Descartes

also finds support in his claim that the nature of body is extension. If a body

30 Descartes very frequently refers to bodies as causes. See his discussion of change in Le Monde, where he claims first that change in the created world happens in accordance with the laws of nature, and then that “by ‘nature’ here I do not mean some goddess or any other sort of imaginary power. Rather, I am using this word to signify matter itself, in so far as I am considering it taken together with all the qualities I have attributed to it, and under the condition that God continues to preserve it in the same way that he created it. For it follows of necessity, from the mere fact that he continues thus to preserve it, that there must be many changes in its parts which cannot, it seems to me, properly be attributed to the action of God (because that action never changes), and which therefore I attribute to nature. The rules by which these changes take place I call the ‘laws of nature’” (CSM I 92-3/AT XI 37). Here Descartes explains change in the world by pointing to matter taken together with the qualities he has attributed to it, namely, “that its parts have had various different motions from the moment they were created, and furthermore that they are all in contact with each other on all sides without there beings any void between any two of them” (CSM I 92-3/AT XI 37). So Descartes thinks that change in the world depends on the motion of bodies, coupled with the absence of empty space. It is important to notice that Descartes also claims that change must be attributed to matter in motion on the ground that the action of an unchanging God can’t explain change.

Della Rocca argues that Descartes identifies bodies themselves as the particular causes of motion in his discussion of the third law of motion in Principles, Part 2 at CSM I 240/AT VIIIA 61 (Della Rocca (1999), pp. 52-54). He notes, and I agree, that this passage provides important evidence against the occasionalist interpretation of Descartes’ view of body-body causation, since the passage is one in which Descartes is “giving us his official account of the causation of motion”, rather than speaking loosely or casually about bodies as causes as even an occasionalist might do in nontechnical passages (Della Rocca (1999), p. 52).

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is simply an extended thing, then it has no features which could constitute

active powers. This objection is the focus of the next Section.

3. The causal powers of res extensa

At Principles 1.53, Descartes claims that “each substance has one

principal property which constitutes its nature and essence, and to which all

its other properties are referred”.31 The principal attribute of corporeal

substance is extension in length, breadth and depth and “[e]verything else

which can be attributed to body presupposes extension, and is merely a

mode of an extended thing”.32 And in Principles Part Two §23, Descartes

claims that

[t]he matter existing in the entire universe is thus one and the same, and it is always recognized as matter simply in virtue of its being extended. All the properties which we clearly perceive in it are reducible to its divisibility and consequent mobility in respect of its parts, and its resulting capacity to be affected in all the ways which we perceive as being derivable from the movement of parts.33

Descartes’ identification of extension as the principal attribute of body and

his account of the relationship between the principal attribute of a

substance and its other properties are the bases of an important objection

to the claim that Cartesian bodies have causal powers. Hattab puts the

point this way:

[g]iven that all the properties of matter are derived from its divisibility and the consequent capacity of its parts to be moved, Descartes leaves no room for active forces or causal powers originating from the nature of bodies.

31 CSM I 210 / AT VIIIA 53.32 CSM I 210 / AT VIIIA 53.33 CSM I 232/AT VIIIA 52

20

Properties such as active forces are not ultimately reducible to extension so they do not belong to body.34

Notice that Hattab infers the claim that “Descartes leaves no room for

active forces or causal powers originating from the nature of bodies” from

the claim that he holds that all the properties of matter are reducible to its

divisibility and consequent mobility. So she takes Descartes’ claim that all

the properties of matter are reducible to its divisibility and consequent

mobility to mean that he holds that all the properties of matter originate

from the nature of body, i.e. extension. But the claim that all the properties

of matter originate from the nature of body conflicts with Descartes’ central

point in Principles Part Two §23.

Principles Part Two §23 begins with the claim that “[a]ll the variety in

matter, all the diversity of its forms, depends on motion”.35 Descartes’ aim

in this section is to explain this point. He notes first that “[t]he matter

existing in the entire universe is thus one and the same, and it is always

recognized as matter simply in virtue of its being extended”.36 This claim

follows from Descartes’ assertion that variety in matter depends on motion:

if variety in matter depends on motion, then matter considered in itself is

undifferentiated extension. His next claim explains the relationship

between the nature of matter and the properties which cause variety in

matter: he says that “[a]ll the properties which we clearly perceive in

[matter] are reducible to its divisibility and consequent mobility in respect

34 Hattab (2000), p. 96.35 CSM I 232/AT VIIIA 5236 CSM I 232/AT VIIIA 52

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of its parts, and its resulting capacity to be affected in all the ways which

we perceive as being derivable from the movement of parts”.37 This claim is

primarily a descriptive one. But it has a proscriptive overtone: we should

ascribe to matter only those properties which we clearly perceive to be in

matter and those properties are reducible to its divisibility and consequent

mobility. Since he claims that “any variation in matter or diversity in its

many forms depends on motion”, he must think that motion is something we

clearly perceive to be in matter and so is something reducible to the

divisibility and consequent mobility of matter.38 But motion is not reducible

to the divisibility and consequent mobility of matter in the sense that it

originates from the divisibility and consequent mobility of matter.39 Given

that Descartes claims in Principles Part Two §23 that all the properties

which we clearly perceive to be in matter are reducible to its divisibility and

consequent mobility and that motion is a property of matter, his claim that

37 CSM I 232/AT VIIIA 52-338 CSM I 232-3/AT VIIIA 52-339 Descartes makes this point clear in his hypothetical account of creation in The World. There Descartes first posits the creation of matter conceived as “a real, perfectly solid body which uniformly fills the entire length, breadth and depth” of his imagined world and then suggests that “this matter may be divided into as many parts having as many shapes as we can imagine, and that each of its parts is capable of taking on as many motions as we can conceive” (CSM I 91/AT XI 33-4). Finally, he proposes that God really does divide matter into parts and suggests how he would do so: [i]t is not that God separates these parts from one another so that there is some void between them: rather, let us regard the differences he creates within this matter as consisting wholly in the diversity of the motions he gives to its parts. From the first instant of their creation, he causes some to start moving in one direction and others in another, some faster and other slower (or even, if you wish, not at all); and he causes them to continue moving thereafter in accordance with the ordinary laws of nature (CSM I 91/AT XI 34).

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all the properties which we clearly perceive to be in matter are reducible to

its divisibility and consequent mobility cannot mean that all of these

properties originate from its divisibility and consequent mobility. By

“reducible to” he means something other than “originate from”.

What does “reducible to” mean, for Descartes in Principles Part Two

§23?

1. The properties of matter are reducible to extension in the sense that

the existence of these properties does not require anything over and

above, or other than, a finite parcel of extension. So, e.g., spherical is

reducible to extension in the sense that it is does not require for its

existence anything over and above, or other than, a finite parcel of

extension.

This view seems to accord with an analysis of modes as “ways of being

extended”: Garber gives such an analysis in Descartes’ Metaphysical

Physics:

Descartes wants to make all of the properties of body geometrical. And so for him, modes, the term he comes to choose in preference to accident, are to be the expression of the very essence or attribute, in his terminology. For him, no accidents are to be merely tacked onto a substratum; for him all accidents are to be either propria or accidentia propria, intimately linked to the essence of the substance: as Descartes put it, all of the modes of body must be understood through its essence, its principal attribute, extension (see Pr I 53). And thus, when he claims that the essence of body is extension, he is not merely saying that all bodies have extension and necessarily so, as his scholastic contemporaries might have meant such a claim; he is saying something stronger, that everything that can really be

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attributed to body as such must be some way of another of being an extended thing.40

Objection to 1.:

“Spherical” and “moving” might both be ways of being an extended thing,

but spherical does not require for its existence anything over and above or

other than a finite parcel of extension. But motion does require for its

existence something over and above or other than a finite parcel of

extension. So “ways of being extended” can’t mean reducible to extension

where being “reducible to extension” means not requiring for existence

anything over and above or other than a finite parcel of extension. And

being “reducible to extension” does not mean requiring nothing for

existence over and above or other than a finite parcel of extension, since

this view is incompatible with the claim that motion is a mode of matter.

2. The claim that the properties of matter are “reducible to extension” in

Principles 2.23 expresses the same point made in Principles 1.53 where

Descartes says that the properties of matter presuppose and are referred to

extension. Descartes there explains the point in epistemological terms: he

says that the properties of matter are “unintelligible except in an extended

thing” (Principles 1.53).41

40 Garber, Descartes’ Metaphysical Physics, p. 69.41 Why the reduction language in Principles 2.23? N.B. the Latin verb is reducere, but see the French: Il n'y a donc qu'une même matière en tout l'univers, et nous la connaissons par cela seul qu'elle est étendue; parce que toutes les propriétés que nous apercevons distinctement en elle, se rapportent à ce qu'elle peut être divisée et mue selon ses parties, et qu'elle peut recevoir toutes les diverses dispositions que nous remarquons pouvoir arriver par le mouvement de ses parties. Perhaps the reduction language

24

If 2. is correct then Descartes can attribute causal powers to bodies even if

those powers don’t originate from the nature of extension, or if they require

something over and above, or other than, a finite parcel of extension.

A fundamental corporeal causal power in Descartes’ natural

philosophy is a moving body’s power to move another body. (I say that this

power is a fundamental one, since a great many other causal powers will

either be reducible to or depend on this one.) At Principles 2.43. Descartes

identifies one body’s power to move another with the former’s “power of

continuing to move”. So we must determine whether it makes sense to

attribute to a body the power of continuing to move.

Descartes’ claim that the changes in motion which occur when a

moving body collides with another body are due to the moving body’s power

of continuing to move gives rise to a different objection to the view that

Cartesian bodies can have genuine causal powers, which has to do with the

source of a body’s power of continuing to move. Hattab cites Descartes’

claim in the Second Meditation that self-motion doesn’t belong to the nature

of bodies as support for the general conclusion that “[b]odies are inert on

their own, requiring an external source of motion to begin to move and

echoes the methodological reduction advocated in Rules for the Direction of the Mind, 5ff. Reduce involved questions to the simplest question whose answer is required by the more involved questions. E.g., what properties can matter have? is reduced to the question what is matter? The latter question is simple since there is no more basic question that can be asked. And we can intuit the answer. Then we build our account of the properties of matter based on our intuition of the nature of matter as extension.

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continue to move”.42 In the Second Meditation, Descartes reports his

conception of the nature of bodies prior to engaging in methodological

doubt. He says that he understood a body to be something which “can be

moved in various ways, not by itself but by whatever else comes into contact

with it. For, according to my judgement, the power of self-movement, like

the power of sensation or of thought, was quite foreign to the nature of

body”.43 But he retracts this claim in the Fifth Set of Replies:

You also question my statements that I had no doubts about what the nature of body consisted in, and that I attributed to it no power of self-movement, and that I imagined the soul to be like a wind or fire, and so on; but these were simply commonly held views which I was rehearsing so as to show in the appropriate place that they were false.44

Furthermore, in his letter to Mersenne of October 28, 1640 he says that “[i]t

is a big mistake to accept the principle that no body moves of itself. For it

is certain that a body, once it has begun to move, has in itself for that

reason alone the power to continue to move”.45

Notice that Descartes says in his letter to Mersenne that “a body,

once it has begun to move, has in itself for that reason alone the power to

continue to move”.46 This suggests that he holds that a body’s power to

continue to move is constituted by its being in motion. Since being in

motion is a property that presupposes and is referred to extension, the

property is compatible with Descartes’ account of the relationship between

42 Hattab (2000), p. 96. 43 CSM II 17/AT VII 2644 CSM II 243/AT VII 35145 CSM III 155/AT III 213 46 Ibid.

26

the nature of matter and its properties in Principles 1.53 and 2.23. But why

should we agree that bodies have in themselves the power to continue to

move if they are in motion? This claim finds support in Descartes first law

of nature: “each thing, in so far as it is simple and undivided, always

remains in the same state, as far as it can, and never changes except as a

result of external causes”.47 In other words, we know by the first law of

nature that a body in motion will remain in motion unless checked by

something else. Since it is the case that a body in motion will remain in

motion unless checked by something else, we should agree that bodies have

in themselves the power to continue to move if they are in motion. The

principle at work here seems to be the following: (1) X has the power to

continue to φ if (a) X is actually φing and (b) X will cease to φ only if

something else makes it cease.48 Note that Descartes does not need to

47 CSM I 241/AT VIIIA 6348 We might think that if Descartes really does endorse this principle, then his claim that creatures depend on God for their existence so long as they exist is in trouble. For the principle as applied to existence yields the following claim: X has the power to continue to exist if (a) X is actually existing and (b) X will cease to exist only if something else makes it cease. In the Fifth Set of Objections Gassendi raises an objection along these lines against Descartes claim that creatures depend on God for their existence (CSM II 210/AT VII 301-2). Descartes responds to Gassendi’s objection as follows: “You say that we have a power which is sufficient to ensure that we shall continue to exist unless some destructive cause intervenes. But here you do not realize that you are attributing to a created thing the perfection of a creator, if the created thing is able to continue in existence independently of anything else (CSM II 255/AT VII 371). What is interesting about this reply is that Descartes does not attack Gassendi’s line of reasoning, i.e. he does not deny that it makes sense to hold that an existing thing has the power to continue to exist if it will continue to exist in the absence of a destructive cause. Rather, he points out that this view misattributes to a creature a perfection that belongs to creators alone. What is the perfection that belongs to creators alone? Descartes might

27

establish that (a) and (b) are necessary conditions for (1); his view makes

sense so long as they are sufficient conditions for (1). This principle seems

to me to be unobjectionable. I clearly have the power to continue to

breathe if I am actually breathing and will only cease to breathe if

something else makes me cease.

Gary Hatfield denies that Cartesian bodies have in themselves the

power to continue to move. He thinks that God is directly responsible for

mean that power to continue to exist independently belongs to a creator alone. Why is this so? Descartes might mean that God, the sole creator, is the only being with the power to continue to exist independently. If so, then his response begs the question?? I think that it is more likely that the perfection that belongs to creators alone is the power to cause the existence of something. Aquinas defends this view in Summa Theologiae 1.45.5. He says that “to produce being absolutely, and not merely as this or that being, belongs to the nature of creation” (Aquinas. “Summa Theologiae.” In Basic Writings of Saint Thomas Aquinas, vol. 1, ed. Pegis. Indianapolis: Hackett, 1997, p. 440). Aquinas draws a distinction between producing being absolutely and producing this or that being in order to distinguish the creative act, which is proper to God, from the acts of creatures. Only God produces being absolutely, i.e. only God makes be something from nothing. Creatures cause changes in things whose existence depends on God. This means that no creature can keep itself in being, since to be able to keep something in being is to be able to produce being absolutely. If this is Descartes’ point, then his response to Gassendi amounts to the following. To cause existence is among the perfections of a creator; it is one of the features which distinguish creators and creatures. To attribute to a creature the power to continue to exist is to attribute to that creature the power to cause existence. This response indicates that he does not endorse without qualification the principle that X has the power to continue to φ if (a) X is actually φing and (b) X will cease to φ only if something else makes it cease. But this response also suggests that Descartes does not object to the line of reasoning which grounds the principle itself, but rather to its application to existence, which stands in need of a creative cause. The latter belief finds support in the view that to cause the very existence of something is to create it from nothing. For this reason, I don’t think that Descartes’ claim that bodies in motion have in themselves the power to continue to move conflicts with his claim that creatures can’t keep themselves in existence.

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this power. He reasons as follows. Since Descartes appeals to the first law

of nature to support his claim that bodies have in themselves the power to

continue to move and since the first law of nature is grounded in divine

immutability, it follows that a body’s power to continue to move is grounded

in divine immutability. This means that God is directly responsible for a

body’s power to continue to move. Hatfield makes this point in the

following passage:

Descartes gives no reason why bodies should tend to persist in their own state other than the immutable nature of the divine action that preserves bodies at each moment. A fortiori, in explaining the tendency to persevere he does not appeal to the force that a body has by virtue of its motion. Indeed, the relation is just the reverse: ‘the force of a body to act…is simply the tendency of everything to persist in its present state’, a tendency that does not follow from any property of matter, but rather from an attribute of God. Just as with the preservation of the quantity of motion, it is difficult to see how a tendency to move could be grounded upon the immutability of God, unless God were directly responsible for the tendency itself.49

Hatfield cites Descartes’ claim in Principles, Part Two §43 that a

body’s power to act on another body “consists simply in the fact that

everything tends, so far as it can, to persist in the same state, as laid down

in our first law”.50 This claim follows from the claims that (1) a body’s

power to act on another body is constituted by its power to continue to

move and (2) a body’s power to continue to move is established by the first

law of nature. Hatfield infers from Descartes’ appeal to the first law of

nature in claim (2) that God is directly responsible for a body’s power to

continue to move. He justifies this inference on the ground that the first

49 Hatfield (1979), p. 126.50 CSM I 243/AT VIIIA 66

29

law of nature follows from divine immutability. I think Hatfield is mistaken

in thinking that a body’s power to continue to move “does not follow from

any property of matter”.51 I think that it is constituted by a property which

belongs to any body which has this power, namely, that body’s property of

being in motion. And I think that Descartes is entitled to attribute to a body

in motion the power to continue to move on the ground that X has the

power to continue to φ if (a) X is actually φing and (b) X will cease to φ only

if something else makes it cease.

My position on this issue is prima facie similar to Michael Della

Rocca’s. Della Rocca defends Descartes’ claim that bodies have the power

to continue to move and so to move other bodies on the ground that

Descartes holds that what a body tends to do is a function of its nature. If

this is the case, then a body’s tendency to remain in motion belongs to it by

nature. Since Descartes thinks that a body’s power to continue to move

constitutes its power to move other bodies, the claim that a body’s tendency

to remain in motion belongs to it by nature entails that its force or power to

move other bodies belongs to it by nature. Della Rocca notes that

[i]n holding that a body’s nature is the source of what it can do causally, Descartes, as I have interpreted him, is in agreement with the Aristotelian-scholastic tradition. On this tradition, a body’s nature or form is the locus of causal explanations. Now…these forms or natures, as they were traditionally conceived to be, were rejected by Descartes. But in rejecting this conception of the natures of physical objects, he did not reject the general view that we should turn to the natures of bodies in order to account for their causal powers.52

51 Hatfield (1979), p. 126.52 Della Rocca (1999), p. 67.

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I think Della Rocca is right that Descartes’ rejection of substantial forms

does not include a rejection of the view that bodies have genuine causal

powers. But I have shown that he thinks that it is absurd even for

proponents of substantial forms to hold them to be direct principles of

action, and that he endorses the view of some Scholastics that substances

act directly through their accidents alone. So I don’t think that he

considers the claim that bodies have causal powers to depend on the claim

that bodies have the tendency to remain in motion by nature. Rather I think

that he considers the claim that bodies have causal powers to depend on the

claim that they have mechanistic properties which constitute such powers.

Chief amongst these is the power to continue to move, which is constituted

by a body’s property of being in motion, as discussed above. So my view

does not result in the problem which Della Rocca raises with respect to his

own: “on the view I have attributed to Descartes, the nature of a body

consists in or at least somehow involves its tendency to remain in its current

state. It is not immediately clear how or if this view is compatible with his

view that extension constitutes the nature of a body”.53

Della Rocca, Michael. “If a Body Meet a Body.” New Essays on The Rationalists, eds. Gennaro and Huenemann. Oxford: Oxford University Press, 1999, pp. 48-81.

Des Chene, Dennis. Physiologia: natural philosophy in late Aristotelian and Cartesian thought. Ithaca: Cornell University Press, 1996.

53 Della Rocca (1999), p. 69). Tad Schmaltz rejects Della Rocca’s account on this ground. See Schmaltz (2003), p. 744.

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Nadler, Steven. “Introduction.” Causation in early modern philosophy : Cartesianism, Occasionalism, and Preestablished harmony, ed. Nadler. University Park, PA: Pennsylvania State University Press, 1993.

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