Causation and mental causation

Causation and Mental CausationJaegwon KimIAn epistolary event occurred in 1643 that will live in the history of the debate on mental

causation. In the May of that year, Princess Elisabeth of Bohemia dispatched to Descartes

what must be one of the most celebrated philosophical letters, challenging Descartes to

explain:How the mind of a human being can determine the bodily spirits [i.e., the fluids in

the nerves, muscles, etc.] in producing voluntary actions, being only a thinking

substance. For it appears that all determination of movement is produced by the

pushing of the thing being moved, by the manner in which it is pushed by that

which moves it, or else by the qualification and figure of the surface of the latter.

Contact is required for the first two conditions, and extension for the third. [But]

you entirely exclude the latter from the notion you have of the body, and the

former seems incompatible with an immaterial things.1A need for explanation arises for Elisabeth because she takes contact as a necessary

condition for physical causation: the cause—at least, the proximate cause—of the motion

of a material body must be in spatial contact with that body, a condition that plainly

cannot be met by an immaterial causal agent outside physical space. The idea that

causation requires contact survives even in Hume, a philosopher who is commonly

thought to have held a deflationary view of causation as consisting solely in de facto

regularities. One of the conditions Hume laid down for causation is that of contiguity in

“space and time” between cause and effect, either direct or mediated by a chain of

contiguous cause-effect pairs. (We will recur to the contiguity condition below.)1 Elisabeth to Descartes, May 1643. This quotation is taken from Garber (2001, 172).

2Elisabeth’s challenge is surely reasonable and intelligible, both in

commonsensical terms as well as in light of what Descartes had written, in Meditation II,

about bodies and causes of their motions:By a body I understand whatever has determinate shape and a definable location

and can occupy a space in such a way a to exclude any other body; it can be

perceived by touch, sight, hearing, taste or smell, and can be moved in various

ways, not by itself but by whatever else comes into contact with it (Descartes

1641, 17).There may well have been earlier philosophical concerns about the powers of the mind to

bring about changes in the physical world,2 but, for many of us, the exchanges between

Descartes and Elisabeth are our first encounter with the mental causation debate in the

modern period. Descartes continues to loom large in contemporary discussions of many

central issues in the philosophy of mind, and our current concerns with mental causation

are no exception.

What is of interest to us here is Elisabeth’s invocation of a specific feature of

mind-body causation in her challenge to Descartes, namely that to cause a material body

to move, physical contact with the body is required. Such contact, in modern terms,

presumably imparts energy, or transfer momentum, from one body to another, and this

fact constitutes the causal relation between them. Elisabeth’s complaint, which could be

our complaint, is that such a conception of causation leaves no room for mental causation

within Descartes’s dualism. Minds, being essentially extensionless and not even in

physical space, cannot meet the contact requirement; in fact, we can attach no coherent

sense to the idea of contact between an immaterial mind and a material body. So either

mental causation, at least the mental-to-physical variety, is a metaphysical impossibility,

or the very idea has no intelligible sense.2 See Caston (1997).

3IIMental causation has been a flash point of debates in the philosophy of mind for over

three decades, ever since the publication of Donald Davidson’s “Mental Events” (1970).

In this paper Davidson claimed that there are no “strict” laws about mental phenomena—neither mental-physical laws nor mental-mental laws—and that such laws are required to

underwrite causal relations. This at first blush appeared to quickly entail that mental

causation was not possible. However, Davidson had a deft reply: All that his two

principles imply is that any causal relation must instantiate a strict physical law, and that

what is required for a mental event to enter into a causal relation is for it to have an

appropriate physical description under which it can instantiate a physical law. From this

Davidson’s “anomalous monism” follows: All individual mental events—in fact, all

individual events3—that enter into causal relations are physical early debate on mental causation in the contemporary period began when

several philosophers noticed,4 apparently independently, that although Davidson’s

anomalous monism allowed individual (or “token”) mental events to be causes and

effects, it failed to give any role to mental properties, or mental descriptions, of these

events in determining what causal relations they enter into. The reason is simple: since,

on Davidson’s view, all strict laws are physical and they apply to individual events solely

in virtue of the fact that these events have certain physical properties, what mental

properties they have—what mental kinds (e.g., pain, desire, thought) they fall under—becomes entirely irrelevant to their causal properties—or so it seemed to his critics.

Though Davidson’s anomalous monism may not be a form of “token” epiphenomenalism,

it was generally perceived as a form of “type” epiphenomenalism (in the terms

introduced by McLaughlin 1989), the position that psychological characteristics and

features contribute nothing to the causal powers of objects and events that have them. The

position has the consequence that if we were to redistribute psychological properties over

the events and objects of this world—or even if these properties were entirely removed—3 Here we assume that the mental-physical dichotomy is both exhaustive and exclusive. Also, Davidson

believes that strict laws (if there are any) can be found only in physics.4 Stoutland (1980), Honderich (1982), Sosa (1984), McLaughlin (1989).

4that would not change a single causal relation as long as their physical properties are

preserved. Davidson tried to defend anomalous monism against the epiphenomenalist

charges in Davidson (1993); however, few seem to have found his efforts did not escape philosophers’ attention that Davidson’s troubles with mental

causation crucially depended on his conception of causation—in particular, the condition

that causally related events must instantiate “strict” laws. There has been some

controversy about how to understand the strictness of strict laws, or what Davidson meant

by the term. Strict laws of course must be laws—that is, as Davidson explicitly notes in

Davidson (1970), must be capable of supporting counterfactuals and subjunctives and

also be capable of confirmation by observation of positive instances (that is, inductively

projectible). There seem two further features that make for the strictness: first, strict laws

are totally exceptionless (in this regard, they contrast with laws or generalizations hedged

with ceteris paribus clauses), and, second, they are often (always?) found as part of a

theory that is in some sense “complete” and gives comprehensive coverage over its

domain. It is not easy to spell out this second condition in clear terms, something that

Davidson himself seems never to have done. In practice, exceptionlessness is what does

most of the work, and for most purposes this has seemed sufficient. So a natural question

to raise, when we are faced with Davidson’s epiphenomenalist predicament, is why we

should tie causation to strict laws. Why can’t there be causation where there are no strict

laws in Davidson’s sense? This question is especially appropriate given the fact that

Davidson never stated a clear reason, much less a detailed argument, for his requirement

of strict laws for causal relations.

IIIOne strategy that will naturally occur to many is to relax, or abandon, Davidson’s

requirement of strict laws in favor of a condition that allows nonstrict laws, or laws

hedged by ceteris paribus clauses, to underwrite causal relations between individual

events. Jerry Fodor is one such philosopher. He admits that “even the best psychological

laws are very likely to be hedged” (Fodor 1989, 72), and then continues “it [is] no longer

5clear why hedged psychological laws can’t ground mental causes; and, presumably, if

hedged psychological laws can, then strict physical laws needn’t” (ibid.). But how can a

ceteribus paribus law, a law whose antecedent, say F-events, does not necessitate its

consequent, G-events, ground a causal relation between an F-event and a G-event? Given

the law, it is amply possible for an F-event to occur without being followed by a G-event.

Being qualified by a ceteris paribus clause, the law is immune to falsification by such

counter-instances; that in fact is the whole point of “ceteris paribus” ’s reply is based on his special reading of the “ceteris paribus” clause. He

writes:

The first—and crucial—step in getting what a robust construal of the causal

responsibility of mental requires is to square the idea that Ms [mental events of

kind M] are nomologically sufficient for Bs [bodily events of kind B] with the

fact that psychological laws are hedged… [If] it’s a law that M → B ceteris

paribus, then it follows that you get Bs whenever you get Ms and the ceteris

paribus conditions are satisfied. This shows us how ceteris paribus laws can do

serious scientific business since it captures the difference between the

(substantive) claim that Fs cause Gs ceteris paribus and the (empty) claim that Fs

cause Gs except when they don’t” (Fodor 1989, 73).The heart of Fodor’s strategy, then, appears to be the thought that whenever we have a

serious ceteris paribus law “Ms cause (or are followed by) Bs, ceteris paribus”, there is a

set C of conditions (as yet not fully specifiable) such that “Whenever C obtains, Ms cause

(or are followed by) Bs” is a strict, exceptionless law. The reader will have noticed the

alternate formulations, “cause (or are followed by)”, in the preceding sentence. This was

to reflect Fodor’s unexplained move, in the quoted passage, from “M → B ceteris

paribus”, which only states that M is (nomologically) sufficient for B ceteris paribus to

“Ms cause B (or “Fs cause G”) ceteris paribus” (or “Fs cause G”). This slide between

nomological sufficiency and causality occurs throughout Fodor (1989), and it is

indicative of the fact that Fodor’s conception of causality is strictly and simply based on

6nomological regularity.5 So his problem with ceteris paribus laws—that is, his solution to

Davidson’s epiphenomenalism problem—consists in interpreting “ceteris paribus” nomic

regularities so that they will yield causation. Fodor’s suggestion, then, is that ceteris

paribus regularities can ground ceteris paribus causal claims, and that whenever the

unspecified, and unknown, set of additional set of conditions C is satisfied, we have

causation tout court.6

But this, to my mind, is to mislocate the real problem. What one should worry

about in this context is not ceteris paribus clauses but a more fundamental question about

causation and regularities. This question concerns whether or not we can get causation

out of regularities, whether these are “strict” or hedged with ceteris paribus clauses, or

whether they are mere “de facto” regularities (Humean “constant conjunctions”) or given

a suitable modal force (“physical/nomological necessity”, “lawlikeness”, “projectibility”,

and so on). As early as 1925, C.D. Broad made a simple observation (Broad 1925, 96):“Again, if causation be nothing but regular sequence and concomitance, as some

philosophers have held, it is ridiculous to regard psycho-neural parallelism and

interaction to be mutually exclusive alternatives. For interaction will mean no

more than parallelism, and parallelism will mean no less than interaction.”

7Actually, the situation is not be quite as simple as Broad describes, for causation, or

causal interaction, has directionality whereas psychoneural correlations under a strict

parallelism are entirely symmetric and it would be difficult to determine which of the two

symmetrically correlated events, one mental and one physical, is the cause and which the

effect. But that is the least of the problems faced by the regularist, or nomological,

approach to causation.

5 Fodor briefly considers the possibility of noncausal laws, that is, nomological regularities that do not

constitute causal relations, at Fodor (1989, 65), but waves it off in his typically lighthearted way.6 It’s a bit of a mystery how we can ever know these “unknown” conditions are satisfied and hence how we

can know a causal relation exists in a given situation.7 Thanks to Brian McLaughlin for bringing this paragraph to my attention.

7First, there is the much discussed cases in which two phenomena are correlated,

with nomological necessity, because they are collateral effects of a single cause.8 One of

the two effects may always occur a little earlier than the other so that we may mistakenly

think that the first is the cause of the second. There must be many such cases in medicine

where a single underlying pathological state gives rise to two distinct symptoms, one

occurring earlier than the other. The regularity connecting the two symptoms may be

projectible and lawlike, and there seems no reason to deny that it holds with nomological

necessity (we could even suppose it strict and exceptionless, though this is unlikely). The

regularity, though it arises from underlying causal processes, clearly does not constitute a

causal relation—a relation in which one event brings about ions with the following structure present another difficulty. We observe a

regular connection between two events, A and B, with A preceding B, and we may be

tempted to postulate a causal connection between them, with A as cause and B as effect.

In fact, a believer in a purely regularist-nomological conception of causation is

committed to this conclusion. However, it may well turn out that the observed correlation

between A and B is due to A’s regular correlation with event C and B’s regular correlation

with event D, where C causes D. The correlation from A to B is only a surface

manifestation of an underlying causal process involving C and D. It will be easy enough

to find instances exemplifying this situation in medicine in which an underlying

pathological process gives rise to regular connections between symptoms caused by the

various stages in the progression of the pathology. Closer to home, where mental

causation is concerned, regular sequences of mental events may well be cases of this

kind. If so, the impression that we are observing mental-to-mental causation would only

be an impression. The fact would be that the observed sequence of mental events is

grounded in, and is explained by, an underlying causal process between the neural

substrates of the mental events. There is no direct causal relationship between the

successive mental events in the sequence; the only genuine causal relations present here

relate the neural substrates of the mental sequence. Thus, the relationship between the

two successive mental events is like that between the shadow cast by a moving car at an

8 For extensive discussions of “causal forks”, see Wesley C. Salmon (1984). Broad notes such cases in

Broad (1925, esp. 115-117).

8instant and the shadow of the car an instant later. The moving shadows do not constitute a

causal sequence; nor do a sequence of mental events grounded in a series of causally

connected neural substrates.9 It should be clear that the issues about ceteris paribus laws

do not touch these difficulties with the regularist-nomological conception of to soothe our fear of epiphenomenalism (“epiphobia”), Fodor tells us:According to the present view, the properties projected in the laws of basic

science are causally responsible, and so too are the properties projected in the

laws of the special sciences. Notice, in particular, that even if the properties that

the special sciences talk about are supervenient upon the properties that the basic

sciences talk about, that does not argue that the properties that the special sciences

talk about are epiphenomenal (Fodor 89, 66).But this is no cure of epiphobia. Our discussion shows that though there may be

projectible special-science properties and there may be special-science laws, that does not

guarantee that there is causation in the special sciences. Fodor continues as follows:Not, at least, if there are causal laws of the special sciences. The causal laws of

the special sciences and causal laws of basic sciences have in common that they

both license ascriptions of causal responsibility (Fodor 89, 66).To be sure, if there are causal laws in psychology, they will license ascription of causal

responsibility to psychological properties and ground psychological causal relations. The

crucial question unaddressed by Fodor is whether psychological laws are causal laws—that is, whether the regularities we observe in the psychological domain are causal

regularities, or mere mirror images of the causal regularities at a more fundamental

(presumably, neural/physical) level. Fodor’s neglect of this question is a reflection of his

seemingly unconscious slide between regularities and causal regularities, and laws and

9 This is the gist of what I have called the “supervenience argument”; see Kim (1998, 2005).

9causal laws, which itself seems to be an outcome of his unreflective commitment to a

regularist-nomological view of the issue of mental causation cannot be resolved either way by merely invoking the

regularist or nomological approach to causation. In saying this, I should not be

understood as committing myself to the view that the nomological model of causation

does not work at any level; it is possible that it works at the fundamental physical level.

Because it is the bottom level with nothing below it, regularities may be all we can get; it

makes no sense to speak of “underlying” mechanisms or processes at a “lower” level. Or

we can perhaps take this to mean that, although only “constant conjunctions”, but no

causation, exist at the fundamental level (Hume was right about this level), causal

relations can, and do, exist at higher levels. These are interesting and intriguing issues but

we must set them aside and move nomological approach, which once was the reigning approach to causation as

well as explanation, seems to have lost favor with a large number of philosophers. The

tide now seems to have turned in favor of the counterfactual conception of causation

whose modern version is due to the seminal work of David Lewis (1973a). This approach

has recently attracted a lot of attention from an active and energetic group of

philosophers, and there appear to be numerous ongoing research projects attempting to

develop a satisfactory counterfactual analysis of causality. The core idea of the

counterfactual conception is that c is a cause of e just in case e is counterfactually

dependent on c—that is, if c had not occurred, e would not have occurred. Since

counterfactual dependence is not transitive whereas causation is, Lewis explained “c

causes e” as the ancestral of counterfactual dependence, that is, in terms of there being a

series of events linking c with e such that any event is this series (except c) is

counterfactually dependent on its predecessor. There are numerous outstanding

difficulties with the counterfactual approach, among them the problems of

overdetermination and preemption—problems that refuse to go away. The current

10literature is rife with increasingly clever and ingenious counterexamples and equally (if

not more) ingenious remedies to evade or dissipate them.10 The impression one gets

looking in from outside is that it is going to be by no means an easy affair to achieve a

reasonably simple and intuitively well-motivated account of causation along the

counterfactual lines, and the increasing number of epicycles being piled on top of the

epicycles already there reminds one of the ultimately fruitless search of the “fourth”

condition of knowledge prompted by the Gettier Problem. I don’t want to say that the

ongoing research on the counterfactual analysis of causation is without value; far from it,

it may yield—I believe it has already yielded—some valuable insights into our causal

talk, just as the Gettier-inspired work in epistemology has contributed much to our

understanding knowledge and justification. Our present concern is not with the ultimate

viability of the counterfactual approach to causation; it is a more restricted one about

explaining mental causation in terms of counterfactuals, although in doing this our

discussion will unavoidably involve some general issues about causation and

such general issue concerns the apparent dependence of counterfactuals, at

least those involved in causal attributions, on laws and regularities, and if this is the case,

embracing the counterfactual approach to causation will have no advantages over the

regularist-nomological approach we considered earlier. Consider the causal claim: The

striking of the match caused it to light. On a simple counterfactual analysis, this amounts

to the assertion of the following counterfactual:(C) If this match had not been struck, it would not have all current counterfactual theorists of causation use the semantics of

counterfactuals developed by Robert Stalnaker (1968) and David Lewis (Lewis 1973b),

based on comparative similarity among possible worlds. According to this scheme, (C) is

true just in case the consequent of the conditional “the match lighted” is true at the world

that, apart from the fact that the match was not struck in that world, is the closest to the

10 An excellent place to sample some of this is Collins, Hall, and Paul (2004).

11actual world in all other respects (we use this somewhat simplified formulation; this will

make no difference). Assume (C) is true. That means that in the closest world in which

the match was not struck, it did not light. How do we know that this world is closer to the

actual world than is the closest world in which the match was not struck but it

nonetheless lighted? The obvious, and the only possible, answer seems to be that, in the

actual world, dry matches struck in the presence of oxygen usually and reliably ignite,

and that it is our knowledge of this regularity, or ceteris paribus law, combined with

knowledge of the actual circumstances in which the match was struck (e.g., it was dry,

oxygen was present, etc.), that accounts for our knowledge of (C). Or the laws involved

might be more theoretical and concern the chemical composition of the match head, its

combustibility, the characteristics of the surface against which the match was struck, and

so forth. In any case, one crucial aspect in which the comparative similarity is judged

seems to involve the similarity of laws holding in a given world. In the case of (C), it is

difficult to see how evaluations of conditionals like (C) could avoid adverting to laws and

us see how this affects the use of counterfactuals to account for mental

causation. Consider the claim that a sudden attack of migraine headache caused Susan a

frightful sense of anxiety. For the counterfactualist, this amounts to the truth of:(D) If Susan had not had the sudden migraine headache, she would not have

experienced frightful can concede that our commonsense “knowledge”, or assumption, that counterfactuals

like (D) are often true grounds our belief in the reality of mental causation. Our job as

philosophers, in the present context, is to see what makes the likes of (D) true and

whether this justifies the claim that Susan’s migraine headache caused her anxiety. If our

observations relating to (C) are correct, the truth of (D) must depend on the regularity

connecting sudden attacks of migraine headaches and feelings of anxiety. This regularity

could be limited to Susan and a few others like her, or it could be a (ceteris paribus) law

for all people with migraine headaches. It seems to me that even an epiphenomenalist like

12T.H. Huxley can, with consistency, accept a regularity of this kind and acknowledge it to

be lawlike (surely, the connection isn’t accidental or coincidental—not even for an

epiphenomenalist). However, the epiphenomenalist will deny that (D) warrants the causal

claim that the attack of migraine headache caused the sense of fearful anxiety. The

observed regularity arises out of the genuine causal process connecting two neural

substrates on which the headache and the anxiety respectively causally depend. The

situation is fundamentally the same if you believe that the relationship between mental

states and the underlying neural states is better described in terms of supervenience or

realization. As we remarked earlier in regard to Fodor’s nomological approach, the

question is not whether there are these psychological (or psychophysical) regularities or

laws; rather, it is whether these regularities are causal regularities and whether these laws

are causal spite of these and possibly other difficulties, the counterfactual approach to causality

remains popular—among philosophers working on issues about causation (especially, the

analysis of the concept) and among philosophers who aim to defend mental causation

against various epiphenomenalist threats.11 The intuition that supports the counterfactual

approach, I believe, is the close association we form between a cause of an event and a

sine qua non condition of its occurrence. A cause is the condition but for which the effect

would not have occurred. We can grant the legitimacy of this intuition, without

necessarily wedding it to any particular way of making it precise and exact—without, that

is, necessarily explicating it in terms of counterfactuals with the Stalnaker/Lewis-style

semantics, or any other special semantics of conditionals.

But there is another strong intuitive conception of causation that contrasts sharply

with the conception tied to counterfactual dependency, or the sine qua non condition. It is

a productive or generative conception of what causing consists in. On this conception, a

cause is something that produces or generates or brings about its effects, something from

11 For example, LePore and Loewer (1987), Horgan (1989), Loewer (2002).

13which the effects derive or spring forth. This idea was given its classic expression when

Elizabeth Anscombe wrote:There is something to observe here, that lies under our noses. It is little attended

to, and yet still so obvious as to seem trite. It is this: causality consists in the

derivativeness of an effect from its cause. This is the core, the common feature, of

causality in its various kinds. Effects derive from, arise out of, come of, their

causes. For example, everyone will grant that physical parenthood is a causal

relation (Anscombe 1971, 91-92).Indeed, in a recent article, Ned Hall (2004) makes a plausible case for the thesis that there

are two fundamentally distinct notions of causation:Causation, understood as a relation between events, comes in at least two basic

and fundamentally different varieties. One of these, which I call “dependence,” is

simply that: counterfactual dependence between wholly distinct events. In this

sense, event c is a cause of (distinct) event e just in case e depends on c. that is,

just in case, had c not occurred, e would not have occurred. The second variety is

rather more difficult to characterize, but we evoke it when we say of event c that it

helps to generate or bring about or produce another event e, and for that reason I

call it “production” (Hall 2004, 225).According to Hall, three characteristics are central to productive/generative causation:

transitivity, locality, and intrinsicness. Of these what is relevant to our present concerns is

the locality condition, which Hall states as follows: “Causes are connected to their effects

via spatiotemporally continuous sequences of causal intermediaries” (Hall 2004, 225).

This is a generalized version of Hume’s contiguity condition alluded to earlier. Hume’s

own statement is this:I find in the first place, that whatever objects are consider’d as causes or effects,

are contiguous; and that noting can operate in a time or place, which is ever so

14little remov’d from those of its existence. Tho’ distant objects may sometimes

seem productive of each other, they are commonly found upon examination to be

link’d by a chain of causes, which are contiguous among themselves, and to the

distant objects; and when in any particular instance we cannot discover this

connexion, we still presume it to exist (Hume 1739, 75).As Hall notes, causal relations conforming to the dependence idea need not meet the

locality condition; we will see some examples we have seen in earlier sections is that neither the nomological nor the

dependency conception of causation can properly ground mental causation. I argued that

nomological relationships do not deliver the kind of causal efficacy we want for

mentality, and that the counterfactual approach seems to presuppose, or collapse to, the

nomological conception and thereby inherit the latter’s shortcomings. Many

counterfactualists will dispute this claim. We need not concern ourselves with this general

issue about causation. In this section, I will try to argue that the relation of causation as

dependence, or counterfactual dependence, even if it is a proper and useful causal

relation, is not the source of our worries about mental causation. That is, even if we

succeed in showing that mental causation, with causation construed as dependence, is

real, that would not suffice to vindicate mental causal efficacy and thereby dissipate our

epiphenomenalist worries. In my view, what we need to show is that mentality has causal

powers to bring about their effects in a continuous process of generation and production.

Why should we resort to this “thick” variety of causation in thinking about mental

causation? My answer is pretty simple: We care about mental causation because we care

about human agency, and agency requires the productive/generative conception of

causation.12 I don’t have a knock-down argument to prove that agency requires

productive causation; I hope what I will say here makes my claim at least plausible. It

seems to me that mere counterfactual dependence is not enough to sustain the causal

12 In correspondence Barry Loewer has challenged this claim. According to him, “thin” causation, or

dependence, is sufficient to ground agency.

15relation involved in our idea of acting upon the natural course of events and bringing

about changes to realize what we desire and intend. An agent is someone who, because

she has certain beliefs, desires, emotions, intentions, and the like, has the capacity to

perform actions in the physical world—that is, to cause her limbs and other bodily parts

(e.g., her vocal cords) move in appropriate ways so as to bring about changes in the

natural course of events in the outside world—open a door, pick up the morning paper,

and make a cup of coffee. It seems to me that without productive causation, which

respects Hall’s locality condition or Hume’s contiguity condition, such causal processes

are not possible. These causal processes all involve real connectedness between cause

and effect, and the connection is constituted by phenomena like energy flow and

momentum transfer, an actual movement of some (conserved) physical quantity.13 In

saying this we need not impugn the dependency conception of causation; all we need is

the point that agency requires productive causation.14 Note, further, that we need not

claim that dependency is not involved in actions; it may well be that the dependency

involved, say between a limb movement and a desire, has an explanation in terms of the

productive/generative relations between er the component of mental-to-physical causation involved in action,

namely the causation of bodily movements by our desires, beliefs, intentions, and the

like? To endow our mental states with causal powers to move our limbs (or, more

proximately, the powers to bring about changes in our neural states), would it be enough

to show that counterfactuals like the following are true—and that we have reason to

believe them true?If Susan had not wanted to open the window, neural state N would not have

occurred in her brain (where we suppose N triggers an appropriate sequence of

bodily movements).13 I am of course referring to the so-called conservative quantity approach to causation. See Dowe (1992,

2000), Salmon (1994); for an early statement, see Fair (1979). See also the exchange between Dowe (2004)

and the dependence theorist Schaffer (2004).14 For our purposes we need not claim that all cases of action involve productive causation; perhaps we are

willing to regard certain cases of omissions as actions and consider omissions as eligible as causes. See

below for further discussion of omissions.

16If Susan had not experienced the sudden migraine headache, neural state N*

would not have occurred (where we imagine N* to be the neural substrate of an

anxiety attack).We earlier argued how such counterfactuals ultimately involve reference to psychological

or psychophysical regularities, and that their significance for mental causation depends

on the question whether these regularities are causal regularities. Apart from this issue,

there are reasons to be suspicious about relying on counterfactuals alone to defend mental

causation—what such a strategy could s of the counterfactual approach often tout its ability to handle omissions

and absences as causes and the productive/generative approach’s inability to account for

them. We are inclined to take the truth of a counterfactual like:If Mary had watered my plants, the plants would not have diedas showing that Mary’s not watering, an omission, caused the plants’ death and take that

as a basis for blaming Mary for killing the plants. But obviously there was no flow of

energy from Mary to the plants during my absence (that exactly was the problem!); nor

was there any other physical connection, or any spatiotemporally contiguous chain of

causally connected problem with regarding Mary’s omission as a cause of the plants’ death on

the strength of the foregoing counterfactual is that there are indefinitely many other

counterfactuals like it certifying an indefinitely large number of other causes of the

plants’ death:15If George W. Bush had watered my plants, the plants would not have died.15 I saw examples like these in Abbott (1974) for the first time. This paper is recommended to those

interested in the counterfactual approach to causation. See also McGrath (2005).

17If Laura Bush had watered my plants, the plants would not have Hillary Clinton had watered my plants, the plants would not have , you get the idea. Of course I blame Mary for not watering the plants; but we don’t

have to say that I am blaming Mary for causing the plants to die; I am blaming her for

breaking a promise—her promise to water the plants while I was omissions should count as actions, something we do, then by staying in my

room “doing nothing” (I could be taking a long nap), I would be performing countless

actions, like not watering my plants, not writing an email to my niece, not running the

MS marathon, not doing the space walk out of the shuttle Discovery, … Of course these

are not intentional omissions (at least they don’t have to be), but it is difficult to see how

intentional omissions and mere omissions could differ ontologically, specifically with

respect to their causal powers. At any rate, it is by no means clear that its ability to handle

omissions as causes is something that the dependency theorists should celebrate. Not

thinking, not believing, not desiring, and so on are mental omissions. If causation by

mental omissions count as mental causation, that would make mental causation easy—too

easy. My not believing (or disbelieving) that a chest of treasures is buried in my backyard

is a cause of my not digging in my backyard; my not believing treasures are buried in

your backyard causes my not digging in your backyard, and so on ad infinitum. This is

not causation worth if we understand causation in mental causation in the productive/generative sense,

wouldn’t that rule out mental causation—in particular mental-physical causation—too

quickly, without any need for an argument? Especially if we require that causation

requires energy flow or momentum transfer, how could there be such a process from a

mental entity to a physical entity? Remember Elisabeth’s challenge to Descartes: the

18causation of physical motion requires spatial contact, but how could an immaterial mind

outside physical space be in such contact with a material body? Notice that this problem

is not special to Cartesian physics; it arises even under Hume’s concept of causation,

which, as we saw, requires a spatially contiguous chain of causally connected events.

Don’t all such conceptions of causation, conceptions that require some “real” connections

between cause and effect, automatically rule out mental-physical causation (and hence

human agency)? Further, what could “contiguity” mean unless it meant spatial

contiguity? What “real” connection can there be between two immaterial substances

outside space? Wouldn’t the productive/generative conception of causation preclude,

without much ado, mind-to-mind causation as well as mind-to-body causation—that is,

all mental causation?16An answer—the right answer, in my opinion—is contained in a follow-up letter

Elisabeth sent to Descartes. In June 1643, she wrote to Descartes:And I admit that it would be easier for me to concede matter and extension to the

mind than it would be for me to concede the capacity to move a body and be

moved by one to an immaterial thing (Garber 2001, 172).This, I believe, is a remarkable statement which attests to the philosophical astuteness of

Elisabeth. She is saying what some of us have been trying to say for the past two decades;

she is in effect saying that to make sense of mental causation, she would rather

physicalize the mind (“concede matter and extension to the mind”) than accept the

possibility of immaterial minds in causal commerce with material bodies. It is the idea

that mental causation is possible only if mentality is physically reducible. Her remark

expresses this idea succinctly and forcefully; it may well be the very first causal argument

ever for the dominant strain of physicalism on the contemporary scene has been the

nonreductive kind. Nonreductive physicalists, while rejecting Cartesian immaterial minds

16 For an argument for an affirmative answer to this question based on spatial considerations, see Kim

(2005), chapter 3.

19or any nonphysical object, nonetheless resist the idea that mental properties are reducible

to physical properties. Beliefs, desires, intentions, pains, visual images, and the rest,

though they may be supervenient on neural/biological processes, are irreducible to them;

nonetheless, these mental states are claimed to be causally efficacious. But how can the

idea of productive/generative causation be applied to them in relation to neural/physical

states? How can there be energy flow or momentum transfer from a desire, as an

irreducible mental state, to the firing of a group of neurons? In his characterization of

nonreductive physicalism, Terence Horgan, a leading proponent of the position, writes:

First, mental properties and facts are determined by, or supervenient upon,

physical properties and facts. Second (and contrary to emergentism), physics is a

causally complete science; the only fundamental force-generating properties are

physical properties. More specifically, the human body does not instantiate any

fundamental force-generating properties other than physical ones. Third, mental

properties nonetheless have genuine causal/explanatory efficacy, via the physical

properties that “realize” mental properties on particular occasions of instantiation

(Horgan 1996, 498).So, on Horgan’s antireductionist view, a desire (as an individual “token” event) has

“genuine” causal efficacy, say the power to raise my arm to reach for a glass of water, in

virtue of the fact that its neural realizer, an instance of a neural property on which the

desire supervenes, has this causal power.

Horgan’s suggestion, I believe, is fundamentally right: mental events and states

have the causal efficacy that they have because their neural/physical realizers have causal

efficacy. In fact, a mental state, occurring on a given occasion, in virtue of being realized

by a certain neural/physical state, has exactly the causal powers of that physical state.

Where I differ from Horgan is that once we are prepared to say what we have just said,

the next natural step to take—in my view, a step we are compelled to take—is to

reductively identify this particular mental state with its neural/physical realizer (Kim,

1993, 1998). This of course is to jettison the “nonreductive” part of nonreductive

20physicalism. To say what Horgan says, namely that the belief is a distinct state from its

neural realizer, and yet consider each a sufficient cause of the arm rising, is to walk

smack into the problem of overdetermination. And to say that the mental state has causal

efficacy “via” the causal efficacy of its neural realizer carries an apparent epiphenomenal

implication: Given that the neural realizer is a full cause of the arm rising, what causal

work is left for the mental state to contribute? Or, to put the question another way, what

could “via” mean here? What is it for an event to cause something “via” another event

that presumably does the real causing?So the idea of causation as production and generation, or causation as requiring a

“real” connection between cause and effect, can be applied to mentality as long as, and

probably only so long as, mental states have physical realizers. Whether an approach of

this kind leads to reductionism, as I just claimed, or it is compatible with a nonreductive

view of mentality is a further, currently much debated, issue (Kim 2005).References:Abbott, Barbara (1974). “Some Problems in Giving an Adequate Mode-Theoretical

Account of CAUSE”, Berkeley Studies in Syntax and Semantics, vol. 1, ed.

Charles Filmore, George Lakoff, and Robin Lakoff, Berkeley, be, Elizabeth (1971). Causality and Determination, Cambridge: Cambridge

University Press. Page references are to its reprinted version in Causation, ed.

Michael Tooley and Ernest Sosa, Oxford: Oxford University Press, , C.D. (1925). The Mind and Its Place in Nature, London: Routledge and Kegan

, Victor (1997). “Epiphenomenalisms, Ancient and Modern”, Philosophical

Review 106: 309-363.

21Collins, John, Ned Hall, and L.A. Paul, eds. (2004). Causation and Counterfactuals,

Cambridge: MIT on, Donald (1970). “Mental Events”, reprinted in Davidson, Essays on Actions

and Events, New York and Oxford: Oxford University Press, 1980._____ (1993). “Thinking Causes”, in Mental Causation, ed. John Heil and Alfred Mele,

Oxford: Oxford University Press.

Descartes, René (1641). Meditations on First Philosophy, The Philosophical Writings of

Descartes, vol. II, tr. John Cottingham, Robert Stoothoff, and Dugald Murdoch,

Cambridge: Cambridge University Press, , Phil (1992). “Wesley Salmon’s Process Theory of Causality and the Conserved

Quantity Theory”, Philosophy of Science 59: 195-216._____ (2000). Physical Causation, Cambridge: Cambridge University Press._____ (2004). “Causes Are Physically Connected to Their Effects”, in Contemporary

Debates in Philosophy of Science, ed. Christopher Hitchcock, Oxford: Blackwell

, David (1979). “Causation and the Flow of Energy”, Erkenntnis 14: , Jerry A. (1989). “Making Mind Matter More”, Philosophical Topics 17: , Daniel (2001). Descartes Embodied, Cambridge: Cambridge University , Ned (2004). “Two Concepts of Causation”, in Causation and Counterfactuals, ed.

John Collins, Ned Hall, and L.A. Paul, Cambridge: MIT ich, Ted (1982). “The Argument for Anomalous Monism”, Analysis 42: , Terence (1989). “Mental Quausation”, Philosophical Perspectives 3: 47-76._____ (1996). “Reduction, Reductionism”, in The Encyclopedia of Philosophy:

Supplement, ed. Donald M. Borchert, New York: Simon & Schuster , David (1739). A Treatise of Human Nature, London. Page references are to the

L.A. Selby Bigge edition, Oxford: Clarendon Press, 1888.

Huxley, T.H. (1901). Methods and Results: Essays, New York: D. Appleton. A useful

excerpted version can be found in Philosophy of Mind: Classical and

Contemporary Readings, ed. David J. Chalmers, Oxford: Oxford University

Press, 2002.

22Kim, Jaegwon (1993). “Postscripts on Mental Causation”, in Kim, Supervenience and

Mind, Cambridge: Cambridge University Press._____ (1998). Mind in a Physical World, Cambridge: MIT Press._____ (2005). Physicalism, or Something Near Enough, Princeton: Princeton University

, Ernest and Barry Loewer (1987). “Mind Matters”, Journal of Philosophy 93:

, David (1973a). “Causation”, Journal of Philosophy 70: 556-567. Reprinted, with

Postscripts, in Lewis, Philosophical Papers, vol. II, Oxford: Oxford University

Press, 1986.

_____. (1973b). Counterfactuals, Cambridge: Harvard University , Barry (2002). “Comments on Jaegwon Kim’s Mind in a Physical World”,

Philosophy and Phenomenological Research 65: h, Sarah (2005). “Causation by Omission: A Dilemma”, Philosophical Studies

123: hlin, Brian (1989). “Type Epiphenomenalism, Type Dualism, and the Causal

Priority of the Physical”, Philosophical Perspectives 3: , Wesley C. (1984). Scientific Explanation and the Causal Structure of the World,

Princeton: Princeton University Press._____ (1994). “Causality Without Counterfactuals”, Philosophy of Science 61: er, Jonathan (2004). “Causes Need Not Be Physically Connected to Their Effects:

The Case for Negative Causation”, in Contemporary Debates in Philosophy of

Science, ed. Christopher Hitchcock, Oxford: Blackwell , Ernest (1984). “Mind-Body Interaction and Supervenient Causation”, Midwest

Studies in Philosophy 9: ker, Robert (1968). “A Theory of Conditionals”, in Studies in Logical Theory, ed.

Nicholas Rescher, Oxford: and, Frederick (1980). “Oblique Causation and Reasons for Action”, Synthese 43:

351-367.