mental events or states, such as beliefs, desires, feelings, and
perceptions. Typically, the term is used to refer to cases where a
mental state causes a physical reaction: for instance, the mental
state of perceiving a Frisbee flying your way can cause the physical
event of your springing up to catch it. It should also be recognized
that mental causation covers those cases where the causal transaction
occurs just among mental states themselves, as when one entertains a
series of thoughts while planning, deliberating, solving a problem,
remembering, and so on. The term "mental causation" need not cover
such exotica as minds bending spoons (if such feats are to be
believed), psychosomatic illnesses, or controlling one's body through
yogic meditation. Simply waving your hand (a physical event) because
you wish to greet a friend (a mental event) suffices for counting as
an instance of mental causation.
The phenomenon of mental causation, as may be apparent, is thoroughly
commonplace and ubiquitous. But this is not the only reason why it is
significant. It is absolutely fundamental to our concept of actions
performed intentionally (as opposed to involuntarily), which, in turn,
is central to those of agency, free will, and moral responsibility. An
action, as philosophers use the term, is not a mere bodily motion like
involuntarily blinking one's eyes. It is something one does
intentionally, as when one winks to grab someone's attention. The
distinction between a mere bodily movement and an action hinges on the
possibility of mental causation, since actions have mental states,
such as intentions, as direct causes. This distinction, in turn, is
critical for gauging moral responsibility, since we attribute or
withhold judgments of moral responsibility depending upon whether the
agent acted intentionally.
While the phenomenon of mental causation seems obvious enough, the
explanation of how it is possible is far from obvious. There are
certain putative marks distinctive of mental states that pose problems
for their capacity to wield causal powers, marks such as: being a
non-physical substance (problem of spatial location and problem of
conservation); failing to conform to law-like regularities (problem of
anomalism); being extrinsic to an agent's body (problem of
externalism); and being supplanted by brain states (problem of
exclusion).
1. Background to the Problem of Mental Causation
a. Dualism v. Reductive Materialism
The main assumption that generates problems for mental causation is
dualism, the view that mental phenomena and physical phenomena are
fundamentally different from each other. In particular, the mental is
not reducible to the physical: constructing a physical duplicate of a
conscious person does not guarantee that the physical duplicate has a
mind. René Descartes (1596 – 1650) is the classic source for defenses
of dualism. The view that the mental is so reducible is known as
reductive materialism, which maintains that mental phenomena are
nothing but a species of physical phenomena, which consist of purely
physical substances, physical properties, and physical laws governing
their behavior.
Reductive materialism does not face the problem of mental causation,
as mental causation, being nothing more than a species of physical
causation, is no more problematic than just plain old physical
causation. Not so for dualism.
b. Substance Dualism v. Property Dualism
Dualism comes in two main versions: substance dualism and property
dualism. Standard discussions divide the issue along the traditional
problem of mental causation and the contemporary problem of mental
causation. The former is generated by the form of dualism known as
substance dualism, while the latter generated by what is known as
property dualism. It is actually more accurate to say of both problems
that there are several sub-problems associated with each.
Substance dualism comes out of the traditional Christian conception of
a person as consisting of both a body and a soul that can survive the
destruction of the body. Descartes offered the most fully developed
formulation of substance dualism (also called "Cartesian dualism,"
after its founder), so called because the idea is that the mind and
the body constitute each their own "substance." A substance, on
Descartes's view, is anything that can logically exist on its own,
where something can logically exist on its own if one can coherently
conceive of that individual without having to conceive of it with
anything else – a pumpkin, a cow, a ball of wax; things that are not
substances would be things like a sense of humor or a friendly smile,
as they need to be a part of something else in order for us to
conceive of them coherently (a person, in the case of humor, and a
face, in the case of a smile). Descartes's formulation of substance
dualism maintains that the mind has no physical features – no mass,
shape, spatial dimension, and so on. The mind, in other words, has no
physically detectable qualities. Furthermore, under this formulation,
the body has no mental features. This basically means that the brain
does not think, feel, or perceive, a rather odd view by today's
standards.
Property dualism, by contrast, allows for the brain to think, feel,
and perceive, for it allows that all substances are physical, but it
maintains that thoughts, feelings, and perceptions are instances of
mental properties that are not reducible to physical properties.
Properties, unlike substances, are repeatable; that is, a single
property, such the color orange, can occur in many different
substances – a pumpkin and a squash can both be orange. Examples of
mental properties are things like the belief that it is raining, the
desire to stay dry, and other propositional attitudes, as well as
sensations, like pains, itches, and tickles. According to property
dualism, an individual who has exactly the same physical properties as
a conscious person may still lack mental properties. Both property
dualism and substance dualism allow for the possibility of what
philosophers of mind call zombies. These are not the brain-dead
stalkers of Hollywood, but rather creatures that are physically
identical to a fully conscious individual that nonetheless lack a
mental life. Property dualism and substance dualism differ in that
substance dualism entails property dualism, but the converse is not
true.
c. Standard Models of Mind-Body Interaction
There are four basic models of mind-body interaction. These are:
interactionism, the view that the mind and the body directly cause
things to happen in each other;
parallelism, the view that the mind and the body act "in parallel,"
but never casually interact directly;
epiphenomenalism, the view that only the body has causal powers, but
the mind is causally inert; and finally,
reductionism, the view that the mind just is the body, and so whatever
causal efficacy the physical has, the mental also has.
These models can each be formulated in terms of the vocabulary of
either substance dualism or property dualism. In this entry, the
models will be neutral between these two versions of dualism.
What these models say and how they differ are best understood when
applied to a concrete example. Take the case where you have the
misfortune of stubbing your toe. The trauma to your toe sends signals
through nerves in your leg and torso that stimulate those neural
tissues responsible for the capacity to experience pain – call them
C-fibers, the neural correlate of pain. The crucial question is how
the term "correlate" is specified: is the correlation causal or
non-causal, and if causal, do the effects themselves have causal
powers or not? The different models give us different answers to this
question.
i. Interactionism
The critical feature of interactionism is its commitment to "two-way"
causation – mental-to-physical causation and physical-to-mental
causation. Here is the interactionist's story. When you stub your toe
(call this event a), this stimulates the C-fibers in your brain (call
this event b). This neural event b causes you to experience the
sensation of pain (event c.). The pain you feel causes you to get
annoyed (event d), causing a neural event (e), which is the neural
correlate of annoyance.
A diagram may be helpful here. Causal transactions are represented by
arrows. Mental events (like pain and annoyance) go above the bar, and
physical events (like stubbing your toe, C-fiber stimulation (CFS),
and the neural correlate of annoyance (N)) go below it.
Objections to Interactionism: As the picture makes clear, causation
flows from the mental to the physical and from the physical to the
mental. Indeed, this is the hallmark of interactionism, which is
depicted by the arrows from (b) to (c) and (d) to (e). Interactionism
is probably the most common view held by the folk, but as will be
explained below, it faces the problem of spatial location and the
problem of conservation.
ii. Parallelism
Dualism does not necessarily entail interactionism, since one can be a
dualist and yet maintain that there is no causal interaction between
the mental and the physical. This is parallelism. On this model,
mental and physical events do not causally interact; they only
co-occur. When causal transactions do occur, they occur only between
members of their own kind: mental events enter into causal
transactions only with other mental events, and physical events enter
into causal transactions only with other physical events.
Parallelism raises the following pressing question: what guarantees
that the mental event and its physical correlate will be appropriately
coordinated? Why do we feel pain upon bodily trauma on a regular
basis, or seek water when we are thirsty rather than whistle a tune,
or elevate our arm when we want to raise it rather than raise our
foot? Our minds and bodies are remarkably well coordinated for two
systems that are supposed to have no causal contact with each other.
There are two different accounts of how the coordination is achieved:
pre-established harmony, the view of Gottfried Leibniz (1646 – 1716)
and occasionalism, the view of Nicolas Malebranche (1638 – 1715). Both
appeal crucially to God as the source of mind-body coordination.
According to Leibniz's pre-established harmony (1695), the proper
pairing of a mental event and a bodily event was long established by
God. As Leibniz explains, the mind and the body are like two separate
clocks wound up in advance to chime at precisely the same time. On
this view, God is thus fairly "hands-off" when it comes to
coordinating an individual's mind with her body, having done all the
work ahead of time.
Not so on the view developed by Malebranche. According to
Malebranche's occasionalism, coordination is achieved on an event by
event basis; whenever someone wants to raise her arm, God is right
there to make her arm go up (Malebranche 1958, 2:316). The basis for
this view stems out of a previous commitment to a certain view about
causation according to which only God can bring about causes and
effects.
Objections to Parallelism: To modern ears, this convenient appeal to
God to solve the coordination problem is untenable and just too
convenient. In defense of pre-established harmony and occasionalism,
we need to understand that they are driven by prior commitments about
the nature of God and the world as God created it, not simply
introduced to solve a problem about mind-body coordination. However,
those who reject the metaphysical schemes of Leibniz and of
Malebranche will find these solutions unsatisfactory.
iii. Epiphenomenalism
Epiphenomenalism is the view that physical events cause mental events,
but mental events never cause anything, not even other mental events.
It is thus a partial concession to interactionism, as it allows for
causation in "one direction" – from the physical to the mental – and
so it denies parallelism, as it insists upon causal contact from the
physical to the mental. The mind, on this model, is like a shadow cast
by the body, where the body is the only thing that makes things happen
– the mind is just "projected" and is causally inert. This analogy is
inexact, for even shadows do darken the regions upon which they are
cast, and at times, frighten or amuse or do other things. But mental
events are not supposed to do anything, according to epiphenomenalism,
not even cause other mental events.
As odd as the model may initially appear, there is a compelling
motivation for it. It does not encounter the coordination problem
faced by parallelism, because it allows for mental events to be
causally grounded by their physical causes. Thus, the reason why, say,
one feels pain upon stubbing one's toe is that the stubbing causes the
C-fiber stimulation, which then causes the pain in a law-like manner.
Objections to Epiphenomenalism: In spite of its stated virtues,
epiphenomenalism has been thought to be unappealing, precisely because
it does not credit the mind with any causal efficacy. Consequently,
epiphenomenalism is logically consistent with the complete absence of
mentality; mindless bodies would function in exactly the same way, as
the mind has no capacity to generate any causal impact. In short,
epiphenomenalism denies that there is any mental causation. Even
parallelism allows for the mind to have a measure of efficacy since
mental events can, at least, cause other mental events. But under
epiphenomenalism, not even this limited causal efficacy is accorded to
the mind. This makes epiphenomenalism quite objectionable.
iv. Reductionism
With all the difficulties encountered by interactionism, parallelism,
and epiphenomenalism, one may wonder why we don't construe the mind in
wholly physical terms – why, that is, we don't just identify the
mental with the physical. This is the idea behind reductionism. On
this view, mental events just are physical events; the difference
between the mental and the physical lies only in how we conceive of
them, not in how they really are. Thus, there are concepts that are
about mental phenomena and concepts that are about physical phenomena,
but it is possible for a mental concept and a physical concept to pick
out one and the same physical event.
As Figure 4 indicates, mental events just are physical events; there
are no events that are non-physical. For this very reason, mental
causation is just a species of physical causation, and is therefore no
more problematic than plain old physical causation. On this view,
mental causation is just physical causation that has been
conceptualized using mental concepts, or described using mental
vocabulary.
Objections to Reductionism: While reductionism has the virtue of
presenting a clear account of mental causation, it faces the problem
of justifying the reducibility of the mental to the physical. There
are compelling reasons for thinking that the mind is not just a purely
physical phenomenon. Descartes, for instance, gives us two arguments
for the irreducibility of mental substances to physical substances.
The first is the argument from divisibility, which basically claims
that the mind cannot be physical, as physical things have spatial
dimension but minds simply are not the kinds of things that have
spatial dimension. And the second is the argument from conceivability,
according to which it is conceivable that the conceiver does not have
a body, but not conceivable that the conceiver does not have a mind.
While contemporary philosophers no longer work within the framework of
substance dualism, there are other considerations have been used to
support the irreducibility of mental properties to physical properties
(for the irreducibility of phenomenal properties, see Jackson 1982,
Nagel 1974, Kripke 1980, Chalmers 1996; for the irreducibility of
intentional properties, see Davidson 1970, Child 1994).
2. Traditional Problems of Mental Causation
The traditional problem of mental causation begins with the idea that
the mind is its own substance that has no physical characteristics. In
the absence of physical characteristics, it becomes quite puzzling how
the mind is supposed to exert any causal influence. There are two ways
of formulating the problem: the Problem of Spatial Location and the
Problem of Energy Conservation.
a. The Problem of Spatial Location
This problem is based upon a certain assumption about the nature of
causation – that the cause and its effect must be spatially contiguous
(touch each other, so to speak), and thus have spatial location. The
spatial location requirement has ample intuitive support: a stone does
not move unless something pushes against it; a pot of water does not
boil unless heat is directly applied to it; a plant does not grow
unless its roots draw water from the soil; and so on. (Typically, a
given effect has multiple causal factors whose conjunction is
necessary for the effect, and conversely, a given cause produces more
than one effect. Since nothing hangs on observing this nicety, this
entry will help itself to the simplifying talk of one cause per effect
and one effect per cause.) In each of these cases, the causes and
their effects are in spatial contact in one way or another. As a
general matter, nowhere in nature is there causation where the cause
or effect has no spatial location. But this is precisely what
Cartesian mind-body interaction asks us to believe. The problem can be
summed up by the inconsistency among the following statements:
Mental causation: The mind and the body causally interact – thoughts,
feelings, and perceptions, bring about bodily actions.
Spatial location: Wherever there is causation, the cause and its
effect must have spatial location.
Dualism: The mind has no spatial location – there is no spatial
location to thoughts, feelings, or perceptions.
The claim about mental causation (1) and the claim about spatial
location (2) are very intuitive, so dualism would lose much
credibility if it could not make sense of how the two claims could be
true under dualism. However, the three claims do not look like they
are consistent with each other. If causes and effects must have
spatial location, as (1) maintains, then the mental cause of a bodily
event must occur in a spatial location. But (2) denies that mental
events have spatial location, so the assertion that there is mental
causation (3) is not consistent with the conjunction of (1) and (2).
Descartes's colleagues were quite open about their puzzlement. Pierre
Gassendi, for instance, asked:
How can there be effort directed at anything, or motion set up in it,
unless there is mutual contact between what moves and what is moved?
(Cottingham, et al., 1984, p, 236).
Princess Elizabeth of Bohemia, another contemporary of Descartes, was
even more forthright about her puzzlement:
[T]he determination of movement seems always to come about from the
moving body's being propelled – to depend on the kind of impulse it
gets from what sets it in motion, or again, on the nature and shape of
this latter thing's surface. Now the first two conditions involve
contact, and the third involves that the impelling thing has
extension; but you utterly exclude extension from your notion of soul,
and contact seems to me incompatible with a thing's being immaterial
(Anscombe and Geach 1954, pp. 274 – 5).
There are two standard dualist strategies to handle the problem: the
Pineal Gland Reply and the Reply from Quantum Mechanics.
Pineal Gland Reply: Descartes proposed that we could locate the
workings of mental causation in the pineal gland, which Descartes
believed to be the gateway between the mind and the body. We now know
that the pineal gland is responsible for regulating the hormone
melatonin, but aside from Descartes' anatomical inaccuracy, the
strategy of appealing to a physical locus is fundamentally misguided,
because it does nothing to solve the problem. For how, one is right to
ask, can mental causation occur "in" the pineal gland if the mind
cannot be located "in" anything, lacking as it is in spatial
dimension?
Reply from Quantum Mechanics: This reply rejects (2), the spatial
location constraint upon causes and effects as inaccurate. The basis
for this rejection is certain alleged findings in quantum mechanics
where the position of a traveling particle, such as an electron, is
indeterminate. That is, there is a chance that a particle will show up
in a certain region but its presence in that region is purely a matter
of chance, and yet for all its lack of a determinate spatial location,
it is still capable of entering into causal relations. Perhaps minds
are like this as well; they can cause things to happen even if they
have no determinate location. Or so the reply goes. There are three
difficulties with this reply. First, the comparison between minds and
fundamental physical particles is imperfect, for electrons can have a
location, albeit indeterminate, whereas minds, according to the
Cartesian conception, cannot have any location at all. Second, the
jury is still out on the interpretation of these alleged findings; for
all we know, some theory will be able to explain away the appearance
of indeterminacy and model the universe after strictly deterministic
principles. And third, no entities outside of the domain of
fundamental physics – macro-physical entities – have this odd
indeterminacy about their occurrence or location, and so it appears
too convenient to proclaim of minds, a macro-entity by any standards,
that it is like the micro-physical entity of electrons in this one
respect.
b. The Problem of Conservation
This problem draws upon two key assumptions. The first is the idea
that causation is matter of energy transfer, such as when one pool
ball transfers its momentum to another ball upon collision, or when
the calories from ingesting food get converted into bodily energy (for
energy transfer accounts of causation, see Aronson 1985, Dowe 2000,
Fair 1979, and Salmon 1994). The second is the principle of the
conservation of energy, a fundamental law of nature that is taken to
be a cornerstone of contemporary science. According to this principle,
the total quantity of energy in the universe remains fixed at all
times. Energy, of course, comes in many forms – kinetic, chemical,
electrical, thermal, and so on – and energy can be transformed from
one form to another, and loss or gain of energy can happen within a
component part of the universe, but the sum total energy in the
universe as a whole can be neither created nor destroyed. The
principle of conservation entails a significant lemma, which is that
the physical universe is a causally closed system: at no point in the
history of the physical universe can there be outside energy causing
something to happen within the system, nor can energy leave the system
to cause something to happen outside of it.
Insofar as the body is a part of the physical system, it cannot be
caused to move by anything other than something else within that
system. But if the mind is not a part of that system, as Cartesian
dualism maintains, then its causal influence upon the body would be a
foreign source of energy impinging upon the energy equilibrium of the
universe, thereby violating conservation. The inconsistency here is
present in the following statements:
Mental causation: The mind and the body causally interact; thoughts,
feelings, and perceptions, bring about bodily actions.
Conservation: The physical universe is a causally closed physical
system: causal interactions do not increase nor decrease its sum total
energy of the universe.
Dualism: The mind is not a part of the causally closed physical
system: mental events, such as thoughts, perceptions, and sensations,
do not occur within the system.
Again, these statements cannot be true together. The conjunction of
(1) and (3) entail a disruption in the balance of energy in the
physical universe, but (2) denies that this can happen.
Reply from Rejection of Conservation: This reply rejects (2) by
appealing to what is known as "tunneling," a quantum mechanical
phenomenon found in certain types of radioactive decay. When a
particle "tunnels," it effectively escapes a barrier that requires
more energy than it could inherently have, creating a sudden surge of
energy that temporarily disrupts conservation. It is as if a 10
horse-power motor put out 11 horse-power out of nowhere. The
application of this possibility to dualistic mental causation is
tempting: if the non-physical desire to raise one's arm disrupts the
overall energy balance when it causes one's arm to go up, the mental
event "tunnels" to our brain, thereby explaining the disruption of the
sum total of energy. We certainly cannot rule out this scenario from
our armchairs, but this reply is problematic, for the same reason that
it was found problematic when claiming that the mind could be like
electrons in having indeterminate spatial location. Tunneling is found
only at the subatomic level and nowhere else in the natural world. We
do not find it in biology, geology, astronomy, or in any of the other
special sciences. Thus, there is no reason to expect the phenomenon of
tunneling in the realm of mental events.
3. Contemporary Problems of Mental Causation
a. Background to the Contemporary Problems of Mental Causation
The traditional problem of mental causation lies in the commitment to
substance dualism. The contemporary problem, on the other hand, lies
in its commitment to property dualism, along with other assumptions
concerning token physicalism, the causal efficacy of mental events
versus the causal relevance of mental properties, and conditions for
causal relevance.
i. Token Physicalism
Contemporary approaches to the mind typically work within the
framework of physicalism, the view that everything that exists in
space-time is exclusively physical or constituted by the physical. The
optimal way of formulating the doctrine of physicalism is itself a
substantive issue (for comprehensive discussions, see Poland 1994,
Gillett and Loewer 2001, Melnyk 2003, Kim 2005), but the version that
most philosophers work with, or react to, in the mental causation
literature, is token physicalism (see Donald Davidson 1970). According
to token physicalism, each mental event is a particular (also called a
token), which is numerically identical with a physical particular;
this means that a mental event is an occurrence of an event in the
brain or of some other suitably complex physical medium. The converse,
on the other hand is not necessarily true, since there are physical
events that are not mental, such as tsunamis, apples falling to the
ground, magnets attracting iron filings, and so on.
We can illustrate the concept of token identity this way. Say that
Alice sneezes in such a way that the sneezing event was both a loud
noise a as well as an emission of a virus b. If the loud noise was
indeed one and the same event as the emission of the virus, then we
can say that a is token identical with b. The token identity of a
mental event and a physical event conforms to this idea: some mental
occurrence was one and the same event as a physical occurrence. On
Davidson's view, an event is a mental event m just in case it has a
mental property M (or it is describable in terms of mental
predicates); similarly for the relevant aspects of physical events. To
say, then, that a mental event m is token identical with a physical
event p is to say that m and p are just one and the same thing, one
event having both M and P.
Token physicalism it is to be carefully distinguished from what is
known as type physicalism, the view that each mental property M is
identical with, or reducible to, a physical property P. Particulars
are unrepeatable (that is, they are bound to a unique spatio-temporal
region) whereas types are repeatable (that is, they can show up in
different things and at different times). The idea behind type
physicalism can be illustrated this way. The property roundness (call
it "R") and the property circularity ("C") are both types, as they are
repeatable. As it happens, they are one and the same type, which means
that any particular having R necessarily has C. The difference between
token physicalism and type physicalism is basically this: whereas
token physicalism only entails that every particular thing having a
mental property also has some physical property or other, type
physicalism entails that for each mental property, there is a physical
property with which that mental property is identical.
The advantage of token physicalism is that it allows a mental event to
enter into causal transactions in a way that does not violate the
spatial location constraint upon causes, and therefore, does not face
the Problem of Spatial Location: physical events have spatial
location, so if m and p are token identical, then m has whatever
spatial location p has. Nor does it run afoul of the Problem of
Conservation: m just is p (and thus not distinct from p), so m's
causal efficacy does not add anything extra over and above the causal
efficacy of the event p.
ii. The Causal Efficacy of Events versus the Causal Relevance of Properties
Nonetheless, token physicalism still faces problems accounting for
mental causation. While mental events are one thing, the mental
properties in virtue of which those events are efficacious are
another; for a single event can have many properties, but only some of
them may be involved in bringing about an effect. Here is an example
of this. Suppose one steps on a banana peel and falls smack down to
the ground. The banana peel has many properties: its slipperiness and
its yellowness, for instance. But, surely the causally relevant
property was the slipperiness of the peel, not the color of the peel,
for had the peel not been slippery, the falling would not have
occurred (all things being equal), but the falling still would have
occurred even if the peel were a different color. To track this
distinction, let us use the term "efficacy" for events and "relevance"
for the properties of events.
The troubling idea, then, is that while a mental event may be causally
efficacious insofar as it is an event, only its physical properties,
and not its mental ones, are causally relevant for bringing about the
effect. An example of this is the following. Suppose Alice sneezes,
causing Bob to catch her cold. Suppose also that the sneezing event
was a loud noise as well as an emission of a virus. Then, while it is
true to say that the loud noise caused Bob's cold, as the loud noise
is the same event as the emission of the virus, surely it was only the
event's being an emission of a virus that was causally relevant to the
onset of Bob's illness. Under token physicalism, the worry is that
mental properties are like the property of being a loud noise –
completely irrelevant to bringing about the effect. This is the worry
that drives the contemporary problems of mental causation, which are
manifest in the problem of anomalism, the problem of externalism, and
the problem of exclusion. But before introducing these problems, it
will be helpful to lay out a rough account of what it means for a
property to be causally relevant or irrelevant.
iii. A Test for Causal Relevance
What test can we use to determine whether a property is causally
relevant or not? This is a different question from the question of
what it takes for a property to pass that test. Here, we just want to
lay out the test. Let us be clear that properties are causally
relevant to something or other, typically, to the instantiation of
other properties. Causal relevance is thus a 4-place relation where
the relata consist of the cause event c, the effect event e, and
properties F of c and G of e, wherein c causes e to instantiate G in
virtue of the fact that c has F.
To gauge whether properties are causally relevant or irrelevant,
philosophers appeal to the following conditions or counterfactuals:
Property F is causally relevant to property G only if:
Suppose F and G occurred; then if F had not occurred, then G would not
have occurred;
Suppose F and G had not occurred; then if F had occurred, then G would
have occurred;
There is no H such that had H occurred without F, G would not have
occurred, or had F occurred without H, G would still have occurred.
Conditions (1) – (3) convey the idea that G's occurrence is contingent
upon F's occurrence. More specifically, (1) says that F's occurrence
is necessary for G: G doesn't or can't occur unless F occurs. (2) says
that F's occurrence necessitates G: F guarantees G's occurrence.
Finally, (3) says that F is not a mere spurious cause of G: F does not
merely accompany the property H that happens to be the one that's
doing the real causal work. Failure to satisfy any of the three
conditions would indicate that the candidate property is not causally
relevant.
It is important to appreciate that these conditions are only to test
for whether a property is causally relevant. As it was said earlier,
they do not answer the question of what it takes for a property to
pass that test. One way to put this point is to distinguish between
the truth conditions for a claim and the truth makers for the claim:
the truth makers of the claim describe the fact, mechanism, or
elements, in virtue of which the claim is true. Thus, they do not form
an analysis, certainly not a full analysis, as they are only necessary
conditions that may not be jointly sufficient. A genuine analysis
requires that one specify both necessary and sufficient conditions as
well as what it is in virtue of which these very conditions hold – the
truth-maker.
b. Three Contemporary Problems of Mental Causation
In contemporary discussions of mental causation, there are three
stumbling blocks for the satisfactions of the conditions for causal
relevance in the case of mental properties. These are: the problem of
anomalism, the problem of externalism, and the problem of exclusion.
i. Problem of Anomalism
The basic root of the problem of anomalism is the thesis of
psychophysical anomalism, the claim that there are no strict,
exceptionless, laws involving mental states. The problem has been
acknowledged by many philosophers, but its most explicit formulation
has been laid out by Kim (Kim 1989). On a widely received view about
causal relevance, a property is causally relevant only if it is
"nomically subsumed," that is, if it appears in a strict law. The
denial that mental properties can appear in laws of this kind
naturally threatens to render mental properties causally irrelevant.
The threat of epiphenomenalism posed by the problem of anomalism can
be formulated thus:
Nomic Subsumption: A property can be causally relevant only if it
appears in a law.
Anomalism: Mental properties do not appear in laws.
——————————————————
Epiphenomenalism: Mental properties cannot be causally relevant.
This problem of anomalism has its origin in Davidson's theory of
anomalous monism (Davidson 1970). The problem of anomalism has a bit
of an ironic history since the original intent of Davidson's anomalous
monism was to explain how mental causation is possible. Nonetheless, a
number of critics have argued that anomalous monism leads to
epiphenomenalism (Antony 1989, Kim 1989b, 1993c, LePore and Loewer
1987, McLaughlin 1989, 1993). Anomalous monism is made up of two
theses: first, that there are no laws connecting mental properties
with physical properties (this is the thesis called "psychophysical
anomalism"), and second, that every mental event is token-identical
with a physical event, and thus causally efficacious insofar as the
physical event with which it is identical is causally efficacious. It
is the result of the attempt to render consistent the following
seemingly inconsistent set of statements:
Principle of Causal Interaction: at least some mental events interact
causally with physical events.
Principle of Nomic Subsumption: events related as cause and effect
fall under strict deterministic laws.
Principle of the Anomalism of the Mental: there are no strict
deterministic laws on the basis of which mental events can be
predicted and explained.
Each of these principles is independently plausible. The Principle of
Causal Interaction is just the statement that mental causation occurs.
The Principle of Nomic Subsumption needs a bit more explanation. This
entry presents the most common reading of the principle. Suppose event
c is of type F (it has F as a property) and e is of type G. According
to this principle, F can be causally relevant to G only if there is a
law is to the effect that events of type F cause events of type G. For
instance, when a sudden sneeze causes a sleeping baby to awake, the
cause has the capacity to produce that effect because there is a
law-like generalization to the effect that noises above a certain
level cause sleep disturbances. Davidson (1993) has objected to this
construal of causation conflates causation with causal explanation. As
Davidson explains, causal explanations mention properties when
explaining a causal transaction, but statements reporting a causal
transaction do not. When it comes to causation, events cause other
events, according to Davidson, no matter how they are described – no
matter which properties we refer to when talk about the events. This
construal of causation has been roundly criticized (McLaughlin 1993).
The Principle of the Anomalism of the Mental states that there are no
laws involving mental states that are strict, strict in the sense that
they are exceptionless. A cursory look at the following
generalizations reasonably backs this up:
If an agent desires p and believes that doing q can bring about p,
then the agent will do q.
If an agent fears p, then the agent desires not-p.
If an agent wants p with all her heart, but discovers that not-p, then
the agent will be disappointed that not-p.
(A) – (C) represent a very small number of generalizations of folk
psychology, and while they do a good job of covering many cases, we
can easily imagine circumstances under which they would be false.
According to the Principle of the Anomalism of the Mental, this is
true of all generalizations of folk psychology.
While independently plausible, the principles together appear to
generate an inconsistency: if there are no laws couched in mental
terms, as is maintained by the Anomalism of the Mental, but laws are
necessary for causal interaction, which is stated by the Principle of
Nomic Subsumption, then it follows that mental events have no causal
powers, contrary to the first statement, the Principle of Causal
Interaction. Davidson resolves this inconsistency with an appeal to
token physicalism (explained above), where mental events can be
causally efficacious, thanks to their token-identity with causally
efficacious physical events.
Token physicalism, however, is not sufficient for supporting the
causal relevance of mental properties – for securing the idea that a
mental event caused a physical event in virtue of its having a mental
property. In fact, the very argument Davidson gives for token
physicalism through his argument for anomalous monism, has been
interpreted to lead to the causal irrelevance of mental properties.
The interpretation goes as follows: if event c can cause event e only
if there is a strict law covering c and e, and the only laws that are
strict are physical laws (laws relating physical properties) it
follows that c causes e because of c's physical properties; indeed, c
cannot cause e in virtue of its mental property, because mental
properties cannot come together in a law. In short, if strict laws are
necessary for securing the causal relevance of properties, but there
are no strict laws involving mental properties, then mental properties
cannot be relevant on this view.
1. The Appeal to Ceteris Paribus Laws
There are two attempts to solve the problem of anomalism. The first,
advanced by Jerry Fodor, denies that strict laws are necessary for
causal relevance (Fodor 1989, 1991b). While they may be sufficient for
supporting the causal relevance of a property appearing in them, they
are not necessary. Non-strict laws are also capable of supporting the
causal relevance of a property. Thus, the non-strict generalizations
of folk psychology can be recruited to ground the causal relevance of
mental properties after all. This approach offers the following
sufficient condition for the causal relevance of a property:
Ceteris Paribus Causal Relevance: A (mental) property M of an event c
is causally relevant to a (physical) property P of event e if there is
a strict causal law connecting M with P or a non-strict law connecting
M with P.
Problems: This solution faces three objections. The first is that the
ceteris paribus clauses may threaten to render any "law" vacuous that
is so modified, and so strict laws might be what we need after all
(Schiffer 1991, Fodor 1991b). The second is that mental properties
just may not be the kinds of properties that can appear in laws,
strict or otherwise. There are two considerations that have been
availed in support of this skepticism. The first is based upon claims
that normative relations constitutively constrain the distribution of
mental properties, a pattern then cannot also be constrained by laws
(Davidson 1970, 1974; McDowell 1984; Kim 1985). The second is based
upon what is called the "simulation theory of folk psychology," the
idea that mental states are attributed to an agent by placing one's
self in the agent's situation, a process that does not require the
existence of mental laws (see Heal 1995, Gordon 1995, and Goldman
1995). The third objection is that even if mental properties can
appear in laws, they face the problem of exclusion, which briefly is
the problem that the physical properties of an event pre-empt its
mental properties, given the generality of physics – that the physical
domain is completely self-sufficient in bringing about all causal
transactions – and the exclusion principle, which states that a
causally sufficient property of an event excludes the causal relevance
of other properties of the event.
2. The Appeal to Counterfactuals
The second solution to the problem of anomalism has been pursued by
LePore and Loewer 1987, 1989, and Horgan 1989. Like the appeal to
ceteris paribus laws, this approach also denies that strict laws are
necessary for grounding the causal relevance of a property. But
instead of appealing to non-strict laws, this solution appeals to
counterfactual dependencies involving mental properties.
On this view, a mental property can be causally relevant if its
non-occurrence means that the effect also would not have occurred. The
basic idea is this. Suppose we want to know whether one's belief that
there is water in the glass was causally relevant to the motion of
reaching out for the glass. The belief is causally relevant if the
motion of reaching out would not have occurred if the belief had not
occurred; this is just to say that the effect is counterfactually
dependent upon its cause. Here is the account given by LePore and
Loewer 1987:
Counterfactual Causal Relevance: Property M of event c is causally
relevant to property P of event e if:
c causes e,
c has M and e has P,
if c did not have M, then e would not have had P,
M and P are metaphysically independent.
The appeal to causation in (i) does not render this partial analysis
circular, since the analysis is for causal relevance, not causation
per se. Condition (ii) highlights the role of properties in causal
transactions. Condition (iii) states the counterfactual relation
between the properties that allegedly suffices for one's being
causally relevant to the other. Condition (iv) comes from the Humean
view that logically or metaphysically connected properties cannot
stand in a causal relation, and so (iv) is to ensure that M and P are
candidates for causal relevance.
Problem: The main problem with this solution is that the mere holding
of the relevant counterfactuals is not sufficient for causal relevance
(Braun 1995; McLaughlin 1989, p. 124; Kim 2006, pp. 189 – 194). Fires
give off both heat and smoke. Now, if fire is placed near a piece of
wax, the wax melts because of the heat, not the smoke, given off by
the fire. That is, the smoke is not causally relevant to melting the
wax. However, there is a counterfactual dependency of the melting upon
the smoke because smoke, as much as heat, reliably occurs when there
is fire. Thus, there are spurious counterfactual dependencies, and for
all we know, the counterfactual dependency of bodily motion upon
mental properties is as spurious as the dependency of melting upon
smoke. The lesson is this: the counterfactual dependency of G upon F
does not suffice for F's causal relevance to G. In addition, the
counterfactual approach also faces the problem of exclusion.
ii. Problem of Externalism
Externalism is a thesis about semantic content; according to the
thesis, we must take into consideration facts about the physical
environment, as well as the linguistic norms of one's surrounding
community, when individuating contentful mental states (the classic
sources are Putnam 1975, Burge 1979). This is a thesis that affects
intentional states (also called propositional attitudes), the states
that have representational contents, rather than phenomenal states,
the states that have a "what-it-is-like" quality to them. The problem
generated by externalism for the causal relevance of intentional
states is that it renders the content of the intentional state
extrinsic (see Fodor 1987, pp. 27 – 54; McGinn 1989, p. 118).
Causation, as we intuitively understand it, however, involves only the
intrinsic features of objects and events. Consequently, externalist
ways of individuating intentional content make them unsuitable for
causal involvement.
While it is not easy to pin down exactly the distinction between
intrinsic and extrinsic properties, we can get at the general idea
with the following example. Take an individual who is 6 feet tall.
Being 6 feet tall does not depend upon facts in its environment;
whether or not the individual is tall or short, on the other, does so
depend, since whether the individual is tall, say, will depend upon
whether she is among small children. Properties that do not depend
upon the environment are intrinsic; those that do are extrinsic.
To appreciate how causation only involves intrinsic properties,
consider the following scenario. One puts a very convincing
counterfeit dollar into a soda machine, successfully allowing you to
get a soda. It is natural to assume that only the intrinsic features
of the dollar bill – its size, design, texture – were causally
relevant to the transaction, not the fact that the dollar is genuine
or counterfeit, which are extrinsic features, as they involve a
relation to certain facts, namely, where it was originally produced –
at the U.S. mint or in one's garage. These latter properties are
extrinsic features of the dollar and the example illustrates their
causal irrelevance.
Now, when we individuate the contents of a mental state (for those
mental states that have intentional contents) according to standards
of externalism, the content is rendered extrinsic. The classic example
is found in Putnam (1975). Consider the very familiar term, "water."
The meaning of our term "water" is H2O. Now imagine a world, "Twin
Earth," that is just like ours except that the stuff the Twin
Earthlings call "water" happens to be a different chemical compound,
which we can just label "XYZ." As Putnam argues, the meaning of
"water" differs between the two worlds, even if Earthlings and Twin
Earthlings make all the same associations with the stuff both call
"water" – that it is stuff we drink, that it falls from the sky, fills
the lakes and rivers, is the universal solvent, and so on. In spite of
these identical associations, the word "water" is homonymous, meaning
H2O when uttered by an Earthling, but XYZ when uttered by a Twin
Earthling. This point about the meaning of the word transfers over to
the content of our thoughts: when an Earthling and Twin-Earthling are
entertaining thoughts about what both call "water," they are thinking
about different things.
This little scenario demonstrates how content – the meaning of the
intentional state – under externalism, fails to supervene upon the
individual's internal properties, and is therefore extrinsic to the
agent's body. The threat of epiphenomenalism can be formulated thus:
Local Causation: A property F of an event c is causally relevant to
property G of event e only if F is an intrinsic property of c.
Externalism: Intentional properties are not intrinsic properties of
mental events.
——————————————————————-
Epiphenomenalism: Intentional properties are not causally relevant.
The problem is that extrinsic properties generally, as a rule, fail
the test for causal relevance. As the test specified, a property can
be causally relevant only if (among other things) had it failed to
occur, the effect would not have occurred; and had it succeeded in
occurring, then the effect would have occurred. But this pattern of
counterfactual dependencies is not satisfied by externally
individuated contents. Suppose you reach out for a refreshing glass of
water because you believe that there is water in the glass. In order
for that belief to be causally relevant, its absence must result in
the absence of the reaching motion. But this isn't what happens when
we individuate content externally: the physical identical twin who is
thinking about XYZ, not water proper, does exactly the same thing.
Different thoughts do not manifest in different behaviors. As a
result, content bearing mental states are not causally relevant to
behavior.
1. The Appeal to Narrow Content (Internalism)
Solutions to the argument from externalism pursue one of two
strategies; one is to deny the thesis of externalism, premise (2) (see
Fodor 1980), and the other is to deny the thesis of local causation,
premise (1) (see Burge 1995). Let us begin with the denial of
externalism. The strategy here is to appeal to "narrow content."
Narrow content is the content that intrinsic twins have in common;
narrow content, by stipulation, supervenes upon the intrinsic
properties of an individual (Fodor 1991). (Think about the purely
intrinsic features of the dollar bill – features that would be equally
shared by a genuine bill and a counterfeit. The intrinsic features are
their "narrow content.") Unlike broad content, which is individuated
in terms of the external, historical circumstances surrounding the
uses of a term, narrow content is what supervenes upon the internal
properties of the individuals, and is thus shared by you and your
Twin-Earthly counterpart. Narrow content is the content one entertains
under the Cartesian account of mental representation: as you entertain
a thought of water, the content of that thought never "reaches out"
beyond your head. Intentional properties, then, individuated narrowly,
will be just as suited to causing behavior as any other internal
properties of a person.
Problem: The appeal to narrow content certainly gets around the
problem of causal irrelevance that faces broad content, but the notion
of narrow content is highly contentious. Some have even argued that
the notion is incoherent (see Adams et al. 1990). Consider again the
counterfeit dollar. Surely we do not value it because just because it
shares the same intrinsic features as the genuine article; the
difference between the genuine bill and the counterfeit makes all the
difference between the two. The relevance of the extrinsic is
prevalent. Take a different case – the case of gold. When one wants to
purchase a gold ring, one has in mind the metal with a certain
molecular structure, not some alloy that looks like gold but isn't
gold. Our attributive practices honor this attention to the broad way
of individuating content. When we refer to what people are thinking
about, what the contents of their intentional states are, we intend to
refer to the externalistically individuated contents of their mental
states.
2. The Appeal to Wide Causation
The denial of the local causation thesis is the denial of the claim
that only intrinsic properties of a cause can be causally relevant.
The idea is that there can be "broad causation" (see Burge 1989, Yablo
1997). This view requires a little stage setting. On this approach,
there is the causation of bodily motion by neural properties, on the
one hand, and then there is the causation of intentionally
characterized action by broadly individuated mental content. Take, for
instance, one's waving to a friend: by doing this, one performs the
action of greeting a friend, but one also engages in a purely bodily
process that engages one's bones and muscles. On this solution to the
problem of externalism, we have two causal processes – one that
pertains to the proximal visual stimuli that result in the bodily
movement – this would be "narrow causation" – and a different one that
pertains to the appearance of the friend, resulting in the action of
greeting – this would be "broad causation." The friend one has in
mind, of course, is the individual with whom one has had actual causal
contact, not some physically similar but distinct individual (for
example, an extraordinary gathering of molecular components that
result in an object that looks like the friend). And to the extent
that one has in mind the friend and not the freak doppelganger, one's
thought has broad content, which, on this approach, causally results
in the action.
Problem: The very concept of wide causation goes against our ordinary
intuitions about what causation involves. According to our ordinary
intuitions, we assume that causes and their effects must be in spatial
contact with each other or mediated by things that spatially link them
together – that there is no action at a distance. But wide causation
asks us to believe exactly this – that things are caused by situations
that have no physical contact with them. It would make no difference,
it seems, that it was the friend and not the doppelganger that
motivated one to wave. For this reason, wide causation is not an easy
solution (but see Yablo 1997 for a defense).
iii. Problem of Exclusion
It seems undeniable that mental states bring about behavior: it is
because you wanted to catch the Frisbee that you sprung up to catch it
– if you didn't want to catch it, your body wouldn't have moved the
way it did. It is also undeniable that the brain, or more
specifically, our neurophysiological system, is fully sufficient to
bring about all bodily motion. There are many reasons, however, to
think that mental states are not just mere states of the brain. But if
this is the case, then it's not clear what causal role mental states
would have given that their neural correlates are fully equipped to
perform all the causal work. Brain states, in other words, seem to
make the mental states superfluous and therefore irrelevant.
The problem of exclusion can be laid out as follows (this formulation
comes from Yablo 1992, pp. 247 – 248):
Exclusion: If a property F is causally sufficient for a property G,
then no property distinct from F is causally relevant to G, barring
overdetermination.
Closure: For every physical property P, there is a physical property
P* that is causally sufficient for P.
Dualism: For every mental property M, M is distinct from P*.
—————————————————————–
Epiphenomenalism: For every physical property P, there is no mental
property M that is causally sufficient for P.
The exclusion problem does not subscribe to any particular views about
the nature of causation and its relationship to laws. Its standard
formulations just invoke certain widely held physicalist principle
that the physical world is causally closed and comprehensive. The
simple reference to this principle, along with the assumption that
mental properties are not reducible to physical properties, are all
that's needed to set the argument in motion. In addition, its
epiphenomenalist conclusion applies not just to mental properties, but
to any special science property that is not strictly reducible to a
physical property. The argument casts a wide net (Kim 1989b, 1992,
1993b).
The following is a menu of the main strategies that have been pursued
for solving the exclusion problem (see Kim 1989a, 1990 for a
discussion of some of these options):
Reduction Strategy: For every mental property M, there is some
physical property P with which M can be reductively identified.
Supervenience Strategy: Mental properties supervene upon physical
properties, and supervening properties can be causally relevant if
their base properties are causally relevant.
Realization Strategy: Mental properties are realized by physical
properties, and mental properties are causally relevant if their
realizing base properties are causally relevant.
Dual Explanandum Strategy: There are different ways to explain how M
and P are causally relevant.
1. Reduction Strategy
There have been several proposals along these lines, none free of
problems. On one approach, each mental property M is reductively
identified with a physical property P. This is the view known as the
Identity Theory of Mind, which was introduced by U.T. Place in 1956
and by J.J.C. Smart in 1956. The main problem with this approach is
the multiple realizability of mental properties (Fodor 1975, 1980a,
1980b; Putnam 1960). According to this thesis, there are many
different physical properties P1, P2, …, Pn, each of whose
instantiation can suffice for the instantiation of its corresponding
mental property M. If P1 and P2 are distinct realizers of M, then M
cannot be identified with both P1 and P2. This makes sense if we think
of the following example. Suppose Tom and Max are not the same height.
Tom is, however, of the same height as Sally. If this is the case,
then Sally cannot be the same height as both Tom and Max. The upshot
is that no multiply realizable mental property is identifiable with,
and hence, reducible to, a physical property.
On a different approach, which attempts to accommodate the multiple
realizability of mental properties, known as disjunctive reduction, M
is reduced to the disjunction of all the physical property
realizations (P1 or P2 or … Pn), such that generalizations of the form
M if and only if (P1 or P2 or … Pn)
hold as a matter of law. The main problem with this approach is that
it is committed to disjunctive properties whose disjuncts have nothing
in common at the physical level. This makes the disjunct unsuitable
for appearing in laws (Armstrong 1978, 1983).
On another approach, which also attempts to accommodate the multiple
realizability of mental properties, known as species-specific or
"local" reduction, M is reduced to a single physical kind P relative
to some species S, giving us laws of the form
S only if (M if and only if P).
The problem with this approach is that it compromises the idea that a
mental property is species-invariant – that a pain, say, in a human,
is the same mental property as a pain in an octopus, a Martian, or a
computer (see Pereboom and Kornblith 1991).
On another approach yet, it is not mental properties that are reduced
per se, but rather their instances. Property instances are known as
tropes. The idea here is that we can reduce an instance of a mental
property – a mental trope – with a physical trope (see Macdonald and
Macdonald 1986, Robb 1997). Tropes and properties differ in an
important way: while a property is repeatable – whiteness, for
instance, is one and the same entity that can appear in a multitude of
different objects – a trope is not repeatable. The whiteness of a
piece of paper, according to a trope theorist, is a unique instance of
that particular shade of whiteness. The trope strategy is to identify
a mental trope with a physical trope. The idea is that since physical
tropes are causally relevant, identifying a mental trope with a
physical trope secures its relevance as well. However, the trope
approach is only as good as the argument for the claim that a mental
trope is indeed identical with a physical trope. More problematically,
there is a concern that we can ask even of tropes whether a trope is
causally relevant in virtue of its being a mental trope as opposed to
its being a physical trope. That is, the same underlying
epiphenomenalist implications that plague Davidson's token physicalism
may be raised for the trope approach.
2. Supervenience Strategy
The most developed account under this option is given by Yablo (Yablo
1993). As scarlet and crimson are each determinates of the
determinable red, M and P are related as determinable to determinate.
Determinables supervene upon their determinates, and do so with
metaphysical necessity. That is, there is no world in which the
determinable does not appear if one of its determinates is
instantiated.
Yablo argues that the virtue of this approach is that it does not pit
M and P against each other as competitors, "since a determinate cannot
pre-empt its own determinable." (Yablo 1992, p. 250) So just as the
determinate, crimson, does not causally pre-empt its determinable,
red, when we all press our brake pedals at a traffic light that's just
turned crimson, no physical property P pre-empts the determinable
mental property M when an agent performs an action.
Problem: While this approach has intuitive appeal, it is not clear
that a determinate does not causally exclude the determinable.
Consider the determinable, being colored, which has as its
determinates, redness, yellowness, and greenness. The determinable is
certainly present when any of these properties is present, but
different effects ensue upon the instantiation of these properties.
If, for instance, a driver detected a green light, she would have
continued driving, but if she had detected a red light, she would have
brought her car to a full stop. It appears that the determinable,
being colored, was not relevant to either outcome since it was present
with opposite outcomes.
3. Realization Strategy
Shoemaker 2001 appeals to the idea of realization, as it is implicated
in the theory of functionalism and its attendant notion of multiple
realizability, as well as a certain account of the nature of
properties in general according to which properties are causal powers.
(An earlier, but less developed, strategy along these lines is
suggested by Kim 1993a.) On Shoemaker's view, both realized and
realizing properties have causal powers, but the causal powers of the
realized (mental) property form a subset of the causal powers of the
realizing (physical) property. The benefit of this view is that a
subset of causal powers cannot be "excluded" or trumped or overridden
by the superset, as the subset is just a part of the superset. If a
10-pound brick crushes a statue, then the part of the brick that
weighs 8 pounds will certainly be involved in the effect, and not
trumped by the 10-pound brick of which it constitutes a part.
Problem: Gillett and Rives 2005 argue that this account of realization
does not safeguard mental properties from causal exclusion by their
realizing physical properties. The idea is that if physical properties
are fundamental and do all the causal work, then no property realized
by a physical property does further causal work over and above the
work done by the physical realizer. Claiming that the causal powers of
a realized property form a subset of its realizing base does nothing
to help the realized property enter into the causal work-force.
4. Dual Explanandum Strategy
Steuber 2005 argues that causation itself cannot be separated from the
explanatory schemes in which they are expressed. Since psychological
explanations accomplish one thing, while physical or neurobiological
explanations accomplish another, the causal relations they track are
themselves different relations, and thus not in competition with one
another, as there is no one explanandum for them to both explain.
A strategy of this kind has been developed by Dretske (Dretske 1988,
1989). Dretske distinguishes between a triggering cause and a
structuring cause, each cause satisfying two different types of
explanatory interests. Schematically speaking, if we want to know how
a particular behavior came about, we seek to isolate its triggering
cause; such a cause lies within the purview of neurophysiological
explanations. But if we want to know why an agent performed some
particular behavior and not some other type of behavior, we are
seeking its structuring cause, and these are the kinds of causes that
psychological explanations are particularly well suited to picking
out.
Dretske illustrates the difference between a triggering cause and a
structuring cause, as well as how these causes are related to each
other, with the homely thermostat. A thermostat is designed to turn on
the furnace when it registers a certain temperature. The triggering
cause of the switching of the furnace was the cool temperature of the
room, but the wiring that connects the thermostat to the furnace, for
instance, is the structuring cause of the very same effect. The
structuring cause, in short, is the set of pre-existing background
conditions that make it possible for the triggering cause to exert its
particular effect. Most designed artifacts possess this sort of
bi-level causal structure, and so do we. Just as a thermostat
possesses an internal sensor calibrated to turn on the furnace when
the sensor registers a certain temperature, we possess an internal
representational system coordinated with our motor system to trigger
the appropriate bodily movements when our internal states represent
the presence of certain objects in the environment. Which connections
are forged between a given representational state and its
corresponding bodily motion, and how these connections are made, is
largely a matter of the agent's learning history. Learning is the
process during which the representational content is "recruited" as a
cause of the behavior; it structures, so to speak, the relevant links
between the agent's representational states and her motor output.
Problem: Kim 1989a, however, has objected that if we insist that a bit
of behavior has some causal origin that is irreducibly mental, and
therefore non-physical, then this effectively violates the causal
closure of the physical domain. If not, then we are back to the very
problem of exclusion that Dretske's distinction was designed to avoid.
4. Conclusion: Where We are Now
Philosophers are still busy at work trying to make sense of mental
causation. Many criticize the assumptions on which the alleged
problems of mental causation are predicated, particularly Kim's
formulation of the exclusion problem (Bennett 2003, Menzies 2003,
Raymont 2003). Others enjoin us to accept those very positions that
have been cast aside as unavailable, such as type physicalism (Hill
1991), or down-right implausible, such as epiphenomenalism (Bieri
1992, Chalmers 1996, ch.5).
Some have even questioned whether we really have a problem concerning
mental causation (Baker 1993, Burge 1993). Baker 1993 has argued that
once the principles of physicalism are accepted, not only are we
saddled with the exclusion problem, the problem is absolutely
unsolvable. But, Baker continues, the wide-scale epiphenomenalism that
would ensue were we to take the principles of physicalism seriously is
tantamount to a reductio ad absurdum of the principles themselves, so
we must reject the principles, in which case the exclusion problem
dissolves of itself. Baker quite radically proposes that we reject the
causal closure thesis if we wish to hold onto the possibility of
mental causation – indeed, if we want to hold onto the possibility of
macro-causation generally – a possibility that Baker claims is well
testified by the successes of our explanatory practices.
Antony 1991 as well as Kim 1993, however, have argued that the problem
of mental causation is the problem of explaining how and why there is
this explanatory success when it comes to explaining behavior in
mental terms. That is, the problem does not go away by pointing out
that our mentalistic explanations perform quite well. The puzzle is
how they explain so well, given that the metaphysics all point to the
causal irrelevance of the mental.
There are, to be sure, other novel solutions in the making. But the
ideal solution, given the multiplicity of the problems surrounding
mental causation – the problem of anomalism, the problem of
externalism, and the problem of exclusion – is one that can solve all
the problems together, perhaps not with just one account that
simultaneously solves all three, but maybe a patchwork account, each
of whose components mutually support the others.
5. References and Further Reading
Adams, F., David Drebushenko, Gary Fuller, and Robert Stecker, (1990),
"Narrow Content: Fodor's Folly," Mind and Language, 5: 213-29.
Anscombe, E. and Geach, P. (1954), Descartes: Philosophical Writings,
Indianapolis: Bobbs-Merrill Company.
Antony, L. (1989), "Anomalous Monism and the Problem of Explanatory
Force," The Philosophical Review 98: 153-87.
Antony, L. (1991), "The Causal Relevance of the Mental: More on the
Mattering of Minds," Mind and Language, 6: 295-327.
Armstrong, D., (1978), Universals and Scientific Realism, Vol. I, A
Theory of Universals, Vol. II, Cambridge: Cambridge University Press.
Armstrong, D, (1983), What is a Law of Nature? Cambridge: Cambridge
University Press.
Aronson, J. (1971), "On the Grammar of 'Cause'," Synthese 22: 414-430.
Baker, L. (1993), "Metaphysics and Mental Causation," in Heil and Mele
(1993): 75-95.
Bieri, P. (1992), "Trying out epiphenomenalism" Erkenntnis 36, 283-309.
Braun, D. (1995) "Causally Relevant Properties." Philosophical
Perspectives 9: 447-75.
Burge, T. (1986), "Individualism and Psychology," Philosophical
Review, 95: 3-46.
Burge, T. (1993), "Mind-Body Causation and Explanatory Practice," in
Heil and Mele (1993): 97-120.
Burge, T. (1989), "Individuation and Causation in Psychology," Pacific
Philosophical Quarterly, 70: 303-322.
Byrne, A., 1993, The Emergent Mind, Ph.D. Dissertation. Princeton.
Chalmers, D. (1996), The Conscious Mind: In Search of a Fundamental
Theory, Oxford: Oxford University Press.
Child, W. (1994). "Anomalism, uncodifiability, and psychophysical
relations." Philosophical Review, 102: 215-245.
Churchland, P. (1981), "Eliminativist Materialism and the
Propositional Attitudes," in Journal of Philosophy 78: 67-90.
Cottingham, J., Stoothoff, R., Murdoch, D., eds., (1984), The
Philosophical Writings of Descartes, vol. 2, Cambridge: Cambridge
University Press
Davidson, D. (1970), "Mental Events," reprinted in Davidson (1980): 207-227.
Davidson, D. (1974), "Psychology as Philosophy," reprinted in Davidson
(1980): 229-44.
Davidson, D. (1980), Essays on Actions and Events, Oxford: Clarendon Press.
Davidson, D. (1993), "Thinking Causes," reprinted in Heil and Mele (1993): 3-17.
Davies, M., and Stone, T., (1995), Folk Psychology: The Theory of Mind
Debate, Oxford: Blackwell Press.
Dowe, P. (2000), Physical Causation, Cambridge: Cambridge University Press.
Dretske, F. (1989), "Reasons and Causes," Philosophical Perspectives, 3: 1-15.
Dretske, F. (1993), "Mental Events as Structuring Causes of Behavior,"
in Heil and Mele (1993): 121-136.
Fair, D. (1979), "Causation and the Flow of Energy," Erkenntnis 14, 219-250.
Fodor, J. (1975), The Language of Thought. New York: Thomas Crowell.
Fodor, J. (1980), Representations: Philosophical Essays on the
Foundations of Cognitive Science, Cambridge, MA: MIT Press.
Fodor, J. 1980b), "Methodological Solipsism Considered as a Research
Strategy in Cognitive Science," The Behavioral and Brain Sciences 3:
63-109. Also reprinted in Fodor (1980).
Fodor, J. (1980a), "Special Sciences," in Fodor (1980).
Fodor, J. (1989), "Making Mind Matter More," Philosophical Topics, 17: 59-80.
Fodor, J. (1987), Psychosemantics, Cambridge, MA: MIT Press.
Fodor, J., (1991a), "A Modal Argument for Narrow Content," Journal of
Philosophy 88: 5-26.
Fodor, J. (1991b), "You Can Fool Some of the People All the Time,
Everything Else Being Equal; Hedged Laws and Psychological
Explanations," Mind, 100: 19-33.
Gillett, C. (2002), "The Dimensions of Realization: A Critique of the
Standard View," Analysis, 62: 316-323.
Gillett, Carl, and Barry Loewer (eds.). (2001) Physicalism and Its
Discontents, Cambridge: Cambridge University Press.
Gillett, C. and Rives, Bradley (2005), "The Non-Existence of
Determinables: Or, a World of Absolute Determinates as a Default
Hypothesis," Nous, 39, pp. 483-504.
Goldman, A. (1995), "Interpretation Psychologized," in M. Davies and
T. Stone, (eds.) (1995).
Gordon, R., (1995), "The Simulation Theory: Objections and
Misconceptions," in M. Davies and T. Stone, (eds.) (1995).
Heal, J. (1995), "Replication and Functionalism," in M. Davies and T.
Stone, (eds.) (1995).
Heil, J. and Mele, A. (1993) (eds.), Mental Causation, Oxford: Clarendon Press.
Hellman, G., and Thompson, F. (1975), "Physicalism: Ontology,
Determination, Reduction," Journal of Philosophy, 72: 551-64.
Hill, C. (1991). Sensations: A Defense of Type Materialism. Cambridge:
Cambridge University Press.
Horgan, T. (1989), "Mental Quausation," Philosophical Perspectives 3: 47-76.
Jackson, F. (1982), "Epiphenomenal Qualia," Philosophical Quarterly 32: 127-36.
Kim, J. (1984a), "Concepts of Supervenience," Philosophy and
Phenomenological Research, 65: 153-76.
Kim, J. (1984b), "Epiphenomenal and Supervenient Causation," Midwest
Studies in Philosophy, 4: 31-49.
Kim, J. (1985), "Psychophysical Laws," in LePore and McLaughlin (1985): 369-86.
Kim, J. (1989a), "Mechanism, Purpose and Explanatory Exclusion,"
Philosophical Perspectives, 3: 77-108.
Kim, J. (1989b), "The Myth of Nonreductive Materialism," Proceedings
of the American Philosophical Association, 63: 31-47, reprinted in Kim
(1993).
Kim, J. (1990), "Explanatory Exclusion and the Problem of Mental
Causation," in Villanueva (1990): 36-56.
Kim, J. (1993), Supervenience and Mind, Cambridge: Cambridge University Press.
Kim, J. (1993a), "Multiple Realization and the Metaphysics of
Reduction," in Kim (1993): 309-35.
Kim, J. (1993b), "Postscripts on Mental Causation," in Kim (1993): 358-67.
Kim, J. (1993c), "The Non-Reductivist's Trouble With Mental
Causation," in Heil and Mele (1993): 189-210.
Kim, J. (2005), Physicalism, or Something Near Enough. Princeton
University Press.
Kim, J. (2006), Philosophy of Mind, 2nd edition, Cambridge MA: Westview Press.
Kripke, S. (1980), Naming and Necessity, Cambridge, MA: Harvard
University Press.
Kripke, S. (1982), Wittgenstein on Rule-Following and Private
Language, Cambridge, MA: Harvard University Press.
Leibniz, G.W. (1695), "New System of the Nature of Substances and
their Communication, and of the Union Which exists Between the Soul
and the Body," reprinted in G.W. Leibniz: Philosophical Texts, eds.
R.S. Woolhouse and R. Franks, (1998), Oxford: Oxford University Press,
143-152.
LePore, E., Lower, B. (1987), "Mind Matters," Journal of Philosophy, 84: 630-42.
LePore, E., Lower, B. (1989), "More on Making Mind Matter,"
Philosophical Topics, 17: 175-91.
LePore, E., McLaughlin, B. (1985) (eds.), Actions and Events:
Perspective on the Philosophy of Donald Davidson, Oxford: Basil
Blackwell.
Lewis, D. (1983), "New Work for a Theory of Universals?" Australasian
Journal of Philosophy, 61: 343-77.
Macdonald, C., Macdonald, G. (1986), "Mental Causes and Explanation of
Action," The Philosophical Quarterly, 36: 145-58.
Malebranche, N. (1958) Oeuvres complètes de Malebranche, A. Robinet,
ed., Paris: J. Vrin.
McDowell, J. (1984), "Functionalism and Anomalous Monism," in LePore
and McLaughlin (1985): 387-98.
McGinn, C. (1989), Mental Content, Oxford: Blackwell Press.
McLaughlin, B. (1989), "Type Epiphenomenalism, Type Dualism, and the
Causal Priority of the Physical," Philosophical Perspectives, 3:
109-35.
McLaughlin, B. (1993), "On Davidson's Response to the Charge of
Epiphenomenalism," in Heil and Mele (1993): 27-40.
McLaughlin, B. (1995), "Varieties of Supervenience," in E. Savellos
and Umit D. Yalcin, eds., (1995).
Melnyk, A. (2003), A Physicalist Manifesto: Thoroughly Modern
Materialism. Cambridge: Cambridge University Press.
Nagel, T. (1974), "What Is It Like to Be a Bat?," Philosophical Review
83: 435-50.
Poland, J. 1994. Physicalism: The Empirical Foundations. Oxford:
Oxford University Press.
Putnam, H. (1960), "Minds and Machines," in Mind, Language and
Reality: Philosophical Papers 2, Cambridge: Cambridge University
Press.
Putnam, H. (1979), Mind, Language and Reality: Philosophical Papers 2,
Cambridge: Cambridge University Press.
Putnam, H. (1975), "The Meaning of 'Meaning'," in Putnam (1979): 215-71.
Robb, D. (1997), "The Properties of Mental Causation," Philosophical
Quarterly 47: 178-94.
Robinet, A. (1958) (ed.) Oeuvres complètes de Malebranche, Paris: J. Vrin.
Salmon, W. (1994), "Causality Without Counterfactuals," Philosophy of
Science 61, 297-312.
Savellos, E., and Yalcin, U.D., (1995), Supervenience: New Essays,
Cambridge: Cambridge University Press.
Schiffer, S. (1991), "Ceteris Paribus Laws," Mind, 100: 1-17.
Shoemaker, Sydney. (2001), "Realization and Mental Causation," in
Gillett and Loewer (eds.), pp. 74-98.
Stoljar, D., 2001, "Two Conceptions of the Physical," Philosophy and
Phenomenological Research, 62: 253-81.
Stueber, K. (2005), "Mental Causation and the Paradoxes of
Explanation," Philosophical Studies 122: 243-77.
Woolhouse, R.S., and Franks, R. (1998) (eds.), G.W. Leibniz:
Philosophical Texts, eds. Oxford: Oxford University Press, 143-152.
Yablo, S. (1992), "Mental Causation," The Philosophical Review, 101: 245-280.
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