Functionalism

Functionalism is a theory about the nature of mental states. According
to functionalism, mental states are identified by what they do rather
than by what they are made of. This can be understood by thinking
about artifacts like mousetraps and keys. In particular, the original
motivation for functionalism comes from the helpful comparison of
minds with computers. But that is only an analogy. The main arguments
for functionalism depend on showing that it is superior to its primary
competitors: identity theory and behaviorism. Contrasted with
behaviorism, functionalism retains the traditional idea that mental
states are internal states of thinking creatures. Contrasted with
identity theory, functionalism introduces the idea that mental states
are multiply realized. Objectors to functionalism generally charge
that it classifies too many things as having mental states, or at
least more states than psychologists usually accept. The effectiveness
of the arguments for and against functionalism depends in part on the
particular variety in question, and whether it is a stronger or weaker
version of the theory. This article explains the core ideas behind
functionalism and surveys the primary arguments for and against
functionalism.

1. Functionalism Introduced

Functionalism is a theory about the nature of mental states. According
to functionalists, mental states are identified by what they do rather
than by what they are made of. Functionalism is the most familiar or
"received" view in among philosophers of mind and cognitive science.
2. The Core Idea

Consider, for example, mouse traps. Mouse traps are devices for
catching or killing mice. Mouse traps can be made of most any
material, and perhaps indefinitely or infinitely many designs could be
employed. The most familiar sort involves a wooden platform and a
metal strike bar that is driven by a coiled metal spring and can be
released by a trigger. But there are mouse traps designed with
adhesives, boxes, poisons, and so on. All that matters to something's
being a mouse trap, at the end of the day, is that it is capable of
catching or killing mice.

Contrast mouse traps with diamonds. Diamonds are valued for their
hardness, their optical properties, and their rarity in nature. But
not every hard, transparent, white, rare crystal is a diamond—the most
infamous alternative being cubic zirconia. Diamonds are carbon
crystals with specific molecular lattice structures. Being a diamond
is a matter of being a certain kind of physical stuff. (That cubic
zirconia is not quite as clear or hard as diamonds explains something
about why it is not equally valued. But even if it were equally hard
and equally clear, a CZ crystal would not thereby be a diamond.)

These examples can be used to explain the core idea of functionalism.
Functionalism is the theory that mental states are more like mouse
traps than they are like diamonds. That is, what makes something a
mental state is more a matter of what it does, not what it is made of.
This distinguishes functionalism from traditional mind-body dualism,
such as that of René Descartes, according to which minds are made of a
special kind of substance, the res cogitans (the thinking substance.)
It also distinguishes functionalism from contemporary monisms such as
J. J. C. Smart's mind-brain identity theory. The identity theory says
that mental states are particular kinds of biological states—namely,
states of brains—and so presumably have to be made of certain kinds of
stuff, namely, brain stuff. Mental states, according to the identity
theory, are more like diamonds than like mouse traps. Functionalism is
also distinguished from B. F. Skinner's behaviorism because it accepts
the reality of internal mental states, rather than simply attributing
psychological states to the whole organism. According to behaviorism,
which mental states a creature has depends just on how it behaves (or
is disposed to behave) in response to stimuli. In contrast
functionalists typically believe that internal and psychological
states can be distinguished with a "finer grain" than behavior—that
is, distinct internal or psychological states could result in the same
behaviors. So functionalists think that it is what the internal states
do that makes them mental states, not just what is done by the
creature of which they are parts.

As it has thus far been explained it, functionalism is a theory about
the nature of mental states. As such, it is an ontological or
metaphysical theory. And this is how it will be discussed, below. But
it is also worthwhile to note that functionalism comes in other
varieties as well. Functionalism could be a philosophical theory about
psychological explanations (that psychological states are explained as
functional states) or about psychological theories (that psychological
theories take the form of functional theories.) Functionalism can also
be employed as a theory of mental content, both as an account of the
intentionality of mental states in general (what makes some states
intentional is that they function in certain ways) or of particular
semantic content (what makes some state have the content "tree" is
that it plays a certain role vis-à-vis trees.) Finally, functionalism
may be viewed as a methodological account of psychology, the theory
that psychology should be pursued by studying how psychological
systems operate. (For detailed discussion of these variations, see
Polger, 2004, ch. 3.)

Often philosophers and cognitive scientists have subscribed to more
than one of these versions of functionalism together. Sometimes it is
thought that some require others, or at least that some entail others
when combined with certain background assumptions. For example, if one
believes, following Franz Brentano, that "intentionality is the mark
of the mental," then any theory of intentionality can be converted
into a theory of the ontological nature of psychological states. If
so, intentional functionalism may entail metaphysical functionalism.

All this being said, metaphysical functionalism is the central
doctrine and probably the most widely endorsed. So in what follows the
metaphysical variety will be the focus.
3. Being as Doing

Before looking at the arguments for and against functionalism, it is
necessary to clarify the idea that, for mental states, being is doing.

Plausibly a physical stuff kind such as diamond has a physical or
structural essence, i.e., being a thing of a certain composition or
constitution, quite independently of what they do or can be used to
do. It happens that diamonds can cut glass, but so can many other
things that are not diamonds. And if no diamond ever did or could cut
glass (perhaps Descartes' evil demon assures that all glass is
impenetrable), then they would not cease to be diamonds.

But it is also plausible that not all stuffs are made up in this way.
Some things may be essentially constituted by their relations to other
things, and by what they can do. The most obvious examples are
artifacts like mousetraps and keys. Being a key is not a matter of
being a physical thing with a certain composition, but it is a matter
of being a thing that can be used to perform a certain action, namely,
opening a lock. Lock is likewise not a physical stuff kind, but a kind
that exists only in relation to (among other things) keys. There may
be metal keys, wood keys, plastic keys, digital keys, or key-words.
What makes something a key is not its material composition or lack
thereof, but rather what it does, or could do, or is supposed to do.
(Making sense of the claim that there is something that some kinds of
things are supposed to do is one of the important challenges for
functionalists.)

The activities that a key does, could do, or is supposed to do may be
called its functions. So one can say that keys are essentially things
that have certain functions, i.e., they are functional entities. (Or
the kind key is a functional kind.)

The functionalist idea is, in some forms, quite ancient. One can find
in Aristotle the idea that things have their functions or
purposes—their telos— essentially. In contemporary theories applied to
the mind, the functions in question are usually taken to be those that
mediate between stimulus (and psychological) inputs and behavioral
(and psychological) outputs. Hilary Putnam's contribution was to model
these functions using the contemporary idea of computing machines and
programs, where the program of the machine fixes how it mediates
between its inputs and standing states, on one hand, and outputs and
other standing states, on the other. Modern computers demonstrate that
quite complex processes can be implemented in finite devices working
by basic mechanical principles. If minds are functional devices of
this sort, then one can begin to understand how physical human bodies
can produce the tremendous variety of actions and reactions that are
associated with our full, rich mental lives. The best theory, Putnam
hypothesized, is that mental states are functional states—that the
kind mind is a functional kind.

The initial inspiration for functionalism comes from the useful
analogy of minds with computing machines, as noted above. Putnam was
certainly not the first to notice that this comparison could be
theoretically fruitful. But in his "functionalist papers" of the 1950s
and 1960s, he methodically explored the utility, and oversaw the
transition of the idea from mere analogy to comprehensive theory,
culminating with his classic defense of the functional state theory in
his 1967 paper, "The Nature of Mental States." There Putnam advanced
the case for functionalism as a serious theoretical hypothesis, and
his argument goes beyond the mere claim that it is fruitful to think
of minds as being in many ways similar to machines. This argument aims
to establish the conclusion that the best theory is the one that holds
that minds "just are" machines of a certain sort.
4. The Case for Functionalism

Many arguments for functionalism depend on the actuality or
possibility of systems that have mental states but that are either
physically or behaviorally distinct from human beings. These arguments
are mainly negative arguments that aim to show that the alternatives
to functionalism are unacceptable. For example, behaviorists famously
held that psychological states are not internal states at all, whether
physical or psychical. But, the argument goes, it is easy to imagine
two creatures that are behaviorally indistinguishable and that differ
in their mental states. This line of reasoning is one of a family of
"perfect actor" or "doppelgänger" arguments, which are common fare in
philosophy of mind:

P1. If behaviorism is true, it is not possible for there to be a
perfect actor or doppelgänger who behaves just like me but has
different mental states or none at all.

P2. But it is possible for there to be a perfect actor or doppelgänger
who behaves just like me but has different mental states or none at
all.

P3. Therefore, behaviorism is not true. (by modus tollens)

In a well-known version of this argument, one imagines that there
could be "Super-Spartans" who never exhibit pain behavior (such as
flinching, saying "ouch") or even any dispositions to produce pain
behavior (Putnam 1963).

The most famous arguments for functionalism are responses not to
behaviorism but to the mind-brain identity theory. According to the
identity theory, "sensations are brain processes" (Smart 1959). If
mental state kinds are (identical to) kinds of brain states, then
there is a one-to-one relation between mental state kinds and brain
state kinds. Everything that has sensation S must have brain state B,
and everything that has brain state B must have sensation S. Not only
that, but this one-to-one correlation must not be accidental. It must
be a law of nature, at least, and perhaps must hold with an even
stronger sort of necessity. Put this way, the mind-brain identity
theory seems to make a very strong claim, indeed. As Hilary Putnam
notes,

the physical-chemical state in question must be a possible state of a
mammalian brain, a reptilian brain, a mollusc's brain (octopuses are
mollusca, and certainly feel pain), etc. At the same time, it must not
be a possible (physically possible) state of the brain of any
physically possible creature that cannot feel pain. Even if such a
state can be found, it must be nomologically certain that it will also
be a state of the brain of any extraterrestrial life that may be found
that will be capable of feeling pain before we can even entertain the
supposition that it may be pain. (Putnam 1967: 436)

The obvious implication is that the mind-brain identity theory is
false. Other mammals, reptiles, and mollusks can experience pain, but
they do not have brains like ours. It seems to follow that there is
not a one-to-one relation between sensations and brain processes, but
rather a one-to-many relation. Mental states, then, are not uniquely
realized (as the identity theory requires); they are instead multiply
realized.

And even if (by chance) it turns out that mammals, reptiles, and
mollusks all have similar brains (so that in fact there is a
one-to-one correlation), certainly one can recognize the possibility
that it might be discovered that terrestrial or extraterrestrial
creatures who experience pains but do not have brains like those of
human beings. So it is surely not necessary that there is a one-to-one
relation between mental state kinds and brain states kinds, but that
is exactly what the identity theory would require. This is bad news
for the identity theory, but it is good news for functionalism. For
functionalism says that what makes something a mental state is what it
does, and it is fully compatible with the diverse brains of mammals,
reptiles, and mollusks that they all have mental states because their
different brains do the same things, that is, they function in the
same ways. Functionalism is supported because it is a theory of mind
that is compatible with the likely degree of multiple realization of
mental states.

Another pair of arguments for functionalism are what can be called the
Optimistic and Pessimistic Arguments. The optimistic argument leans on
the possibility of building artificial minds. The Optimistic Argument
holds that even if no one ever discovers a creature that has mental
states but differs from humans in its brain states, surely one could
build such a thing. That is, the possibility of artificial
intelligence seems to require the truth of something like
functionalism. Functionalism views the mind very much as an engineer
does: minds are mechanisms, and there is usually more than one way to
build a mechanism. The Optimistic Argument, then, is a variation on
the multiple realization argument discussed above; but this version
does not depend on empirical facts about how our world is in fact, as
the multiple realization argument does.

The Pessimistic Argument claims that the alternatives to functionalism
would leave people unable to know about and explain the mental states
of one another, or of other creatures. After all, if two creatures
function in the same ways, achieve the same results, have isomorphic
internal states, etc., then what could justify the claim that one has
mental states and the other does not? The identity theory says that
the justification has to do with what kinds of stuff the creatures are
made of—only the one with the right kind of brain counts as having
mental states. But this flies in the face of our ordinary practices of
understanding, attributing, and explaining mental states. If someone
says, "I am in pain," or "I believe that it is sunny outside," one
doesn't have to cut the speaker open and find out whether they have a
human brain in order to know that they have a pain or a belief. One
knows that because the speaker not only produce those noises (as the
behaviorist might say), but because they have internal states that
function in certain ways. One can test this, as psychologists often
do, by running experiments in a laboratory or, as ordinary people do,
by asking questions and observing replies. That is, we can find out
how the systems function. And if functionalism is correct, that is all
we need to know in order to have knowledge of other minds. But if the
identity theory is correct, then those methods are at best heuristics,
and the observer may yet be wrong. One cannot know for certain that
the speaker has pains or beliefs unless one knows what kind of brain
the speaker has. Without knowing about brains, we can only infer that
others have beliefs on the basis of the behavioral symptoms they
exhibit, and we already know (see above, regarding behaviorism and
Super-Spartans) that those can lead us astray. But that is crazy, the
argument goes, and if one really believed it then (given that in
general one doesn't know what kinds of brains other people have)
nobody would be justified in believing anything about the beliefs of
other people and creatures . And that is crazy.

The trouble with the Optimistic Argument is that it is
question-begging. It assumes that one can create artificial thinking
things without duplicating the kinds of brain states that human beings
have, and that is just what the identity theory denies. The trouble
with the Pessimistic Argument is that it seems to exploits a very high
standard for knowledge of other minds — namely infallibility or
certainty. The objection gets its grip only if the requirement to
infer facts about others minds does undermine the possibility of
knowledge about those minds. But we regularly acquire knowledge by
inference or induction, and there is no special reason to think that
inferences about minds are more problematic than other inferences.

The multiple realization argument is much more nuanced. Its
interpretation is a matter of some dispute. Although there has been
increasing resistance to the argument lately, it remains the most
influential reason for favoring functionalism over the alternatives.
And even if the multiple realization argument is unsound, that result
would only undermine one argument for functionalism and not the thesis
itself.

The next two sections will consider two objections to functionalism
that aim to show that the theory is untenable. Both objections assume
that mental states are, as the functionalist insists, multiply
realizable. The objections try to show that because of its commitment
to multiple realization, functionalism must accept certain unpalatable
consequences. The conclusion of each argument is that functionalism is
false.
5. Searle's Chinese Room

John Searle's "Chinese Room Argument is aimed at computational
versions of functionalism, particularly those that specify the
relevant functions in terms of inputs and outputs without fixing the
internal organization of the processes. Searle stipulates that "Strong
AI" is the thesis than an appropriately programmed computer literally
has mental states, and that its program thereby constitutes an
explanation of its mental states and (following the functionalist
inspiration) of human mental states (1980). Searle then describes a
scenario in which a system that carries out the program consists in
some books and pieces of paper, a pencil, he himself—John Searle—all
inside a room. People on the outside pass questions written in Chinese
into the room. And Searle, by following the directions (the program)
in the books, is able to produce answers to those questions. But
Searle insists that he does not understand Chinese and has no beliefs
about the questions and answers. After all, one may suppose with him,
he doesn't even recognize that they are questions and answers written
in Chinese, or any language at all for that matter. And he thinks it
would be absurd to say that the room itself understands Chinese or has
beliefs about the questions and answers. So, he concludes, the version
of functionalism represented by Strong AI must be false. Having the
right functions, at least when they are specified only by inputs and
outputs, is not sufficient for having mental states.

Searle's Chinese Room is a version of the "twin" or "doppelgänger"
style objections to functionalism, in which some system is specified
to be functionally isomorphic to a mental system, e.g., one that
understands stories written in Chinese. Since functionalism holds that
being is doing, two systems that do the same things (that is, that are
functionally the same) should also be the same with respect to their
mental states. But if Searle is correct, the system including the
books and himself is functionally but not psychologically identical to
a person who understands Chinese. And if so, this is incompatible with
functionalism.

Searle considers a number of responses to his thought experiment, and
offers his own replies. Probably the most serious response is that
Searle begs the question when he asserts that the whole collection of
stuff in the room including the books and himself, i.e., the whole
system, does not understand. The "Systems Reply" holds that if
functionalism is true then the whole system does understand Chinese,
just as a Chinese speaker does even though it would be wrong to say
that her brain or her tongue or some part of her understands Chinese
by itself.

On the other hand, Searle's example does dramatically illustrate a
worry that has been expressed by others: Even if there are many ways
of being a thinking thing, it does not follow that anything goes. In
the Chinese Room thought experiment, nothing is specified about the
details of instructions that Searle follows, the program. It is simply
stipulated that it produces the correct outputs appropriate to the
inputs. But many philosophers think that it would undermine the claim
that the room understands if, for example, the program turned out to
be a giant look-up table, a prepared list of all possible questions
with the corresponding appropriate answer (Block 1978). The giant
look-up table seems like too "dumb" a way to implement the system to
count as understanding. So it's not unreasonable to say that Searle
has shown that input-output functionalism can't be the whole story
about mental states. Still, that's a much more modest conclusion than
Searle aimed for.
6. Zombies

Searle's Chinese Room objection focuses on contentful mental states
like belief and understanding, what are generally called intentional
states. But some philosophers conclude that functionalism is a good
theory of intentional states but that it nevertheless fails because it
cannot explain other sorts of mental states—in particular, they say
that it cannot explain sensations and other conscious mental states.

Putting the point in terms of Searle's Chinese Room: the whole system
might, in some sense, understand Chinese or produce responses that are
about the questions; but, in Thomas Nagel's famous phrase, there is
nothing that "it is like" to be the Chinese Room. The whole system
does not enjoy what it is doing, it does not experience sensations or
emotions, and it does not feel pains or pleasures. But Searle himself
does have experiences and sensations—he is a conscious being. So, the
reasoning goes, even if functionalism works for intentional states, it
does not work for consciousness.

Early versions of this concern were discussed under the name "absent
qualia." But the current fashion is to cast the discussion in term of
twins or doppelgängers called zombies. (This terminology was
introduced by Robert Kirk 1974, but has recently, for lack of a better
expression, taken on a life of its own.) The general idea is that
there might be two creatures which are physically or functionally
identical but that differ in the mental states in a particularly
dramatic way: one has normal conscious mental states, and the other
has none at all. The second twin is the philosophical "zombie."

The logical structure of the zombie argument is just the same as with
the other twin and doppelgänger arguments, like the Super-Spartans
discussed above:

P1*. If functionalism is true, it is not possible for me to have a
zombie twin, i.e., a doppelgänger who functions just like me but has
no mental states.

P2*. But it is possible for me to have a zombie twin.

P3*. Therefore, functionalism is not true. (by modus tollens)

There are several differences between the premises of the zombies
argument and those of the earlier argument against behaviorism. First,
while most versions of functionalism entail P1*, it is not obvious
that all must. Fred Dretske, for example, endorses a version of
functionalism that rejects P1* (1995). But more crucially, the
justification for P2* is far less clear than that for P2. P2 makes a
very weak claim, because mere behavior—movement, rather than what some
philosophers would call action—is relatively easy to generate. This
much as been commonplace among those who theorize about the mind at
least as far back as Descartes' familiarity with mechanical statues in
European water gardens. P2* makes a potentially much stronger claim.
It seems to suggest that the zombie could be not just behaviorally
identical but also functionally identical in any arbitrary sense of
function and in as much specificity as one might want. But this is
quite controversial. In the most controversial form, one might suppose
that "functional" identity could be arbitrarily fine-grained so as to
include complete physical identity. In this variation, the twins would
be physically identical creatures, one of whom has conscious mental
states and the other of whom lacks consciousness altogether.

The challenge for the functionalist, as Ned Block has argued, is to
find a notion of function and a corresponding version of functionalism
that solve "the problem of inputs and outputs" (Block 1978).
Functionalism must be specified in terms of functions (inputs and
outputs) that are sufficiently general to allow for multiple
realization of mental states, but sufficiently specific to avoid
attributing mental states to just about everything. This is tricky. A
version of functionalism that is too specific will rule out certain
genuinely psychological systems, and thereby prove to be overly
"chauvinistic." A version of functionalism that is too general will
attribute mental states to all sorts of things that one doesn't
ordinarily take to have them, and thereby prove to be overly
"liberal." Is there any non-arbitrary cut-off between liberalism and
chauvinism? Is there any way to navigate between this Scylla and
Charybdis? This is the big unanswered question for functionalists.
7. Stronger and Weaker Forms of Functionalism

At this point two clarifications are in order. These clarifications
reveal some ways in which functionalism comes in stronger or weaker
versions.

The first clarification pertains to the varieties of functionalism. As
noted in Section 2, there are many versions of functionalism. Here the
focus has been on metaphysical versions. But the variations described
earlier (metaphysical, intentional, semantic, explanatory,
methodological, and theoretical) represent only one dimension of the
ways in which various functionalisms differ. Functionalist theories
can also be distinguished according to which mental phenomena they are
directed toward. The standard way of classifying mental states is as
intentional (such as beliefs and desires) or conscious or qualitative
(such as sensations and feelings.) Of course some philosophers and
psychologists believe that all mental states turn out to be of one
sort. (Most commonly they hold that all kinds of mental states are
intentional states of one sort or another.) But that need not be a
factor here, for the classification is only for expository purposes.
Specifically, one can hold that functionalism is a theory of
intentional states, of conscious states, or of both. The strongest
claim would be that functionalism applies to all mental states.
William Lycan (1987) seems to hold this view. Weaker versions of
functionalism apply to only one sort of mental state or the other. For
example, Jaegwon Kim (2005) appears to hold that something like
functionalism applies to intentional states but not to qualitative
states.

The second clarification pertains to the scope or completeness of a
functionalist theory. Functionalism claims that the nature of mental
states is determined by what they do, by how they function. So a
belief that it is sunny, for example, might be constituted in part by
its relations to certain other beliefs (such as that the sun is a
star), desires (such as the desire to be on a beach), inputs (such as
seeing the sun), and outputs (such as putting on sunglasses.) Now
consider the other beliefs and desires (in the above example) that
partially constitute the nature of the belief that it is sunny. In the
strongest versions of functionalism, those beliefs and desires are
themselves functional states, defined by their relations to inputs,
outputs, and other mental states that are in turn functionally
constituted; and so on. In this case, every mental state is completely
or purely constituted by its relations to other things, without
remainder. Nothing can exist as a mental state on its own, only in
relation to the others. In contrast, weaker versions of functionalism
could allow some mental states to be basic and non-functional For
example, if functionalism applies to all mental states, one could hope
to explain intentional states functionally while allowing for
conscious mental states to be basic. Then the belief that it is sunny
might be constituted, in part, by its relations to certain sensations
of warmth or yellowness, but those sensations might not be functional
states. Generally speaking, philosophers who do not specify otherwise
are assuming that functionalism should be the strong or pure variety.
Impure or weak versions of functionalism—what Georges Rey calls
"anchored" versions—do not succeed in explaining the mental in terms
of purely non-mental ingredients. So whatever other value they might
have, they fall short as metaphysical theories of the nature of mental
states. Some would deny that weak theories should count as versions of
functionalism at all.
8. Conclusion

There are many more variations among functionalist theories than can
be discussed herein, but the above clarifications are sufficient to
give a flavor of the various nuances. It is safe to say that in one
version or another, functionalism remains the most widely accepted
theory of the nature of mental states among contemporary theorists.
Nevertheless, recently, perhaps in view of the difficulties of working
out the details of functionalist theories, some philosophers have been
inclined to offer supervenience theories of mental states as
alternatives to functionalism. But as Jaegwon Kim correctly pointed
out, supervenience simply allows us to pose the question about the
nature of mental states, it is not an answer. The question is: Why do
mental states supervene on the physical states of the creatures that
have them, or at least of the world altogether? Functionalism provides
one possible answer: Mental states supervene on physical states
because mental states are functional states, i.e., they are realized
by physical states. Much remains to be said about such a theory, and
to many philosophers the arguments for it do not seems as decisive in
2008 as they did in 1968. But there is no denying that it is an
intriguing and potentially powerful theory.
9. References and Further Reading
a. References
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One. Cambridge, MA: Harvard University Press.
Block, N. (ed.) 1980b. Readings in Philosophy of Psychology, Volume
Two. Cambridge, MA: Harvard University Press.
Block, N. and J. Fodor. 1972. What Psychological States Are Not.
Philosophical Review 81: 159-181.
Chalmers, D. 1995. Facing up to the problem of consciousness. Journal
of Consciousness Studies, 2, 3: 200-219.
Cummins, R. 1975. Functional analysis. The Journal of Philosophy
LXXII, 20: 741-765.
Fodor, J. 1968. Psychological Explanation. New York: Random House.
Fodor, J. 1974. Special sciences, or the disunity of science as a
working hypothesis. Synthese 28: 97-115. Reprinted in Block 1980a.
Kim, J. 2005. Physicalism, or Something Near Enough. Princeton:
Princeton University Press.
Kirk, R. 1974. Zombies v. Materialists. Proceedings of the
Aristotelian Society, 48: 135-152.
Lewis, D. 1970. How to Define Theoretical Terms. Journal of Philosophy
68: 203-211.
Lewis, D. 1972. Psychophysical and Theoretical Identifications. The
Australasian Journal of Philosophy 50: 249-258.
Lewis, D. 1980. Mad Pain and Martian Pain. In Block (ed.) 1980b.
Lycan, W. 1981. Form, Function, and Feel. Journal of Philosophy 78: 24-50.
Lycan, W. 1987. Consciousness. Cambridge, MA: The MIT Press.
Millikan, R. 1989. In Defense of Proper Functions. Philosophy of
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Polger, T. 2000. Zombies Explained. In Dennett's Philosophy: A
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Putnam, H. 1960. Minds and Machines. In Hook (ed) Dimensions of Mind
(New York: New York University Press). Reprinted in Putnam (1975c).
Putnam, H. 1963. Brains and Behavior. Analytical Philosophy, Second
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in Putnam (1975c).
Richardson, R. 1979. Functionalism and Reductionism. Philosophy of
Science 46: 533-558.
Richardson, R. 1982. How not to reduce a functional psychology.
Philosophy of Science, 49, 1: 125-137.
Searle, J. 1980. Minds, Brains, and Programs. The Behavioral and Brain
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Shapiro, L. 2000. Multiple Realizations, The Journal of Philosophy, 97, 635-654.
Shapiro, L. 2004. The Mind Incarnate, Cambridge, MA: The MIT Press.
Shoemaker, S. 1975. Functionalism and Qualia. Philosophical Studies
27: 291-315. Reprinted in Block (1980a).
Shoemaker, S. 1984. Identity, Cause, and Mind. New York: Cambridge
University Press.
Smart J. J. C. 1959. Sensations and Brain Processes. Philosophical
Review, LXVIII: 141-156.
Sober, E. 1985. Panglossian Functionalism and the Philosophy of Mind.
Synthese 64: 165-193.
Wright, L. 1973. Functions. Philosophical Review 82, 2: 139-168.
b. Suggested Reading
Block, N. 1978. Troubles with functionalism. C. W. Savage (ed.),
Minnesota Studies in the Philosophy of Science, Vol. IX (Minneapolis,
MN: University of Minnesota Press). Reprinted in Block (1980a).
Block, N. 1980c. Introduction: What is functionalism? In Block (1980b).
Kim, J. 1996. Philosophy of Mind. Boulder, CO: Westview.
Polger, T. 2004. Natural Minds. Cambridge, MA: The MIT Press.
Putnam, H. 1967. Psychological Predicates. Reprinted in Block (1980)
and elsewhere as "The Nature of Mental States."
Rey, G. 1997. Contemporary Philosophy of Mind. Boston: Blackwell Publishers.
Shoemaker, S. 1981. Some Varieties of Functionalism. Philosophical
Topics 12, 1: 83-118. Reprinted in Shoemaker (1984).
Van Gulick, R. 1983. Functionalism as a Theory of Mind. Philosophy
Research Archives: 185-204.