Greg Detre
Sunday, 03 March, 2002
�Solutions to the mind/body problem usually try to answer questions such as: What is the ultimate nature of the mental? At the most general level, what makes a mental state mental? Or more specifically, What do thoughts have in common in virtue of which they are thoughts?�
�Cartesian Dualism said the ultimate nature of the mental was to be found in a special mental substance.
Behaviorism identified mental states with behavioral dispositions;
physicalism in its most influential version identifies mental states with brain states.
Functionalism says that mental states are constituted by their causal relations to one another and to sensory inputs and behavioral outputs.�
�Functionalism has three distinct sources
First, Putnam and Fodor saw mental states in terms of an empirical computational theory of the mind.
Second, Smart�s "topic neutral" analyses led Armstrong and Lewis to a functionalist analysis of mental concepts.
Third, Wittgenstein�s idea of meaning as use led to a version of functionalism as a theory of meaning, further developed by Sellars and later Harman.�
concepts like �carburetor� and �kidney� are functional concepts, defined in terms of the role they play
uses an example of a machine that has two states, depending on whether it�s had an even or odd number of inputs
according to functionalism:
1. �the nature of a mental state is � constituted by its relations to other states and to inputs and outputs�
�all there is to being in pain is that it disposes you to say �ouch�, wonder whether you are ill, it distracts you, etc.�
2. �Mental states can be totally characterized in terms that involve only logico-mathematical language and terms for input signals and behavioral outputs. Thus functionalism satisfies one of the desiderata of behaviorism, characterizing the mental in entirely non-mental language�
3. �S1 is a second order state in that it consists in having other properties, say mechanical or hydraulic or electronic properties that have certain relations to one another. These other properties, the ones quantified over in the definitions just given, are said to be the realizations of the functional properties. So, although functionalism characterizes the mental in non-mental terms, it does so only by quantifying over realizations of mental states, which would not have delighted behaviorists.� ???
4. �One functional state can be realized in different ways. For example, an actual metal and plastic machine satisfying the machine table might be made of gears, wheels, pulleys and the like, in which case the realization of S1 would be a mechanical state; or the realization of S1 might be an electronic state, and so forth�
5. �Just as one functional state can be realized in different ways, one physical state can realize different functional states in different machines. This could happen, for example, if a single type of transistor were used to do different things in different machines.�
6. �Since S1 can be realized in many ways, a claim that S1 is a mechanical state would be false (at least arguably), as would a claim that S1 is an electronic state. For this reason, there is a strong case that functionalism shows physicalism is false: if a creature without a brain can think, thinking can�t be a brain state� (see below on functionalism + physicalism)
�in the early days of functionalism, a first order property was often said to realize a functional property in virtue of a 1-1 correspondence between the two realms of properties. But such a definition of realization produces far too many realizations
What is left out by the post hoc correlation way of thinking of realization is that a true realization must satisfy the counterfactuals implicit in the table� (see 3)
considers the psychological theory T, with pain as the 17th mental term
�In
this way, functionalism characterizes the mental in non-mental terms, in terms
that involve quantification over realizations of mental states but no explicit
mention of them; thus functionalism characterizes the mental in terms of
structures that are tacked down to reality only at the inputs and outputs.� ???
conceptual
functionalism
a common sense �folk� theory � the functional definitions are aimed at capturing our ordinary mental concepts
like a development of logical behvaioruism,
where pain = a disposition to pain behaviour
�But as Geach and Chisholm pointed out, what counts
as pain behavior depends on the agent�s beliefs and desires. Conceptual
functionalists avoid this problem by defining each mental state in terms of its
contribution to dispositions to behave--and have other mental states.�
psychofunctionalism
empirical psychological theory � the functional definitions are not supposed to capture ordinary concepts, but are only supposed to fix the extensions of mental terms
the scientific nature of the mental consists in something �organisational� (analogous to computational structure)
Theories of the mind prior to functionalism have been concerned both with:
what there is
dualism: there are both mental + physical substances
physicalism + behaviourism: monistic (there are only physical substances)
functionalism: does not tell us whether the beings that have pains have any non-physical parts
(it does not rule out a machine which is operated by
an immaterial soul, so long as the soul is willing to operate in the
deterministic manner specified in the table)
what gives each type of mental state its own identity, for example what
pains have in common in virtue of which they are pains
dualism: non-physical answer
behaviourism: what pains have in common in virtue of which they are pains is something behavioural
phsyicalism: physical answer
functionalism: what pains have in common--what makes them pains--is their function
Two categories of physicalist theses:
type physicalism
�competes with functionalism, making a metaphysical claim about the physical nature of mental state properties or types (and is thus often called "type" physicalism). As mentioned above, on one point of view, functionalism shows that type physicalism is false.�
token physicalism
�there are more modest physicalisms whose thrusts are ontological rather than metaphysical. Such physicalistic claims are not at all incompatible with functionalism. Consider, for example, a physicalism that says that every actual thing is made up of entirely of particles of the sort that compose inorganic matter. In this sense of physicalism, most functionalists have been physicalists. Further, functionalism can be modified in a physicalistic direction, for example, by requiring that all properties quantified over in a functional definition be physical properties. Type physicalism is often contrasted with token physicalism. (The word �teeth� in this sentence has five letter tokens of three letter types.) Token physicalism says that each pain (for example) is a physical state, but token physicalism allows that there may be nothing physical that all pains share, nothing physical that makes a pain a pain.�
�It
is a peculiarity of the literature on functionalism and physicalism that while
some functionalists say functionalism shows physicalism is false (See the
papers by Putnam, Fodor, and Block and Fodor in Block (1980), some of which are
also in the other anthologies), others say functionalism shows physicalism is
true. (See the papers by Lewis and Armstrong in Block (1980) and Rosenthal
(1991).)�
�Lewis is a conceptual functionalist about having
pain. �Having pain� on Lewis� regimentation, could be said to be a rigid
designator of a functional property. [A rigid designator names the same thing
in each possible world. �The color of the sky� is non-rigid, since it names red
in worlds in which the sky is red. �Blue� is rigid, since it names blue even in
worlds in which the sky is red.] �Pain�, by contrast is a non-rigid designator
conceptually equivalent to a definite description of the form �the state with
such and such a causal role�. The referent of this phrase in us, Lewis holds,
is a certain brain state, though the referent of this phrase in a robot might be
a circuit state, and the referent in an angel would be a non-physical state.
Similarly, �the winning number� picks out �17� in one lottery and �596� in
another. So Lewis is a functionalist (indeed a conceptual functionalist) about
having pain. In terms of the metaphysical issue described above--what do pains
have in common in virtue of which they are pains, Lewis is a functionalist, not
a physicalist. What my pains and the robot�s pains share is a causal role, not
anything physical. Just as there is no numerical similarity between 17 and 596
relevant to their being winning numbers, there is no physical similarity
between human and Martian pain that makes them pains. And there is no physical
similarity of any kind between human pains and angel pains. However, on the
issue of the scientific nature of pain, Lewis is a physicalist. What is in
common to human and Martian pain on his view is something conceptual, not
something scientific.�
listing (monadic, e.g. pain, sensation of red) mental state terms is not realistic with a large number of terms, especially when some are systematically related (i.e. each is not an unrelated primitive predicate), so we need a combinatorial apparatus
language of thought = a system of syntactically structured objects in the brain that express the propositions in propositional attitudes
twin earth arguments: meaning + content are in part in the world, and in part in the language community
long-arm inputs + outputs = includes the objects that one sees + manipulates
short-arm inputs + outputs = that stop at the surfaces of the body
�thinking of the intentional contents thereby characterised as narrow � supervening on the non-relational physical properties of the body�???
procedural
semantics = conceptual role semantics:
�the functional state [of the word �momentum�] can
be seen in terms of the role of the word �momentum� itself in thinking, problem
solving, planning, etc. But if understanding the meaning of �momentum� is this
word�s having a certain function, then there is a very close relation between
the meaning of a word and its function, and a natural proposal is to regard the
close relation as simply identity, that is, the meaning of the word just is
that function. (See Peacocke, 1992.) Thus functionalism about content leads to
functionalism about meaning, a theory that purports to tell us the metaphysical
nature of meaning.�
characterised as the �damn/darn� problem:
there is a small but significant difference in mental state belied by my saying �damn� as opposed to �darn� when I stub my toe
�So the different functionalized theories appropriate to the two responses will affect the individuation of every state connected to those utterances, and for the same reason, every state connected to those states, and so on.�
�The upshot is that the functionalist needs a way of individuating mental states that is less fine-grained than appeal to the whole theory, a molecularist characterization�
would the army of people representing neurons remote-controlling a robot body have qualia???
Lewis proposes that we include much of human physiology in our theory to be functionalised � to avoid liberalism, but at the risk of chauvinism
avoid liberalism by characterizing functional roles teleologically
�A major problem for this point of view is the lack of an acceptable teleological account. Accounts based on evolution smack up against the swamp-grandparents problem. Suppose you find out that your grandparents were formed from particles from the swamp that came together by chance�
�Functionalism dictates that mental properties are second order properties, properties that consist in having other properties that have certain relations to one another. But there is at least a prima facie problem about how such second order properties could be causal and explanatory in a way appropriate to the mental. Consider, for example, provocativeness, the second order property that consists in having some first order property (say redness) that causes bulls to be angry. The cape�s redness provokes the bull, but does the cape�s provocativeness provoke the bull? The cape�s provocativeness might provoke an animal protection society, but isn�t the bull too stupid to be provoked by it?�
conceptual vs psycho- functionalism???
propositional attitudes = simply mental/attitude-states (e.g. beliefs) that can be expressed as propositions, right???
Fodor�s productive argument???
narrow intentional contents??? different to short-arm???
what is the difference between content and meaning???