### Realizer Functionalism

```Functionalism
OBJECTIONS
Functionalism
 Something is a functional kind iff it can be analyzed in
terms of a causal role (e.g., something is an F iff it play
the F-role).
 F is realized by P in X iff P plays the F-role in X.
 A property is multiply realizable iff it can be realized by
different things in different objects.
The Pain Role
 The Pain Role: (1) An internal mental state, (2) typically
caused by tissue damage, (3) which can result from
kicking, burning, etc. and (4) which commonly causes
crying, frowning, and whimpering, as well as (5) anger,
the desire for it to stop, the belief that one is in pain, etc.
Functionalism
 Realizer Functionalism: Mental states are states that play
a characteristic causal role. To be in pain is to be in the
state that plays the pain role.
 Role Functionalism: Mental states are higher-order
properties, like the property of having some state or
other that plays the characteristic causal role. To be in
pain is to be in some state or other that plays the pain
role.
Preview
In the previous chapter we noticed that mental states can
be multiply realized. In humans the state which realizes
pain is (say) c-fiber firing; in squid it’s (say) d-fiber firing.
Multiple realization raises a puzzle: what do old Eight-legs
and I have in common when we are both in pain? It can’t
be c-fiber firing because Eight-legs has no c-fibers (or so I
will assume). And it can’t be d-fiber firing because I have
no d-fibers (or so I will assume). In virtue of what, then, is
it true that Eight-legs and I are both in pain?
Functionalism provides an answer to this puzzle.
Ravenscroft, p.50.
Realizer Functionalism
1) Pain = R.
2) R = c-fiber firing.
3) [So] Pain = c-fiber firing.
Realizer Functionalism
Pain = R.
2) In humans, R = c-fiber
firing.
3) [So] In humans, pain = cfiber firing.
1)
Pain = R.
2) In squids, R = d-fiber
firing.
3) [So] In squids, pain = dfiber firing.
1)
Realizer Functionalism
 The Relativized Identity Theory: Mental states are
identical to physical states of the brain. To be in pain-forhumans is to have C-fibers firing, to be in pain-for-squids
is to have D-fibers firing, to be in pain-for-Orkans is to
have activity in silicon chip E, etc.
Realizer Functionalism
Pain = R.
2) In humans, R = c-fiber
firing.
3) [So] In humans, pain = cfiber firing.
1)
Pain = R.
2) In squids, R = d-fiber
firing.
3) [So] In squids, pain = dfiber firing.
1)
Realizer Functionalism
Hamlet = H.
2) In 1990, H = Mel Gibson.
3) [So] In 1990, Hamlet =
Mel Gibson.
1)
Hamlet = H.
2) In 1996, H = Kenneth
Branagh.
3) [So] In 1996, Hamlet =
Kenneth Branagh.
1)
Realizer Functionalism
The 1990 Hamlet = H in
the 1990 movie.
2) H in the 1990 movie =
Mel Gibson.
3) [So] The 1990 Hamlet =
Mel Gibson.
1)
The 1996 Hamlet = H in
the 1996 movie.
2) H in the 1996 movie =
Kenneth Branagh.
3) [So] The 1996 Hamlet =
Kenneth Branagh.
1)
Realizer Functionalism
Pain = R.
2) In humans, R = c-fiber
firing.
3) [So] In humans, pain = cfiber firing.
1)
Pain = R.
2) In squids, R = d-fiber
firing.
3) [So] In squids, pain = dfiber firing.
1)
Realizer Functionalism
Pain-in-humans = R in
humans.
2) R-in-humans = c-fiber
firing.
3) [So] Pain-in-humans = cfiber firing.
1)
Pain-in-squids = R in
squids.
2) R in squids = d-fiber
firing.
3) [So] Pain-in-squids = dfiber firing.
1)
Realizer Functionalism
 The Relativized Identity Theory: Mental states are
identical to physical states of the brain. To be in pain-forhumans is to have C-fibers firing, to be in pain-for-squids
is to have D-fibers firing, to be in pain-for-Orkans is to
have activity in silicon chip E, etc.
Role Functionalism
 Role Functionalism: Mental states are higher-order
properties, like the property of having some state or
other that plays the characteristic causal role. To be in
pain is to be in some state or other that plays the pain
role.
Role Functionalism
 Role Functionalism: Mental states are higher-order
properties, like the property of having some state or
other that plays the characteristic causal role. To be in
pain is to be in some state or other that plays the pain
role.
 The Disjunctive Identity Theory: Mental states are
identical to physical states of the brain. To be in pain is to
either be a human and to have C-fibers firing or to be a
squid and to have D-fibers firing or to be an Orkan and to
have activity in silicon chip E or…
Role Functionalism
Functionalists have often touted the phenomenon of multiple
realization as a basis for the claim that the properties studied
by cognitive science are formal and abstract—abstracted from
the material compositional details of the cognitive systems.
What our considerations seem to show is that cognitive
science properties so conceived threaten to turn out to be
heterogeneous disjunctions of properties after all. And these
disjunctions seem not to be suitable as nomological
properties –properties in terms of which laws and causal
explanations can be formulated. If this is right, it would
disqualify mental properties, construed as second-order
properties as serious scientific properties.
-Kim, p.166
The Master Argument
1) If Functionalism is correct, then either (a) Realizer
2)
3)
4)
5)
6)
Functionalism is correct, or (b) Role Functionalism is
correct.
If (a), then the Relativized Identity Theory is correct.
The Relativized Identity is incorrect.
If (b), then the Disjunctive Identity Theory is correct.
The Disjunctive Identity Theory is incorrect.
[So] Functionalism is incorrect.
```