Patricia
Churchland has a problem with the fact that many functionalists have
“ignored neuroscience”. Indeed they've also “rejected
reductionism” (1986). However, I suspect that this is much less
true today than it was when Churchland wrote those words in 1986.
Not only do many functionalists ignore neuroscience, they
also take some pride in doing so. Or, as Churchland surmises,
functionalists may think that
“the
less known about the actual pumps and pulleys of the embodiment of
mental life, the better, for the less there is to clutter up one's
functionally oriented research” (1986).
I
would say that the primary reason for this functionalist ignorance of
all things neuroscientific is that functionalists believe that
“computational (functional) psychology” can only then be
seen as an “autonomous science”. They may believe that if
neuroscience had the last word on these matters (or if it were all a
question of reduction in the end), then such functionalists wouldn't
really have any territory they could call their own.
Of
course one can be this kind of functionalist and still be a
physicalist. Though can functionalists also be reductionists? Yes, in
principle; though primarily because of the multiple realizability
argument (which is tackled later), that would rarely be the case. In
principle, a functionalist could also know lots of neuroscience and
still not find his mind “cluttered up” (as Churchland puts it).
Indeed he may know loads of neuroscience and argue that all the
cognitive sciences should
still be seen as autonomous.
According
to Churchland, Zenon Pylyshyn
puts the case for this neat division of labour thus:
i)
“... cognitive scientists will figure out the functional/cognitive...”
ii)
“... neuroscientists can untangle the underlying physical devices
that instantiate the cognitive 'program'...” (1986)
At
first glance it simply seems to be counter-productive to argue that
these two departments should never interact (or clutter each other up).
It depends, though, on whether that separation is complete or not.
And Churchland herself says that it's “doubtful” that “anyone
really holds that extreme version of the research ideology” (1986).
Nonetheless, Churchland does go on to say that “certainly milder
versions [of this approach] have won considerable sympathy”. And
she too says that the “autonomy of psychology is the rationale”
behind that.
Just
as Churchland thinks that it's a bad idea for functionalists or
psychologists to ignore neuroscience, so she also thinks it's an
equally bad idea for neuroscientists (or eliminative materialists) to
ignore functionalism or psychology. She writes:
“Neuroscientists
would be silly to make a point of ignoring psychological data... just
as psychologists would be silly to make a point of ignoring all
neurobiological data.” (1994)
Indeed
if pressed (or looking from the outside looking in) it would seem
almost impossible for either neuroscientists to ignore psychology or
for psychologists to ignore neuroscience. Though, when one looks at
the history, one quickly sees that this was indeed the case. Perhaps
the most obvious example was the “black
box” position adopted by behaviourists from the 1920s
to the 1960s. (This was the position in which the mind-brain
was simply seen as a receptacle for stimulations or the locus of
various inputs and outputs.)
Churchland
continues by mollifying psychologists about that scareword -
“reductionism”. She tells psychologists or functionalists not to
worry. She says that by “reductionist research strategy” she
“does
not mean that there is something disreputable, unscientific or
otherwise unsavoury about high-level descriptions or capacities per
se.” (1994)
Churchland
says something that may even surprise some philosophers. She argues
that reductionism can exist side-by-side with what she calls
“high-level descriptions or capacities”.
In
any case, reduction is vitally important in many sciences and it
comes up with many important results. Nonetheless, it doesn't follow
from this that all forms of reductionism have no room for
“higher-level descriptions”. Indeed E.O. Wilson put a similar
point (though about another area) when he wrote the following:
“Major
science always deals with reduction and resynthesis of complex
systems, across two or three levels of complexity at a step. For
example, from quantum physics to the principles of atomic physics,
thence reagent chemistry, macromolecular chemistry, molecular
biology, and so on – comprising, in general, complexity and
reduction, and reduction to resynthesis of complexity, in repeated
sweeps.”
Churchland
herself says that
“research
techniques reveal structural organisation at many strata: the
biochemical level; then the level of the membrane, the single cell,
and the circuit; and perhaps yet other levels, such as brain
subsystems, brain systems, brain maps, and the whole central nervous
system” (1989).
Nonetheless,
E.O. Wilson is of course well aware that the “very word
'reductionism'” has a “sterile and invasive ring, like a scalpel
or catheter”. He goes on to say that the
“[c]ritics
of science sometimes portray reductionism as an obsessional disorder,
declining towards a terminal stage one writer recently dubbed
'reductive megalomania'” (1998).
The
main argument against reduction in the philosophy of mind is the
multiple realisability argument, as first advanced by Hilary Putnam
in 1967 in his 'The
Nature of Mental States'.
Churchland
tackles this subject and makes a distinction between type-type and
token-token reductions. The gist of the argument is that just as
various types of mental function or state can be multiply realised,
so can various types in physics. Basically, that doesn't make the
reduction either problematic or unscientific.
Take
the scientific type temperature.
Churchland writes:
“Notice
that what was reduced [in thermodynamics] was not temperature tout
court, but temperature of gas. The temperature of a gas is mean
kinetic energy of the constituent molecules, but the temperature of a
solid is something else again...” (1986)
Thus
reduction in this and in other cases is domain-specific. Or as
Churchland puts it:
“The
initial reduction in thermodynamics was relative to a certain domain
of phenomena, to wit, gases...”
However,
this domain-specificity, according to Churchland, still means that
“it was a bona fide reduction for all that”. As a result,
did it make thermodynamics a special science (as psychology,
economics, etc. are seen as special
sciences)? Not according to Churchland. She says that that
thermodynamics isn't “independent and separate from physics”.
Does
that means that the special sciences aren't “independent and
separate from physics” either? Surely it does.
In
fact Churchland deals with the case of psychological functionalism
and multiple realisability herself. She says that
“if
human brains and electronic brains both enjoy a certain type of
cognitive organisation, we may get two distinct domain-relative
reductions” (1986).
Churchland
concludes by saying that the “domain-relative” reductions just
discussed aren't thereby “phony reductions or reductions manqué”.
And it “certainly does not mean that psychology can justify [its]
methodological isolation from neuroscience” (1986).
However,
just to backtrack a little, it isn't correct to say that Churchland's
examples are token-token reductions because, for example, the
temperature of a gas (as opposed to that of a solid or of plasma)
is still dealing in types. It's just a lower-level type of a
higher-level type. That is, we have the lower-level type [the
temperature of a gas] and the higher-level type [temperature]. Indeed
there will even be sub-types within the type [temperatures of gases]
which would include different kinds of gases (though they too would
still be type-reductions, not token-reductions).
All
this can clearly be distinguished from, say, the attempt to reduce a
single person's mental state (qua token)
to its physiological and physical reduction-base. Then again, mental
types are also problematic, as we will now see.
Some
philosophers (i.e., not psychologists or cognitive scientists) do say
that such reductions are unscientific – at least the reductions of
mental types or functions. This may all depend on whether mental
functions can be distinguished form the category of mental
states. That is, reductions of mental functions may be less
problematic than reductions of mental states. After all, mental
functions can be seen as abstracta; whereas that's not the case with
all – or any - mental states.
Take, for
example, Jaegwon Kim's solution to all this: it seems to be old-style
reductionism. Or at least he puts the reductionist position when he
says that the “reductionist identifies pain with neural state N”.
The question is whether or not pain can be seen functionally. And
even if it isn't seen that way, is it still problematic from a
scientific point of view?
Kim
does argue that pain as a "scientific kind... must go” and
that elimination or reduction is the answer. That's primarily because
- in Kim's case at least - of the problems associated with what's just been discussed: the multiple realisability of mental kinds
in many and various physical substrates.
This
is what Kim himself writes on this subject:
“....
the frank acknowledgement that MR [multiple realisability] leads to
the conclusion that pain as a property or kind must go. Local
reduction after all is reduction, and to be reduced is to be
eliminated as an independent
entity.” (1992)
Kim
accepts that pain and mental states/qualities exist: it's just that
he doesn't deem them to be scientific kinds or properties.
Functionalist
Dualism: Biology & Brains Matter
It's
ironic that many of the functionalists and cognitive scientists who
accuse all and sundry of being “dualists” should themselves be
categorised in this way.
For
example, many call John Searle a dualist. Searle, in return,
says that those who stress function and ignore biology are
effectively creating a non-material Cartesian reality populated with
functions or computations (i.e., rather than with “ideas” or “thoughts”).
Patricia Churchland, on the other hand, doesn't use the word
“dualist”, though she does say
the following:
“Many
philosophers who are materialists to the extent that they doubt the
existence of soul-stuff nonetheless believe that psychology ought to
be essentially autonomous from neuroscience, and that neuroscience
will not contribute significantly to our understanding of perception,
language use, thinking, problem solving, and (more generally)
cognition.” (1989)
Put
that way, it seems like an extreme position. Basically, how could
materialists (when it comes to the mind) possibly ignore the brain?
It's one thing to say that “psychology is distinct from
neuroscience”: it's another thing to say that psychology is
“autonomous from neuroscience” and that “neuroscience will not
contribute significantly to our understanding” of cognition and
whatnot. Sure, the division of labour idea is a good idea. Though to
see the “autonomous” in “autonomous science” as being about
complete and total independence is surely a bad idea. In fact it's
almost like a physicist stressing the independence of physics from
mathematics.
Churchland
thinks that biology matters. In this, she has the support of many others.
For
example, the Nobel laureate Gerald Edelman
says that the mind
“can
only be understood from a biological standpoint, not through physics
or computer science or other approaches that ignore the structure of
the brain” (1996).
In
addition, you perhaps wouldn't ordinarily see Patricia Churchland and John
Searle as being bedfellows; though they are on this issue. So it's
worth quoting a long passage from Searle which neatly sums up some of
the problems with non-biological theories of mind. Searle writes:
“I
believe we are now at a point where we can address this problem as a
biological problem [of consciousness] like any other. For decades
research has been impeded by two mistaken views: first, that
consciousness is just a special sort of computer program, a special
software in the hardware of the brain; and second that consciousness
was just a matter of information processing. The right sort of
information processing -- or on some views any sort of information
processing --- would be sufficient to guarantee consciousness.....
it is important to remind ourselves how profoundly anti-biological
these views are. On these views brains do not really matter. We just
happen to be implemented in brains, but any hardware that could carry
the program or process the information would do just as well. I
believe, on the contrary, that understanding the nature of
consciousness crucially requires understanding how brain processes
cause and realize consciousness.. ” (1999)
In
a sense, then, if one says that biology matters, one is also saying
that functions aren't everything (though not that functions
are nothing). Indeed Churchland takes this position to its
logical conclusion when she more or less argues that in order to
build an artificial brain one would not only need to replicate its
functions, but also everything (physical) about it.
Here
again she has the backup of Searle. He
writes:
“Perhaps
when we understand how brains do that, we can build conscious
artefacts using some nonbiological materials that duplicate, and not
merely simulate, the causal powers that brains have. But first we
need to understand how brains do it.”
Of
course we can say that we can have an artificial mind without
having an artificial brain. Though isn't it precisely this position which many dispute (perhaps Churchland does too)?
In
any case, to use Churchland's own words on this subject, she says
that
“it
may be that if we had a complete cognitive neurobiology we would find
that to build a computer with the same capacities as the human brain,
we had to use as structural elements things that behaved very like
neurons” (1986).
Churchland
continues by saying that
“the
artificial units would have to have both action potentials and graded
potentials, and a full repertoire of synaptic modifiability,
dendritic growth, and so forth”.
It
gets even less promising for functionalism when Churchland says that
“for
all we know now, to mimic nervous plasticity efficiently, we might
have to mimic very closely even certain subcellular structures”.
Put
that way, Churchland makes it sound as if an artificial mind (if not
artificial intelligence) is still a pipe-dream.
Readers
may also have noted that Churchland was only talking about the
biology of neurons, not the biology of the brain as a whole. However,
wouldn't the replication of the brain (as a whole) make this whole
artificial-mind endeavour even more complex and difficult?
In
any case, Churchland sums up this immense problem by saying that
“we
simply do not know at what level of organisation one can assume that
the physical implementation can vary but the capacities will remain
the same”.
That's
an argument which says that it's wrong to accept the
implementation-function “binary opposition” (to use a phrase from
Derrida) in the first place. Though that's not to say - and
Churchland doesn't say - that it's wrong to concentrate on functions
or cognition generally. It's just wrong to completely ignore the
“physical implementation”. Or, as Churchland says at the
beginning of one paper, it's wrong to “ignore neuroscience” and
focus entirely on function.
Churchland
puts the icing on the cake herself by stressing function. Or, more
correctly, she stresses the functional levels which are often
ignored by functionalists.
Take
the cell or neurone. Churchland writes
that
“even
at the level of cellular
research, one can view the cell as being the functional unit with a
certain input-output profile, as having a specifiable dynamics, and
as having a structural implementation in certain proteins and other
subcellular structures” (1986).
Basically,
what's being said here is that in many ways what happens at the macro
level of the mind-brain (in terms of inputs and outputs) also has an
analogue at the cellular level. In other words, functionalists are
concentrating on the higher levels at the expense of the lower
levels.
Another
way of putting this is to say what Churchland herself says: that
neuroscientists aren't ignoring functions at all. They are, instead,
tackling biological functions, rather than abstract cognitive
functions.
References
-
'Reductionism
and Antireductionism in Functionalist Theories of Mind'
(1986), in The Philosophy of Mind: Classical Problems/Contemporary
Issues (1992/1997), edited by Brian Beakley and Peter Ludlow.
- 'Neural
Representation and Neural Computation' (1989)
Edelman,
Gerald, quoted in John Horgan's The
End Of Science (1996)
Kim,
Jaegwon, 'Multiple
realization and the metaphysics of reduction' (1992)
- 'Mental Causation' (chapter 6) in his Philosophy
of Mind
(1996)
Searle,
John, 'Consciousness'
(1999)
Wilson,
E.O., quoted in What
Philosophers Think (2003),
edited by Julian Baggini and Jeremy Stangroom.
-
Consilience: The Unity of
Knowledge (1998)
