A DEDUCTIVE
ARGUMENT FOR
THE
REPRESENTATIONAL THEORY OF THINKING
William
G. Lycan
Wilfrid
Sellars, Jerry Fodor and others[1]
have argued that to think is to harbor and deploy a physically realized
mental representation.To put the
thesis not much less crudely: for S to think or "occurrently believe"
that P is for there to be a state of S's central nervous
system that (a) plays a characteristic information-storing role in S's
behavioral economy and (b) bears the semantic or propositional content
that P.The state bears that
content in much the same sense and in much the same way that a sentence
of English or another natural language means that P??at least compositionally,
in the sense of having proper parts and its meaning being a function of
the meanings of those parts[2]
(though the state may be diffuse and highly distributed rather than modular
or physically salient as public linguistic tokens are, and it has its content
naturally rather than (in part) conventionally as public linguistic tokens
do).The representational theory,
as I am calling it, is thoroughly empirical rather than purely philosophical,
since the existence of any central nervous system whatever is a thoroughly
empirical fact.
The
arguments for the representational theory take a number of impressively
different forms.The theory has also
come in for a good deal of criticism in recent years,[3]
and there too the arguments take a number of impressively different forms.I
have vigorously if not conclusively defended representationalism before;
in this paper I shall add one more argument to the "pro" side of the profuse
debate.
1.
The Deductive Argument
I
begin with an interesting rhetorical fact that has been underemphasized:We
representationalists tend to think not only that our view is true, but
that it is fairly obvious.Sometimes
in philosophical debate one needs to know not only what a party is claiming
but what epistemic status that party attaches to the claim.[4]Opponents
of the representational theory should be aware that this is one of those
philosophical occasions.Representationalism
is not supposed to be a hunch, a bold speculation or a wild throw of the
dice, but rather a truth that is pretty plain once a few not very controversial
assumptions have been accepted.Of
course some philosophers have rejected representationalism nevertheless,
perhaps disagreeing with the assumptions I have in mind.But
some philosophers who have not visibly repudiated the assumptions
have also rejected representationalism, sometimes suggesting that the representational
theory is gratuitously daring and/or outlandish.(Thus,
"Of course I'm a physicalist and a realist about beliefs and desires, but
I don't believe in little sentences written in brain matter or anything
crazy like that."My main opponents
are philosophers who are physicalists and intentional realists but who
do not believe in little sentences written in brain matter.)
Though
I shall be arguing that the representational theory is fairly obvious,
I emphasize that I am not about to indulge in brute a priorism.Representationalism
is an unmistakeably empirical and fallible claim.But
as Fodor said in The Language of Thought, representationalism is
also "the only game in town."No credible
alternative picture of thinking has taken the field??no matter how strongly
one may suspect that thinking is something other than physical mental
representation.[5]My
argument is intended to bring out this empirical obviousness as well as
the truth of representationalism.[6]
Let
us start the argument by considering what is at the same time one of the
most humdrum facts of human life and one of the most amazing facts of the
physical universe: natural-language speakers' staggering ability to understand
indefinitely long, totally novel sentences on the spot.Since
the 1950's, linguists have rightly marvelled at that fact, modestly called
by Chomsky "the creative aspect of language use," and at the uncountable
number of possible sentences that a normal speaker could and would understand
on the spot but for performance limitations.Linguists
have been driven by this infinitary or at least unbounded ability to suppose
that the sentences that are understood must be composed of atomic, semantically
primitive elements drawn from a finite and finitely learnable stock of
morphemes, and that the meanings of sentences are compositionally determined
by productive, recursive rules for arranging morphemes into certain combinations
and orders.(That, surely, is what
syntax or grammars of natural languages are for.)Speakers
must somehow have mastered those recursive rules even if they have never
explicitly represented the rules to themselves.
Notice
that in saying all this the linguists have not just rallied to an a
priori guidon.The morphemes-plus-compositional-rules
theory is empirical and fallible; it might be false.But
it is the only game in town.One cannot
now imagine any other explanation for the striking facts of speakers' near-universal
understanding (call those facts collectively "the unboundedness of understanding").[7]For
well-known reasons,[8]
Behaviorism will never do.Divine
inspiration is always a possibility, as Socrates says at the end of Meno,
but not a very likely one.
The
Chomskyan argument from unbounded competence out of finite resourcesto
recursive structure is familiar and overwhelmingly persuasive.How
could the thing be otherwise, barring either magic or divine intervention?[9]
But
now forget public natural languages and consider thinking.As
Dennett has noted,[10]
we have "essentially limitless powers" to think about different things
and states of affairs.(If the universe
contains things we simply cannot and could not in principle think about,
those things are remote to the nth degree.)We
may distinguish at least four claims here, in decreasing order of strength:
(i)
that any possible fact could in principle be an object of human thought;
(ii)
that any actual fact or nomologically possible fact could in principle
be an object of human thought;
(iii)
that within reason any actual or actually possible fact could in
principle be thought??that is, that although human capacities are ultimately
limited, the limitations have no measurable day-to-day effect and for practical
purposes, die Gedanken sind frei;
(iv)
that in real life, we can think nondenumerably many things, and one is
hard put to imagine any particular source of things we intractably could
not think or imagine.
In
one or more such sense, thinking is a universal capacity.Thought
can be about anything, where `can' and `anything' have one or another nondenumerable
range of values; possible propositional contents of thought are practically
unlimited.For short, I shall refer
to this unobjectionably vague feature as "the unboundedness of thinking."[11]
Take
this unboundedness of thinking as a premise, (I).Add
physicalism regarding the mind: the thesis that every psychological fact
about any human being is token-identical with some physical fact or other.Alternatively,
so as not to deter those who argue that physicalism is false of sensations,
add just (II) physicalism about thinking in particular.I
ask anyone who doubts physicalism about thinking to grant it just now for
the sake of discussion.
Now,
if the Chomskyan morphemes-plus-compositional-rules theory is the only
game in towm as regards the creativity/novelty/unboundedness of public-linguistic
understanding, then presumably a parallel theory is the only game in town
as regards the unboundedness of thinking.If
we cannot come up with a credible alternative in the former case, then
we cannot come up with one in the latter, for structurally the two are
exactly alike.If physicalism (II)
is true, then to explain the unboundedness of thinking, we need a finite
stock of semantically primitive physical elements and a compositional system
of recursive rules to project the atomic semantic values of the elements
into the composite semantic values of whole complex thoughts.
One
might suppose that if physicalism were not true, the unboundedness
of thinking would be easier to explain.Indeed,
for the nonphysicalist the two explanatory problems are not structurally
alike, since it is open to the nonphysicalist to insist that die Gedanken
are indeed frei in a way that physical public speech is not: the
mind has the power to think any uncountable number of things, each one
simply, primitively, and all of a piece,without
any sort of compositional analysis or recursive strategies.Quite
so.But the nonphysicalist does not
thus offer an explanation, but mystery and an appeal to magic.How
does the nonphysical mind accomplish its feat of unbounded thinking?It
just does; it is wonderful.My point
is that if one does seek an explanation of the unboundedness of thinking,
that extraordinary and very striking human capacity, one will not find
it in nonphysicalism, and so one is advised to accept (II) after all.[12]
Thus
we should proceed to (III): If the unboundedness of thinking holds, then
so far as one can see, we need a finite stock of primitive elements and
a compositional system of recursive rules to project the atomic semantic
values of the elements into the composite semantic values of whole complex
thoughts.And again given (II), the
elements must be physical and the rules must be physically realized (of
course not by being themselves represented).Thus
(IV): Human beings have systems of physical states, and/or host physical
events, that serve as semantically primitive elements of a lexicon, and
human beings (somehow) physically realize rules that combine strings of
those elements into configurations having arbitrarily complex propositional
contents in virtue of the semantic values of the primitives' having been
projected by the principles of composition.
(IV)
is the doctrine of representationalism??QED.And
granted (I)-(III), (IV) should be obvious.
2.
Obviousness and the Empirical
How
could a thesis about people's central nervous systems be both entirely
empirical and obvious to a philosopher who has done no relevant
scientific or other experimental research whatever?
Happily
for philosophers everywhere, there is a range of entirely empirical fact
that is accessible from one's armchair.Viz.:One
can often attend to some indisputable everyday pre- and non-philosophical
facts of life and draw some indisputably reasonable inferences from them,
without injecting any tendentious philosophical ideas.I
shall illustrate this possibility by elaborating a philosophically harmless
example.
Imagine
that we are aliens, perhaps visiting Jovians, inspecting Los Angeles and
scrutinizing in particular its dominant life form, the automobile.We
see only the automobile's outside, as it variously crawls and races along
the asphalt, but we note that its behavior is systematic: people who visibly
intend to go to certain places get into such a contrivance and then (usually)
end up in the places they wanted to go.An
automobile, we discern, is a device that takes travellers' travel-intentions
as inputand outputs the destinations
intended.How might such a thing do
such a thing?
Without
doing more than looking at a functioning automobile from a distance, we
Jovians could reasonably infer the following:There
being no sail, poles or jetstream, the auto moves by dint of its high-friction
contact with the road, specifically because its wheels (for such they are)
turn without slipping.Thus some inner
mechanism applies torque to the wheels to make them turn.A
power source is required to drive that mechanism, and there must also be
some system of cogs, gears, belts, rods, or their functional equivalents
to convert whatever sort of energy is produced by the power source into
kinetic energy and transmit kinetic energy to the wheels.
Meanwhile,
the driver must have constant and minute control over the transmission
process, since both the speed and the direction of the vehicle are a function
of the driver's intentions.There
must be a device (which might naturally be called an "accelerator"), directly
accessible to the driver inside the car, that affects either the amount
of energy generated by the power source or the flow of energy from the
power source to the wheels??presumably the former, since otherwise there
would be superfluous energy to be got rid of and wasted.Moreover
the accelerator's effect various continuously, like that of a rheostat,
rather than like that of a switch.Further,
there must be a similarly accessible steering mechanism that controls direction,
by turning the front wheels continuously left or right.Still
further, there must be a device to overcome the heavy vehicle's inertia
when a sudden slowing or stop is required??call it a "brake."The
brake may be a special feature of the acceleration system (as when jet
pilots slow down by reversing their jets), or it may be a mechanically
separate component that acts more directly on the wheels; but it is not
a sail, a parachute or an anchor.
Thus
we already know a good deal about auto mechanics without even looking through
the car window, much less raising the hood.If
we allow ourselves a closer look and listen, we can infer still more.The
power source very probably is a combustion engine of some sort, since neither
an electrical nor a nuclear engine would make noise??the noise is in particular
one of muffled explosions??and the auto emits gases typical of combustion
byproducts.Periodically the auto
is seen to stop for infusion of a specially marketed fluid, presumably
fuel of some sort.
Assuming
the power source is indeed a combustion engine, at least five more components
must be posited.There must be a fuel
reservoir, a fuel line, a carbureting device to mix oxygen into the fuel,
and a combustion chamber with at least one compressible wall.Moreover
there must be a standing auxiliary power source at all times available
to ignite the fuel when the auto has not been used for some time; a battery
is the obvious though by no means only choice.
I
have said that "we already know" a good deal of auto mechanics without
looking inside even a single auto.Skeptically
inclined philosophers who are stingy in the matter of knowledge ascriptions
would be reluctant to give in on this one.We
speculating Jovians do not really know the things we have speculated.There
are alternative possibilities that we have not specifically ruled out.Perhaps
cars are shot out of their garages by powerful slingshots, maintained in
motion by internal gravity wheels, and steered by pre-programmed home computers.Or
perhaps they are pulled along their actual routes by powerful magnets hidden
underground.Or perhaps they obey
divine commands, and their innards are irrelevant.Or
perhaps they work by telepathy, or simply by magic.
The
existence of such alternatives is real, but not very impressive.The
slingshot and magnet hypotheses could be ruled out by only slightly closer
external observation of drivers and autos.The
remaining competitors cannot be ruled out in that way, but are implausible
given our general knowledge of the world and the methodological assumptions
of science.None of the alternatives
is a live option.The auto must
instead work in something like the way we have hypothesized.But
this "must" is still empirical in character, and expresses nothing even
so strong as nomic necessity.
So
too with representationalism.The
representationalist asks, "What else could it be?," meaning not that there
is no conceivable alternative but only that at least for an intentional
realist, the conceivable alternatives are not live options.Representationalism
may still turn out to be wrong, but it is hard feasibly even to imagine
a real-world alternative.
3.
Objections and Replies
I
claim that the argument of section 1 constitutes a powerful defense
of representationalism as I have characterized that doctrine.Now,
there are further claims that have sometimes obligingly been tacked
onto representationalism by its critics, such as that the brain-realized
representations are physically salient, or that they actually have syntactic
forms characteristic of natural languages, or that they have syntactic
forms characteristic of the predicate calculus, or whatever.I
doubt that any of those generously supplied further claims is true.But
no representationalist qua representationalist has ever been committed
to any of them.
There
is a gap, however, between my conclusion (IV) and a fully-fledged representational
theory of thinking:Though I claim
that physical states of people's nervous systems have semantic values,
which (off the record) I understand in terms of reference and truth-conditions,
I have said nothing about what it is that endows a bit of brain
matter with its semantic value.If
the semantic value of a mental morpheme is a referent or extension in particular,
in virtue of what does the referential relation hold between the morpheme
and the external referent?This is
Wittgenstein's question, "What makes my image of him into an image of him?"[13]An
answer to it would be what Fodor calls a "psychosemantics."A
fully-fledged representational theory of thinking would incorporate a psychosemantics.
I
emphasize that I offer no psychosemantics here.[14]If
my conclusion (IV) is correct, there must exist a correct psychosemantics;
but its details must be left for another occasion.
Let
me now address two quick objections to the deductive argument itself; then
I shall go on to anticipate three more substantive criticisms.The
first objection[15]
is that premise (III) simply begs the entire question; at any rate representationalism
appears to me as the "only game in town" only because (III) gives all other
games away.If one accepts (III),
then of course representationalism seems painfully obvious.But
why should we accept (III)?
I
reply that, as before, we should accept (III) because its consequent is
the only known or imagined viable explanation of its antecedent.Indeed,
in one very crude sense of "recursive," to say that a device produces infinitary
output from a finite stock of elements just is practically to call
the device recursive.Again, we must
grant??as I do??that (III) might be false, but since we cannot see how
(III) could be false, we are entitled to assume (III) to be true, until
someone should come up with an alternative, nonrecursive account of the
unboundedness of thinking.I shall
consider one attempt at one, below.
The
second quick objection is that even if my deductive argument is in fact
sound, I have oversold it.I have
billed it as a deductive proof, but since premise (III) rests on admittedly
explanatory considerations as we have just seen, we should consider the
argument instead as a piece of abductive reasoning, as an inference to
the best available explanation.Thus
more modestly understood, the argument is more likely to convince, and
in particular the now only tentative assumption of (III) will seem less
arrogant and be less rash.Representationalism
is the best going explanation of the unboundedness of thinking in a physical
system, even if it is not the only possible explanation.
If
forced to rhetorical retreat of this sort, I would of course accept the
weaker explanationist position.And
I grant that my deductive argument is at bottom a special case of inference
to the best explanation.[16]But
what I am emphasizing in this paper is that it is a very special
case.The point of my automobile example
was that from time to time the world presents us with a striking sort of
datum, viz., a datum that, practically speaking, admits of only
one explanation.In such a case,
it is tempting to describe one's reasoning as "inference to the only
explanation," an inference perhaps intermediate in strength between ordinary
explanatory inference and deductive demonstration.[17]Admittedly,
the difference between this inference and ordinary abduction is one of
degree, not of kind, since it is fallible and relies on one's overall view
of the world; "only" in "only explanation" means "only feasible," not "only
conceivable."But I think the rough
distinction is worth preserving, and that is why I resist the proposed
deflation of Fodor's claim and the forensic status of my argument.
I
now turn to tougher opposition: an eliminativist response, an instrumentalist
and/or "environmentalist" response, and a Connectionist response.
1.
An eliminativist denies the argument's first premise (I), on the grounds
that no one ever thinks anything at all.[18]Eliminativism
is a position I respect, but reject (on Moorean grounds combined with the
inadequacy of arguments for the position[19]).This
paper offers no answer to a staunch eliminativist, but if one really is
an eliminativist one already has trouble enough.
2.
There is a type of philosopher, descended from Heidegger, Dewey, Wittgenstein
or Ryle, who abhors inner-process, causal-mechanical views of thinking
and who sees thinking as rather a matter of outward aspect and/or environmental
surround.This "instrumentalist/
environmentalist" (i/e) view has many importantly distinct versions, but
here I can address it only generically.[20]The
i/e-ist claims that although brain processes are causally implicated in
thinking, they do not constitute the truth-makers of thought-ascriptions;
they are not part of what thinking itself is.What
a person thinks is determined by that person's behavior in response to
stimuli and/or that person's social context and/or the explanatory interests
of that person's friends and/or "interpretation" on the friends' part.If
this is right, then (I)-(III) do not after all entail (IV):There
is an alternative physicalist explanation of the unboundedness of thinking,
one that does not invoke semantically charged brain processes.Physically
realized mental-morphemes-plus-compositional-rules might exist without
being localized in individual humans' central nervous systems.
True,
they might, and the objection is correct: (IV) is not a logical
consequence of (I)-(III).But this
is yet another case of the only game in town.For
to pursue the i/e alternative we have to ask what outer, behavioral-cum-social-cum-predictive
physical states of affairs could physically realize mental-morphemes-plus-compositional-rules.Behaviorist
resources are notoriously not up to the task.Conventions
and social practices are rich and various, but they all presupposes thinking
on the part of a social group's members.This
does not necessarily lead to circularity, since someone might devise a
recursive social theory of thinking that specified a base set of
thoughts without reference to other thoughts or thinkers and then defined
a larger class of thoughts by reference to the base thoughts.But
what would actually be the base thoughts in such an account?It
is hard even to speculate.Moreover,
wherein would the base thoughts have their semantic values, without
reference to further thoughts?I
am not suggesting such a theory is impossible.I
am saying only that we cannot now begin to see how it would go, much less
provide even a sketch of it.
If
my argument from unboundedness is to be valid, we need a bridge premise
to get (IV) from (I)-(III).I propose:
(B)If
(I), (II) and (III), then (IV).
(B)
neatly restores validity to the argument.(B)
is not logically true, but I have a hard time doubting that (B) is true.[21]
3.
It may be complained that as a matter of plain fact the representational
theory is not the "only game in town," but has real-world competitors.The
leading alleged competitor would be contemporary Connectionism.[22](In
capitalizing the term I am following recent neologism and referring to
a philosophical contention again reminiscent of Wittgenstein and Ryle,
roughly that intelligent human capacities, thinking and rationality are
somehow holistically emergent from connectionist architecture in the brain
rather than being a matter of the manipulation of internal representations
according to rules.[23]I
shall use lower-case `c' when meaning just the type of engineering or programming
architecture.)
But,
logically speaking, either connectionism or Connectionism is entirely compatible
with representationalism, and arguably it is an instance of representationalism.[24]In
any case, any Connectionist who wanted to deny the representational theory
would have to find something wrong with my deductive argument, and nothing
about connectionist architecture itself immediately suggests any criticism
of the argument.That connectionist
architecture differs topologically from von Neumann architecture seems
to affect the argument not at all, though the difference is of much importance
to the practice of AI itself.In particular,
that representation is distributed rather than modular is no embarrassment
to the representational theory; in fact, it entails it.
But
the matter cannot be dismissed quite so handily.As
Stanley Munsat and Stephen Stich have pointed out to me, a Connectionist
might deny (III), the Chomskyan premise that if thinking is unbounded in
my sense then there must be a recursion on a finite stock of semantic primitives;
connectionist architecture might be put forward as a genuinely alternative,
competing way of getting unbounded competence from finite resources.(This
would be a very radical and important suggestion, given the enormous power
and persuasiveness of Chomsky's original argument.)
But
it is still hard to see how connectionist architecture alone could do that.Consider
again the case of a subject's hearing a long, novel sentence and immediately
producing an equally complex and contextually appropriate utterance in
response.Our Connectionist would
have to claim that the response was mediated by the activation pattern
on the system's hidden units but also that no mental morphemes or semantic
primitives could be abstracted from the activation pattern itself.This
impossibility of abstraction seems to me very unlikely.Take
the example of NETtalk, a connectionist program that (after training) audibly
pronounces English words given written text.[25]NETtalk's
accomplishment is very impressive, for each of three paradigmatically connectionist
and Connectionist reasons.First,
the task is very tricky, since the actual function from English spelling
to oral pronunciation is highly irregular.Second,
the function is also many-many rather than one-one or many-one, since the
pronunciation of a given letter or letter-group depends heavily on intralexical
context.Third and most notably for
philosophy of mind, the machine is initially given neither rules of phonology
nor representations that look like rules of any other kind, but only a
general and topic-neutral learning algorithm that adjusts various activation
levels between word-presentation trials.At
first the feat seems like magic.And
philosophically, to some, it seems like a Rylean/Wittgensteinian dream
come true??highly intelligent behavior unmediated by representations
and rules.
However:As
is well known, mature NETtalk activation patterns at the hidden layer are
found to be partitioned into disjoint classes.There
are 79 of those classes, and as many people have pointed out, this is no
accident; they correspond to the 79 distinct letter-to-phoneme moves that
are mastered by a normal competent speaker of English.Now
it also turns out, under a "cluster analysis" carried out by Rosenberg
and Sejnowski (op. cit.) that involved grouping by similarity along
certain parameters and averaging of values, that the 79 classes are also
grouped into two main superclasses and various hierarchically organized
subdivisions of those.The two main
superclasses correspond to the vowels and consonants of English,
and the subdivisions (again, made on the basis of a general similarity
metric) correspond to familiar vowel and consonant subtypes.Thus,
out fall all the phonemes of English phonology.Though
NETtalk is handed no phonological rules by its creators, it acquires phonological
categories in the process of learning its job, and, we may say counterfactually,
it would not have achieved its extraordinary accomplishment had it not
acquired those categories.It is still
extraordinary, as well, that the categories cannot in any simple way be
read off the raw graphological input; nonetheless NETtalk acquires them,
and accordingly, it seems to me natural to ascribe phonological concepts
to NETtalk (though one may quibble over what rich computational properties
a feature of a system might be required to have in order to count as a
bonafide concept rather than merely a discriminative ability).[26]
In
similar wise, one would expect, the familiar morphemes would fall out of
a connectionist syntax and semantics for a general natural-language-understanding
machine.(This expectation is reinforced
by the known psychological robustness of morphemes in humans,[27]
though I do not like to sully the a priori nature of my argument
by officially appealing to psychological experiment.)Indeed,
one can argue from the presumed supervenience of actual and counterfactual
linguistic differences on the connectionist architecture, to the claim
that there would have to be systematic counterfactual differences in the
activation pattern, however holistically they would need to be characterized,
and those systematic differences would presumably constitute differences
of semantic elements.[28]Notice
also that in the case of human language (as Jay Rosenberg has pointed out
in conversation), the back-propagation of error used to "train up" connectionist
networks is conducted in semantic terms, e.g., by misunderstanding or by
correction.
But
all this is beside the point, for our concern here is not with the explanation
of public linguistic behavior, but with the unboundedness of thinking.Notice
that even if the Connectionist objection did work against Chomsky for the
case of natural language understanding, it does not obviously apply to
thinking at all.Thinking itself
is not a matter of turning an input into an output, even though it is functionally
specified ultimately in terms of inputs and outputs and other psychological
states.How would a connectionist
machine itself have the capacity to think an indefinite number of indefinitely
complex and novel thoughts?Either
it could not, or (surely) it would do so by having a finite repertoire
of physical states it could be in that would implement those thoughts.Any
Connectionist is free to seize the former disjunct and add that a great
virtue of connectionist machines is that they do not need to have
individually specifiable "thoughts" in order to transform their inputs
into intelligent outputs; this claim would be very much to the liking of
some Connectionist converts I know.But
notice (carefully!) that to say this is to suggest the quining or elimination
of thinking, not an alternative to the Chomskyan explanation of the unboundedness
of thinking.So I do not see that
(III) is in danger.[29]
Still,
the NETtalk example strongly suggests a possible revision in the representationalist's
conception of mental morphemes.
4.
An Alternative Picture
It
is not unnatural, though it is inaccurate, to characterize representationalists
as advocates of "brain writing."We
representationalists do often write or speak as if it is bits of brain
matter that have semantical properties, just as bits of ink do when
suitably arranged on pieces of paper.More
properly, since propositional attitudes are not physical individuals but
states of or events occurring within physical systems, what we have meant
is that brain states and events have the semantical properties.But
either way, admittedly, we have conceived the relevant attitude-tokens
as admitting of forthrightly neurophysiological description, whether or
not those tokens are morphologically salient in the brain.
Now,
consider NETtalk again.Even after
NETtalk has been trained up (cf. fn 26), no state of its units described
in hardware terms corresponds to its concept or "concept" of /ey/,
nor any such state to its sophisticated "belief that" the input word "weigh"
is pronounced /wey/.NETtalk's concepts
were discovered only by a very abstract statistical analysis, and, more
to the point, they can noncircularly be characterized only in the same
abstract statistical terms.They are
none the less real for this, but they are the less meaty (so far as the
"units" of a "connectionist network" being simulated on a digital computer
can themselves be called meaty).NETtalk's
having a concept or a "belief" is (a large mass of) NETtalk's units' collectively
having a certain statistical, hence essentially mathematical, property.
So
too, perhaps, with human concepts and beliefs.Dennett
notes that if our brains' architecture is connectionist, the "brain-thingamabob
[that] refers to Chicago" would per se have to be described statistically
and in terms of the whole connectionist system or a very large sector of
it.[30]And
although our brains' architecture is very unlikely to be literally connectionist
(there being no internal "supervisor" or "teacher" to provide instant correction
of error), our brains are more connectionist than they are von Neumann.It
is a strong possibility that the NETtalk model extrapolates to brains??that
human belief-states are not hardware-described states, but only statistical
patterns manifested by largeish regions of the brain.For
a person to have the belief that P is for a functionally cognitive/representational[31]
region of that person's brain to exhibit such-and-such a statistical feature,
and??in light of Twin-Earth examples??for that feature to be causally grounded
in whatever objects and properties figure in the proposition that P.As
with NETtalk, this grounded-statistical-abstraction picture makes intentionality
and belief none the less real or objective.(For
reasons of euphony, let me revise that label and make it "the grounded
abstract-statistical picture," acronym "GASP.")An
i/e-ist who thinks in particular that intentional content depends on interpretation
could not accept GASP, for the statistical properties of brain regions
and their causal groundings are entirely independent of interpretation.
The
last two sentences sound alarmingly like Dennett's protestations in "True
Believers"[32]
that his own interpretion-based view does not rob his concept of belief
of its objectivity.Alarmingly, not
because Dennett's view does not preserve objectivity (it does so, by making
attitude content a matter of whether someone's taking a certain interpretive
stance would in fact achieve good predictive results).Rather,
because (a) for Dennett, attitude content is still conceptually constructed
out of purpose-relative interpretation, in my view an unhealthy feature
for a theory of content to have; (b) Dennett's objectivity does not amount
to determinacy, and he explicitly endorses Quine's indeterminacy
thesis for content; (c) for Dennett, a thing's innards (including the matter
of whether it even has any) are conceptually irrelevant to its having intentional
states; (d) Dennett himself has always used mathematical abstractions,
such as centers of gravity, kinematic vectors, and the Equator, to illustrate
the sort of view he favors, and in an important recent paper, "Real Patterns,"[33]
he emphasizes the reality of mathematical abstractions and de-emphasizes
interpretation.
I
am all right as regards (a), (b), and (c).GASP
has none of the three implications I find objectionable.In
particular, abstract statistical properties of NETtalk's sort owe nothing
to interpretation, even hypothetical interpretation; GASP-content is still
determinate (so far as has been shown); and a believer's innards must have
highly articulate structure in order to support the type of statistical
abstraction to which I am appealing.But
what of (d)?What distinguishes GASP
from Dennett's view on that score?
Actually
I think we need to note what distinguishes Dennett's mathematical examples
themselves from his view.I have always
found his appeal to mathematical abstractions incongruous with his own
underlying interpretivism.Centers
of gravity and the Equator are real and as they are, independently of (even
hypothetical) interpretation; they are determinate features of physical
systems; and the systems whose features they are have, and must have, the
physical structure needed to support the abstraction that reveals them.Thus,
they do not well illustrate the basic position he actually defends.For
that reason, I am not uncomfortable with (d) once (a)-(c) have been set
aside.[34]
But
to return to this paper's central theme:Arguments
for representationalism often double or triple as arguments for physicalism
about thinking and as defenses of the propositional-attitude part of folk
psychology, and the three issues tend to get mixed up and run together.My
main minimal point here is that if one simply assumes both physicalism
about thinking and the probity of folk psychology, representationalism
is, in light of the unboundedness of thinking, almost inevitable.Even
better, if one defends both physicalism about thinking and the probity
of folk psychology, representationalism is almost inevitable.If
on the other hand one chooses to question either physicalism about thinking
or the probity of folk psychology, one is fighting on another front entirely,
and against very well entrenched and powerful opponents.[35]
Department
of Philosophy
University
of North Carolina
Chapel
Hill, NC27599-3125
USA
FOOTNOTES
[1]Sellars,
Science, Perception and Reality (London: Routledge and Kegan Paul,
1963), Science and Metaphysics (London: Routledge and Kegan Paul,
1968), and, to say the least, elsewhere; Fodor, The Language of Thought
(New York: Crowell, 1975); RePresentations (Cambridge, MA: Bradford
Books / MIT Press, 1981); Psychosemantics (Cambridge, MA: Bradford
Books / MIT Press, 1987), and, t.s.t.l., e.See
also Hartry Field, "Mental Representation," Erkenntnis, Vol. 13
(1978), and the papers collected in Part I of my Judgement and Justification
(Cambridge: Cambridge University Press, 1988).
[6]I
originally entitled this paper "A New Argument...."But
since first drafting it, I found something very close to my deductive argument
on pp. 147-148 of Fodor's Psychosemantics,
loc. cit., in
Fodor's appeal to the "productivity" of intentional states.It
had also been hinted at in Gilbert Harman's formal comment on Loar (op.
cit.), and encapsulated in a sentence on p. 93 of John Haugeland's
Artificial Intelligence: The Very Idea (Cambridge, MA: Bradford
Books / MIT Press, 1985).And, more
recently, see J.A. Fodor and Z.W. Pylyshyn, "Connectionism and Cognitive
Architecture: A Critical Analysis," Cognition 28 (1988).
To
the extent that we can discover the properties of the language faculty,
we can construct `unlearnable languages,' languages that cannot be acquired
by the language faculty because at every point it will make the wrong choices,
the wrong guesses as to the nature of the language.(Language
and Problems of Knowledge (Cambridge, MA:MIT
Press, 1988), p. 150)
Indeed,
Chomsky points out, any imaginable creature's language faculty would have
to have some structure or other, and so could be crashed in the way described.(See
also J.A. Fodor, The Modularity of Mind (Cambridge, MA: MIT Press
/ Bradford Books, 1983), pp. 120-126).But
structural constraints of this sort do not affect Chomsky's argument for
recursion, for they place no practical limits on what human beings
can understand in the course of everyday life, and in particular they do
not reduce the infinitude of competence.
[12]This
is not to deny that a nonphysicalist might adopt the Chomskyan model, so
long as the nonphysicalist's idea of mental contents were sufficiently
articulated.I thank Bill Alston
for pointing out that the present claim offers no embarrassment to nonphysicalism
per se.
[19]For
brief criticism of the main arguments, see my "Ideas of Representation,"
loc. cit.Briefly:The
(in one way) scientific ill-behavedness of intentional phenomena per
seis no reason for doubting the
existence of intentional items; nor does the alleged poverty of folk psychology
considered as science convince me that folk psychology has not succeeded
brilliantly for a folk science, or that that success should not
be taken at face value as licensing the standard abductive inference to
the truth of the view, or that the success is not quite amazing considered
on its own.And I am more certain
that I myself and other people have thoughts than I am of the premises
of any purely philosophical argument designed to convince me to the contrary.