Transcript There’s No Such Thing as Conscious Thought

Inner Speech
Michael Johnson
VAP HKU
Outline
1.
2.
3.
4.
5.
Two Puzzles
Separatism
Why Inner Speech?
The Computational Explanation
Conclusion
1. TWO PUZZLES
Puzzle #1
Suppose we can think about propositions,
probability distributions, and utility functions,
and can compute expected utilities from them
(or whatever). What does making any of these
states conscious gain us?
What is the purpose of conscious thought? If
thinking is computational, how could something
as obviously non-formal as consciousness make
any difference?
Thinking in French
In About.com’s “French Language” article, author
Laura K. Lawless speaks about the virtues of daily
French practice:
“Thinking about French every day will help you
learn how to think in French, which is a key element
of fluency.”
Lawless assumes a quite natural view, namely that
one can think in this or that natural human
language.
Thinking in English
It seems to me, a monolingual English speaker,
that whenever I’m conscious of thinking, I’m
thinking in English. Sometimes I can’t find the
words to express what I want to say, and there’s
a ‘gap’ in the interior monologue. I suppose it’s
filled with thinking—thinking of what to say—
but I don’t experience that thinking. All the
thinking I experience is English-thinking.
Thinking in Language
“[A]fter much practice, we no longer really need
to call forth a symbol, we do not need to speak
out loud in order to think. The fact remains that
we think in words or, when not in words, then in
mathematical or other symbols. Without
symbols we would further hardly raise ourselves
to the level of conceptual thought.” Frege,
Puzzle #2
Let’s call thinking in English or French or
Cantonese ‘inner speech.’ What the last
observation suggests is that inner speech is the
phenomenal character of thought. This itself is
puzzling because we know that the language of
thought is not English (or French or Cantonese).
Why is thought (≠ English) experienced as
English?
Arguments that LOT ≠ English
Extensional inequivalence:
• Pre-linguistic infants think (else they can’t
learn languages).
• Deaf adult humans who don’t know signlanguage (or a spoken language) think.
• Non-human animals think.
Arguments that LOT ≠ English
Computational inadequacy:
• LOT articulates elements unarticulated by
English (PRO, pro, etc.)
• LOT is scopally unambiguous where English is
not– every thought of “Every boy loves some
girl” is determinate as to the order of the
quantifiers.
Puzzle #2 is Deeper
It wouldn’t really matter if LOT were English. It
would still be weird for it to have a phenomenal
character similar to perceived spoken English.
One way to see this is to suppose
representationalism (e.g. Dretske 1997) is true.
The p.c. of a conscious state = the property that
state represents.
The Puzzle, Assuming Rep’ntationalism
Then since the p.c. of perceived spoken English
is roughly the same as the p.c. of inner speech,
they should represent roughly the same thing.
But my auditory perceptions of English
represent sounds, and the vast majority of my
thoughts (those not about sounds) don’t
represent sounds.
Puzzle #2
I don’t want to assume that representationalism
is true. But the assumption foregrounds a
genuine oddity, no matter your theory of
consciousness: thought and perception of
spoken English (Cantonese/ whatever) are
radically different. Why should they be
phenomenally similar?
2. SEPARATISM
Puzzle #1 Redux
Many of our perceptual states are conscious, in
that they have phenomenal characters.
Suppose as a result of retinal stimulation, our
visual perception module can segment scenes
into edges, edges into boundaries, boundaries
into objects, objects into parts, etc. What does
making any of these states conscious gain us?
Consciousness as a Free-Rider
Nothing, and that’s the standard view. That
these states are conscious is necessitated by
their causal and representational properties (or
whatever). We can’t make a state without the
relevant causal/ representational properties
conscious, and we can’t make a state with them
non-conscious.
Consciousness as a Free-Rider
Maybe thoughts are like perceptions. They have
phenomenal characters that supervene on their
causal and representational properties.
Consciousness adds nothing, because
consciousness cannot be added to anything.
An example of such a view might be Dennett
[cite]. In Dennett’s view, for a state to be
conscious is just for it to occupy a certain sort of
influential role with respect to memory and
action. Something that doesn’t occupy that role
can’t be “made conscious” unless that means
“made to occupy that role.” [Dennett thinks that
there isn’t any phenomenal consciousness
though, just access consciousness.]
Problem
But only some very small number of thoughts
are conscious. So we face a dilemma: either we
reject the claim that the causal or
representational properties of thoughts
necessitate their having p.c.’s or we find some
causal or representational difference between
the conscious ones and the others. What could
such a difference be? (Cf. Dennett)
Reason to Reject Thoughts with P.C.
The conscious properties of perceptions are not
affected by our past experiences. I don’t learn
how to see redness when I look at red things.
But until I learn, say, French, none of my
thoughts are accompanied by inner French. I
can’t see “in French” but I can think “in French”.
Second Reason
Everyone with normal, functioning sensory
faculties sees/ tastes/ feels/ etc. things in much
the same way. But what it’s like for me and a
cognitively normal monolingual French speaker
to think that it’s mom’s birthday on Tuesday is
different.
Puzzle #2 Redux
Even if we manage this dilemma, we’re still
stuck with Puzzle #2. Why is the phenomenal
character of thought so much like the auditory
perception of English (Cantonese) utterances?
Separatism
Separatism holds that thoughts are never
conscious. What happens in the case of inner
speech is that a thought causes a perceptual
state, and the perceptual state is conscious (as
outlined in the solution to Puzzle #1). So
thinking about my mother has no p.c. but it
might cause states that do, like a mental image
of my mother or an auditory “image” of the
word ‘mom.’
Evidence for Separatism
The strongest evidence for separatism (with
respect to thought vs. inner speech, at least) is
the more-or-less complete overlap (modulo
motor activation) between brain activation in
speech production and brain activation in inner
speech production.
Brain Areas Implicated in Speech
• Lexical selection: left middle of temporal gyrus
• Syntactic encoding: Rolandic operculum, left
inferior frontal gyrus
• Phonological code retrieval: right SMA, left
anterior insula, middle temporal gyrus
(Wernicke’s area)
• Phonological encoding: the left posterior
inferior frontal gyrus (Broca’s area) and the
left mid superior temporal gyrus (STG)
The Brain and Inner Speech
Importantly, in both inner speech and auditory
visual imagery (imagining someone else saying
something), all these brain areas are active.
Many researchers (e.g. Bookheimer 2002) think
the brain activity in inner speech is the same as
in overt speech– just a little less strong, and
minus the motor activation. (There’s equivocal
evidence that some areas are differentially
sensitive.)
Broca’s Area
Finally, patients with damage to Broca’s area can
suffer expressive aphasia– an inability to speak
or write words.
Transcranial magnetic stimulation of Broca’s
area has been shown to inhibit inner speech
(interferes with a covert syllable-counting task).
Some evidence suggests Broca’s area is more
active in inner speech than overt speech.
Why Inner Speech?
But here’s where the current consensus ends,
and problems remain unresolved. How does
inner speech help?
If you’re thinking in a logically perspicuous
language (LOT), why go to the lengths of
translating that into a less perspicuous language
(English), which you then proceed to not think
in? Why inner speech?
The Problem
Let’s be clear where we are. We had a puzzle as
to why thoughts are conscious in the first place,
and a puzzle as to why the phenomenal
character of thoughts was English (or French or
whatever). Separatism has a solution to both
puzzles: it denies that thoughts are conscious
and maintains that the phenomenal character of
inner speech is expected, given that inner
speech is more-or-less auditory imagery.
The Problem
But the analog of both puzzles reappears. Now
it’s not “why is thought conscious?” but “why is
unconscious thought accompanied by inner
speech?” Furthermore, why is it inner speech,
given that we know that English is less logically
perspicuous than LOT?
3. WHY INNER SPEECH?
Three Explanations
Here are three potential explanations:
1. There’s no benefit to inner speech, it’s a sideeffect of something else.
2. There’s a benefit to inner speech, namely
that it’s conscious whereas thought is not
and cannot be (the separatist consensus).
3. There’s a benefit to inner speech, but one
that has nothing to do w/ its consciousness.
Side-Effect Explanation
Here’s the sort of story one might tell: for
conversation, we need to translate LOT into
English quickly. Maybe the mechanism that does
that translates all the thoughts in the relevant
buffer, without regard to whether you want to
give voice to them. So when you’re sitting by
yourself, that’s what you’re hearing– even
though it does you no good at all.
Something Like This?
This particular explanation won’t work (why in
the world would it route them through hearing?
What you need for rapid conversation is quick
translation from thought to speaking.)
But could something like it work?
Not a Side-Effect
I don’t think so. There’s a fair bit of literature on
the benefits gained by inner speech. They
include higher self-awareness, greater
intelligence, improved mathematical ability, and
better memory.
Inner speech is doing something. The question is
how it is doing it.
Consciousness Explanation
A second possible explanation goes something
like this: “Wow, if the separatist is right, then
thoughts aren’t conscious. But consciousness
has all these benefits right? Like, it’s a “global
workspace” that makes information available,
um, globally. So we translate our thoughts into
inner speech to gain the consciousness benefits
inner speech has by right of its perceptual
nature.”
Wrong Order of Explanation
But this line of reasoning has the order of
explanation backwards. It’s fine to say that the
computational role (e.g. global accessibility) of
something necessitates its having a phenomenal
character. But things don’t go the other way:
p.c.’s don’t necessitate things having certain
computational roles. And even if they did, that
wouldn’t explain why you couldn’t give thought
the relevant c.r. and skip the inner speech.
Linguistic Encoding
There’s also the question as to how something
linguistically encoded (like inner speech) could in
principle be globally accessible. Just how many
mental faculties can process language?
Computational Explanation
I’m going to argue for the third possibility. Inner
speech does have a purpose (contra possibility
#1), but that purpose doesn’t lie in the fact that
it’s conscious (contra #2). Instead, inner speech
has computational properties that make it of
use; its consciousness is a side-effect of its
status as a perception, not what’s worthwhile
about it. The consciousness of inner speech is a
red herring.
4. THE COMPUTATIONAL
EXPLANATION
Adding Numbers
Suppose I ask you, out loud, to add “five million,
four hundred and three thousand, nine hundred
and ninety four and four hundred and forty six
thousand, eight hundred and thirteen.”
Probably, you can’t do it. Maybe you can, if you
were quick enough to write down the numbers
as I was saying them. And then when you solved
the problem you’d use paper and pencil as well.
Why Not Native?
But why don’t you use your native number
representations and your native addition
algorithm to solve the problem? Why not take
your concept of 5,403,994 (which was activated
when you understood me saying “five million,
four hundred and three thousand…”) and your
concept of 446,813, and then add them
together using LOT’s addition algorithm?
Possibilities
• Maybe LOT can’t add. You can think 5, and you
can think 2, and you can think 5 + 2, but
there’s no program in LOT that will take you
from there to 7.
• Maybe LOT can’t add large numbers. Maybe
its addition algorithm is a lookup table that
doesn’t handle arguments higher than 8.
More Possibilities
• Maybe there is a native algorithm for addition,
but it’s inefficient for large inputs.
• Maybe we can add natively, but we can’t
convert the sums back into English.
• Maybe we are like chimps and gorillas and
don’t even have the concept of 446,813. You
can’t compute functions over representations
you don’t have.
Benefits of Paper
Benefits of Paper
Even if you have no native concept of numbers,
or no means of natively computing sums with
such concepts, you can still write down Arabic
numerals and compute sums with them
(provided you can recognize shapes and you
remember what shapes to write down when you
see which other shapes, etc. You can be a
Chinese… er… Arabic Number Room, even as an
innumerate.
Visualization
And when we don’t have paper, we can resort to
the next best thing: mental paper. We can
imagine the symbols written out– re-create our
perceptions of the written symbols– and
manipulate them in imagination.
Arabic numerals provide an advantageous
representational format for solving arithmetic
problems.
The suggestion then is that linguistic expressions
provide an advantageous representational
format for solving epistemic problems (what
should I believe, given my evidence?).
The way I’m imagining this happening is this.
Suppose for whatever reason our native
machinery can’t work out some instance of, say,
disjunctive syllogism. Let’s say that it’s just
incapable of inferring the right disjunct from a
disjunction and the negation of its left disjunct.
We have the ability to translate these LOT
premises (conditional and antecedent) into
English. So suppose we do that and get:
“P or Q”
“not-P”
Now the problem no longer requires us to
execute disjunctive syllogism. If we’ve learned
the rule “When you’ve got something of the
form ‘P or Q’ and something of the form ‘not-P,’
you may conclude ‘Q’”, then a simple step of
modus ponens gets us to “Q,” and translating
back into Mentalese gets us our answer.
The Lesson
Learning rules to manipulate symbols in inner
speech gets us around the need to have the
ability to manipulate the analogues of those
symbols in thought.
Let’s spell out the possible advantages again:
1. Maybe our native algorithms can’t solve
certain decision problems or can’t solve
decision problems with a certain degree of
complexity.
Remember that some of the benefits of inner
speech (according to psychologists) are higher
intelligence and higher mathematical ability.
2. Maybe the native algorithms are, from the
point of view of the problems we want to solve,
crude heuristics which we can improve upon.
Consider the Wason selection task. To solve it, I
have to think about it. Why is that? Because my
native heuristic gives me the wrong answer
A final possibility is that inner speech may allow
us to get by without certain concepts. Fodor
argues that you can’t learn concepts like
CARBURETOR. Most people think concepts like
CARBURETOR are not innate. Put those views
together, and it seems likely that we haven’t got
CARBURETOR. But how are we so successful vis
a vis carburetors?
Here perhaps we just skip thought altogether.
We have a stored set of English sentences
involving the word ‘carburetor.’ When we hear a
new ‘carburetor’-sentence, or find ourselves in
circumstances where we’re trained to say
‘carburetor,’ we take out the store of sentences
(or some of them), try to derive consequences
from them and the new sentence, and if any of
the consequences translate back into Mentalese
as “duck!” we behave appropriately.
Final Thought
We’re a lot smarter than everything else on the
planet. Why is that? It’s common to think that
language has something to do with smarts. This
is appealing, because then we only have to posit
one difference between us and the non-human
animals: either language gives us smarts, or
smarts gives us language; so having one gives us
both.
Why We are So Clever
Fodor suggests: “[A] creature that knows what
would make its thoughts true and what would
cause it to have them, would be in a highly
advantageous epistemic position:…”
Why We are So Clever
“It would be able, with premeditation, to cause
itself to have true thoughts. In particular, to
construct, with malice aforethought, situations
in which it will be caused to have the thought
that P if and only if the thought that P is true.
I think it's likely that we are the only creatures
that can think about the contents of our
thoughts.”
Suggestion
So Fodor’s claim is that we’re so smart because
we can think about the contents of our
thoughts. But why do we have this ability and
apes not? Suggestion: we don’t. It’s not that we
can think about the contents of our thoughts,
but that we can represent the contents of our
thoughts in inner speech, and reason with these
representations in the way that Fodor suggests.
5. CONCLUSION
Two Puzzles
Puzzle #1: Why are thoughts conscious? What
does consciousness add?
Puzzle #2: Why is the phenomenal character of
thoughts English? Shouldn’t it… not be?
The Separatist Solution
According to separatism, the solution to the
puzzles runs as follows. Thoughts aren’t
conscious, they cause other states that are. So
puzzle #1 does not arise. These other states are
(roughly) auditory imagery. So the phenomenal
character of these states is precisely as we’d
expect. Hence puzzle #2 does not arise.
The Lingering Puzzles
But this only pushes the problem back.
New puzzle #1: Why have thoughts and these
other things? What do they add?
New puzzle #2: And, of all things, what does
their linguisticiness add? Isn’t LOT better than
natural language (more perspicuous, e.g.)?
The Computationalist Solution
I’ve tried to suggest some ways in which
linguistic representations could allow us to
overcome computational limitations in the
native machinery. They can conceivably
augment the representational and
computational power of our innate endowment.
Perhaps, in allowing us to represent our own
thoughts, they distinguish us from our lesssmart cousins.
From Here
This is all very sketchy. My future plan of
research is to investigate the empirical literature
on the precise advantages of inner speech vs.
lack thereof, and try to pinpoint what it’s
actually doing (besides just outlining the
possibilities).