Date: Wed, 11 Jun 1997 03:19:20 -0400
From: Paul Marsden <PMarsden@compuserve.com>
Subject: Dennett on the Web
To: "INTERNET:memetics@mmu.ac.uk" <memetics@mmu.ac.uk>
>.......or read Dennett's Consciousness Explained, and his article on the=
web
> "Real Consciousness."
>Where is this article on the web?
www.tufts.edu/as/cogstud/publist.htm
Larry
Here is Dennett's article on realism and consciousness, this and his othe=
r
articles can be found at the above address. I've posted this because
there have been calls for someone to situate memetics (the central plank =
of
Dennett's multiple drafts model) in the tradition of philosophy, and
Dennett does it more succinctly than I probably could. I am nevertheless=
writing an article to be submitted to the jom on this, which is probably =
a
better forum for this sort of navel gazing, and if it is published I will=
eagerly await replies.
Paul
Real Consciousness
in Consciousness in Philosophy and Cognitive Neuroscience, A. Revonsuo & =
M.
Kamppinen, eds., Hillsdale, NJ:
Lawrence Erlbaum, 1994.
Real Consciousness
In Consciousness Explained (Dennett, 1991), I put forward a rather detail=
ed
empirical theory of consciousness, together with
an analysis of the implications of that theory for traditional
philosophical treatments of consciousness. In the critical response to
the book, one of the common themes has been that my theory is not a
"realist" theory, but rather an eliminativist or
verificationist denial, in one way or another, of the very reality of
consciousness. Here I will draw together a number of those
threads, and my responses to them.Endnote 1
It is clear that your consciousness of a stimulus is not simply a matter =
of
its arrival at some peripheral receptor or transducer;
most of the impingements on our end-organs of sense never reach
consciousness, and those that do become elements of our
conscious experience somewhat after their arrival at your peripheries. To=
put it with bizarre vividness, a live, healthy eyeball
disconnected from its brain is not a seat of visual consciousness--or at
least that is the way we are accustomed to think of these
matters; the eyes and ears (and other end organs) are entry points for ra=
w
materials of consciousness, not the sites themselves
of conscious experiences. So visual consciousness must happen in between
the eyeball and the mouth--to put it crudely.
Where?
To bring out what the problem is, let me pose an analogy: you go to the
racetrack and watch three horses, Able, Baker and
Charlie, gallop around the track. At pole 97 Able leads by a neck; at pol=
e
98 Baker, at pole 99 Charlie, but then Able takes
the lead again, and then Baker and Charlie run neck and neck for awhile,
and then, eventually all the horses slow down to a
walk and are led off to the stable. You recount all this to a friend, who=
asks "Who won the race?" and you say, well, since
there was no finish line, there's no telling. It wasn't a real race, you
see, with a finish line. First one horse led and then another,
and eventually they all stopped running. =
The event you witnessed was not a real race, but it was a real event--not=
some mere illusion or figment of your imagination. Just
what kind of an event to call it is perhaps not clear, but whatever it wa=
s,
it was as real as real can be. =
Now consider a somewhat similar phenomenon. You are presented with some
visual stimuli, A followed by B, which provoke
various scattered chains of events through your brain; first the chain of=
events initiated by A dominates cortical activity in some
regions, and then chain B takes over, and then perhaps some chain C,
produced by an interaction between chain A and B,
enjoys a brief period of dominance, to be followed by a resurgence of cha=
in
A. Then eventually all three (or more) chains of
events die out, leaving behind various traces in memory. Someone asks you=
:
which stimulus did you become conscious of first:
A or B (or C)? =
If Descartes's view of consciousness were right, there would be a
forthright way of telling. Descartes held that for an event to
reach consciousness, it had to pass through a special gateway, which we
might call the Cartesian bottleneck or turnstile, which
Descartes located in the pineal gland or epiphysis. But everybody knows
that Descartes was wrong. Not only is the pineal
gland not the fax machine to the soul; it is not the Oval Office of the
brain. It is not the "place where it all comes together" for
consciousness, nor does any other place in the brain fit this description=
=2E
I call this mythic place in the brain where it all comes
together (and where the order of arrival determines the order of
consciousness) the Cartesian Theater. There is no Cartesian
Theater in the brain. That is a fact. Besides, if there were, what could
happen there? Presumably, we care about consciousness
because it matters what happens in our conscious lives--for instance, pai=
ns
that never become conscious are either not pains at
all, or if they are, they are not the sort that cause us suffering. (e.g.=
,
the pains that keep us from sleeping in contorted positions,
like those unfortunates congenitally insensitive to pain.) But for what
happens in consciousness to matter, surely it must make a
difference--something must get done because of what happened there--but i=
f
all the important work gets done at a point, (or
just within the narrow confines of the pea-sized pineal gland) how does t=
he
rest of the brain play a role in it? =
All the work that was dimly imagined to be done in the Cartesian Theater
has to be done somewhere, and no doubt it is
distributed around in the brain. This work is largely a matter of
responding to the "given" by taking it--by responding to it with
one interpretive judgment or another. This corner must be turned somehow =
by
any model of observation. On the traditional
view, all the taking is deferred until the raw given, the raw materials o=
f
stimulation, have been processed in various ways. Once
each bit is "finished" it can enter consciousness and be appreciated for
the first time. As C. S. Sherrington (1934) put it: =
The mental action lies buried in the brain, and in that part most
deeply recessed from outside world that is furthest
from input and output. =
In the Multiple Drafts Model developed by Marcel Kinsbourne and me
(Dennett, 1991, Dennett and Kinsbourne, 1992), this
single unified taking is broken up in cerebral space and real time. We
suggest that the judgmental tasks are fragmented into
many distributed moments of micro-taking (Kinsbourne, 1988, Damasio, 1989=
).
The novelty lies in how we develop the
implications of this fragmentation. =
It may seem at first as if we are stuck with only three alternatives:
A. Each of these distributed micro-takings is an episode of unconscious
judgment, and the consciousness of the taken element
must be deferred to some later process (what we call the Stalinesque show=
trial in a Cartesian Theater). But then how long
must each scene wait, pending potential revision, before the curtain rise=
s
on it?
B. Each of these distributed micro-takings is an episode of conscious
judgment (multiple mini-cinemas). But then why don't we
all have either a kaleidoscopic and jumbled "stream of consciousness" or
(if these distributed micro-takings are not
"co-conscious") a case of "multiple selves"? Is our retrospective sense o=
f
unified, coherent consciousness just the artifact of an
Orwellian historian's tampering with memory? As several commentators have=
asked, how can the manifest coherence, seriality,
or unity of conscious experience be explained? =
C. Some of the distributed micro-takings are conscious and the rest are
not. The problem then becomes: what special property
distinguishes those that are conscious, and how do we clock the onset of
their activity? And, of course, since distributed
micro-takings may occur slightly "out of order," what "mechanism" serves =
to
unify the scattered micro-takings that are
conscious, and in each case, does it operate before or after the onset of=
consciousness (i.e., which phenomena are Orwellian
and which are Stalinesque)?
Our view is that there is a yet a fourth alternative: =
D&K. The creation of conscious experience is not a batch process but a
continuous process. The micro-takings have to
interact. A micro-taking, as a sort of judgment or decision, can't just b=
e
inscribed in the brain in isolation; it has to have its
consequences--for guiding action and modulating further micro-judgments
made "in its light", creating larger fragments of what
we call narrative. The interaction of micro-takings, however it is
accomplished in particular cases, has the effect that a modicum
of coherence is maintained, with discrepant elements dropping out of
contention, and without the assistance of a Master Judge.
Since there is no Master Judge, there is no further process of
being-appreciated-in-consciousness, so the question of exactly
when a particular element was consciously (as opposed to unconsciously)
taken admits no non-arbitrary answer. =
So there is a sort of stream of consciousness, with swirls and eddies,
but--and this is the most important "architectural" point of
our model--there is no bridge over the stream. Those of you familiar with=
A. A. Milne and Winnie the Pooh will appreciate
the motto: =
You can't play Pooh-sticks with consciousness.
As "realists" about consciousness, we believe that there has to be
something--some property K--that distinguishes conscious
events from nonconscious events. Consider the following candidate for
property K: a contentful event becomes conscious if
and when it becomes part of a temporarily dominant activity in cerebral
cortex (Kinsbourne, 1988, and in preparation).
This is deliberately general and undetailed, and it lacks any suggestion =
of
a threshold. How long must participation in this
dominance last, and how intense or exclusive does this dominance need to
be, for an element to be conscious? There is no
suggestion of a principled answer. Such a definition of property K meets
the minimal demands of "realism," but threatens the
presumed distinction between Orwellian and Stalinesque revisions. Suppose=
some contentful element briefly flourishes in such a
dominant pattern, but fades before leaving a salient, reportable trace on=
memory (a plausible example would be the
representation of the first stimulus in a case of metacontrast--a
phenomenon described in detail in Dennett, 1991, and Dennett
and Kinsbourne, 1992). Would this support an Orwellian or a Stalinesque
model? If the element participated for "long enough"
it would be "in consciousness" even if it never was properly remembered
(Orwell), but if it faded "too early" it would never
quite make it into the privileged category, even if it left some traces i=
n
memory (Stalin). But how long is long enough? There is
no way of saying. No discontinuity divides the cases in two. =
The analogy with the horse race that wasn't a horse race after all should=
now be manifest. Commentators on our theory
generally agree with us that (1) the time of representing should not be
confused with the time represented, and (2) there is no
privileged place within the brain "where it all comes together." They do
not all agree with us, however, that it follows from (1
and 2) that the Orwellian/Stalinesque distinction must break down at some=
scale of temporal resolution, leaving no fact of the
matter about whether one is remembering mis-experiences or mis-rememberin=
g
experiences. Here, some claim, we have gone
overboard, lapsing into "verificationism" or "eliminativism" or
"anti-realism" or some other gratuitously radical position. This is
curious, for we consider our position to be unproblematically "realist" a=
nd
materialist: conscious experiences are real events
occurring in the real time and space of the brain, and hence they are
clockable and locatable within the appropriate limits of
precision for real phenomena of their type. (For an extended defense of
this version of realism, see my "Real Patterns," 1991b.)
Certain sorts of questions one might think it appropriate to ask about
them, however, have no answers, because these
questions presuppose inappropriate--unmotivatable--temporal and spatial
boundaries that are more fine-grained than the
phenomena admit. =
In the same spirit we are also realists about the British Empire--it real=
ly
and truly existed, in the physical space and time of this
planet--but, again, we think that certain sorts of questions about the
British Empire have no answers, simply because the British
Empire was nothing over and above the various institutions, bureaucracies=
and individuals that composed it. The question
"Exactly when did the British Empire become informed of the truce in the
War of 1812?" cannot be answered. The most that
can be said is "Sometime between December 24, 1814 and mid-January, 1815.=
"
The signing of the truce was one official,
intentional act of the Empire, but the later participation by the British=
forces in the Battle of New Orleans was another, and it
was an act performed under the assumption that no truce had been signed.
Even if we can give precise times for the various
moments at which various officials of the Empire became informed, no one =
of
these moments can be singled out--except
arbitrarily--as the time the Empire itself was informed. Similarly, since=
You are nothing over and above the various subagencies
and processes in your nervous system that compose you, the following sort=
of question is always a trap: "exactly when did I (as
opposed to various parts of my brain) become informed (aware, conscious) =
of
some event?" Conscious experience, in our
view, is a succession of states constituted by various processes occurrin=
g
in the brain, and not something over and above these
processes that is caused by them. =
The idea is still very compelling, however, that "realism" about
consciousness guarantees that certain questions have answers
(even if they are currently unknowable), and I have recently been fieldin=
g
a variety of objections on that theme. Michael
Lockwood, a commentator who is happy to declare himself to be a Cartesian=
materialist, nicely summed up the intuition that I
am calling in question. "Consciousness," he said, with an air of
enunciating something almost definitional in its status, "is the
leading edge of perceptual memory." (Lockwood, 1993)
"' Edge'? " I retorted. "What makes you think there is an edge?" Consider=
what must be the case if there is no such edge. The
only difference between the Orwellian and Stalinesque treatment of any
phenomenon is whether or not the editing or
adjustment or tampering occurs before or after a presumed moment of onset=
of consciousness for the contents in question.
The distinction can survive only if the debut into consciousness for some=
content is at least as accurately timable as the events of
micro-taking (the binding, revising, interpreting, etc.) whose order
relative to the onset of consciousness defines the two
positions. If the onset of consciousness is not so sharply marked, the
difference between pre-presentation Stalinesque revision
and post-presentation Orwellian revision disappears, and is restorable on=
ly
by arbitrary fiat.
This is not verificationism in any contentious sense. Another analogy wil=
l
make this clear. Andy Warhol anticipated a future in
which each person would be famous for fifteen minutes. What he nicely
captured in this remark was a reductio ad absurdum
of a certain (imaginary) concept of fame. Would that be fame? Has Warhol
described a logically possible world? If we pause
to think about his example more carefully than usual, we see that what
makes the remark funny is that he has stretched
something beyond the breaking point. It is true, no doubt, that thanks to=
the mass media, fame can be conferred on an
anonymous citizen almost instantaneously (Rodney King comes to mind), and=
thanks to the fickleness of public attention, fame
can evaporate almost as fast. But Warhol's rhetorical exaggeration of thi=
s
fact carries us into the absurdity of Wonderland. We
have yet to see an instance of someone being famous for just fifteen
minutes, and in fact we never will. Let some one citizen be
viewed for fifteen minutes by hundreds of millions of people, and
then--unlike Rodney King--be utterly forgotten. To call that
fame would be to misuse the term (ah yes, an "ordinary language" move, an=
d
a good one, if used with discretion). =
If that is not obvious, then let me raise the ante: could a person be
famous--not merely attended-to-by-millions-of-eyes, but
famous--for five seconds? Every day there are in fact hundreds if not
thousands of people who pass through the state of being
viewed, for a few seconds, by millions of people. Consider the evening ne=
ws
on television, presenting a story about the
approval of a new drug. Accompanying Dan Rather's voice-over, an utterly
anonymous nurse is seen (by millions) plunging a
hypodermic into the arm of an utterly anonymous patient. Now that's
fame--right? Of course not. Being seen on television and
being famous are different sorts of phenomena; the former has
technologically sharp edges that the latter entirely lacks. =
What I have argued, in my attack on the Cartesian theater, is that being =
an
item in consciousness is not at all like being on
television; it is, rather, a species of mental fame. Almost literally.
Consciousness is cerebral celebrity--nothing more and nothing
less. Those contents are conscious that persevere, that monopolize
resources long enough to achieve certain typical and
"symptomatic" effects--on memory, on the control of behavior and so forth=
=2E
Not every content can be famous, for in such
competitions there must be more losers than winners. And unlike the world=
of sports, winning is everything. There are no higher
honors to be bestowed on the winners, no Hall of Fame to be inducted into=
=2E
In just the way that a Hall of Fame is a redundant
formality (if you are already famous, election is superfluous, and if you=
are not, election probably won't make the difference),
there is no induction or transduction into consciousness beyond the
influence already secured by winning the competition and
thereby planting lots of hooks into the ongoing operations of the brain.
Instantaneous fame is a disguised contradiction in terms, and it follows
from my proposed conception of what consciousness is
that an instantaneous flicker of consciousness is also an incoherent
notion. Those philosophers who see me as underestimating
the power of future research in neuroscience when I claim that no further=
discoveries from that quarter could establish that there
was indeed a heretofore undreamt-of variety of evanescent--but
genuine--consciousness might ask themselves if I similarly
undervalue the research potential of sociology when I proclaim that it is=
inconceivable that sociologists could discover that
Andy Warhol's prediction had come true. This could only make sense, I
submit, to someone who is still covertly attached to the
idea that consciousness (or fame) is the sort of semi-mysterious property=
that might be discovered to be present by the tell-tale
ticking of the phenomenometer or famometer (patent pending!). Endnote 2 =
Consider a question nicely parallel to the Orwell-Stalin stumpers I decla=
re
to be vacuous: did Jack Ruby become famous
before Lee Harvey Oswald died? Hmm. Well, hundreds of millions witnessed
him shooting Oswald on "live" television, and
certainly he subsequently became famous, but did his fame begin at the
instant his gun-toting arm hove into view, while Oswald
was still alive and breathing? I for one do not think there is any fact w=
e
don't already know that could conceivably shed light on
this question of event ordering. =
The familiar ideas die hard. It has seemed obvious to many that
consciousness is--must be--rather like an inner light shining, or
rather like television, or rather like a play or movie presented in the
Cartesian Theater. If they were right, then consciousness
would have to have certain features that I deny it to have. But they are
simply wrong. When I point this out I am not denying
the reality of consciousness at all; I am just denying that consciousness=
,
real consciousness, is like what they think it is like. =
References
Damasio, A., 1989, "The brain binds entities and events by multiregional
activation from convergence zones," Neural
Computation, 1, 123-32.
Dennett, D. C., 1991, Consciousness Explained, Boston: Little, Brown.
Dennett, D. C., 1991b, "Real Patterns," J.Phil., 87, pp.27-51.
Dennett, D. C., 1993, "Living on the Edge," Inquiry, 36, pp. 135-59.
Dennett, D. C., forthcoming a, "The Message is: There is no Medium,"
Philosophy and Phenomenological Research.
Dennett, D. C., forthcoming b, "Is Perception the 'Leading Edge' of
Memory?" in A. Spadafora, ed., Memory and Oblivion,
Locarno conference. =
Dennett, D. C., and Kinsbourne, M., 1992, "Time and the observer: the whe=
re
and when of consciousness in the brain,"
Behavioral and Brain Sciences, 15, pp.183-200.
Dennett, D. C., and Kinsbourne, M, 1992b, "Escape from the Cartesian
Theater," (response to commentators), Behavioral
and Brain Sciences, 15, pp.183-200.
Flanagan, Owen, 1992, Consciousness Reconsidered, Cambridge, MA: MIT Pres=
s.
Kinsbourne, M., 1988, "Integrated field theory of consciousness," in A.
Marcel and E. Bisiach, eds., Consciousness in
Contemporary Science, Oxford Univ. Press.
Kinsbourne, M., in preparation, "The distributed brain basis of
consciousness."
Lockwood, M., 1993, "Dennett's Mind,: Inquiry, 36, pp. 59-72
Sherrington, C., 1934, The Brain and its Mechanism, Cambridge Univ. Press=
=2E
Endnotes
1.This paper draws on Dennett and Kinsbourne, 1992b, Dennett, 1993,
forthcoming a and b.
2. Owen Flanagan (1992), esp. pp.14-15, pp.82-83, has made the claim in
detail. He supposes, for instance, that the 40-herz
phase-locked oscillation championed by Singer, von der Malsburg, and
others, and suggested by Crick and Koch as a key
mechanism in consciousness, might serve as the missing ingredient that
could trump my short-sighted verificationism. "Never say
never" he advises me. Well, now that neuroscience's love affair with
40-herz is beginning to cool off (because of problems that
were always inherent in the idea--people were asking too much of it), let=
's
look more closely at the prospects. If Crick and
Koch are taken to be proposing a mechanism for securing cerebral
celebrity--the underlying mechanism by which some
contents win and others lose in competition--then they are not offering a=
rival view, but merely specifying details I left blank in
my sketch. Ignore the problems and suppose they are right (I would love t=
o
have an account of the detailed mechanisms, after
all). Notice that it is logically impossible for a 40-herz oscillation
mechanism to resolve temporal onset questions below the
two-pulse minimum of 25msec, and any plausible competition-for-entrainmen=
t
model would surely require considerably more
time--moving us inexorably into a window of indeterminacy of the size I
postulated: several hundred milliseconds. Alternatively,
if Flanagan supposes that Crick and Koch are claiming that 40-herz
entrainment causes a subsequent state-change (which
could be an instantaneous transduction into some new medium, for instance=
),
then he is simply insisting on the very concept of
consciousness I am challenging--that consciousness requires entrance into=
a
"charmed circle". =
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