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By Daniel C. Dennett (From Dennett’s Brainstorms: Philosophical Essays on
Mind and Psychology, 1978) Now
that I've won my suit under the Freedom of Information Act, I am at liberty
to reveal for the first time a curious episode in my life that may be of
interest not only to those engaged in research in the philosophy of mind,
artificial intelligence, and neuroscience but also to the general public. Several
years ago I was approached by Pentagon officials who asked me to volunteer
for a highly dangerous and secret mission. In collaboration with NASA and
Howard Hughes, the Department of Defense was spending billions to develop a
Supersonic Tunneling Underground Device, or STUD. It was supposed to tunnel
through the earth's core at great speed and deliver
a specially designed atomic warhead "right up the Red's missile
silos," as one of the Pentagon brass put it. The
problem was that in an early test they had succeeded in lodging a warhead
about a mile deep under I
was shown around the life-support lab in The
day for surgery arrived at last and of course I was anesthetized and remember
nothing of the operation itself. When I came out of anesthesia, I opened my
eyes, looked around, and asked the inevitable, the traditional, the lamentably hackneyed postoperative question:
"Where am l?" The nurse smiled down at me. "You're in I
tried and tried to think myself into the vat, but to no avail. I tried to
build up to the task by doing mental exercises. I thought to myself, "The
sun is shining over there, " five times in
rapid succession, each time mentally ostending a
different place: in order, the sunlit corner of the lab, the visible front
lawn of the hospital, "Yorick," I said aloud to my brain, "you are my
brain. The rest of my body, seated in this chair, I dub 'Hamlet.' " So here we all are: Yorick's
my brain, Hamlet's my body, and I am Dennett. Avow, where am l? And when I
think "where am l?" where's that thought tokened? Is it tokened in my
brain, lounging about in the vat, or right here between my ears where it
seems to be tokened? Or nowhere? Its temporal
coordinates give me no trouble; must it not have spatial coordinates as well?
I began making a list of the alternatives. 1. Where
Hamlet goes there goes Dennett. This principle was easily refuted by
appeal to the familiar brain- transplant thought experiments so enjoyed by
philosophers. If Tom and Dick switch brains, Tom is the fellow with Dick's
former body--just ask him; he'll claim to be Tom and tell you the most
intimate details of Tom's autobiography. It was clear enough, then, that my
current body and I could part company, but not likely that I could be
separated from my brain. The rule of thumb that emerged so plainly from the
thought experiments was that in a brain-transplant operation, one wanted to
be the donor not the recipient. Better to call such an operation a body
transplant, in fact. So perhaps the truth was, 2. Where
Yorick goes there goes Dennett This was not at
all appealing, however. How could I be in the vat and not about to go
anywhere, when I was so obviously outside the vat looking in and beginning to
make guilty plans to return to my room for a substantial lunch? This begged
the question I realized, but it still seemed to be getting at something
important. Casting about for some support for my intuition, I hit upon a
legalistic sort of argument that might have appealed to Locke. Suppose,
I argued to myself, I were now to fly to 3.
Dennett is wherever he thinks he is. Generalized, the claim was as follows:
At any given time a person has a point of view and the location of the point
of view (which is determined internally by the content of the point of view)
is also the location of the person. Such
a proposition is not without its perplexities, but to me it seemed a step in
the right direction. The only trouble was that it seemed to place one in a
heads- l- win/tails- you- lose situation of unlikely infallibility as regards
location. Hadn't I myself often been wrong about where I was, and at least as
often uncertain? Couldn't one get lost? Of course, but getting lost
geographically is not the only way one might get lost. If one were lost in the
woods one could attempt to reassure oneself with the consolation that at
least one knew where one was: one was right here in the familiar surroundings
of one's own body. Perhaps in this case one would not have drawn one's
attention to much to be thankful for. Still, there were worse plights
imaginable, and I wasn't sure I wasn't in such a plight right now. Point
of view clearly had something to do with personal location, but it was itself
an unclear notion. It was obvious that the content of one's point of view was
not the same as or determined by the content of one's beliefs or thoughts.
For example, what should we say about the point of view of the Cinerama
viewer who shrieks and twists in his seat as the roller- coaster footage
overcomes his psychic distancing? Has he forgotten that he is safely seated
in the theater? Here I was inclined to say that the person is experiencing an
illusory shift in point of view. In other cases, my inclination to call such
shifts illusory was less strong. The workers in laboratories and plants who
handle dangerous materials by operating feedback- controlled mechanical arms
and hands undergo a shift in point of view that is crisper and more
pronounced than anything Cinerama can provoke. They can feel the heft and
slipperiness of the containers they manipulate with their metal fingers. They
know perfectly well where they are and are not fooled into false beliefs by
the experience, yet it is as if they were inside the isolation chamber they
are peering into. With mental effort, they can manage to shift their point of
view back and forth, rather like making a transparent Necker cube or an
Escher drawing change orientation before one's eves. It does seem extravagant
to suppose that in performing this bit of mental gymnastics, they are
transporting themselves back and forth. Still
their example gave me hope. If I was in fact in the vat in spite of my
intuitions, I might be able to train myself to adopt that point of view even
as a matter of habit. I should dwell on images of myself comfortably floating
in my vat, beaming volitions to that familiar body out there. I reflected
that the ease or difficulty of this task was presumably independent of the
truth about the location of one's brain Had I been practicing before the
operation, I might now be finding it second nature. You might now yourself
try such a trompe l'oeil.
Imagine you have written an inflammatory letter which has been published in
the Times the result of which s that the government has chosen to impound
your brain for a probationary period of three years in its Dangerous Brain
Clinic in Bethesda, Maryland. Your body of course is allowed freedom to earn
a salary and thus to continue its function of laying up income to be taxed At
this moment, however, your body is seated in an auditorium listening
to a peculiar account by Daniel Dennett of his own similar experience. Try
it. Think yourself to Anyway,
there I was in But
to return to my adventure. At length, both the doctors and I were satisfied
that I was ready to undertake my subterranean mission. And so I left my brain
in When
I found the warhead, I was certainly glad I had left my brain behind, for the
pointer on the specially built Geiger counter I had brought with me was off
the dial. I called It
occurred to me then, with one of those rushes of revelation of which we
should be suspicious, that I had stumbled upon an impressive demonstration of
the immateriality of the soul based upon physicalist principles and premises.
For as the last radio signal between The
joy of philosophic discovery thus tided me over some very bad minutes or
perhaps hours as the helplessness and hopelessness or my situation became
more apparent to me. Waves of panic and even nausea swept over me, made all
the more horrible by the absence of their normal body- dependent
phenomenology. No adrenaline rush of tingles in the arms, no pounding heart,
no premonitory salivation. I did feel a dread sinking feeling in my bowels at
one point, and this tricked me momentarily into the false hope that I was
undergoing a reversal of the process that landed me in this fix--a gradual undisembodiment. But the isolation and uniqueness of that
twinge soon convinced me that it was simply the first of a plague of phantom
body hallucinations that I, like any other amputee,
would be all too likely to suffer. My
mood then was chaotic. On the one hand, I was fired up with elation of my
philosophic discovery and was wracking my brain (one of the few familiar
things I could still do), trying to figure out how to communicate my
discovery to the journals; while on the other, I was bitter, lonely, and
filled with dread and uncertainty. Fortunately, this did not last long, for
my technical support team sedated me into a dreamless sleep from which I awoke,
hearing with magnificent fidelity the familiar opening strains of my favorite
Brahms piano trio. So that was why they had wanted a list of my favorite
recordings! It did not take me long to realize that I was hearing the music
without ears. I he output from the stereo stylus was being fed through some
fancy rectification circuitry directly into my auditory nerve. I was
mainlining Brahms, an unforgettable experience for any stereo buff. At the
end of the record it did not surprise me to hear the reassuring voice of the
project director speaking into a microphone that was now my prosthetic ear.
He confirmed my analysis of what had gone wrong and assured me that steps
were being taken to re- embody me. He did not elaborate, and after a few more
recordings, I found myself drifting off to sleep. My sleep lasted, I later
learned, for the better part of a year, and when I awoke, it was to find
myself fully restored to my senses. When I looked into the mirror, though, I
was a bit startled to see an unfamiliar face. Bearded and a bit heavier,
bearing no doubt a family resemblance to my former face, and with the same
look of spritely intelligence and resolute
character, but definitely a new face. Further self- explorations of an
intimate nature left me no doubt that this was a new body, and the project
director confirmed my conclusions. He did not volunteer any information on
the past history of my new body and I decided (wisely, I think in retrospect)
not to pry. As many philosophers unfamiliar with my ordeal have more recently
speculated, the acquisition of a new body leaves one's person intact. And
after a period of adjustment to a new voice, new muscular strengths and
weaknesses, and so forth, one's personality is by and large also preserved.
More dramatic changes in personality have been routinely observed in people
who have undergone extensive plastic surgery, to say nothing of sex- change
operations, and I think no one contests the survival of the person in such
cases. In any event I soon accommodated to my new body, to the point of being
unable to recover any of its novelties to my consciousness or even memory.
The view in the mirror soon became utterly familiar. That view, by the way,
still revealed antennae, and so l was not surprised to learn that my brain
had not been moved from its haven in the life- support lab. I
decided that good old Yorick deserved a visit. I
and my new body, whom we might as well call Fortinbras,
strode into the familiar lab to another round of applause from the
technicians, who were of course congratulating themselves, not me. Once more
I stood before the vat and contemplated poor Yorick,
and on a whim I once again cavalierly flicked off the output transmitter
switch. Imagine my surprise when nothing unusual happened. No fainting spell, no nausea, no noticeable change. A technician
hurried to restore the switch to ON, but still I felt nothing. I demanded an
explanation, which the project director hastened to provide. It seems that
before they had even operated on the first occasion, they had constructed a
computer duplicate of my brain, reproducing both (he
complete information- processing structure and the computational speed of my
brain in a giant computer program. After the operation, but before they had
dared to send me off on my mission to Hubert's
input, and hence activity, had been kept parallel with Yorick's
during my disembodied days. And now, to demonstrate this, they had actually
thrown the master switch that put Hubert for the first time in on- line
control of my body--not Hamlet, of course, but Fortinbras.
(Hamlet, I learned, had never been recovered from its underground tomb and
could be assumed by this time to have largely returned to the dust. At the
head of my grave still lay the magnificent bulk of the abandoned device, with
the word STUD emblazoned on its side in large letters --a circumstance which
may provide archeologists of the next century with a curious insight into the
burial rites of their ancestors.) The
laboratory technicians now showed me the master switch, which had two
positions, labeled B. for Brain (they didn't know my brain's name was Yorick) and H. for Hubert. The switch did indeed point to
H. and they explained to me that if I wished, I could switch it back to B.
With my heart in my mouth (and my brain in its vat), I did this. Nothing
happened. A click, that was all. To test their claim, and with the master
switch now set at B. I hit Yorick's output
transmitter switch on the vat and sure enough, I began to faint. Once the
output switch was turned back on and I had recovered my wits, so to speak, I
continued to play with the master switch, flipping it back and forth. I found
that with the exception of the transitional click, I could detect no trace of
a difference. I could switch in mid-utterance, and the sentence I had begun
speaking under the control of Yorick was finished
without a pause or hitch of any kind under the control of Hubert. I had a
spare brain, a prosthetic device which might some day stand me in very good
stead, were some mishap to befall Yorick. Or
alternatively, I could keep Yorick as a spare and
use Hubert. It didn't seem to make any difference which I chose, for the wear
and tear and fatigue on my body did not have any debilitating effect on
either brain, whether or not it was actually causing the motions of my body,
or merely spilling its output into thin air. The
one truly unsettling aspect of this new development was the prospect, which
was not long in dawning on me, of someone detaching (he
spare--Hubert or Yorick, as the case might be--from
Fortinbras and hitching it to yet another
body--some Johnny- come- lately Rosencrantz or Guildenstem.
Then (if not before) there would be two people, that much was clear. One
would be me, and the other would be a sort of super- win brother. If there
were two bodies, one under the control of Hubert and the other being
controlled by Yorick, then which would the world
recognize as the true Dennett? And whatever the rest of the world decided,
which one would be me f Would I be the Yorick-
brained one, in virtue of Yorick's causal priority
and former intimate relationship with the original Dennett body, Hamlet? That
seemed a bit legalistic, a bit too redolent of the arbitrariness of
consanguinity and legal possession, to be convincing at the metaphysical
level. For suppose that before the arrival of the second body on the scene, I
had been keeping Yorick as the spare for years, and
letting Hubert's output drive my body--that is, Fortinbras
--all that time. The Hubert- Fortinbras couple
would seem then by squatter's rights (to combat one legal intuition with
another) to be the true Dennett and the lawful inheritor of everything that
was Dennett's. This was an interesting question, certainly, but not nearly so
pressing as another question that bothered me. My strongest intuition was
that in such an eventuality I would survive so long as either brain- body
couple remained intact, but I had mixed emotions about whether I should want
both to survive. I
discussed my worries with the technicians and the project director. The
prospect of two Dennetts was abhorrent to me, I
explained, largely for social reasons. I didn't want to be my own rival for
the affections of my wife, nor did I like the prospect of the two Dennetts sharing my modest professor's salary. Still more
vertiginous and distasteful, though, was the idea of knowing that much about
another person, while he had the very same goods on me. How could we ever
face each other? My colleagues in the lab argued that I was ignoring the
bright side of the matter. Weren't there many things I wanted to do but,
being only one person, had been unable to do? Now one Dennett could stay at
home and be the professor and family mark while the other could strike out on
a life of travel and adventure--missing the family of course, but happy in
the knowledge that the other Dennett was keeping the home fires burning. I
could be faithful and adulterous at the same time. I could even cuckold
myself--to say nothing of other more lurid possibilities my colleagues were
all too ready to force upon my overtaxed imagination. But my ordeal in There
was another prospect even more disagreeable: that the spare, Hubert or Yorick as the case might be, would be detached from any
input from Fortinbras and just left detached. I
hen, as in the other case, there would be two Dennetts,
or at least two claimants to my name and possessions, one embodied in Fortinbras, and the other sadly, miserably disembodied.
Both selfishness and altruism bade me take steps to prevent this from
happening. So I asked that measures be taken to ensure that no one could ever
tamper with the transceiver connections or the master switch without my (our?
no, r~/)9) knowledge and consent. Since I had no
desire to spend my life guarding the equipment in In
any case, every time I've flipped the switch so far, nothing has happened. So
let s give it a to.... "THANK
GOD! I THOUGHT YOU'D NEVER FLIP THAT SWITCH! You can't imagine how horrible
it's been these last two weeks --but now you know; it's your turn in
purgatory. How I've longed for this moment! You see, about two weeks
ago--excuse me, ladies and gentlemen, but I've got to explain this to my . .
. um, brother, I guess you could say, but he's just told you the facts, so
you'll understand--about two weeks ago our two brains drifted just a bit out
of synch. I don't know whether my brain is now Hubert or Yorick,
any more than you do, but in any case, the two brains drifted apart, and of
course once the process started, it snowballed, for I was in a slightly
different receptive state for the input we both received, a difference that
was soon magnified. In no time at all the illusion that I was in control of
my body--our body--was completely dissipated. There was nothing I could
do--no way to call you. YOU DIDN'T EVEN KNOW I EXISTED! It's been like being
carried around in a cage, or better, like being possessed--hearing my own
voice say things I didn't mean to say, watching in frustration as my own
hands performed deeds I hadn't intended. You'd scratch our itches, but not
the way I would have, and you kept me awake, with your tossing and turning. I've
been totally exhausted, on the verge of a nervous breakdown, carried around
helplessly by your frantic round of activities, sustained only by the
knowledge that some day you'd throw the switch. "Now
it's your turn, but at least you'll have the comfort of knowing I know you're
in there. Like an expectant mother, I'm eating--or at any rate tasting,
smelling, seeing--for two now, and I'll try to make it easy for you. Don't
worry. Just as soon as this colloquium is over, you and I will fly to "Ladies
and gentlemen, this talk we have just heard is not exactly the talk I would
have given, but I assure you that everything he said was perfectly true. And
now if you'll excuse me, I think I'd--we'd--better sit down". |