Brains in a Vat - Different Perspectives - Yuval Steinitz

8/9/2019 Brains in a Vat - Different Perspectives - Yuval Steinitz

1/11

Brains in a Vat: Different PerspectivesAuthor(s): Yuval SteinitzReviewed work(s):Source: The Philosophical Quarterly, Vol. 44, No. 175 (Apr., 1994), pp. 213-222Published by: Wiley-Blackwellfor The Philosophical QuarterlyStable URL: http://www.jstor.org/stable/2219742.

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2/11

ON

MCDOWELL ON THE CONTENT

OF

PERCEPTUAL

EXPERIENCE

213

in

giving

n

exposition

fone of thehorns f

thedilemma.One hornof the

dilemma

is

that

f

we

take consciousness o be

inseparable

rom he

norm-governed

otion f

self-consciousnessnd from

eflective

nd

self-critical

ttitudes owards

neself,

hen

it does seemhardto acceptthatDennett'sframework,nwhichconscious ontents

are

a

selection f thecontents hat

go

to and

fro

between

ubsystems,

ill

capture

ll

of

the

phenomena;

ut

by

the same token

frog's

isual

xperience

will

not

count

s

contentfulnd

conscious,

s McDowell

claims t does.

But,

on the other

horn,

f

we

shrink he

phenomenon

f consciousness o exclude

self-consciousness

nd

thereby

include

he

experience

f unself-consciousreatures uch

as

frogs

s

conscious,

hen

it seems

o

me

the

dual

strategyadopted

of(l)

generalizing

ennett's dea

of

ccess

relations,

nd

(2)

defusing

McDowell's

epistemological

larms

which motivatehis

criticismf

Dennett

provides

quite dequate

defence

f

Dennett

gainst

McDowell.

Columbia

niversit

BRAINS IN

A

VAT: DIFFERENT PERSPECTIVES

BY YUVAL

STEINITZ

In his

Brains

n a

Vat" Putnam

rgues

with

reat

anachegainst ntological,

xternal-

world

cepticism. ltimately,

owever,

is

arguments

re

uncompelling.

n

fact,

hey

seem

disingenuous

n

places.

This

paper

has two

parts.

n

the first

argue

that

even

if

Putnam's

inguistic

arguments

re

enough

o

convince modern

inguistic

ceptic

like

Putnam

himself),

they

re

certainly

nsufficient

o

win

over an old-school

ontological ceptic'

that

is,

a

sceptic

who sees

ontology

s

a

field f

philosophy

more fundamental

han the

theoryf referencelikeDescartes t the outset fhisMeditations).s

I

shallexplain,

Putnam's

reliance n causal

semantics

o achieve

his

anti-sceptical

esultwould

beg

the central

uestion

gainst

ertain

inds f

sceptics.

n the

second

part

argue

that

Putnam's

arguments

re not

sufficient

o

win

over

his

own

camp

of

linguistic

philosophers,

ot

venwhen

hiscausal semantics

s

taken

or

ranted.

is

arguments,

if

valid,

might

ndercut

he

possibility

f

what

shall call

a

comprehensiveceptical

scenario,

but

they

have

little o

say

about the

possibility

f what shall call

partial

sceptical

cenarios.

Before

presentingmy

criticism,

et me

briefly

ummarizePutnam's

linguistic'

argumentgainst

xternal-world

cepticism.

utnam

rgues

hat

ceptical ropositionslike I ama brain n a vat'

henceforth

IV),

that

s,

brain

ubjected

oa

sophisticated

computer

which

performs

omprehensive

imulation

f

reality,

re

self-refuting.

H.

Putnam,

Reason,

Truth nd

HistoryCambridge

UP,

1981),

pp.

1-21;

see also the

related

discussion

pp.

49-74.

All

page

references

re to this book.

?

The

Editors

f

The

Philosophicaluarterly,

994.


3/11

214

YUVAL STEINITZ

His

argument

s

as follows:

n

order

for his

proposition

o

acquire

its

presumed

realistic

meaning,

he

ermsbrain' nd

vat' must

efer

o realbrains

nd vats.

However,

according

o causal

semantics,

word can

refer o an

object

only

f that

object

s

somehowcausallyconnectedwith theutterance r thought f the word. Thus in

order

for he word

vat'

to refer o

an

actual

vat,

and

not

to

refer o a 'vat in

the

image'

(p.

15),

or

be a mere cluster

f

random,

meaninglessmarkings,

here

must

be

some causal connection

etween he

perception

f some

actual

vat and the

fact

that

the word vat'

was

written,

aid

or

conceived.

Returning

ow

to the

BIV

proposition:

f

the

speaker

s a

genuine

BIV,

then t s

impossible

hathe should

ever have

observed he vat

he

is

in,

or

any

vat,

brain

or

computer

whatsoever.

hus the word vat'

in

his

usage

does not refer o real

vats,

but

only

to 'vats

n

the

mage',

and

the

entire

roposition

ails o

refer.

f,

on

the

otherhand, the speaker

s

not a

BIV,

then his

proposition

as

reference,

ut

is

obviously

alse.Hence

the

proposition

I

am a BIV' either

ails o

refer

r is false.

But

if

t fails o

refer o the vat

containing

he

brain, .e.,

if

t

refers

o mental

images

rather

han

to real

objects,

hen t is also false

p.

15).

For what

it would

(actually)

ell he

assumedBIV

is that

he is

a

BIV in the

mage,

whilewhat

he would

(actually)

e is a

BIV

in

reality.

o

it

is

necessarily

alse.

Taken

together,

he two

parts

of this

paper

place

Putnam

n

a

dilemma.

On the

one

hand,

as the

ceptical

cenario

e.g.,

he

BIV

story)

s renderedmore

comprehensive,

it becomes

increasingly ecessary,

rom

he

sceptic'sperspective,

o

discard the

realistic,

ausal

theory

f reference

pon

whichPutnam's

nti-sceptical

rgument

s

based. On the otherhand,as the

sceptical

cenario s renderedmore

partial,

ndirect

causal connections

with xternal

eality,

hich re sufficient

orrealistic

eference,

become

increasingly

lausible.

I. THE

ONTOLOGIST'S

PERSPECTIVE

The BIV

hypothesis

s an

updated

version

f

the

sceptical

rguments resented

n

Descartes' first

Meditation,

hatthe

entireworld

might

e

only

a self-made

igment

of

his

magination,

r rather

fiction

enerated y

an evil

genius.

The first

ine

of

defence or he

sceptic

houldbe to stress he

disjunctive

atureof this laim:

I

cannotknow

whether

a)

I

am

a

bodily

person

who

perceives

ndependent

eal-

ity,

r

b)

everything

s

only

dream

n

my

mind.

Adapting

his

formulation

o

the BIV

hypothesis,

he

sceptical

disjunction

an be

formulatedhus:

I

cannotknow

whether

a)

I

am

a

bodily

person

who

perceives ndependent

eal-

ity,

r

b)

I

am

a BIV.

An unprejudiced onsideration,hescepticwillargue,willfind he twodisjuncts o

be

equally

plausible.

There can

be

no reasonfor

referring

ne overthe

other,

ince

any possible xperience

would

be

compatible

withboth.

Does this

mphasis

n the

disjunctive

ature f

scepticism

ose

a new

challenge

fromPutnam's

perspective?

t

first

lance

it seems

not. Putnam could

elegantly

?

The Editors f

The

Philosophical

uarterly,

994.


4/11

BRAINS

IN

A

VAT

215

tackle

the

above

disjunction

much as he

responded

o the BIV

proposition

lone:

he

might

rgue

that,

or

BIV,

the

disjunction

I

am a

bodily

erson

or

a

BIV'

fails

to

acquire

ts ssumedreference

nd

meaning

because,

for

BIV,

theterms

body',

'brain', computer' nd 'vat' failto refer. t follows hat fthescepticaldisjunction

is

meaningful

n

the

presupposed

ommon

sense, .e.,

if it

acquires

its

assumed

reference

o a real

body,

brain,

computer

nd

vat,

rather han

referring

o

purely

mental

ntities,

hen

disjunct a)

mustbe true.

But

here, contend,

we can see how from n

old-stylentologist'serspective,

.g.,

from he

perspective

f

a Cartesian

for whom

ontology

s

the most

fundamental

philosophical

ield,

utnam's

rgument

ndeed

begs

the

question. eing

philosopher

of

anguage

t

heart,

utnamdecidesthe

question

f

the

theory

f reference efore

decidingmajor ontological

ssues,

uch as

the

existence

f an

external,

erceivable

world.As Casati and

Dokic2

rieflyemarked,

utnam

resupposes 'meta-language'which s

inappropriate

or real

BIV,

and

only

hen ddresses he

sceptical

isjunction.

It turns ut that

his

apparent

efutation

f the

BIV

propositions

ests

pon

the

prior

assumption

hat he

speaker

s,

after

ll,

a

bodily

erson

who has a

direct

erceptual

contact

with

eality,

r

thathe at least

acitly

elieveshimselfo be such

a

person,

r,

alternatively,

hathe at least

tacitly

elieves

most

members

f

his

society

o

be such

persons.3

or

it

s

only

by relying

n such realistic

resuppositions

or

on some nternal

realistic

resuppositions,

s

argued

by

Dell'

Utri4),

hatthe assumedcausal

theory

f

referenceecomes

cceptable.

And

suchrealistic

remises

o indeed

beg

the

question.

Of course

Putnam

might espond

hat,

rom is

inguisticerspective,

his

begging

ofthequestion' s no liabilityt all,but rather signof thevalidity f hisargument.

For,

s Geach

remarks,5

t

s

the

mark f validdeductive

rgument

hat ts onclusion

is

mplied

y

ts

premises.

ut fPutnam's

rgument

s

ntended

o convince

sceptical

ontologist,

e should

recognize

hat the above

'question-begging'

ill,

for such

a

sceptic,

ntirely

ndercut

he force f his

arguments.

or the

ontologist

maintains,

as

I

shall soon

explain

in

greater

detail,

that

choosing

a

theory

f reference

s

conditioned

y

one's

chosen

ontology,

nd not

vice

ersa.

Consider,

for

xample,

he above

sceptical

disjunction.

he Cartesian

pproach

sees thisdoubt about

the natureof

man,

which

may

be

compressed

nto

the well-

knownconundrum What am I?', as a key ssue ofphilosophy. shallnow argue

that his

undamental

cepticism,

hichPutnam laims o

have

rendered

mpossible,

2

R. Casati

andJ.

Dokic,

'Brains in a

Vat,

Language

and

Meta-Language',

Analysis

1

(1991), pp.

91-3.

3

On the social

background

of Putnam's

linguistic rgument

ee

Massimo Dell'

Utri,

'Choosing Conceptions

of Realism:

the

Case

of

the

Brains

in

a

Vat',

Mind

99

(1990), pp.

79-90

(cf. p.

83).

4 Dell'

Utri

p.

90.

His

reconstruction

uggests

hat

Putnam's

argument

gainst

scepti-

cism

presupposes

nternal

ealism. have

opted,

however,

o

agree

with

Brueckner,

Brains

in

a

Vat',

Journal fPhilosophy

3

(1986), pp.

148-67,

note

2,

that this

argument

hould

be sharplydistinguished romPutnam's internalrealismas expressedin the restof the

book

(all

the

more so

since Brueckner's

nterpretation

as confirmed

y

Putnam

himself).

I was thus

surprised

o

discover

n

Realismwith

HumanFace

(Harvard

UP,

1992),

ch.

7,

that

Putnam reiterates

his BIV

argument

s an outcome of internal

realism.

contend,

however,

that

my argument

gainst

Putnam

works

against

both

interpretations.

5

P.

Geach,

Reason

nd

ArgumentOxford

UP,

1976),

p.

18.

?

The Editors

f

The


994.


5/11

216

YUVAL

STEINITZ

assumesthat

any

decisions

oncerning

he

right heory

f reference re

absolutely

dependentupon

decisions

about central

ontological

ssues.

Therefore,

rom

the

ontologist's oint

of

view,

the

ontological

ssues nvolvedhave

clear

recedence.

Putnammight till esist yclaiminghat inceontological cepticstateheir iews

and

argue

for

them,

he

question

of

whether

hey

ssert

nything

whether heir

wordshave real

meaning

nd reference must

n

some

sense

be

prior

o whether

what

they ay

is

true.

This,

I

believe,

s

partially

rue

about

meaning,

but

it

must be

wrong

about

reference. s

Quine

emphasized,

reasonable

heory

f referencemust llow us to

say

what there

s

not. And

since

therecan be no

reference

o

what there s

not,

anyone

who

denies

the

existence

f the external

world

or

who deniesthe existence

of

ghosts,

nicorns,

tc.)

mustnot be disturbed

y

the

obvious fact hat

his

words

'external

world',ghosts'

nd unicorns'

o not

refer. his

seems n ine

with utnam's

own

argument,

or

hough

e accusesthe

BIV-sceptic

f

being

ncapable

of

referring

to the real vat which contains

him

according

o

his

story,

e

does not accuse

him

of

being ncapable

of

referring

o

anything

hose existence e

denies,

.g.,

his

hands,

his

friends,

tc.

(and

we shall see

in

the

imagineddialogue

below where

t

would

lead him

f

he

did).

Coming

back to the

ontologist's

oint

of

view,

think

he best

way

to illustrate

the

significance

he above differencef

approach might

cquire

is

by

considering

Berkeley's

mpirical

dealism.

Obviously,

he

theory

f reference erived

rom

n

ontological

tance such as

Berkeley's

s

incompatible

with

Putnam'srealistic ausal

theory

freference.

Indeed,

both

Berkeley

nd Putnamwere

ooking

or

way

to

escape

the

cepticism

Descartes

unfolds

n the

first

hapters

f

the Meditations.ut

Berkeley

reaches

a

differentolution.

He

maintains hat hebestmethod

f

overcoming cepticism

s

to

neutralize t

by

giving

up

realism

and then

re-adjusting

he

theory

f reference

accordingly.6

e would thus laim thatwords uch as

'brain',

vat', etc.,

houldnot

be conceived s

denoting

bjective

bjects

hich re

independent

f

any

perceiver,

or

as

denoting

ubjectivebjects,

.e.,

objects

whichowe their

xistence,

iz.,

heir

nternal

reality,

o the

inguistic

ractice

f

any particular

ociety,

ut rather s

referring

o

the commonperceptionsfGod and man,perceptions rojected yGod onto His

creatures'minds.

If

Berkeley's

ebuttal f

cepticism

s

nternally

oherent,

henPutnam's

rgument,

claiming ny

surrender f realism o

be

self-refuting,

s

not

responsive

o it.

Putnam,

quite

surprisingly,

oes

not endeavour to demonstrate hat

dealistic

r

solipsistic

approaches

annotbe

accompaniedby compatible

heories

freference

hich

make

their xternal-world

cepticism

elf-coherent.7

These

considerations

uggest

hatthere s

another nd indeed

a

major

difficulty

withPutnam's

and

Dell'

Utri's)

responses

o

traditional

cepticism:

he

IVsto?y

oes

6

Principles

f

Human

Knowledge,

ecs

87-90.

7

A transcendental

rgument

or

hat

purpose

is set forth

y

Kant,

who

asserts hat

our

concept

of

self-identity

cquires

its

meaningonly gainst

the assumed

background

f

exter-

nal

reality:Critiquef

PureReason

B

276.

This view

actually mplies

thatthe

Cogito

s

already

sufficiento confute xternal-world

cepticism.

? The Editors f

The


994.


6/11

BRAINS

IN

A

VAT

217

not onstitute

n

adequate

ersion

f

ld,

xternal-world

cepticism.

utnam laims

that

real

BIV is

incapable

of

expressing

cepticism

ecause his

words fail to refer.

Or,

as

suggested y

Dell' Utri's

reconstruction,

n

actual BIV

would not have the

internal)

realisticanguage required or xpressing isfears nd doubts.But what forcedoes

thisclaim

have

against, ay,

an

idealistic

olipsist,

ho claims

the entireworld

to

exist

n

his

mind,

without

ssuming

single

external

ntity?

uch

a

solipsist

an

think f

himself,

.e.,

his

soul,

as the

only

thing

hat

exists,

without

ontradicting

himself

y

appealing

to

realistic

anguage.

Thus

Putnam's

rgument

gainst

xternal-world

cepticism

as

well as Dell'

Utri's

version

f

it)

is a bit

tricky:

he

representative

ceptic

s held

to doubt

everything

outsidehis

mind,

xcept

his

brain,

vat and

computer,

hich

do

lie

outsidehis

mind.

He is then

found

ncapable

of

forming

irect r

indirect

erceptual

onnections ith

those solated slandsofexternal ealityeft ehind.And thisrenders isscepticism

self-refuting.

This

shows that Putnam's

refutation f

external-world

cepticism

s

heavily

dependent

upon,

and hence

limited

o,

a

specially

ooled

sceptical

hypothesis,

n

which

here

s

an

external

eceivinggent.

here

this

deceiving gent

s

furtherssumed

to be

of

a

materialistic

ature,

.g.,

the

vat-computer

ystem,

utnam an

argue

that

it has to be

perceptually

onnected o the

sceptic,

n

orderto be

referredo.

Now,

in

order o see

more

clearlywhy

Putnam's

rgument

s

entirely

neffective

gainst

ther,

more

conclusive

xpressions

f external-world

r material

cepticism,

onsider he

resultswerehe to try o apply tto Berkeley'sdealism:

Berkeley:

ll

there

s are

souls and

ideas.

Putnam:

his is

self-refuting.

ndeed,

any

external-world

cepticism

s

self-refuting,

as I

have

demonstrated

n

the

case of

BIV,

for

f

t s

true,

hen he

ceptic's

words and ideas fail

to refer o

those

material,

xternal

objects

which

constitute is

deluding

nvironment.

o

if

we are brains n

a

vat,

we

cannot

say

or think

hat

we

are.

Berkeley:

ut

my

tory

s

different

n

my tory

here re no

material,

xternal

bjects,

and hence

no

causal connectionwith

such

objects

s

necessary

or their

description.

[Putnam

would do

well

to end the discussion

t

this

uncture.

For were he to

press

his

point,

he

would be

forced

o

argue

thatthe

existence

f an

external,

bjective

referent

s

a

necessary

ondition

not

ust

for

reference

ut for

meaningfulness

oo.

He would

have to do this

n

orderto extend

his

linguistic rgument

o

Berkeley's

idealism,

hat

s,

n

order o

doubtthe

meaningfulness

f

Berkeley's

ntirely

egative

existential

ropositions

bout

an

objective,

xternal

reality.

But such a view has

unwelcome

ntological

onsequences.]

Putnam: his iswrong oo.True,your tory oes not contain nyexternal,material

objects.

But have

you

not

ust spoken

about

such

objects,

while

denying

their

ery

xistence?

hus,

according

o

my

ausal

theory

f

meaning,

here

mustbe some

ausal,

perceptual

onnection etween

your

wordsor ideas of

material

bjects

nd

at least one

exemplar

f such an

object,

n

orderfor

? The Editors f

The

Philosophical

yarterly,

994.


7/11

218

YUVAL

STEINITZ

your

wordsto

acquire

their

revalent

meanings, hough

you

believe them

to have no

referencet all. So either

here

re

material

bjects

r

there re

not. If

there

re,

your

external-world

cepticism

s

false.

f

there re

not,

thenyoucould notsayand meanthatthere re not.

Berkeley:

now

see

the true

nature

of

your argument.

our

demand for a

causal

connection ith he

object

we

speak

bout,

or

at

east

for causal

connection

with ther

bjects

of

the same

kind,

s none other

han a

disguised

ersion

of

the ancientParmenidean

doctrine hat It cannot

be said that

anything

is

not'.8

ndeed,

you

ostensibly

lter

t

by claiming

hat It cannot be

said

that

anything

s

causally

unconnected'.But since

therecan be no

causal

connectionwithwhat

there s

not,

your

demand boils down to

the

same

ontological

onsequences,

hat

s,

the nflated

ntology

f

objects

or

at

least

kinds fobjects) hat ssuesfrom he old riddleofnon-being.9

In

the last few

pages

we have

seen

why

Putnam's

anti-sceptical

rgument

s

ineffective

gainstwidely

omprehensive

ceptical

cenarioswhich

ermit

o external

reality

solipsism),

r at least

no material

reality idealism).

Let us summarize

he

discussion o

far

by

stressing

wo

major

points:

1.

Putnam

rgues

hat

ceptical

ssertions

uch

as

'Reality

s an

all-encompassing

dream',

r

I

am a

BIV',

are

self-refuting,

nd

triumphantly

laims

hat

e

has revealed

a

substantial

nconsistency

n

ontologicalcepticism.

ut have

uggested

hat utnam's

satisfaction

ould be

warranted

nly

f his

realistic ausal

theory

f

reference ere

true ome hatmay. have alsodemonstratedhatPutnammight indtquitedifficult

to force

stubborn

ntological

ceptic

o

accept

his causal

theory

f

reference

n

the

first

lace.

For the

ontological

oubtsraised

by

such a

sceptic

re

not

restrictedo

ontology.

ather,

hey pread

to

the

prevalent

ausal

semantics

s

well.

Note, then,

hat

he

contradictionhatPutnam

laimed

o

have

revealed,

etween

thecausal

theory

f

reference

n

the one

hand,

and some

major

sceptical

rguments

on

the

other,

would not

mmediately

in over

a

true

ntological

ceptic.

n

fact,

his

contradiction

might

only

serve to

emphasize

how extensive he

ramificationsf

traditional

ntological

cepticism

eally

re.

2. nstead f eing rue omewhatmay, nd nstead fbeingnelementaryypothesis

or

an axiom

about the

theory

f

reference,

utnam's

ausal

theory

f

references

clearly ependent

pon

an

implicit ntological

tance: ither

pon

external

ealism,

s

suggested y

Brueckner,

r

upon

internal

ealism,

s

suggested y

Dell'

Utri.

Well,

why

hould

not

Putnam

dopt

one of

these

conceptions

f

realism'

as

Dell'

Utri

puts

t)

as his

premise?

ake,

for

nstance,

nternal ealism: s

it not

possible,

t

least

n

principle,

hat

this

theory

s

indeed

necessary

or

thinking

nd

referring,

s

Putnam nd

Dell' Utri

suggest?'0

8See M. Furth,Elements ofEleatic Ontology',Journal f he istoryf hilosophy(1968),

p.

116.

9

These

unwelcome

onsequences

f

Putnam's

rgument

were

first

ointed

ut n

Philosophia

16

(1986)

by

P.

Tichy,

Putnam on

Brains

n a

Vat',

pp.

144-5,

and

by

F.B.

Farrell,

Putnam

and the

Vat-People', p.

154.

'0

Putnam

ch.

3;

Dell' Utri

sec. V.

?

The Editors f

The

Philosophical

uarterly,

994.


8/11

BRAINS IN

A

VAT

219

This is not

to

the

point

here.

Assuming

hat

xternal ealism

nd

internal

ealism

are

false,

then Putnam's

causal semantics

oes

too.

In

that

case,

Putnam's

anti-

sceptical

rgument,

nd Dell' Utri's

reconstruction

f

it,

go

as

well.

Assuming,

n

the otherhand,thatone oftheseontological tanceshappensto be true, hentheir

arguments

gainst cepticism

re valid but useless. or

if

external r internal

ealism

is

true,

hen all forms f

external-world

cepticism, .g.,

the

BIV

story,

olipsism,

Idealism,

the Evil Genius

story,

tc.,

are

nstantlyalsfied

y

this

ery

ssumption.

he

question

has been

explicitly

egged

at

the

outset.

There

is no

need

for

Putnam's

BIV

reference

tory.

II.

A

BIV

PERSPECTIVE

In the firstartof thispaper I showed hatPutnam's rguments ineffectivegainst

old-style

ntological cepticism.

his is

because

scepticism

f

this

ort

might

ecome

so

comprehensive

hat t

must

nfluence

he

heory

freference

referred

y

the

ceptic.

In

the

following

ages

I

shall

evaluate he force

f Putnam's

rgumentsgainst

more

moderate

ceptic,

who

considers

single

BIV

placed

in

a

real,

rich

material

surrounding,

nd who

happens

o take

or

ranted

utnam's ausal

theory

f

reference.

Must he

accept,

underthose

ssumptions,

utnam's olution

f

BIV-scepticism?

Putnam

resents

heBIV

hypothesis

s a

story

bout

a

mad scientist ho

performs

the

experiment.

he

following

tory rovides

reasonable

equel,

n

the

sense that

itdoes notcontradictny major physical rinciples r the aws of ogic. tspurpose

is

to show

hat hehermetic

eparation

etween

BIV,

on

theone

hand,

nd

objective

reality,

n

the

other,

might

ot be

as

air-tight

s

Putnam

maintains. t would

follow

that ven

f

sceptical

IV were o

accept

Putnam's ealistic ausal

theory

f

reference

(as

no

CartesianBIV

would),

till

here

might

e

circumstances

n

which

his

assertion

'I

am a

BIV'

would

acquire

ts

ssumedrealistic

eference,

nd

hence be

meaningful

and

succeed

n

referring

n

the

ordinary

ense.

Imagine

a brain

n

a

vat named Alex.

Apart

from

he

unfortunate

act

hathis

nerve-endings

re

connected o a

computer,

Alex is a normal

person

n

all

other

respects.

ike most

people,

Alex

does not

belong

to the

category

f thosewho

waste

their imeon

philosophical

meditations.oubts suchas 'Am I a BIV?' have never

enteredhis

mind.

One

day

it occurs to

the

mad scientist o

documenthis

sensational

xperiment.

He

buys

video

camera,

films he

BIV

system

nd the

computer

ontrolling

t,

and

that

very

vening

creens hefilm or

his

friends.

uddenly

he

realizes hathis

circle

of

friends

ncludes,

n

some

weird

ense,

Alex as

well.

t

would be

unfair,

e

thinks,

to

prevent

Alex from

eeing

hefilm:

After

ll,

haven't hurthim

enough

by

putting

him

nto

the vat?'

But how

could Alex watch

he

film?

nd

how

could

he be

prevented

rom

ealizing

thathe himselfsthefilm's ero,whichmighteopardizesomepsychologicalspects

of the

experiment?

In

order

to

accomplish

his,

he

mad

scientist

ecides that t

would

be

best

f

the

computer

made Alex

meet

him

omewhere,

fter

whichhe

would nvite

im

to

watch

the

film

t his home.

Since

the

film

hows

nothing

bout

the

way

the

brain

was

?

The Editors

f The

Philosophical

uarterly,

994.


9/11

220

YUVAL

STEINITZ

removedfrom

ts

body

and

put

into the

vat,

there s

no

reason for

Alex to

realize

that

he

is

looking

t

himself.

And so

it was.

The

computer

erformed

perfect

imulation f a

party

t which

the mad scientistnvitedAlex tohis home.Therehe showedhimthefilmboutthe

BIV.

(Obviously

our

amazed hero

watched the film

through

the

electrodes

permanently

ttached

to his

visual

nerves,

ust

as

he

saw

all

the

other

things

hat

constituted is

world.)

Nevertheless,

few

days

ater t

occurred o Alex

for he

first ime n

his

life o

raise a

sceptical

uestion:

Might

be a

BIV

myself?'.

After

urning

hisdoubt

over

n

his

mind

day

and

night,

e

finally

went to

the

library

obviously

simulated

ibrary)

o

read an

essay

ntitled

Brains

n

a

Vat'. On

page

50 he

came

upon

the

following

onclusion:

So,

if

we are

Brains

n

a

Vat,

we

cannotthink hatwe are'. 'That poorbrain saw in thefilm', hought lex. Even

if

t

had

suspected

ts

true

predicament,

hat

very

hought

n its

part

would be self-

refuting.'

nd

so he

sighed

n

relief.

The moral:

Alex

considered

he

possibility

f

being

a

BIV,

and

conceived the

concepts

brain'

nd vat'

n

his

mind,

s a

result f

ome

causal,

perceptual

onnection

with

he real

vat

containing

im.

Hence his

words

nd doubts

eem to

acquire

their

assumed

reference

nd

meaning.

Does

the fact

hathis

observation

ook

place

by

means

of a

film

rojected

rom

a

computer

memory,

nd

transmittedo hisbrain

via

electrodes,

revent

he

fulfilment

oftherequired ausal connection?

Putnam,

uite

urprisingly,

laims hat

tdoes.

Here he

sharply

iffersrom

ripke,

another

roponent

f the

causal

theory

f

reference,

ho

argues

hat ven

the

most

indirect nd

heavily

mediated

causal

connection

s

sufficientor

the

establishment

of full

eferential

elations

etween

he

concepts

r

names

and the

objects,

hrough

what he calls

a

causal

(historical)

hain'."

According

o

Kripke,

blind man can

refer

o

light,

ven

though

he

has

never een

it,

or

anything

imilar o

it.

Thus,

if

Alex

opted

for

the

Kripkean

nterpretation

f

the

causal

theory

f

reference,

e

would be

'allowed' to

refer o

vats

and

computers,

ven

though

he

grasped

their

concepts hrough

iscourse

with computer, n thecondition,fcourse, hat hose

concepts

were

programmed

nto the

computer

y

someone

whose

concepts

of vat

and

computer

o

refer.

Putnam

pp. 11-12),

n

contrast,

ismisses he

referential

alue

of such

very

weak

causal

connections:12

Although

he

machine does

not

perceive

pples,

fields,

or

steeples,

ts

creator-

designers

id.

There is

some

ausal

connection

etween he

machine

nd

the real-

world

apples,

etc.,

via

the

perceptual

xperience

nd

knowledge

f

the

creator-

designers.

ut such a

weak

connection

an

hardly

uffice

or

reference.

"

S.

Kripke, Naming

nd

Necessity

Oxford:

Basil

Blackwell,

1980),

p.

139.

12

Putnam's

position

here

concerning

the

insufficiency

f

such weak

connections con-

trasts

not

only

with

Kripke's,

but also

with

his own

earlier

writing

on

this

topic:

cf.

'Explanation

and

Reference',

reprinted

n

his

Mind,

Language

nd

Reality

Cambridge

UP,

1975),

p.

202.

?

The Editors f

The

Philosophical

uarterly,

994.


10/11

BRAINS IN A VAT

221

And he

ustifies

hiswith

he

following rgument:

The machine s

utterly

nsensitive

o the

ontinuedxistence f

pples,

fields,

teeples,

etc.

Even if ll these

hings

eased

o

exist,

he machinewould still iscourse

ust

as

happily n the sameway.That is whythe machinecannotbe regarded s refer-

ring

t all.

But thisview

s indeed

very

odd.

It

implies

hatwhen we read

in

a book

about

penguins

n

Antarctica,

we should

claim

that

the

word

penguin

annot refer o real

penguins,

s thewritten

ord and the

book

are no less nsensitivehanthe

computer

to the

continuedexistence

of

penguins.

s

the

assumption

hat this book

might

continue o be read

'just

as

happily

n

the same

way',

even

if

penguins

ceased

to

exist',

nough

to

disqualify

he

book's referentialalue? And if

o,

then

what would

be the reference f the entry penguin' in the insensitive 930 editionof the

Encyclopaedia

ritannica?

Putnam

might

rgue

thatthe

book could

in

principle

e re-edited nd

updated,

and

that

he 1930

edition ould be

replaced

by

the

2030

edition.But

then,

n

exactly

the same

way,

the

mad scientist

onducting

he

BIV

experiment

ould

update

the

computer

memory

oncerning

he

extinctions,

hould

theyunfortunately

ccur,

of

penguins, pples,

or

steeples.

He could also

program

he

computer

o

update

tself

periodically,

erhaps

ven

using

heBritannica

ear-books.

ncidentally,

hesevolumes

are

printed

nowadays

from

nformationhat

s

processed

nd

stored

n

a

computer

memory,

nd

transmitted

o

the

printer

ia electronic

mediations.

Thus we

must

opt

for

Kripke's

version,

nd

stipulate

hat the

mere fact that

sensations re

processed

nd transmitted

y

a

computer,

r

by any

artificialr non-

artificial eans

whatsoever,

annot liminate he

required

ausal connection etween

a

word

and

its

supposed

referendum,

n

the condition hat

such

a connection

does

exist n

the first

lace.

In

'a

causal

(historical)

hain' the

first

ink

s what matters:

through

t

the whole chain

should

be

perceptually

inked o

reality.

All

other

inks

need

not

be

perceptual,

ot even the ast ink

which

onveys

he

term

ight

o a

blind

man,

or

the

term

at o a BIV.

Therefore,

fAlex

suspects,

s a

result f

his

computer-

mediated

watching

f a film

or

even

as a

result f a

computer-mediatedeading

f

a

description

f

vats),

hathe

might

e a

BIV,

his doubts re

ultimately

eaningful

and

capable

of

referring.

What then

should our

sceptic

believe,

f he

suspects

his

true

predicament,

hile

assuming

he existence f a

rich

ndependent

world

of

objects

outside

of

his own

world?

Surely, being sceptical,

he

cannot

reject

the

possibility a possibility

acknowledged y

Putnam s

well)

that he

computer's

memories nd

programs

re

at

least

partly

function

f external

eality.

herefore t would

be

only

reasonable

for

him

to

hypothesizeeven

though

he can

never

verify

t)

that the

words brain'

and

'vat'

in

his

anguage

may

cquire

a

real

reference fter

ll.

I think t has become evidentby now that the onlyway to preservePutnam's

argument

gainst

BIV

scepticism

s to

adopt

a

more

rigid

version f

the

BIV

story,

one that

liminates

ny

causal

inkage

with xternal

eality

hatever.

ot

surprisingly,

indeed,

Putnam

hints t this second line

of

defence

when

he moves

to consider

strange

ossible

world

n

which

every

entient

eing

s

and

always

was

a

brain

n

?

The

Editors

f

The

Philosophical

uarterly,

994.


11/11

222

YUVAL

STEINITZ

a vat'

(p.

14).

Such a

comprehensiveceptical

cenario,

he seems to

believe,

must

be either

elf-refuting

r false.

But this s cold comfort.

irst,

ecause treturns s to the

first

orn f

the

dilemma,

i.e., to our previousconclusion that such a comprehensiventological scepticism

necessitates

hanging

he

theory

f reference

ccordingly.

econd,

because even

if

Alex refused o

accept

this,

nd

steadfastly

eld to

Putnam'srealistic ausal

theory

of

reference,

e still ould not hakeoff

cepticism. ceptics

re also

concerned bout

partial

ceptical

cenarios. o the ctual

disjunction

lex s

facing

s

not meredouble

but

a

triple

isjunction:

(a)

I

am a

person

with

body,

perceiving

bjective eality;

(b)

I

am a BIV

controlled

y

a

computer,

ut

part

of

the'computer's

imulation

of

reality

riginates

n

the observations

f

its

programmers

or,

alternatively,

n

the observations f attached roboticsensorymechanisms),who do perceive

objective

eality;

(c)

I

am a

BIV,

and there s

nothing

lse outside

my system.

Or,

alternatively,

all scientists

nd

programmers

re themselves

IVs.)

Of

course,

Putnam

may happily

laborate

upon

the

possible

realization f the ast

comprehensive

cenario

c),

which

permits

im

on

the

condition f

neglecting

ur

previous rguments

f

section

)

to

rely

upon

his

hypothesis

hat

cepticism,

n

such

a

case,

is

self-refuting....

Yet this hould not comfort

im,

nor should t comfort

ny

BIV-sceptic.

For

as

longas disjunctb) cannot be excluded, cepticismeems to remain s plausible s

ever.

13

Tel-Aviv niversitnd Universit

f

Haifa

'3

I

would like to thank Naomi

Goldblum,

Noah

J.

Efron and Zev

Bechler

for

helpful

comments.

?

The Editors f

The


994.

Documents

Brains in a Vat - Different Perspectives - Yuval Steinitz