cogito, ergo sum: inference or performance? by jaakko hintikka
TRANSCRIPT
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
1/16
Sorry or he
conditionofhis
document.
almost
idn't
put
n
on hesystem,
ut
t is
an
mportant
ork;
and f
l
didn't o
t
I would
be doing
omething
ess
mportant
t
the moment.
Steve
Bayne
.
www.hist-analytic.org
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
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WADSWORTH
STUDIES
IN
PHILOSOPHICAL
CRITICISM
Alexander Sesonsheand, Noel Flemi.ng,
Edi,tors
HUMAN
UNDERSTANDING:
Studies
n
the
philosophy
of
David
Hume
J
META.MEDITATIONS:
Studies
n
Descartes
PLATO'S MENO:
Texr
and
Criticism
META.MEDITATIOT{S:
Studies n Descartes
edircd
b1
Alexander
Sesonsfr'e
nd
Noel
Flerrting
UNIVERSITY
OF
CALIFORNIA'
SANTA
BARBARA
Wadsuorth.
Publish'ing
Cornparyt'
nc'
BELMONT'
CALIFORNIA
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
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COGITO,
ERGO
SUM:
INFERBNCB
OR
PERFORMANCE?*
f aahoHinti,kha
rv
2n
l.
Cogito,
crgo sum as a
problem.
The
fame
(some
would
say the no-
toriety)
of
thc ntltgc cogito, ergo fl,rm makes
one
expect that scholarly
industry hns
147.
::
Scc c.g.
L. BlancheqLes ant4cddents u
"Je
pense,
onc
e
suis"
(Paris,
1r)20);
iricrrnc
Gilson,
Etudes ur Ie r6le de a
pensie
midi6,uale dns
a
Cogito,
Ergo
Sum
5
Augustine's
anticipation.
t cannot be denied,
of
course, hat
the sim
larities
are
striking.
One may wonder, howevcr,
whether they are
a
there
is
to the matter.
Perhaps
here are also dissimilarities
betwee
Descartes
nd
Augustine
mportant
enough o
justify
or at least o
ex
plain
the
one's reluctance
to acknowledge
lrc cxtent
of
the
other
anticipation.
But we cannot
tell whether
thcrc is more ro
Descarte
cogito,ergosum han there s to St. Augustinc's irrilar argumentbe
fore
we
can ell exactly
what
there s to the
cogittt:lrgrrmcnt.
If
there are important
differences
betwccn
l)cscartes and
hi
predecessors,he
questionwill alsoarise
whcthcr
sonlc
of
thc
anticipa
tions
are
closer han
others.
For instance,
Descartcs
orrkl have
oun
the
principle
n St.
ThomasAquinasas
well as
n
St. Augustine.
Which
of
the
two
saints omes
loser o
the cogito, ergo
sum?
3.
What
is the relation
of
cogito ta sum?
Whnt
kind
of topica
questionsdoes
cogito, ergo
sum
give
rise
to?
Onc
of rlrc rnost
m
portant
questionss undoubtedly
hat
of
the logical
orrrr
of
l)cscrrrtc
inference.
s it a
formally valid inference?
f not, wh:rc s krgical
wrong
about tl
But there
s an even
more fundamental
uestion
lrlul tltcsc.
)oc
Descartes's
ictum really
express n inference?
Thrrt it tkrcs s sug
gestedby the
particle
ergo.
According to Descartes, owcvcr, lry
sry
ing cogito,
ergo sa.m e
doesnot logically
(syllogisticrlly)
tlctlucc
szr
from
cogito but
rather
perceives
ntuitively
("by
^
sirnplc lcf of nrcn
tal vision")
the self-evidence
f
sum3
Similarly,
Dcscartcs
r.crrsionr
says hat
one'sown
existences
ntuitively obviouswithorrr
Irringing
n
cogito
asa
premise.a
ometimes'he
ntimates
hat
his
"first
llrirrciplc"
really
the
existence f his
mind-and not the
principlc
ro$ittt,
crl4
sum,by
means
f
which
this existence
s
apparently
dcdrrce
l.b
)nt.chc
formulates he cogito
principle
Ls
ego cogitansexisto
withorrt
rrsirrg
he
word.ergo
at all.6
But if it is true
that the
Cartesian
ictum does not
cxprcss n
inference,
equally
perplexing
questions
re bound to
arisc. Nor orrly is
SCEuttres
e Descartes,
ublished
by
C,
Adam and P. Tannery
(1, tris,
ttr)7
1913),
VII,
140;
The Philosofhical Worhs
of Descartes,
rans.'by ii. S. llulrlnn
and
G. R. T. Ross
(London,
1931),
I, 38. In the sequel,
lrcse'crlitionr rvill
lrc
referred to as AT and HR,
respectively,with
Roman-numerals cferrirrg to
vol-
umes.Normally I
shall
not
follow Haldine and Ross's
ranslation,howcvci'; I slrtl
make use of the existing ranslations
notably
of those
by N, I(ernp Srrritlr
rrrl by
=rather
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
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52
Meta.Meditations:
Studies
n Descartes
the
particle
ergo then
misplaced;
he word
cogito is likewise out of
place
n a sentencewhich only serves
o
call
attention
to
the
self-evi-
denceof sum.
But
is
the
word cogito perhaps
calculated o express
he
fact that
thought is needed or
grasping
ha;t
sum
is
intuitively evident?
Was it
perhaps
an ndication of the
fact
that
intuition was
not for Descartes
n
irrational event but an act of
the thinking mind, an
"intellectual
intui-
tion," as t hasbeenaptly expressed??ven f
this is
part
of
the mean-
ing of the word, the
question
will
remain
why Descartes
wanted to
stress he fact in connection rryith
this
particular
insight.
The
same
point
would equally well apply
to most
of
the other propositions
of
the Cartesiansystem;
and
yet
Descartes
does
not
say,
for example,
cogito, ergo Deusert n the way
he
says
ogito,
ergo sum.
Clearly the word cogito
must havesome
urther
function in Des-
cartes's
entence.
ven if the sentence
did not express
syllogistic
in-
ference, t expressed omethingsufficiently
like
an
inference
to
make
Descartes all his
sentence
reasoning
ratiocinium),8
refer
to exPress-
ing it as nferring
(inferre),s
and
call
sum a conchtsion
conclusio).1o
As Martial Gueroult has trenchantly summedup the problem: "lo
Descartes
se refuse ) consid6rer e Cogito
comme
un
raisonnement.
.
. . 2" Pourquoi s'obstine-t-il
alors au moins
trois reprises
Inquisitio
aeritatis,
Discours,Principes)
pr6senter
e Cogito
sous
a forme
qu'il
lui d6nie?"11
Since he word
cogi.to
s
not dispensable
nd since
t is not
iust
a
premise
rom which the
conclusionsum
s deduced,
he
relation
of
the
two
becomee
problem. One
of
the
main objectives
of
this
essay
s to
clear
up their relation.
4.
Cogito, ergo sum as
a logical nf
erence,But can
we be sure
hat
Descartes's
ictum does not express
a logical
inference?
n many
re-
spects t seems lausible o think that it does. ts logical form seems
quite
easy o define. n
the sentence
I
think"
an individual
receives
an
attribute; or a modern
ogician t is
therefore
of the form
"B(a)."
In
the sentence I
am," or "I
exist," this
same ndividual
is
said to
exist.
?
L.
J.
Beck,
The Method of Descartes
(Oxfoid,
1952), ch.
iv.
8
AT
X,
523;
HR
I,
324.
e
AT VII,
352;HR 11,207;
f
'
AT
III, 248.
ToPrincipid
philosophiae
,9; AT VIII' 7;
HF.1,222; cf.
AT II, 37, and
AT
v,147,
11
Martial
Gueroult,
"Le
Cogito et
la
notion
'pour
penser il faut 6tre,"'
Cogito,
Ergo Sum
53
How
can one represent
such
a sentence ormally?
If
Quine
is right in
claiming
hat
"to
be is to be
a valueof a bound
variable," he
formula
"
(Ex) (x
=
4) serves
he
purpose. nd evcn f hc s not
right in
genera
in
this
particular casehis
claim is obviously
itrstified:
"4
exists"and
"there exists
at least
one ndividual
identical wirh a" are
clearly synon-
ymous. Descartes's
ictum
therefore seems o bc
concerned
with
an
implication
of
the
form
(1) B(a) = (Ex) ( r= a) .
Descartes
erceiveshat he
thinks; hence
he obtnins hc
prcrniseB(a).
If
(l)
is true,
he
can vse modus
ponens
o
corrclrrtlc h;rt he
exists
Those who
want to
interpret the
Cogito as a logicnl irrfcrcnce
may
now
claim that
(1)
is in fact
true, and even ogicnlly
provnblc;
or
is
not
B(a)>
(Ex)(x=a&B(x))
a
provable
ormula
of our lower
functional calculi?
Arrrl docs
nor
this
formula
entail
(l)
in
virtue of
completelyunproblcrrrnric
lirrciplcs?
t
may seem hat an affirmative nswermust be givcn t
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54
Meta.Meditations:
Studies
in Descartes
But even
f we
make
his
allowance,
here remain
plenty
of difi-
culties.
As we
saw,
Descartes
ometimes
enies
hat in
ti"
cogito
^rgr-
ent sum
is
deduced
.rom
cogito.
But
on the
view
we are
criticizing
the argument
s
a deduction.
The view
is herefore
unsatisfacrory.
It
is also
unsatisfactory
because
t does
not
help
us to
unierstand
the
role of
the
cogito
argument
n
the
cartesian
system.
n so far
as
I
can
see, t docs
not,
for
example,
help
us to
appreciate
he
conse-
quences
Descartcs
wantcd
to draw
from
his first
and
foremost
nsight.
The gravcstobjcction,however, till remainso be made. t may
be_shown
hat thc
provabiliry
of
(l)
in the
usual
systems
f functional
calculus
(quantificrtion
theory)
has
nothing
to do
with
the
question
whether
thinking
crrtails
cxisrence.
n attempt
to interpret
Deicartes's
argument
n tcrrns
of the
provabfity
of
(l)
is thereforl
bound
ro
re-
main
fruitlcss.
By this
I
mcnn
the following:
if
we have
a closer
look
at the
qFstems f
logic
irr
which
(l)
can
be
proved,
we
soon discover
that
they
arc based
on
imporrant
existential
presappositions,
s have
else-
where
called hem.tn
fh.y
make
more
or les
tacit use
of the assump-
tion
that
all thc
singular
erms
with
which
we have o deal really refir
to
(designatc)
s.nrc
actually
existing
ndividual.l'
In our
example
his
amounts
o
nssuriling
hat
the
term
which replaces
n
(1)
muslnot
be
mpty.
But
sincc he
term
in
question
s
"I,"
this
is
just
another
way
of
saying
hnt
I
exist.
t turns
out,
therefore,
ghat
we in
fact
decided hat
the
sentence
I exist"
is true
when
we decided
that
the
sentence
I
think"
is
of
the
form B(a)
(for
the
purposesof the
usual
systems
of
functional
loglc).ls
That
we
were
then
able
to infer
(Er)
(x
=
a)
from
B(a) is undoubtedly
rue, but
completely
beside
he
point.
.
It
is
lxrssible
o
develop
a
system
of logic
which
dispenses
ith
thc
cxistcutial
presuppositions.lT
f in
such a
iystem
we
could infer
"I
exist" fronr "I rhink"-i.e. (Er) (x = a) from B(a)-it would be
r{
In
"llxistential
Presuppositions
and
Existential
Commitments,,,
foarnal
of
Phllotophy,
LVI
(l9t9),
tzs-ijl.
Itr
All the
singular
terms
(e.g.
lirmes
or
pronouns)
which
in
an application
mry bo nubstit-uted
or
a free individual
variable
are assumed
o
do
soi iod as
a
conlc(llrcncc nll
the free
individual
variables
have
to behave
like
singular
rerms
which
rcnlly
posscss
reference
or
"bearer."
vulearlv-,teferend').
ttt(if.
Leibniz'
incisive
remark:
',And
to
iw i think,
theiefore
I
ow.
ls not
propcrly
to provc
exisrence
by
thought,
since
to'think
and
to bi ttrintinc
is
rhe
crnrc
rhirrgi
nnd
to say, Iam
thinking,
is
already
to
say, / arrz,,
Nouaeaui
Essais,
u. by A.
(i.
l ,nngley
La
Salle,
U.,1949),IV,
7, ec.7).-
lTSrrch
Cogito,
Ergo
Sum
highly relevant to
the
question
whether thinking
implies existence
Descartes's ense.
ut this we cannot
do.
The
truth of
a
sentence
f t
form
(1)
turns entirely
on existential
presuppositions.
f
they are
giv
up, the
provability
of
(1)
goes
by
the
board.
My
point
may
perhaps
be
illustrated
by
meansof
an exam
consrructed or us
by
Shakespeare.
amlet did
think a
great
ma
things;
does t follow that he existed?
5, Descartes'semptation In spite of all this, tl'rcrcare passag
Descarteswhich seem o suppoft the interpretation undcr
criticism
do
not
want
to
deny
that it
expresses
ne of. hc thirrgs
)escartes
h
more
or
lessconfusedly n mind when
he fbrmuhtcd lris famous
d
tum. But it is important
to realize hat this interprctntion
is dcfcctive
important respects. t does not
help
to elucidatc
n nrry way
somc
Descartes'smost explicit and most careful
formulations. It is
at bes
partial
interpretation.
One can seewhy
some nterpretation like thc onc wc
ltnvc
bc
criticizing attracted fi"r""tt"r. It
gave
him what
must
hnvc scctnc
very usefulway of defending is own doctrinesand of silcncingcr
cism. He could always
ask:
How can it possib ly
be tmc of sornc
that he thinks unless
e exists?
nd if
you
challenge hc prcrrrisc
h
he s thinking
(why
cannot he all-powerful
malin
gtnic
nttl
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
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56
Metu-Meditations;
Studies
in
Descartes
Did
Descartes
earize
hat
it
is
misguided
o
represent
his
insight
n
the
wav
we
hrl:
b:"-tt
air""rrr"gi'rt
is
very
diffcurt
to
ter.
cer-
ainty
e
.".,
,:11r:g
;
{ry.
ii"t
r.".,
..o
h^u"
"ii"dl
r,o*.u.r,hat
on
this
interpretation
the'""riairu'"r
his
argument
depends
essen-
ially
on
existential
pt.*pp"rii#.
i.,
when
he
tried
to present
his
f;111il:T::ff::,r,,
n;dedu;;;"-
,
,g.o_.rricar,,
ronir,
e
uied
,,uzecan;;;"t{id:{d"..}:',-t*,il11',X;;*:{,;if
",iUy:;
ntis)" AT vII, 16.6; -fl lt,-iii.?r,-i,
,r"r._ent
s
an
he
more
e-
arkabre
since
t
prima.
acie'.rtirr"ai.r-
whar
Descarres
ays
n
the
hird
Meditation
ibout,t;;;
.
.".-"l"rro*.0
only
in
themsitves,
and
ot
as
referred
:"
,:T.
-_other
hing,,,
namely
if,r,
,,iilf
cannoq
trictry
speakins,
e..farse."
t;rr;;";"dicts
the
plain
facl
rhar
we
an
think
of
(nientaty
"""ria.rj"i.iJ-"s,
or
princi
Hamret,
u.irhout
hereby
commiming
ourselves
"
."irr"i"i"g
that
they
exist.
he
fact
arso
emains
att",
o.r"".resresorted'to
the
interpreta-
ion
we
have
been
.crilicjzing
ffiry
in
his
more
popurar
writ-
ngs'
As
Guerourt
noticed,
n.
a?.,
""a'r.ro*
to
it
in
the
Meditationes.
is
most
explicit
usg
o{
ii
o."ul,
io"n))nrr"n" de la a6rit6,in a dia_
oguewhose idactic
"t
rt*i-irr'ffi
particurarry
-p-nrrir"a
uy
rnesr
assirer.le
.r""ri.Jr
*rrr
"-li"r
rr*r"r*ii"r;fTh:
cogito
rgumenr,
otabty
hose
n
tn"
uiiii)ti""*
.;;-;ri*;,piiioropuo,
eem
o
presuppose
difierent
"r.rpro"rlro
or
n"
".fi,rri"o .,"',.
-
6'
Existentiar
inconsistency.
In
order
to
understand
this
second
nterpretation
of
the
Cogito
*"
n"""
;;;":
a
closer
rorr.
",
,i"
rogi"
f
Descart.s's
amed
argument.
Descartes,s
ormurations
in
the
Aledita_
iones
and,
lsewhere
TSSgst
hat
his
,"roti
_"y
u"
"*p*rr.J
iy'r"yinghat
it
was
mpossibt"
nit:ni-
*
a'."yit,
,rrrt.nc".
one
w^y
irtwhich
,?"#::,'"".',:lX,i::-diF.t'.'iii.:"r.nr,*,"iilliebeen
n.r"i*.J-n;r;;1tt-"ot
exist'"
As
a
preliminary
o
o*-r*ay
or
tt..t,,,"i..;ffi
f
;T:q::::::;::+;:?ff
l*i;S:Ll[
ould
not
have
maintai".a'rrra
i"rr*
;til*
our
o
be
closely
erated
o
the
easons
hy
he
asserted
r,"
fo._.i
iir
"_
rigt
t.
What,
hen,
are
h.r.
r."rorr;f
##;.reral
characteristic
f
the
entence
De
Gau'e
does
not
.*irr"
-"L.rr
it
awkward
or
De
GauIIe
o
asse*
tl2o
I
shall
uy
to
formulrt.
iii,
g"rr.r"l
"h"r""terisJc,ny
Cogito,
Ergo
Sum
57
sayine
that
it
is
existentially
nconsistent
or
De
Gaulle
to
assert
(to
;;;i
ini,
,."..n"e.
The
notion
of
existential
nconsistency
may
be
a"n"'.a
as
follows;
let
p
be
a sentence
and
a
a
singular
term
(e'g'
a
name,
a
pronoun,
or
a
definite
description)'
We
shall
say
that
p
is
existentiaity
nconsistent
or
the
persoireferred
to
by a
to
utter
rf
znd
only
if the
longer
sentence
(2) "P;
and
4
exists"
is
inconsistent
in
the ordinary
sense
f
the
word)'
In
order
to-avoid
our
own
obiections
we
must
of
"oottt
require
thlt
thc
notion
of
ordi-
nary
inconsisrency
which
is
used
n
the
definition
involves
no
existen-
;i;i'p;;pp;sitiois.
Provided
that
this
is
the
casc,
wc
may
write
(2)
more
formally
as
(2)',
"p
&
(Ex)
(t
=
a)-"
(As
the informed
reader
has
no
doubt
already.^1ntiT1'^Ye
should
really
use
quasi
uotes
nstead
f
double
quotes
n
(2)
and
(2)")
-*
'A
;ti;"i
tlforr""t".ion
of
the
definition
shows
hnt
thc
notion
of
existentialnconsistencyeally formulates general cilsotlwlty ccrtain
,i"r"-.r,*
are mpossidle
o
defend
although-the
sentcnces
y mcnns
of
*tti.n
they
are
m"de
m"y
be
consistent
nd
ntelligiblc'
nsentl.:-f
lty-
ing
that
1i;
is
incorrsistJnt,
e
could
have
said
hat
p
cntrrils
d
docs
,ro-t
"*irti
(without
the
use
of
any
existential-presupposirions
lut
otherwise
n
the
ordinary
sense
of entailment)'
Uttering
stlcll
il. scn-
tence,
,
will
be lr"ry
a*k*"rd
for
the
bearer
of
a: it
mcnns
rtnlrrlrg
a
,r"a"-"rr,
which,
if
tme,
entails
hat
its
maker
does
not
exist'
It
is mportan
to
rcalize
hat
the
ills
of such
statuments
nnnot
bc
blamed
on
the
sentences
y means
of
which
they
are
madc'el.
n
fnct'
the
notion
of
existential
ntonsistency
cannot
be applied
nt
nll
ttt
scn-
tences.
As we defined he notion, it is a relation between scntenccond
21
t mav
be wonh
while
to recall
here
the
distinction
betwcctl
0
ficlltctlcci
"o
o*.r"r"i,?ii'r,-"i"-.r..
A
sentence
s
of
course
a
grammaticnl
.cnlity
tltrtt
i"uoi"a,
no
reference
to
any
particular
utterer
or any
particular
tlmc
()t
lltttrtlll('c'
An
utterance
, ,r,
"u"tJ-?l
"p"L"rt-""t1
that
may
6e'specified
by.spccifyirrg
tlre
;;J;;ce,
the
speaker,
nd
the
occesion
n'which
he
makes
his utterrrrrcc'
--':-
U*;""1
or
i""irtiirr"
*tt."tt""'
(with
prima-facie
fact-strtitrg
intcnt)
"r.
,*iJ
"*"-pt",
"f
tiiiiiriri.
(lt
"
term
doeinot
seem-especially
ho'py,
lrttt
i';hillt;;;f
i;;;"-il
;ppears
to
be
rather
widespread.)
A
statctttcttt
s rtt
event
(an
act)
occurring;;[;;;;"out
"o"**t'
Usirally
it is a sPecctr'nt:t
'f
n
on
that.
For
our
purposes
a st{tcnrcrrt
rr'y
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58
Meta-Meditations:
Studies
in
Descartes
a
singular
erm
rather
than
a
property
of
sentences.
he
notion
of
existential
nconsistency,
however,
can"often
be
applied
to
statements
in a.fairly
narural
sense.
n
order
to
specify
"
,tii"rn"rrt
we
have
to
specify (inter
alia)
the
sentence
ttered (t
y,
q)
and
its
utterer.
If
the
latter
refers
to himself
by
means
of the
singni"r
term
& when
he
makes
his
statemenr'
we
may
say
that
the
notiori
appries
o the
statement
f
and
only
if it
applies
o
4
in relation
o &.
A
simple
example
will make the situation crear.The sentences
"De
Gaulle
does
not
exist"
and
"Descartes
does
not
exist"
a.re
not
in-
consistent
or
otherwise
objectionable
any
more
than
the
moot
senrence
"Homer
does
not
exist."
None
of
them
is
farse
for logicar
rasons
alone.
whar
would
be
(existentiaily)
inconsisrenr
would
be
the
at-
tempt
of a
certain
man
(De
Gaulle,
Descartes,
r
Homer,
respectively)
to
use
one
of these
sentences
o
make
a
$atement.
uttered'by
some-
body
else,
he
sentences
n
question
need
not
have
anything
#o'g
o,
even
strange
about
hem.
It lies
close
at
hand
to
express
his
important
feature
of the
no-
tion
of
existential
nconsistencyby
me"ns
of'a
term
which
has
ecently
"ligygd
wide currency. The inconsistency (absurdity) of an existen-
tially
inconsistent
statiment
can
in
a
sense
e
said
ao'b"
of
[r4or*n-
tory
(pefiormative)
character.
t depends
n
an
act
or
"performance,,,
nlmely
on
a certain
person's
act
of-uttering
a
sentence'(or
of other-
wise
making
a statement);
t does
not
depen"cl
olery
on
the
means
used
for
the
purpose,
hat
is,
on the
..rrt"rr""
which
is"
being
uttered.
The
sentence
s
perfectly
correct
asa
sentence,
ut
the
,tt"tript
of a
certain
man
to
utter
it
assertively
s curiorr-sly
ointless.
f
one
of these
days
should
eadin
the
morning
paper,
"T/hele
s
no
De
Gaulle
any
more,,,
could
understand
what
is
belng
said.
But
no
one
who
knows
charles
de
9"*":""11 *tp
be-ing
puzzled
by
these
words
if they were utteredby De Gaulle himself;
he
only
way
of
making
sense
f ihem
would
be
to
give them
a nonliteral
meaning.
-
we
can
here
see
how
the
existential
nconsistency
of De
Gaulre,s
fictional
utterance
(as
well
as
the
inconsistency
of
oiher
existentially
inconsistent
statements)
mani.fests
tself.
Normally
a
speaker
wants
his
hearer
to believe
what
he
says.
The
whore
"l"ngo"g6-game',
of fact-
stating
discourse
s
based
on
the
assumption
hai
ttrls
ii normally
the
""::.By:
nobody
can
make
his
hearer
believe
hat
he
does
nor
""lrt
Uy
telling
him
so;
such
an
anempr
s rikely
to
have
he
opposite
esult.
The
Cogito,
Ergo
Sutn
59
Iomrtically"
means
here
something
ike
"{91
melely
logical
reasons"')
,l'his
destirctive
effect
is
of
couise
conditional
on
the
fact
that
the
Ircarer
nows
who
the
maker
of
the
statement
s,
that
is,
that
he
identi-
lics
he
speaker
s
he same
man
he
uttered
sentence
s
about'
In'a
special
case
a self-defeating
ttemPt.of
this.kind
can
be
rnade
withoirt
saying
or
writing
anything
or.
doing
anything
to,TpT-
,,f,i..
f"
iryittg
,6 tri"t
"
others-beliive
something
must
normally
do
something'wliich can be heard or seen
or
felt'
But
in
trying
to-
make
myself
bJlieve
something
here
is
no
need
to
say
anything.aloud
or to
write'anything
on p"p"i.
The
performance
hiough
w6ich
existential
inconrirtlt"y"r.ir.,
can in
this
case
be
merely.nl.lttcmlt
to
think-
nlor"
"".oritely,
an
attemPt
to
make
oneself
bclicvc-that
one
does
not exist.22
This
transition
from
"public"
speech-acts
o
"privfttc"
thought-
acts,
however,
does
not
afiect
the
essential
eatures
of
d-rcir
ogic.
The
reason
why
Descartes's
ttempt
to
tbink
that
he docs
n
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
8/16
60
Meta-Meditations:
Studies n
Descartes
In
a
frequently
occurring
special
case
such an
omission
s not
only natural
but almost
nevitable.
t is the
case n
which the
speaker
refers
to
himself
by
means
of the
first-person
singular
prorroo'n
,I."
This
pron_ounnevitably
refers
to
whoever
happens
o
-be
speaking.
The
specification
inconsistentor
. . . to
utterl'therefore."i,tc"r
to
the-tautology
"inconsistent
or
whoever
happens
o
be speaking
o ut-
ter," and-may
herefore
be
omitted
almost
always.
n
a special
case, he
notion of existential nconsistencymay therefore be definedfor sen-
tencessimpliciter
and
ot
only
for ,"nt"n".,
thought
of
as being
ut-
tered
by
some
particular
speaker.
These are
the
sentences
hich
con-
tain
a first-person
singular
pronoun.
The
existential
nconsistency
of
such
a sentence
will
mean
that
its
utterer
cannot
add
"and
I exist"
without
contradicting
himself
mplicity
or
explicitly.
-
There
are
purposes,
owevel,
for
whiCh
t may be
misleading
o
forget
the
specification.
Forgetting
it
may be dangerous
ince t lEads
one
to
overlook
the
important
similarities
which obtain between
exis-
tentially
inconsistent
entences
nd
existentially
nconsistent
tatements.
In a
perfectly
good sense,existentially nconsistentsentences re alr
right
as
sentences.
hey
may
be
said to
be consistent
and
sometimes
even
significant (e.g.
when
they
occur
as
parts of more
complicated
sentences).
According
to
their
very definition,
existentially-
ncon-
sistent
sentences
re
not
so much
inconsistent
as
such
as
absurd for
anyone
o utter.
Their
(existential)
nconsistency
s therefore
of
per-
formatory
character
exactly
in the
samesense
as hat
of the existen-
tially
inconsistent
tatements.
he
only difference
berween he
two lies
in
the fact
that,the
latter
are inconsiitent
for some
particular man to
make
while
the former
are
inconsistent
or anyone
1o utter.
The in-
consistency
of existentially
nconsistent
sentences
means
hat whoever
tries
to
make
somebody anybody)
believe
hem, by
so doing,
helps o
defeat
his
own
purpose.2s
uch an attempt
may
take the form
of utter-
ing
the
sentence
ssertively;
or it may
take
the form
of trying to
per-
suade
neself
of the
truth
of the
sentence
n
question.
In
the
same
way
as
existentially
inconsistent
sentences
defeat
themselves
hen
they
are
uttered'or
thought
of, their
negations
erify
themselves
when they
are
expressly
uttered
o,r
otherwise
professed.
such
-sentences
may
'therefore
be
called
existentially
self-verifying.
,,I
Cogito , I l rg ,o
Sun
6
8. Descartes'snsight.
Now
rvc
ltrtvc rt 'rtr ' l t t ' .1
r
point
where
w
cnn express
recisely
he import
of l)csc:tt ' t t 's's
rrsiglrr
or
nt least o
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8/10/2019 Cogito, ergo sum: Inference or performance? by Jaakko Hintikka
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62
Meta-Meditations:
Studies
in
Descartes
been
ess
misleading
or
Descartes
o
say,
"I
am n
that I
think,,,
or
.,By
thinking
I
perceive
my
existence,"
han
to say,
',I think, therefore
I
am."
It
may
be worth
noting
that
one of
our formulations
was
closely
anticipated
by
St. Thomas
Aquinas
when he
wrote:
,,Nullus
pot.Jt
cogltare
se non
esse um
assensu:
n hoc
enim
quod cogitat
aliquid,
percipit
se esse" De
aeritate,
X, lZ,
ad
7).
The
peculiarity
of-this
relation
explains
Descartes's
acillation
n expressing
t in that'he
some-
times
speaks
f the
Cogito
as an inference
and
sometimes
s a rcaliza-
tion of the intuitive
self-evidence
f
its
latter
half.
Similarly
we
may now
appreciate
he function
of
the
word
cogito
in
Descartes's
entence s
well
as his
motives n
employing
it. It
serves
o express
he
performatory
character
of Descartes's
nsight; it
refers
to
the
"performance" (to
the
act
of thinking)
through
-tticn
he
senrence
I
exist"
may be
said o
verify
itself.
Foi this reaJon.
t has
a most
important
function
in Descartesi,
.rrt"n"".
It cannot
t" ,"-
placed by
any
arbitrary
verb.
The
performance
(act)
through
which
the
existential
self-verifiability
is
manifested
cannot be
any rbiuary
human
activity,
contrary
to
what
Gassendi laimed.
t
cannot be an act
of walking or an act of seeing. t cannot even be an instanceof arbi-
trarymental
activity,
say
of willing
or
of
feeling.
It
must be
just
what
we said
t is:
an attempt
to think
in the
sense
f making
myself believe
(an
attempt
to
think
cam
assensu,
sAquinas
put
it)
that I do not
exist.
Ffence
Descartes's
hoice
of the
word cogito.
This
particular
word is
ncit
absolutely
ndispensable,
owever,
or
the act
of ihinking
to
which
it
refers
could
also
be called
an
act
of doubting;
and Des-aftes
does
admit
thatJris
insight
is
also
expressible
y
dubito, ergo
sum
(in
Re-
chercbe
de a
a6rit6,
AT X,
523;
HR
I,324;
cf. alsoPrincipia
philoso-
phiae,I,7).
But
did
I not say
that
the
performance
hrough
which
an exis-
tentially self-verifying senrence erifies tself may aFo be an act utrer-
ing itl
Is this not
incompatible
with
Descartes's
use
of the word
cogito?
There
is
no
incompatibility,
for Descartes
says exactly the
same.
n his
second
meditation
on first
philosophy he
says
n so
many
words
that
the sentence
I
e{ist" is necessarily
rue
,,whenever
I uttef
it
or conceive
t in
my
mind"-"quoties
a
me
profertur, vel
mente
concipitur" (AT
VII, 25;
HR I, 150).26
introspection)
rather
vague.
Nor
does
Gueroult
rearize
hat
the loeical
aspect
of
Cogito,
Ergo
Sum
The
performatory
character
of l)cscnrtcs's
irtsigltt
PresuPPos
cl'raracterisiic
eature of
his famous
mcth(,(l
of
tkrttlrt which
has
fr
quently
been commented on
in othcr
colltcxls,
l)csc:lrtcs's
doubt
do
not consist n
the
giving
up of
all opiniorrs,
rts t skcptic's
tloubt
mig
Nor
is it an attempt
to iemove
certaitr
sltct'ilit'
s()ttlccs
of
mista
from our
thinking, like Francis
Bacon's.
lt rttttottttts
() lltl
active
tempt to think
the contrary of
what
we ttsurtl ly
rclicvc.
ior
this
rea
Deslartes
could claim
that in an
importnnt
lloittt
tlris
rrrtltc:r
loctrina
doubt
of his defeats tself. A
skeptic'spnssivc
krttlrt
'ottlt l
ttcvcr
do
The performatory
character
of Dcscilrtcs's
llrigllt
is
irr fnct
p
and
parcel-of
the
general
strategy
of
fuis
rcdttrti()
trl
tltsrlrdrntt
(
perhaps
ather
projiectio
ad absurdum.)
of
skcptit ' isrrr,
l ' lris
sl
rltcgv
6.onght out
very welt
by Richard
Popkin
in
lris tttpor'l
tnt
.u,ol' l