### TL;DR
**What is knowledge?**
The question of "what consti...
Edmund L. Gettier III was an American philosopher and Professor Eme...
Here is one kind of example:
> "Imagine that we are seeking wate...
Another example of a Gettier Problem:
Pluto was a planet
For ...
Here is a brief video explanation of Gettier's first counter exampl...
ANALYSIS
23.6
JUNE
1963
IS
JUSTIFIED TRUE BELIEF KNOWLEDGE?
v
ARIOUS attempts have been made in recent years to state necessary
and sufficient conditions for someone's knowing a given proposition.
The attempts have often been such that they can be stated in a form
similar to the
fo1lowing:l
(a) S knows that
P
IFF
(i)
P
is true,
(ii)
S
believes that
l',
and
(iii)
S
is justified
in
believing that
P.
For example, Chisholm has held that the following gives the necessary
and sufficient conditions for knowledge
:2
(b)
S knows that
P
IFF
(i)
S
accepts P,
(ii) S has adequate evidence for P,
and
(iii)
P
is true.
Ayer has stated the necessary and sufficient conditions for knowledge as
follows
:3
(c)
S
knows that
P
IFF
(i) P is true,
(ii) S is sure that
P
is true, and
(iii) S has the right to be sure that
P
is true.
I
shall argue that (a) is false in that the conditions stated therein do not
constitute
a
sttficietzt
condition for the truth of the proposition that S
knows that
P.
The same argument will show that (b) and (c) fail if
'
has adequate evidence for
'
or
'
has the right to be sure that
'
is sub-
stituted for
'
is justified in believing that
'
throughout.
I
shall begin by noting two points. First, in that sense of
'
justified
'
in which S's being justified in believing P is a necessary condition of
S's knowing that P, it is possible for a person to be justified in believing
a proposition that is in fact false. Secondly, for any proposition P, if
S is justified in believing
P,
and P entails Q, and S deduces Q from P
and accepts
Q
as a result of this deduction, then S is justified in believing
Q. Keeping these two points in mind,
I
shall now present two cases
Plato seems to be considering some such definition at
Th~aefetz~.
201, and perhaps
accepting one at
Meno
98.
2
Roderick
M.
Chisholm,
P?rceivin,o:
a
l'hilosop~~ical
Sfdy,
Cornell University Press (Ithaca,
New
York,
1957),
p. 16.
A.
J.
Ayer,
The Pr~blem of Knowledge,
Macmillan (London, 1956),
p.
34.
121
ANALYSIS
23.6
JUNE
1963
IS JUSTIFIED
TRUE
BELIEF
KNOWLEDGE?
By
EDMUND
L.
GETTIER
V
ARIOUS attempts have been made in recent years to state necessary
and sufficient conditions for someone's knowing a given proposition.
The attempts have often been such that they can
be
stated in a form
similar to the following:
1
(a)
S knows that P
IFF
(i)
P
is
true,
(ii) S believes that P, and
(iii) S
is
justified in believing that P.
For
example, Chisholm has held that the following gives the necessary
and sufficient conditions for knowledge:
2
(b) S knows that P IFF
(i)
S accepts P,
(ii) S has adequate evidence for P,
and
(iii) P
is
true.
Ayer has stated the necessary and sufficient conditions for knowledge
as
follows:
3
(c)
S knows that P
iFF
(i)
P
is
true,
(ii) S
is
sure that P
is
true, and
(iii) S has the right to be sure that P
is
true.
I shall argue that
(a)
is
false in that the conditions stated therein do not
constitute a
stlfficient
condition for the truth
of
the proposition that S
knows that P. The same argument will show that (b) and
(c)
fail
if
, has adequate evidence
for'
or ' has the right to be sure
that'
is
sub-
stituted
for'
is
justified in believing
that'
throughout.
I shall begin by noting two points. First, in that sense
of'
justified'
in which S's being justified in believing P
is
a necessary condition
of
S's knowing that P, it
is
possible for a person to be justified in believing
a proposition that
is
in fact
false.
Secondly, for any proposition P,
if
S
is
justified in believing P, and P entails Q, and S deduces Q from P
and accepts
Q
as
a result
of
this deduction, then S
is
justified in believing
Q. Keeping these two points in mind, I shall now present two cases
1 Plato seems to be considering some such definition at
Tbeaetetus
201,
and perhaps
accepting one at
Meno 98.
2 Roderick M. Chi5holm,
PBrceiving:
a
Philosopbical
Study, Cornell University Press (Ithaca,
New
York, 1957), p. 16.
3 A.
J.
Ayer,
Tbo
Prob/em
of
Knowledge,
Macmillan (London, 1956), p. 34.
121