E. Gettier – “Is Justified True Belief Knowledge?”
A) S knows that P IFF i) P is true
ii) S believes that P
iii) S is justified in believing that P.
B) S knows that P IFF i) S accepts P
ii) S has adequate evidence for P.
iii) P is true
C) S knows that P IFF i) P is true
ii) S is sure that P is true
iii) S has the right to be sure that P is true.
A is false in that the conditions stated do not constitute a sufficient condition for the truth of the
proposition that S knows that P.
Same argument will show that B and C fail
„has adequate evidence for‟ and „has the right to be sure that‟ is not „justified in believing that‟
„justified‟ (S being justified in believing P) makes it possible for a person to be justified in believing a
proposition that is false
For any proposition P, if S is justified in believing P, and P entails Q, and S deduces Q from P and
accept Q as a result of this deduction, then S is justified in believing Q: S→P→Q
Suppose Smith and Jones applied for a certain job
Suppose Smith has strong evidence for the following proposition:
D) Jones is the man who will get the job, and Jones has ten coins in his pocket.
Smith‟s evidence for D might be that the president of the company assured him that Jones would in
the end be selected and that he counted the coins in Jones‟s pocket ten minutes ago
Proposition D entails:
E) The man who will get the job has ten coins in his pocket.
Suppose Smith accepts E on the grounds of D, for which he has strong evidence
In this case, Smith is justified in believing that E is true
Imagine, unknown to Smith, that he, himself will get the job and that he, himself has ten coins in his
E is then true
D is false In this example, all of the following are true:
i) E is true
ii) Smith believes that E is true