The Gettier Problem

William S. Larkin

I. Significance

A. Epistemological goal is to respond to skeptical argument.

B. One strategy is to deny the premise that knowledge requires certainty.

C. Justification:

1. True belief is not sufficient for knowledge; since a belief can be true by accident or lucky guesswork, and knowledge cannot be a matter of luck or accident.

2. So knowledge requires justification—i.e., having sufficient reasons for one’s beliefs.

3. How good do the reasons have to be?

a. Infallible: Reasons for P must deductively entail the truth of P—not possible to have reasons when P is false.

b. Fallible: Reasons for P need not deductively entail the truth of P—it is possible (but improbable) to have reasons when P is false.

D. Certainty =df infallible justification

E. If justification is required for knowledge but want to reject that certainty is required for knowledge, then we must say that fallibly justified true belief is sufficient for knowledge.

F. But Gettier argues that fallibly justified true belief is not sufficient for knowledge.

G. So it seems that we cannot reject the idea that knowledge requires certainty.

II. Gettier Cases

A. Goal: Show that fallible justified true belief is not sufficient for knowledge.

B. So design cases to meet the following conditions:

1. S believes that P.

2. S has sufficient but fallible justification for believing that P.

3. P is true.

4. S does not know that P.

C. Barcelona Case

1. S believes that either Jones owns a ford or Brown is in Barcelona.

2. S has sufficient (fallible) justification for believing this disjunction:

a. S has sufficient justification for believing that Jones owns a Ford.

b. S validly deduces that either Jones owns a Ford or Brown is in Barcelona. (S has no information about Brown’s whereabouts.)

c. Valid deduction transmits justification without loss.

3. It is true that either Jones own a Ford or Brown is in Barcelona; because Brown happens to be in Barcelona.

4. S does not know that either Jones owns a Ford or Brown is in Barcelona

a. It is a lucky accident that his justified belief is true.

b. Lucky accidents do not count as knowledge.