Sunday, December 20, 2009

The Gettier Problem

This is the essay in which Gettier introduced the Gettier problem. He was just trying to get tenure, I understand.


Steve said...

What I heard about this paper was that his colleagues were trying to get him tenure. He was about to lose his position due to lack of publications, and his colleagues knowing that he was a first rate thinker and not wanting to lose him raided his office and found this now famous piece of writing which they sent to the relevant journal without his knowledge.

That's what I heard, anyway.

Steve Lovell

Bilbo said...

I just heard about the Gettier problem recently. It must be trickier than it first appears, otherwise there seems to be a simple solution: Belief in the truth of a proposition P2, caused by belief in proposition P1, is only knowledge if proposition P1 is true.

So I must be missing something.

Anonymous said...


The Gettier problem gets beyond the truth of P1 in your post by creating a situation where P1 and P2 are both true but the underlying causality behind P1 -> P2 is not what the person thinks it is.

Leonard said...

I had the same thought Bilbo.

Anonymous said...

The Gettier problem gets beyond the truth of P1 in your post by creating a situation where P1 and P2 are both true but the underlying causality behind P1 -> P2 is not what the person thinks it is.

Belief in P2 is justified by P1 IFF P1 is true and P1 -> P2 is true.

If a clock shows 8:00 pm (=P1), i am justified in believing that it is currently 8:00 pm (=P2), if its true, that if the clock shows a certain time, then it is currently that time (= P1 -> P2).

If the clock goes wrong, that is, if its false that P1 -> P2, then iam not justified in my belief, althought i might think, that iam justified.

Am i missing something?

Shackleman said...

Me thinks the trouble comes when one marries the idea of "truth" to the idea of "justification".

The two are related, yes, but separate concepts that entail separate things.

The paper I'd want to read would be entitled:

"Is justified false belief knowledge?"

That'd be far more interesting to me.

William said...

I find the Gettier problems interesting because he summarizes in a single case, one free of statistics, how it is that statistics can lie.

Jim S. said...

I was taught that Gettier never published again after this.

Anonymous said...

Leonard: even a stopped clock tells the right time twice a day. Think synthetically not analytically.

Marc said...


Although not entirely incompatible with what you heard, a former professor of mine mentioned that an informal conversation Gettier had with Plantinga, who was aware of Gettier's tenure concerns and found the essay to be good, prompted him to publish it.

-- Marc

Steven said...

What a way to get tenure, huh...

Clayton said...


There are variants on the original Gettier cases where the subject reasons from no false propositions but still lacks knowledge. (Richard Feldman first discussed these cases in a 1974 article in the Australasian Journal of Philosophy.)

Steve said...

Justification is a slippery term. Firstly it has both "internalist" and "externalist" readings.

Externalists see it as primarily an assessment of the belief. So reliabilists (a common species of externalist) think that a justified belief is one which is formed by a process which is reliable; i.e. a process which reliably produces true beliefs.

Internalists think justification is mainly about assessing the believer. If the believer believes what they should believe then they are justified in holding them.

In the case of the stopped clock it looks like the internalist will say that the belief is justified but the externalist will not. However this does not get the externalist out of Gettier's problem because they immediately run into a problem about the levels of description of belief forming processes.

If I look at a stopped clock and form a belief about the time, then which of the following belief forming processes have I used?

(1) Looking at a clock
(2) Looking at that clock
(3) Looking at a stopped clock
(4) Looking at a clock on a Tuesday
(5) Looking at a clock showing the time 8pm
(6) Looking at a clock at 8pm
(7) Looking, at 8pm, at a clock showing the time 8pm

There are lots of other possible descriptions of the process used, and we will want to say some describe reliable processes and others do not. But all of these descriptions may apply to our case. How does the externalist decide which level of description to prefer? I think the obvious answer is to say that the correct levels of description are the levels at which we act ... but that will just lead back to internalism and reinstate Gettier's problem.

I think the key to understanding Gettier cases are concepts of accidental truth and accidental justification.

I strongly recommend reading Zagzebski's book "Virtues of the Mind" which has some lovely Gettier related material.

Steve Lovell

Bilbo said...

Wikipedia has a long article on the Gettier problem:

My simple solution was thought of by others, and then as Clayton pointed out, more difficult examples were offered.

Bilbo said...

And from a wikipedia article on Edmund Gettier: "Gettier was educated at Cornell University, where his mentors included the ordinary language philosopher Max Black and the Wittgensteinian Norman Malcolm. Gettier, himself, was originally attracted to the views of the later Wittgenstein. His first teaching job was at Wayne State University in Detroit, Michigan, where his colleagues included Keith Lehrer, R. C. Sleigh, and Alvin Plantinga. Because he was short on publications, his colleagues urged him to write up any ideas he had just to satisfy the administration. The result was a three-page paper that remains one of the most famous in recent philosophical history. Gettier has since published nothing, but he has invented and taught to his graduate students new methods for finding and illustrating countermodels in modal logic, as well as simplified semantics for various modal logics."

I got my BA in philosophy at Wayne State. But my epistemology class was taught by a visiting professor. Perhaps that's why I never heard of Gettier.