I had a chat with an old grad student chum last evening, where he brought up the Gettier problem in epistemology. I hadn't thought about it in over
ten years, and thought I would throw it out to the community for comments and insight.
The classic definition of knowledge in philosophy is when a person has justified true belief about a state of affairs. Thus there are three parts to
a knowledge claim: belief, truth, and justification.
In order for me to claim that I have knowledge about a certain state of affairs, I must believe in that claim. This is usually the least contentious
part of the classic definition.
Further, my belief in a state of affairs must be true in order for me to claim knowledge about it. There are many theories of truth in philosophy, so
there is much discussion here.
However, it does not appear that my true belief is enough to warrant a knowledge claim without being able to justify that claim. For example, I might
say that, "at this very moment, there is a lady in a red dress by the Eifel Tower." Now, my belief in this state of affairs might indeed be true,
but at this point I'm just guessing. For my true belief to rise to the level of knowledge of this state of affairs, I must have some justification
for this. I can't just be lucky, or have it just happen to be true.
So the justified true belief theory of knowledge holds sway for a long time, until Edmund Gettier comes along in 1963 and publishes a three page
article that raises questions to the standard theory. In short, he provides a series of counter examples to show that there are states of affairs
where I can have justified true belief about a state of affairs, but still not have knowledge about them.
Here is one example: Say I am in a field, and I see a rabbit. So I have a belief that there is a rabbit in a field. I am justified in my belief
because my senses are working normal, I am not dreaming, etc. However, when I go to look at the rabbit up close, I see that it is not a real rabbit,
but a statue of a rabbit. But finally, when I get a little closer, I realize that there is a real rabbit behind the statue.
So the problem is this: I believe there is a rabbit; my belief is justified; and my belief is also true, since there is indeed a rabbit in the field.
However, there's something fishy about my claim that I had knowledge about there being a rabbit in the field.
Anyway, that's the short of it. Now there's a whole branch of epistemology dedicated to unraveling the Gettier problem, and coming up with a
possible fourth component of knowledge that might be needed in order to make a claim of knowledge. If anyone's interested in reading more, the wiki
article on the Gettier problem