How does Edmund Gettier's article "Is Justified True Belief Knowledge?" actually undermine epistemology?

Gettier’s assertion in this article is that a person can be justified in believing a proposition is true, that proposition can actually be true, and yet that person cannot be said to have knowledge that the proposition is true. He gives the example of Smith and Jones, who have both applied for a job that Smith has reason to believe that Jones will be hired for. Smith has supposedly been told by the president of the company that Jones will be hired, and Smith has just counted ten coins in Jones’s pocket, and from this information he infers conjunctive proposition (a) “Jones will be hired and Jones has ten coins in his pocket.” (a) entails: (b) “The person who will be hired has ten coins in their pocket.”

Gettier’s point is that if we want to claim that the necessary and sufficient conditions of knowledge are that:

S knows that P IFF*

i. P is true,

ii. S believes that P, and

iii. S is justified in believing that P.

We find that there are all sorts of ways for this to occur in which we don’t intuitively consider the result to be knowledge. An educated “lucky guess” is not the same as knowing something.

I’ve modified the pronouns here to be gender-neutral to show another example of Gettier’s conclusion. Smith can be completely correct and justified in believing (b), but Smith didn’t know that Ms. Jones, who also applied for the job, and also has ten coins in her pocket, is the one who will be hired. He has a justified true belief that is not knowledge because he doesn’t know that the company president meant that Ms. Jones would be hired, not Mr. Jones. So it is possible to be justified in believing a false proposition or an objectively true proposition understood wrongly. 

The second example that Gettier uses talks about all the evidence that Smith has that Jones owns a Ford. This example shows that Smith’s evidence, when you add a few more details, doesn’t actually indicate that Jones owns a Ford, although Jones does in fact own a Ford. So the justified true belief turns out to be a coincidence rather than knowledge.

Does Gettier’s answer to the question of the status of justified true belief undermine epistemology? Technically, since epistemology is the study of knowledge, what can be known, and the ways in which we are able to know things, it can’t be undermined as a whole so easily. Since Gettier’s article establishes an argument against calling justified true belief knowledge, but does not establish (or even address) an answer to the question of whether we can have knowledge in the first place, I would not say that it is a step toward undermining epistemology. There could be other ways to define knowledge, and even if we are still having trouble defining knowledge that doesn’t necessarily mean that we can’t know anything. If this article were an argument against our ability to know things for sure, and we all agreed wholesale with it, it could pose a threat to epistemology as an area of study. But for the most part, one person’s position on a topic doesn’t discourage the rest of us from studying it.

 *(IFF stands for if and only if.)