Why Should I Care About Philosophy?

Why Should I Care About the Gettier Problem?

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Part of the ‘Why Should I Care About Philosophy?’ series.

In philosophy, epistemology is the study of knowledge. Unsurprisingly, one of the central questions of epistemology is “What is knowledge, anyway?” Surprisingly, that question goes under the name “The Gettier Problem.”

Edmund Gettier was able to affix his name to the problem of giving a philosophical account of the nature of knowledge by exposing a flaw in an account of knowledge that had been popular for a long time. According to this traditional account, knowledge is “justified, true belief.” In other words, a person knows that a claim is true if and only if (A) that claim is true, (B) the person believes that it is true, and (C) the person has good reasons for thinking that claim is true. Gettier showed that this account is incorrect by coming up with cases where subjects have justified, true beliefs, but nonetheless don’t know.

Suppose you ask your friend the score to last night’s baseball game. Your friend is a huge fan and always knows the score. She tells you that the Yankees won, 9-3. In fact, your friend didn’t check the scores today, but just made something up at random in order to not seem ignorant. Yet, fortunately, it really is the case that the Yankees won 9-3. You trust your friend’s report, and you have good reason to, so your belief is justified. And it is, in fact, true. But because you’re basing your belief on something that was actually a total guess, you don’t really know.

Or imagine a physicist who consults a reliable measurement device that’s always given the right response before. The device indicates the presence of radiation in the test chamber, so the physicist believes that there is radiation in the test chamber, and this belief is certainly justified. But suppose that the device is malfunctioning; the dial is stuck. And suppose further that there really is radiation in the test chamber. So the scientist’s belief is true in addition to being justified. But she doesn’t know it’s true.

Cases like these two are called “Gettier cases:” cases of justified, true belief that do not amount to knowledge. Gettier cases raise an important question: what’s missing? Why aren’t those justified beliefs knowledge; what would we need to add in order to make them into cases of knowledge? And that might seem like an easy question. Looking at those two cases, some thought is likely to come to mind: Oh, all that’s missing is X. If we just add X, then we have knowledge. So knowledge is justified true belief, plus X.

Unfortunately, philosophers have proposed hundreds of possible values for X over the last six decades, and every one has well-known problems. Philosophers’ attempts to solve for X have become increasingly complicated and arcane over time, but with little apparent progress. The problem is much harder than it looks.

Yet the Gettier Problem is still worth puzzling over. Knowledge is one of the most important concepts in human life, and an account of the nature of knowledge is of accordingly broad interest. As Aristotle said, “All people, by nature, desire to know.” What is this thing that all people desire? What exactly are we attempting to obtain through human inquiry? That’s the Gettier Problem.

The Gettier Problem is also of interest because it reveals a kind of weakness in our concepts of a “good reason” or “good evidence” to believe something. The physicist had good reason to believe that there was radiation in the test chamber. Her evidence was very good – it would have been silly for her to believe anything different or to suspend judgment, given the evidence at hand. Yet her reasons still weren’t good enough. They weren’t enough to give her knowledge of a claim that she were very much was interested in knowing the truth of.

Relying on a reliable source or trusting evidence that strongly indicates that a claim is true isn’t enough for knowledge. We need to have reasons that are actually good – good enough for knowledge – or to rely on evidence that really indicates that our beliefs are true. But what is actually good evidence that really indicates the truth of our beliefs? What kind of evidence is good enough for knowledge? What kind of evidence would you have needed in order to know that the Yankees won, 9-3? That, too, is the Gettier Problem.

Knowing what knowledge is and how we can get it are central questions in human intellectual life. It’s worrying, then, that we don’t actually know what knowledge is, or how we can get it! That’s why you should care about the Gettier Problem.

WSICAP aims to give an accessible explanation of what a philosophical problem is and why the philosophers who work on that problem find it interesting and important. If you’d like to explain why a problem that you work on is worth caring about, email us at [email protected]!


  1. I was just telling my friend about that.

  2. I was just telling my friend about that.

  3. That’s a great point

  4. I didn’t know that.