The Gettier Problem: When Justified True Belief Fails

The Gettier problem shows that justified true belief is not enough for knowledge, and that there are possible cases where luck or coincidence can make our beliefs true but not knowledgeable.

The Gettier problem is a philosophical challenge to the classical analysis of knowledge as justified true belief (JTB). It shows that there are cases where a person can have a justified and true belief about something, but still not know it, because the justification is based on false or lucky premises. For example, suppose Bob believes that his friend Alice has a Ford car, because he saw her driving one yesterday. However, unbeknownst to Bob, Alice actually rented the car for a day, and she does not own a Ford. But coincidentally, Alice does have a Ford car in her garage, which she inherited from her uncle and never uses. In this case, Bob’s belief that Alice has a Ford car is justified and true, but it is not knowledge, because his justification is false.

Today we’re going to talk about the Gettier problem, a philosophical puzzle that challenges the traditional definition of knowledge as justified true belief.

So, what is knowledge? Well, you might think that knowledge is just believing something that is true. For example, you might believe that I am wearing a blue shirt, and that is true, so you have knowledge of what I am wearing. But that's not enough for knowledge, because you might also believe something that is true by accident or by guessing. For example, you might believe that I have a pet hamster named Philbert, and that might be true, but you don't really know that, because you have no evidence or reason for your belief. You just made it up.

So, philosophers have added another condition for knowledge: justification. Justification is having a good reason or evidence for your belief. For example, you might believe that I am wearing a blue shirt because you are watching this video and you can see me wearing a blue shirt. That's a good reason for your belief. Or you might believe that I have a pet hamster named Philbert because you saw me post a picture of him on Twitter. That's also a good reason for your belief.

So, according to the traditional definition of knowledge, if you believe something to be true, and you have a good reason for your belief, and your belief is actually true, then you have knowledge. This definition of knowledge is called justified true belief. And it seems pretty reasonable and intuitive, right? Well, not so fast. Some philosophers have argued that there are possible cases where you can have justified true belief without knowledge. These cases are called Gettier cases, and they involve some kind of luck or coincidence that makes your belief true, but not because of your justification.

Let's look at an example. Suppose you are a farmer who owns a field with some sheep in it. You believe that there is at least one sheep in your field, and you have a good reason for your belief: you can see a white fluffy thing in your field that looks like a sheep. However, unknown to you, the white fluffy thing is not a sheep, but a dog that has been painted white by some pranksters. By sheer coincidence, there is also a real sheep hiding behind the dog that you cannot see. In this case, your belief is true and justified, but it seems that you do not have knowledge of how many sheep are in your field, because your belief is based on a false appearance.

This is an example of a Gettier case. The Gettier problem shows that there is more to knowledge than justified true belief. It also shows that knowledge is not as simple or straightforward as we might think. It raises questions about how we form our beliefs, how we justify them, and how we test them for truth. It also challenges us to think more carefully and critically about what we claim to know and how we know it.

The Gettier problem has been debated by philosophers for decades, and there is no consensus on how to solve it. Some philosophers have tried to add a fourth condition to the definition of knowledge, besides belief, truth and justification. This fourth condition is meant to rule out the possibility of luck or coincidence in Gettier cases. For example, some philosophers have proposed that knowledge requires no false lemmas, which means that your justification for your belief must not depend on any false statements or assumptions. Other philosophers have tried to modify the concept of justification, rather than adding a fourth condition. For example, some philosophers have proposed that justification requires reliability, which means that your belief must be formed by a method or process that tends to produce true beliefs in general.

These are just some of the possible solutions to the Gettier problem. There are many other solutions that have been proposed and criticized by philosophers. Some philosophers even doubt that there is a single correct definition of knowledge that can account for all possible cases and intuitions. They suggest that knowledge is a family resemblance concept, which means that it has no clear boundaries or essential features, but rather a set of overlapping and related characteristics that vary depending on the context and purpose of use.

The Gettier problem is one of many philosophical problems that invite us to examine our concepts and assumptions more carefully and critically. It also shows that philosophy can be relevant to other subjects and disciplines, as we often rely on our beliefs and justifications in various fields and activities.