Subject: Epistemology

Professor: Terrance Walsh, SJ, PhD

Scholastic: Peter Lê Hoàng Nam, SJ

Edmund L. Gettier (From Internet)

In 1963, thanks to a two-page article, an American philosopher named Edmund L. Gettier became very famous in philosophical circles. In this short writing, he had reasoned and given two examples to demonstrate that the traditional definition of knowledge as justified true belief was not correct. This, which is usually called the Gettier problem or case, aroused a question for epistemologists to continue to think about so-called knowledge and the possibility for humans to get it. Therefore, it would be very interesting to know what the Gettier problem is and why it can undermine the traditional conception of knowledge.

What is the Gettier problem?

As mentioned above, the Gettier problem is counterexample thought up by Gettier against the traditional definition of knowledge as justified true belief.

To have knowledge, we need to meet two necessary conditions: belief and truth. However, Plato says in the Meno that, true belief should be anchored for it to be knowledge.[1] Epistemologists after Plato think that justification, which is later regarded as a sufficient condition for knowledge, is the element that tethers true belief to make it knowledge. From then on, people view knowledge as true belief which is justified. For example, I have a belief that it is raining (belief); the fact is that it is raining (true); I go out of the house and see drops of water fall down onto my body from the sky (justification). When these three conditions are satisfied, it can be said that I get knowledge that it is raining. I do not need anything more.

Gettier does not refuse these three condition; however, he asserts that in some cases, these three conditions are not enough for a person to get knowledge because they do not constitute necessary and sufficient conditions for an S to claim that he knows P.[2] He gives examples to illustrate his idea. The following is one of his two examples.

Smith’s memory shows him that Jones has a Ford because Jones usually gives Smith a ride while driving the Ford and Jones said that it belongs to him. Jones has never lied to Smith about anything before. Therefore, Smith has strong evidence that

  • Jones owns a Ford.

Smith also has a friend, Brown, but he cannot remember where Brown is now. Smith selects three place names quite at random and then constructs the following three propositions:

  • Either Jones owns a Ford or Brown is in Boston
  • Either Jones owns a Ford or Brown is in Barcelona
  • Either Johns owns a Ford or Brown is in Brest-Litovsk

These three propositions are entailed logically from (1). Supposing the fact is that Jones does not own a Ford and Brown is really in Barcelona, the proposition (b) is still right but Smith does not know it. Therefore, it is not knowledge. Indeed, Smith has a belief that (b), (b) is really true, and Smith is also justified in believing that (b) is true. Although three conditions (belief, true, justification) are satisfied in the above example, it is hard for us to say that it is knowledge, because it seems that (b) is true accidentally.[3]

After Gettier, many people continue to create thousands of cases which are similar to the Gettier case to show that justified true belief is not enough to count as  knowledge. For instance, I have just bought a new thermometer. It works very well and I have no reason to doubt the temperature it shows me. I hang it in my laboratory room. However, for a certain reason, it stops working which is unknown to me and the mercury is at zero degrees Celsius. Tonight, I want to know what the temperature is and I look at it. Of course, it shows me zero degrees Celsius. Supposing that it is zero degrees Celsius at that time in reality, my belief that it is now zero degrees Celsius is true and justified, but it cannot be considered knowledge.

Why does it undermine our conception of knowledge as justified true belief?

Unlike the case of Lucky Lass or lottery which is full of luck, knowledge is a belief which is fixed accurately with reality, on a sound foundation. In other words, knowledge is always true because it is supported by firm reasons that exclude all elements of luck. This is the reason why beginning with Plato, epistemologists do not agree that knowledge is only true belief. They all think that the belief, although it is true, needs to have epistemic justifications to explain why S has this belief. In most cases, defining knowledge as justified true belief seems to be reasonable and acceptable. Through a long history, people found no problem in this definition until the counterexamples of Gettier appear.

In his short article, Gettier only gives us examples to show how wrong it is to think that knowledge is justified true belief. He does not show us what the element which is lacking for the belief to be knowledge. However, by examining the Gettier problem thoroughly, we see that the problem is in the way we justify our belief. In the example of Smith that I mentioned in the first part, the way Smith justifies his belief does not have any connection with the truth. In fact, Smith is justified about the fact that Jones owns a Ford but he is wrong; and the truth that Brown is in Barcelona is unjustified. There can be a gap between a belief which is justified and the truth. Smith believes that Jones owns a Ford and this belief is justified, but the truth is that Brown is in Barcelona. The statement (b) becomes true accidentally outside of the cognitive process of justification of Smith. Because luck still has a place in this case, it cannot be called knowledge, as it has just been said in the first paragraph.

The disconnection between justified belief and truth can also insist on weak evidence used to justify the belief. The way Smith justified his belief that Jones owns a Ford is not sound enough. Although Jones has never lied to him about anything before, it does not mean that Jones does not tell Smith a lie this time. It is the same in the case of the thermometer. A skeptic may say that a brand-new thermometer can also have some problem in its structure when it is produced that we do not know or the seller may deceive me by selling an old one while telling me it is new. The Gettier problem will be solved if Smith discovers that Jones told him a lie or I check my thermometer more carefully before believing the temperature it shows me. In other words, if I am more sensitive in justifying, I will know that my justification about the thermometer is wrong. The justifications in these cases are not strong enough to connect the belief with the truth. So, not all justifications can entail truth. Justified belief may be not true in some cases.

The Gettier problem seems to open the door to skeptics who doubt that humans can get knowledge. Plato thinks that if we can anchor true belief, we can get knowledge. Now, Gettier shows us that even when we have already anchored true belief by justification, we still lack something to have knowledge. Defining knowledge as justified true belief is undermined in this sense. Maybe, what Gettier wants to say is that our justification must be so strong and complete that it can fill the gap between justified belief and truth. However, except a-priori knowledge which is self-justified and always true, our cognitive process of justification can be fallible and not strong enough to get rid of all elements of luck in propositional knowledge. To justify is to offer evidences that supports our belief without having any stronger counterexample against it. This evidence needs supporting from another piece of evidence. It can lead to an infinite regress of evidences until it encounters a sound foundation that does not need support from anything. Today, many epistemologists offer solutions to solve this problem such as foundationism (who thinks that the evidences that support the original belief can be supported by a self-justified and sound belief. This can stop the infinite regress of belief) or coherentism (who thinks that a belief which is coherent with the whole system of S’s belief is strongly justified)… However, each one of these has it own strong and weak points. The question about the possibility for humans to get knowledge epistemologically is still there, challenging the intelligence of human beings from time to time because our conception of knowledge as justified true belief has been undermined.

The two-page article of Gettier has changed a long history of epistemology in regarding knowledge as justified true belief and also opened a new perspective for people to continue to think about knowledge. Even Gettiet himself, though he saw the problem in our traditional conception of knowledge, could not tell us how to correct it. What is knowledge? What are its components? What is the sufficient condition for knowledge? It is not easy to answer these questions because life is so complicated and human intelligence is finite. However, Gettier has shown us that we can never stop to think to find out the way to erase the gap between belief and truth. Trying to search for truth is one of the elements that make human beings philosophical.


Standford Encyclopedia of Philsophy: www.

Internet Encyclopedia of Philosophy:

PRITCHARD, DUNCAN, What Is This Thing Called Knowledge?, London and New York, Routledge Taylor & Francis Group, 2006

KVANVIG, JONATHAN L., The Value of Knowledge And The Pursuit of Understanding, New York, Cambridge University Press, 2003

[1] Meno, 98a

[2] In this writing, I use “S” as a subject, and “P” as a propositional claim.

[3] Read more in Edmund L. Gettier, “Is justified True Belief Knowledge?” Analysis, 23 (1963): 121-123