How a 3 Page Paper Overturned 2000 Years of Philosophy

(This post is part of a series I am starting, see explanation here)

Philosophy is the discussion about fundamental aspects of the world. It is a discussion that was brought to its full in the west more than 2000 years ago with Socrates. Philosophy is incredibly broad, encompassing all areas of human knowledge, from "what is the world like" to "how should the world be". But perhaps most fundamental is the topic of knowledge itself. "How is knowledge possible?" is an incredibly common philosophical question. In fact, I'm sure it's a question most of us have asked ourselves at some time or other. How can we know anything at all? But I want to explore an even more fundamental question, What is Knowledge?.

This question of what is knowledge is perhaps one of the most fundamental questions we can ask. It may even seem like that without knowing what knowledge is how can we claim to know anything. This is why the topic of knowledge appears in some of the earliest western philosophy texts. As luck would have it, such a fundamental topic was actually discussed and seemingly settled in the works of Plato.

What is Knowledge? Knowledge is true, justified belief, or so the answer would go for over 2000 years following from a definition Plato gave. An answer that seemed perfectly satisfactory until Edmund Gettier published his 3-page paper in 1963: Is Justified True Belief Knowledge?. In this paper, using two simple stories overturned what we thought we knew about knowledge.

A Perfect Example of Understandable Philosophy

This paper is beautiful in its simplicity. In 3 pages this paper tells us quite a bit. It sets up the problem well and then gives us some simple stories that let us get an intuitive grasp of what is at stake. This is a mark of great analytic philosophy and a common tool we will see as we explore many different papers.

Gettier starts out by offering a template in which people typically offer analyses of what it is for someone to know something.

(a) S knows that P 
    IFF 
      (i) P is true, 
      (ii) S believes that P, and 
      (iii) S is justified in believing that P.

Here we see some strange features of analytic philosophy. What do S and P and IFF mean? Why use these silly letters? This is one of those things you have to get used to reading over time. IFF means "if and only if". S here is supposed to stand for some person, and P is a proposition. So here's an example substitution.

(a) Steve knows that "it is raining"
    If and only if
      (i) "it is raining" is true, 
      (ii) Steve believes that "it is raining", and 
      (iii) Steve is justified in believing that "it is raining".

Now I called this a template in two senses. One because it is using these variables but also because as the paper shows people often vary these points to fit their own epistemological views. The most commonly modified point is (iii). Instead of just leaving it as "is justified" philosophers often spell out what justification amounts to. For example, "S has adequate evidence for P" or "S has the right to be sure that P is true". You can imagine how different people with different viewpoints might change these points, but fundamentally they still follow this same structure.

Gettier aims to show that this template is inadequate. That we can meet these three criteria and yet fail to have knowledge. Perhaps on of the most amazing features of this paper is that achieves this goal by simply telling some stories.

Gettier Problems

Gettier tells the first story of Smith and Jones who are applying for the same job. Smith has good evidence that Jones is going to get the job instead of himself. Perhaps the president of the company has told him that Jones will get the job or maybe he overheard a conversation with the head of HR. Whatever the evidence that Smith has, it is pretty convincing.

Smith also knows one other weird fact. Jones has 10 coins in his pockets. Perhaps Smith counted the coins himself ten mins ago so he knows this. Now from these two facts, Smith can deduce a further proposition "The person who will get this job has 10 coins in their pocket."

Now here comes the twist. Unbeknownst to Smith, however, Jones isn't getting the job, he is. Also, Smith has 10 coins in his pocket that he doesn't know about. So the proposition "The person who will get this job has 10 coins in his pocket" is actually true!

But did Smith actually know this? It doesn't seem he did. We will let P equal "The person who will get this job has 10 coins in his pocket" and let's look at our criteria. In this scenario, P is true so condition (i) is met. As we've stipulated in the store, Smith does believe P, so (ii) is met. As for (iii), Smith had good reason to believe that Jones would get the job. He had good reason to believe that Jones had 10 coins in his pocket. We need one more premise to get to our conclusion, any proposition that is deduced from justified propositions is itself justified. From there we can see that condition (iii) is indeed met. He had good reason to believe P. So, Gettier concludes, true justified belief is not sufficient for knowledge.

So what are we left with?

Maybe you are convinced by this story or maybe you aren't. Don't worry there are plenty more to offer. These little stories have become known as "Gettier Problems". Whole new areas of research have opened up, people attempting to answer this problem Gettier has posed and then other people coming up with their own Gettier-style stories to disprove those theories.

I wish I had room in this post to go into various reactions to this big upset. There have been a number of strategies. Some feel that all that is needed is to spell out justification more exactly, others think we just need to add a fourth criterion. Of course, there are the radical skeptics who take this has yet another proof that we don't know anything at all, but perhaps more interesting than that are the people who think Gettier has shown something deeper, that internalist accounts of knowledge are inherently flawed.

Next Time

Gettier Problems are fascinating and I could do a whole series just on the various responses people have given to them, but I think I, and probably people who might read this series would get bored if that's all we discussed. For the future, I have quite a few papers I'd love to talk about. One that argues for a paradox-free time travel that actually does change the past, another about an argument against AI, several that discuss the nature of the mind, one which questions whether tables exist, and many more. Philosophy is an incredibly broad area filled with fascinating topics. If you have any suggestions on topics you'd like to cover in the future or feedback on this post, please leave a comment.