Is what you know really knowledge? The Gettier problem.

Gettier’s challenge: Is what you know really knowledge?

What does it take to know something? How do you know you know? With an increased vigilance campaign targeting misinformation in the public space and however that affects the future of our free speech, we should find some value in honestly knowing what we really know. Let’s analyze our traditional view of knowledge and the challenging Gettier problem.

Let’s say we live in the fictional country of Kalendria and know that another country, let’s call it Novara, will develop nuclear weapons within a year. We base our knowledge on what we’ve read about the situation in and around Novara. Now, let’s say that Novara successfully develops nuclear weapons within a year.  

Can we say we knew this, that is, that we had knowledge?

You may claim we did based on our evidence. Still, epistemology, the theory of knowledge, would question whether having justified true beliefs is sufficient for knowledge.

This insight might seem metaphysical and abstract, belonging to armchair philosophers or café intellectuals. However, it’s a problem that can have practical implications in discourse and decision-making. It encourages us to examine our beliefs and question our justification processes critically. Because we might be wrong, even when we’re correct, which is confusing. Let’s build an understanding of what knowledge means in this context.

We’ll return to Novara and Kalendria, but to understand this, let’s look at propositional knowledge. Propositional knowledge is knowledge of facts. It’s something we express in declarative sentences or propositions. For example, we know that:

  • 1+2=3
  • Water boils at 100°C (or 212F)
  • Manila is the capital of the Philippines.

We can say that we, the subjects (S), know that proposition (P).

But how do we get to this proposition? The traditional analysis of knowledge, which we can trace back to Plato’s Theaetetus, states that a subject S (you, your friend, or anyone) knows that a proposition P if and only if (IFF):

  • P is true.
  • S believes that P.
  • S is justified in believing that P.

This analysis is often described as the JTB analysis, where JTB stands for Justified True Belief.

Here’s an example based on a case formulated by philosopher Bertrand Russell. Imagine Alina has been home the whole day. She walks by her analog clock in the kitchen and sees it’s 3 o’clock.

According to the JTB approach, Alina knows about the time if and only if:

  • The statement is true (the time is 3).
  • Alina believes that it’s 3 o’clock.
  • Alina is justified in believing the time is 3 because she has evidence (the clock tells her so, or people pass by and confirm it).

That sounds ok, right? We have a reasonable explanation of knowledge. I could point you to my post about how our incompetence tricks us into believing we’re more competent than we are and end this article here.

But, while it is a good starting point, there’s a twist to the JTB analysis that can throw its usefulness out the window. Even when we think we know something.

The Gettier problem

You see, although we can agree that knowledge relies on all three elements of the Justified True Belief analysis, they are insufficient to claim knowledge. Philosopher Edmund Gettier depicted this with two cases in his 1963 publication “Is Justified True Belief Knowledge?” It’s a three-page article, so you have no excuse for avoiding the read if you’re interested in epistemology and knowledge.

With his two cases, Gettier concludes that you can fulfill the three elements of the JTB analysis (justified true belief) but still lack knowledge. We call this the Gettier problem.

For the sake of argument, let’s go back to Alina’s knowledge about the time of the day, and then later, to really drill in the notion, we’ll return to our more impactful yet scary scenario in Novara and Kalendria.

Alina knows that it’s 3 o’clock. She has fulfilled all the three requirements of the JTB analysis. It is 3 o’clock, she believes it, and she’s justified to believe so. But now, suppose that her kitchen clock, unbeknownst to her, had been broken and stuck at 3 o’clock the whole time. She just happened to have passed the kitchen clock at 3 o’clock.

In this case, we cannot claim that Alina truly knows the time, even after having a justified true belief. She was just lucky that her observed time and the real time coincided. We call this epistemic luck.  

The Gettier problem is not limited to trivial or everyday examples; it has implications for broader domains, including science and society. If we return to the scene in Novara and Kalendria.

Belief: We have a situation where we, Kalendrians, believe that Novara will develop nuclear weapons soon.

Justification: We rely on our internal news and comments about Novara’s despotic regime, Novara’s know-how and resources, and the country’s rhetoric towards countries like ours.

Truth: Novara successfully develops nuclear weapons.

Problem: Unbeknownst to us, the state of Kalendria (or an ally of Kalendria) has been increasing its threats toward Novara lately, both verbally and through military actions and invasions. Novara had no intentions of developing nuclear weapons until recently when the threats became existential.

In other words, the Kalendrians’ belief about Novara developing nuclear weapons is justified based on their internal news and historical patterns. However, the truth is influenced by a separate factor—the escalating threats from Kalendria. This disconnect between justification and truth exemplifies the essence of the Gettier problem.

These types of scenarios matter because we often encounter them. We may provide the correct conclusion even though it was really epistemic luck that made our belief true. If that’s the case, what’s the lesson learned?

This issue also relates to a blind belief in inductive reasoning when we strictly base our decisions on previous experiences (which I’ll explain in a future post).

JTB amendments to solve the Gettier problem

So, how do we solve the Gettier problem?

Some epistemologists have proposed adding or modifying conditions to the JTB analysis (JTB+X). One example is the no false lemmas analysis.

No false lemmas

With the “no false lemmas” analysis, we add a condition to the JTB: the justified true belief cannot be inferred from any false beliefs (or lemmas). More specifically, S’s belief that P is not inferred from any falsehood.

The no false lemmas approach successfully solves the case of Alina and her kitchen clock. Alina doesn’t know the time of the day because she mistakenly believes the clock still works, making it a false lemma.

However, the false lemma cannot solve all the issues of JTB. One famous example tells us of a man who, from a park bench, sees a dog on a field. He believes that

              There’s a dog in the field.

But, suppose the man is not actually observing a dog but a new technological robot dog, which is almost indistinguishable from a real dog. In other words, his assumption that “There’s a dog in the field” is incorrect.

Now, let’s further imagine that unbeknownst to the man, a real dog happens to be hidden in the same field, close by the robot dog. So, the man’s belief turns out to be correct: a dog is in the field.

Contrary to Russell’s clock story, where the subject (Alina) explicitly believes “The clock is working correctly,” the man on the park bench doesn’t form his belief based on a false lemma. He doesn’t explicitly think “This is a real dog” about the robot dog. He simply sees something that looks like a dog and forms the belief that “There’s a dog in the field.”

Other examples

There are many other examples of attempts to resolve the Gettier problem, such as adding different conditions, as mentioned above. Another example is using the “no defeaters” analysis, in which knowledge requires an absence of any undermining evidence unavailable to the subject. Others have tried to replace the justification condition with more specific ones.

Unfortunately, as with the no false lemmas analysis, none of these alternative suggestions have managed to withstand counterexamples.

So, does that mean that the Gettier problem remains unresolved? Yes! That might seem like a bummer, but this ignorance offers other answers.

On the one hand, the failure to formulate a solid approach to understanding knowledge highlights our susceptibility to epistemic luck – and the subjectivity of knowledge. Knowing this can keep us in a humble and dynamic relationship with true knowledge. Why do we believe what we do? How do we justify it? And, if our beliefs were justifiably true but based on falsehoods, would we openly admit our lack of knowledge? Do we keep our fallibility in mind for future events? Would you reformulate your beliefs accordingly?

“I guess I must take robot dogs into account now.”

“I guess Kalendria might be the true threat to nuclear disarmament.”

On the other hand, these unresolved cases give us perspective into the complexity of falsehoods – or, let’s say, misinformation. How do we know that our beliefs carry specific falsehoods, especially when forming our beliefs? Knowing that many of our current true beliefs derive from some falsehoods and that these false beliefs remain in our way of thinking, is it realistic to remove them from public discussions – or even silence them? It makes you think about our ability to identify and stigmatize information reliably, right?  

The modified image of Edmund Gettier was published by DaveGettier (Wikimedia Commons) and licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

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