The Gettier problem represents one of the most significant challenges in the philosophy of epistemology, questioning the traditional analysis of knowledge. The problem arises from Edmund Gettier’s 1963 paper, which presented counterexamples to the well-established definition of knowledge as “justified true belief” (JTB). Gettier’s argument has influenced decades of debates about the nature of knowledge and has led to attempts to revise the JTB account, opening up a wide range of discussions on the concept of knowledge itself.
In this essay, we will explore the Gettier problem, its implications for epistemology, and how philosophers have attempted to resolve or address it. We will begin by reviewing the traditional JTB definition of knowledge, examine Gettier’s counterexamples, and then look at the ongoing philosophical attempts to overcome the challenges posed by Gettier’s problem.
1. The Traditional Definition of Knowledge: Justified True Belief (JTB)
Before Gettier’s challenge, the dominant theory of knowledge in Western philosophy was based on the concept of justified true belief (JTB). According to this theory, for someone to know a proposition (say, “P”), three conditions must be met:
- Belief: The person must believe the proposition P.
- Truth: The proposition P must be true.
- Justification: The person must have sufficient evidence or reasons to justify the belief in proposition P.
The JTB account of knowledge has deep roots in the Western philosophical tradition, especially in the work of Plato. In his dialogue Theaetetus, Plato explores the idea that knowledge consists of belief that is both true and justified. Over time, this theory became the standard view, largely because it seemed to capture the intuitive notion of what it means to know something.
For instance, if someone believes that “it is raining” and they have sufficient evidence to support this belief (perhaps they saw dark clouds and heard the sound of rain), and the belief turns out to be true, then according to the JTB definition, this person can be said to know that it is raining. This seemed like a reasonable and clear definition of knowledge for centuries.
2. The Challenge: The Gettier Problem
Edmund Gettier’s famous 1963 paper, Is Justified True Belief Knowledge?, shook the philosophical foundations of the JTB definition by presenting counterexamples where someone has a justified true belief but lacks knowledge. Gettier’s argument showed that the three conditions (belief, truth, and justification) are not sufficient to guarantee knowledge.
Gettier’s challenge consists of presenting scenarios where a person meets all the JTB conditions, yet, intuitively, they do not seem to possess knowledge. These counterexamples are now known as Gettier cases, and they demonstrate that JTB does not always align with our intuitive understanding of knowledge.
3. The Original Gettier Example
To understand the Gettier problem more clearly, let’s explore his original example:
Imagine a man, Smith, who is applying for a job. He knows that the man who will be hired for the position has ten coins in his pocket. Smith has strong justification for believing this, as he has been told by the company’s hiring manager that the chosen candidate has exactly ten coins in his pocket.
However, Smith is unaware that the hiring manager had made a mistake, and in fact, Smith himself has ten coins in his pocket. Smith doesn’t know this, but it just so happens that Smith is, by chance, the one who is hired, and he also has exactly ten coins in his pocket.
In this case:
- Smith believes the proposition “The man who will be hired has ten coins in his pocket.”
- The proposition is true because Smith, who is hired, has ten coins in his pocket.
- Smith has strong justification for his belief, based on the information he has about the hiring process.
Despite meeting all the conditions for justified true belief, we intuitively feel that Smith does not actually know that the man hired has ten coins in his pocket. This is because the truth of the proposition was, in this case, coincidental; it did not depend on Smith’s justification but rather on a lucky accident. This scenario challenges the sufficiency of the JTB account of knowledge.
4. The Impact of the Gettier Problem
The Gettier problem struck at the heart of the JTB definition of knowledge and called into question whether the three traditional conditions were sufficient for knowledge. In the Gettier case, the person has a true belief that is justified, yet, due to luck or an unexpected factor, they do not seem to possess knowledge. This situation, known as epistemic luck, highlights that the presence of justified true belief does not guarantee knowledge.
The Gettier problem led to a philosophical crisis in epistemology, as many philosophers realized that they had to rethink the very nature of knowledge. If JTB was insufficient for knowledge, then what additional conditions were necessary to guarantee that someone genuinely knows something?
5. Responses to the Gettier Problem
Following the Gettier problem, philosophers attempted to revise the JTB definition by adding new conditions or by offering alternative theories of knowledge. There are several prominent responses to the Gettier problem, each attempting to resolve the issue in different ways.
1. The No False Lemmas (NFL) Condition
One common response is to add the condition of “no false lemmas” to the JTB account. According to this approach, for a person to know a proposition, not only must the belief be true, justified, and held, but the justification for the belief must not rely on any false assumptions or premises.
In the Gettier example with Smith, the justification for Smith’s belief that the man hired has ten coins relies on a false premise—the assumption that the person who is hired has ten coins, when in fact, Smith himself is the one who has ten coins. If the justification is based on false premises, then the belief is not justified in a way that leads to knowledge.
This approach is appealing because it solves the problem in the Gettier case by eliminating the role of false assumptions. However, some philosophers argue that this solution doesn’t address all Gettier-style cases or that it adds unnecessary complexity.
2. The Causal Theory of Knowledge
Another approach to solving the Gettier problem is the causal theory of knowledge, which asserts that there must be a causal connection between the belief and the fact that makes it true. This theory, originally proposed by philosophers like Alvin Goldman, emphasizes that knowledge requires more than just a justified true belief—it also requires that the belief be causally linked to the truth of the proposition.
In Gettier-style cases, the true belief may be caused by an external factor that is unrelated to the justification of the belief, such as luck or coincidence. The causal theory suggests that for a belief to count as knowledge, it must be caused by the relevant fact in the correct way. For instance, Smith’s belief in the ten coins would only count as knowledge if there was a direct causal link between his belief and the actual fact of his being hired.
The causal theory has been influential but has also faced criticisms, especially concerning the difficulties of defining an appropriate causal connection between belief and truth, and its application in more complex situations.
3. The Tracking Theory of Knowledge
Another prominent theory developed in response to the Gettier problem is the tracking theory of knowledge, which states that a belief counts as knowledge if, and only if, it “tracks” the truth in the right way across possible worlds. In other words, if the belief is true, then the person’s belief-forming process must be reliable enough that they would continue to hold the true belief in similar circumstances.
The tracking theory was proposed by philosophers like Robert Nozick, who argued that for someone to know something, their belief must “track” the truth, meaning that in situations where the belief could have been false, they would not have believed it. In Gettier cases, this criterion would prevent the false belief caused by a lucky coincidence from being considered knowledge.
4. Virtue Epistemology
A newer response to the Gettier problem is virtue epistemology, which focuses on the intellectual virtues of the believer rather than on external conditions or additional criteria. According to virtue epistemologists, knowledge arises from the exercise of intellectual virtues like open-mindedness, intellectual courage, and intellectual responsibility. These virtues guide individuals in forming true beliefs in a reliable way, thus avoiding epistemic luck.
From the virtue epistemology perspective, a belief is knowledge if it is formed by a person who has exercised appropriate intellectual virtues in acquiring and justifying their belief. This response does not rely on adding external conditions like “no false lemmas” or causal connections, but rather emphasizes the character and reliability of the knower.
6. Conclusion: The Enduring Legacy of the Gettier Problem
The Gettier problem remains a central issue in contemporary epistemology. It has led philosophers to rethink traditional definitions of knowledge and to propose various alternative accounts of what constitutes knowledge. While the Gettier problem has not been definitively solved, the responses to it—such as the No False Lemmas condition, causal theories, tracking theories, and virtue epistemology—have enriched the field and opened up new areas of investigation.
At its core, the Gettier problem challenges us to reconsider the relationship between justification, belief, and truth. It forces us to ask: What makes a belief genuinely knowledge? Is it enough for a belief to be justified and true, or do we need something more—such as the absence of epistemic luck, a causal connection to the truth, or the exercise of intellectual virtues? As the philosophical debates continue, the Gettier problem remains a crucial issue in understanding the nature of human knowledge and our capacity to know the world around us.