In his seminal 1963 paper, Is Justified True Belief Knowledge?, Edmund Gettier fundamentally challenged the long-standing definition of knowledge, which had been widely accepted in epistemology since at least the time of Plato. According to the justified true belief (JTB) theory, knowledge requires three necessary and jointly sufficient conditions: (1) the proposition must be true, (2) the subject must believe the proposition, and (3) the belief must be justified. This tripartite analysis of knowledge was seen as an intuitive and rigorous framework for understanding what it means to know something. Gettier’s brief but revolutionary paper shattered this consensus by presenting two counterexamples in which all three conditions of the JTB framework were satisfied, yet the resulting belief was not intuitively considered knowledge.
Gettier’s examples revealed a fundamental problem: justified true belief does not necessarily exclude situations in which a belief is true merely by coincidence or luck. This insight exposed the insufficiency of JTB and prompted a profound reevaluation of epistemology, resulting in decades of debate over how to refine or replace the traditional conception of knowledge.
Gettier’s Counterexamples in Detail
First Counterexample: The Job and the Coins
In Gettier’s first example, two men, Smith and Jones, are competing for a job. Smith has strong evidence to believe that “Jones will get the job.” This evidence might include testimony from the employer, observations of Jones’s qualifications, and other relevant factors. Smith also knows that Jones has ten coins in his pocket. From this, Smith infers the proposition: “The person who will get the job has ten coins in their pocket.”
Unbeknownst to Smith, Jones does not get the job; instead, Smith himself is hired. Furthermore, Smith happens to have ten coins in his pocket as well, though he was unaware of this fact when he formed his belief. Consequently, the proposition “The person who will get the job has ten coins in their pocket” is true, and Smith’s belief is justified. However, it is true purely by coincidence, as its truth has nothing to do with the justification Smith initially possessed. Intuitively, we do not consider Smith’s belief to constitute knowledge.
This example demonstrates that even when a belief is true, justified, and held with conviction, it can fail to qualify as knowledge if its truth depends on luck rather than the justification.
Second Counterexample: The Ford and Barcelona
In the second case, Smith has strong evidence to believe that “Jones owns a Ford.” This evidence might include Smith’s prior experience of seeing Jones drive a Ford and Jones’s own statements about owning the car. From this, Smith forms the disjunctive belief: “Either Jones owns a Ford, or Brown is in Barcelona.” Smith has no specific evidence about Brown’s whereabouts, but because the disjunction is true if either disjunct is true, his belief in this proposition is justified.
As it turns out, Jones does not own a Ford, but by sheer coincidence, Brown happens to be in Barcelona. Thus, Smith’s belief in the disjunctive proposition is true and justified, yet its truth is accidental and unrelated to Smith’s justification. Once again, this belief fails to meet our intuitive standards for knowledge.
Philosophical Implications of the Gettier Problem
Gettier’s paper exposed a crucial flaw in the JTB framework: the failure to account for epistemic luck. The two examples demonstrate that it is possible for a belief to be both true and justified while lacking the quality we associate with genuine knowledge. This insight destabilized centuries of epistemological thought and initiated an intense effort among philosophers to identify what was missing from the JTB account or to develop an entirely new conception of knowledge.
The central challenge is to explain why Gettier cases do not qualify as knowledge while preserving the intuition that knowledge involves a close relationship between truth, belief, and justification. Philosophers have offered a variety of responses, each attempting to refine our understanding of knowledge or address the underlying issues raised by Gettier’s counterexamples.
Responses to the Gettier Problem
The No False Lemmas Condition
One early response to Gettier’s challenge was the proposal of a fourth condition: the “no false lemmas” criterion. This condition, initially suggested by philosophers such as Gilbert Harman, posits that knowledge cannot be based on any false premises or intermediate beliefs. In the first Gettier case, for example, Smith’s belief that “The person who will get the job has ten coins in their pocket” is derived from the false premise that “Jones will get the job.” By excluding beliefs based on false lemmas, this approach aims to prevent Gettier-style counterexamples.
While the no false lemmas condition resolves some cases, it does not fully eliminate epistemic luck. For instance, philosophers like Carl Ginet have constructed scenarios in which true beliefs arise without relying on false premises but still fail to qualify as knowledge due to their accidental nature. This reveals that the problem is more fundamental than simply excluding false lemmas.
Reliabilism
Reliabilism, a prominent response championed by Alvin Goldman, shifts the focus from justification to the reliability of the belief-forming process. According to reliabilism, a belief constitutes knowledge if it is produced by a process that reliably generates true beliefs. This approach avoids some of the issues with JTB by emphasizing the causal mechanisms underlying belief formation.
However, reliabilism faces challenges from “new” Gettier cases. For example, even a reliable process can occasionally yield a true belief coincidentally, as in situations where external factors distort the connection between justification and truth. Critics argue that reliabilism alone cannot fully account for the intuitive distinction between knowledge and lucky belief.
The Causal Theory of Knowledge
Another influential response is the causal theory, proposed by Goldman and others, which suggests that knowledge requires a causal connection between the fact and the belief. For example, if a person knows that a tree has fallen, their belief must be causally linked to the actual event of the tree falling. While this theory addresses some cases, it struggles with examples involving abstract truths, such as mathematical or logical knowledge, where causal connections are not easily defined. Furthermore, causal theories still leave room for epistemic luck in certain scenarios.
Virtue Epistemology
Virtue epistemology, advanced by Ernest Sosa and John Greco, introduces the idea that knowledge arises from the exercise of intellectual virtues or cognitive skills. On this view, a belief constitutes knowledge if it is the result of a reliable, skillful, and virtuous process. This framework emphasizes the agent’s epistemic responsibility and seeks to integrate reliability with justification.
While virtue epistemology provides a promising framework for addressing Gettier cases, it is not immune to criticism. Some argue that it lacks precise criteria for distinguishing virtuous belief formation from cases of epistemic luck. Others question whether intellectual virtue can adequately explain the full range of knowledge.
Critiques and Alternative Perspectives
Zagzebski’s Structuring of Gettier Cases
Linda Zagzebski offered a meta-level critique, arguing that the very structure of Gettier cases ensures their persistence. She contends that any theory defining knowledge in terms of independent conditions is vulnerable to counterexamples because it is always possible to construct a case in which the conditions are satisfied yet the belief is true by accident. Zagzebski’s analysis suggests that a more holistic approach to knowledge may be necessary, potentially abandoning the search for necessary and sufficient conditions altogether.
Contextualism
Contextualists, such as David Lewis, propose that the standards for knowledge vary depending on the context. In ordinary contexts, JTB might suffice, but in more skeptical contexts, additional criteria may be required. This approach preserves the flexibility of epistemic concepts but raises questions about the objectivity and stability of knowledge.
Pragmatism
Pragmatists, like Richard Rorty, reject the traditional project of defining knowledge and focus instead on its practical role in inquiry and action. For pragmatists, the Gettier problem highlights the limitations of abstract theorizing about knowledge, encouraging a shift toward examining how beliefs function in real-world contexts.
Conclusion
Edmund Gettier’s challenge to the justified true belief account of knowledge has reshaped the field of epistemology, sparking an enduring debate over the nature of knowledge and the conditions that distinguish it from mere belief. While philosophers have proposed numerous refinements and alternatives, no consensus has emerged, underscoring the depth and complexity of the issues raised by Gettier’s examples. His work remains a cornerstone of epistemological inquiry, illustrating the power of philosophical reasoning to question and refine our most fundamental concepts.
References
Gettier, Edmund L. (1963). “Is Justified True Belief Knowledge?” Analysis, 23(6): 121–123.
Harman, Gilbert. (1973). Thought. Princeton University Press.
Goldman, Alvin I. (1967). “A Causal Theory of Knowing.” The Journal of Philosophy, 64(12): 357–372.
Goldman, Alvin I. (1979). “What Is Justified Belief?” In Pappas, G. S. (Ed.), Justification and Knowledge. D. Reidel.
Sosa, Ernest. (1980). “The Raft and the Pyramid: Coherence versus Foundations in the Theory of Knowledge.” Midwest Studies in Philosophy, 5(1): 3–25.
Zagzebski, Linda. (1994). “The Inescapability of Gettier Problems.” The Philosophical Quarterly, 44(174): 65–73.
Pritchard, Duncan. (2005). Epistemic Luck. Oxford University Press.
Greco, John. (2010). Achieving Knowledge: A Virtue-Theoretic Account of Epistemic Normativity. Cambridge University Press.
Dancy, Jonathan. (1985). Introduction to Contemporary Epistemology. Blackwell.
Ichikawa, Jonathan Jenkins, & Steup, Matthias. (2018). “The Analysis of Knowledge.” The Stanford Encyclopedia of Philosophy.
Bernecker, Sven, & Dretske, Fred (Eds.). (2000). Knowledge: Readings in Contemporary Epistemology. Oxford University Press.