Is Justified True Belief Knowledge? - Classic Text | Alexandria
Is Justified True Belief Knowledge? - Edmund Gettier
"Is Justified True Belief Knowledge?" is a landmark three-page philosophical paper published in 1963 by Edmund Gettier that fundamentally challenged the traditional conception of knowledge that had dominated Western philosophy since Plato. The paper presented two counterexamples demonstrating that justified true belief—the classical tripartite definition of knowledge—is insufficient for capturing what we mean by "knowing" something. This deceptively brief work sparked what became known as "the Gettier problem," one of the most significant epistemological challenges of the 20th century.
The paper emerged during a period of intense analytical philosophical inquiry in the 1960s, when philosophers were rigorously examining fundamental assumptions about knowledge, truth, and belief. Before Gettier's publication, philosophers had largely accepted Plato's definition of knowledge as justified true belief, which had persisted for over two millennia. Gettier's counterexamples, involving carefully constructed scenarios where someone has a justified true belief that nonetheless fails to qualify as genuine knowledge, demonstrated the inadequacy of this traditional definition.
The impact of Gettier's paper was both immediate and enduring, generating thousands of responses and attempted solutions over subsequent decades. Its influence extended beyond epistemology into cognitive science, artificial intelligence, and theories of mind. The paper's elegant simplicity—presenting complex philosophical problems through straightforward scenarios—revolutionized how philosophers approached questions of knowledge and certainty. Notable attempts to resolve the Gettier problem have included requiring that justification be undefeated, adding a fourth condition to the traditional three, or completely reconceptualizing the nature of knowledge itself.
The Gettier problem remains relevant today, particularly in discussions of artificial intelligence, machine learning, and the nature of understanding. The paper's enduring legacy lies not only in its challenge to traditional epistemology but in its demonstration that seemingly simple concepts can harbor profound complexities. Modern philosophers continue to grapple with its implications, suggesting that perhaps the most valuable aspect of Gettier's work is not in providing answers, but in revealing the depth of questions about the nature of knowledge itself.
The remarkable influence of this concise paper raises an intriguing question: How can we be sure of what we know, when even our most carefully justified true beliefs might fall short of genuine knowledge?