Is Justified True Belief Knowledge? is a 1963 paper by Edmund L. Gettier, which challenges the traditional definition of knowledge as "justified true belief." Gettier presents counterexamples to show that this definition is insufficient. In Case I, Smith believes that Jones will get a job and has ten coins in his pocket, based on strong evidence. However, it turns out that Smith, not Jones, will get the job, and Smith has ten coins in his pocket. Despite this, Smith's belief is justified and true, yet he does not know the proposition. In Case II, Smith believes that Jones owns a Ford, based on strong evidence. However, Jones does not own a Ford but is driving a rented car. Despite this, Smith's belief is justified and true, yet he does not know the proposition. These examples demonstrate that the traditional definition of knowledge as justified true belief is inadequate. Gettier argues that the conditions for knowledge stated in the traditional definition do not constitute a sufficient condition for knowledge. The paper is a bilingual edition of Gettier's original work, translated by Paulo Vélez León. It is published in Disputatio, a philosophical research bulletin, and is available under a Creative Commons license. The paper is part of a series of works that challenge the traditional view of knowledge.Is Justified True Belief Knowledge? is a 1963 paper by Edmund L. Gettier, which challenges the traditional definition of knowledge as "justified true belief." Gettier presents counterexamples to show that this definition is insufficient. In Case I, Smith believes that Jones will get a job and has ten coins in his pocket, based on strong evidence. However, it turns out that Smith, not Jones, will get the job, and Smith has ten coins in his pocket. Despite this, Smith's belief is justified and true, yet he does not know the proposition. In Case II, Smith believes that Jones owns a Ford, based on strong evidence. However, Jones does not own a Ford but is driving a rented car. Despite this, Smith's belief is justified and true, yet he does not know the proposition. These examples demonstrate that the traditional definition of knowledge as justified true belief is inadequate. Gettier argues that the conditions for knowledge stated in the traditional definition do not constitute a sufficient condition for knowledge. The paper is a bilingual edition of Gettier's original work, translated by Paulo Vélez León. It is published in Disputatio, a philosophical research bulletin, and is available under a Creative Commons license. The paper is part of a series of works that challenge the traditional view of knowledge.