The Gettier Problem and Justified True Belief

The source provides an overview of the Gettier problem in epistemology, which challenges the long-standing definition of knowledge as justified true belief (JTB). Historically accepted for over 2,000 years, the JTB model proposes that knowledge requires a person to believe something, have justification for that belief, and for the belief to be true. However, the text explains that Edmund Gettier's influential 1960s paper used thought experiments to demonstrate cases where a belief can be justified and true, yet still not constitute genuine knowledge because the truth is achieved by epistemic luck or coincidence. The problem ignited a search for a "fourth condition" (often called ingredient X) to patch this flaw, leading to various proposed solutions like the no false lema approach, the causal theory, and the concept of an undefeated true belief. Ultimately, the Gettier problem highlights the crucial difference between genuinely knowing something and accidentally being right, emphasizing that the quality of the connection between evidence and truth is essential.