Edmund Gettier

Edmund Gettier challenged the traditional definition of knowledge as "justified true belief." He presented scenarios where people had beliefs that were true and justified, yet intuitively do not qualify as knowledge due to a lack of reliability in their justification. This led to significant discussions in epistemology, raising questions about belief, truth, and justification. Gettier's work sparked debates among foundationalism (the idea of basic beliefs) and internalism/externalism (the sources of justification), prompting philosophers to refine how we understand knowledge beyond merely possessing justified true beliefs.