For 2,000 years, the standard philosophical model of knowledge was that it could be defined as a justified true belief. According to this way of thinking, we can know, for example, that we are human because  we believe ourselves to be human;  that belief is justified (others treat us as humans, not as dogs); and  the belief is true. This definition, which dates to Plato, was challenged by Edmund Gettier in one of the most influential works of philosophy published in the last century – a three page paper that produced two clear examples of justified true beliefs that could not, in fact, be considered knowledge.
Gettier's achievement rests on solid foundations provided by his mastery of the critical thinking skill of analysis. By understanding the way in which Plato – and every other epistemologist – had built their arguments, he was able to identify the relationships between the parts, and the assumptions that underpinned then. That precise understanding was what Gettier required to mount a convincing challenge to the theory – one that was bolstered by a reasoning skill that put his counter case pithily, and in a form his colleagues found all but unchallengeable.
Table of Contents
Ways in to the text
Who is Edmund Gettier?
What does Is Justified True Belief Knowledge Say?
Why does Is Justified True Belief Knowledge Matter?
Section 1: Influences
Module 1: The Author and the Historical Context
Module 2: Academic Context
Module 3: The Problem
Module 4: The Author's Contribution
Section 2: Ideas
Module 5: Main Ideas
Module 6: Secondary Ideas
Module 7: Achievement
Module 8: Place in the Author's Work
Section 3: Impact
Module 9: The First Responses
Module 10: The Evolving Debate
Module 11: Impact and Influence Today
Module 12: Where Next?
Glossary of Terms
People Mentioned in the Text
Professor Jason Schukraft teaches Philosophy at The University of Texas at Austin.