<P> The Gettier problem, in the field of epistemology, is a landmark philosophical problem with our understanding of knowledge . Attributed to American philosopher Edmund Gettier, Gettier - type counterexamples (called "Gettier - cases") challenged the long - held justified true belief (or JTB) account of knowledge . On the JTB account, knowledge is equivalent to justified true belief, and if all three conditions (justification, truth, and belief) are met of a given claim, then we have knowledge of that proposition . In his three - page 1963 paper, titled "Is Justified True Belief Knowledge?", Gettier showed, by means of two counterexamples, that there were cases where individuals had justified the true belief of a claim but still failed to know it . Thus, Gettier claimed to have shown that the JTB account was inadequate--it could not account for all of the knowledge . The JTB account was first credited to Plato, though Plato argued against this very account of knowledge in the Theaetetus (210a). </P> <P> The term "Gettier problem", or "Gettier case", or even the adjective "Gettiered", is sometimes used to describe any case in epistemology that purports to repudiate the JTB account . </P>

Who came up with the tripartite theory of knowledge