عنوان مقاله [English]
In Teatetus, Plato defines knowledge as “true Justified belief ”. Known as tripartite definition (or analysis) of knowledge, by 1960s it was a dominant definition for knowledge. In 1963, American philosopher Edmund Gettier in short paper, accepting necessity of three parts, has presented us with two counterexamples to the claim that knowledge is completely justified true belief. Since that, it has given numerous answers to Gettier’s counterexamples. Some of these answers accept Gettier’s objection to sufficiency of three fold conditions, try to complete it by adding a fourth condition. This essay surveys and criticizes answers of this kind and shows that these efforts werenot successful by now and that Gettier’s objection is yet remained.