%0 Journal Article %T Os anulabilismos de Klein e de Swain e o problema de Gettier %A Emerson Carlos Valcarenghi %J Principia : an International Journal of Epistemology %D 2010 %I Universidade Federal de Santa Catarina, Brasil %X In this essay, we intend to show that Peter Klein and Marshall Swain defeasibility theories do not resolve the Gettier problem. Klein postulates, to any Gettier counterexample, that there is a true proposition which, when associated with evidence-e of S, genuinely defeats the justification of p to S. Swain postulates that, to any Gettier-type counterexample, there is a true proposition which, when associated with the set of reasons-R of S, ultimately defeats the justification of S to believe p. To show that Klein an Swain proposals do not resolve that problem, this essay presents two Gettier-type counterexamples for which there are no genuine defeaters of justification of p by e to S and there are no defeaters not ultimately defeated of the justification of the belief of S that p by R. After doing that, we try to show that the obtained conclusion regarding Klein and Swain defeasibility theories can be extended to any defeasibility theory of knowledge. %K problema de gettier %K justifica o da cren a %K anulabilismo %U http://www.periodicos.ufsc.br/index.php/principia/article/view/1808-1711.2010v14n2p175/17950