Réseau LACTO (Langage, Argumentation et Cognition dans les Traditions Orales) Quatrième Rencontre du Réseau Lacto CELHTO, bureau de l'Union Africaine, Niamey, Niger, du 22 au 25 septembre 2015 : JEU ET ORALITE DANS LES SOCIETES A TRADITION ORALE According to the main stream approaches to epistemic notions, knowledge and belief are understood as propositional operators. Thus, • Gildas believes that there is a witch in his village is understood as expressing a proposition. Moreover, • Gildas knows that Gödel proved the completeness of first-order logic, expresses a proposition too. The difference between both is that a belief-proposition can be true if it is " factually " false: in our case the proposition can be true in relation to Gildas's belief, that is, despite the fact that there is no witch in his village. Furthermore, assuming that there is not witch in his village, the following proposition is false • Gildas knows that there is a witch in his village. If the latter is false, from the point of view of the mainstream, there was not knowledge at all, rather it was from the start a belief that has not been verified. 1 The present paper is part of an ongoing project in the context of the research-program Argumentation, Decision, Action (ADA) and the project Logique, Argumentation et Cognition dans les Traditions Orales (LACTO) both supported by the Maison Européenne des Sciences de l' Homme et de la Société-USR 318 and by the laboratory UMR 8163: STL.