  This paper presents and discusses several methods for reasoning from
inconsistent knowledge bases. A so-called argumentative-consequence relation
taking into account the existence of consistent arguments in favor of a
conclusion and the absence of consistent arguments in favor of its contrary, is
particularly investigated. Flat knowledge bases, i.e. without any priority
between their elements, as well as prioritized ones where some elements are
considered as more strongly entrenched than others are studied under different
consequence relations. Lastly a paraconsistent-like treatment of prioritized
knowledge bases is proposed, where both the level of entrenchment and the level
of paraconsistency attached to a formula are propagated. The priority levels
are handled in the framework of possibility theory.
