Qualitative Reasoning Under Uncertainty

In this paper, we focus our attention on the processing of the uncertainty encountered in the natural langusge. Firstly, we explore the uncertainty concept and then we suggest a new approach which enables a representation of the uncertainty by using linguistic values. The originality of our approach is that it allows to reason on the symbolic uncertainty interval ~Certain, Totally uncertain]. The uncertainty scale that we use here, presents some advantages over other scales in the representation and in the management of the uncertainty. The axiomatic of our approach is inspired by the Shannon theory of entropy and built on the substrate of a symbolic many-~-alued logic. So, the uncertainty management in the symbolic logic framework leads to generalizations of classical inferences rules.