Fuzziness, uncertainty and bipolarity : a critical review

1. Gradualness: the idea that many categories in natural language are a matter of degree, including truth. The extension of a gradual predicate is a fuzzy set, a set where the transition between membership and non-membership is gradual rather than abrupt. This is Zadeh’s original intuition [29]. 2. Epistemic Uncertainty: the idea of partial or incomplete information. In its most primitive form, it is often described by means of a set of possible values of some quantity of interest, one and only one of which is the right one. This is possibility theory [31]. 3. Bipolarity : the idea that information can be described by distinguishing between positive and negative sides, possibly handled separately [16], as it seems to be the case in the human brain [2].