The Fuzzy Logic (unsharp logic) is a form of multi-valued logic to deal with (human) reasoning that is approximate rather than precise. In fuzzy logic the degree of truth of a statement is not constrained to the two truth values (1=true, 0=false) as in classic predicate (Boolean) logic but can range (inclusively) between 1 and 0. The problem is discussed since the Greek antiquity (Platon) and the Fuzzy-Set-Theory of L. A. Zadeh (1965). We, however, noticed that the definition of Fuzzy Logic is somewhat vague.