 Lotfi A. Zadeh argues that fuzzy logic is different in character from probability, and is not a replacement for it.He fuzzified probability to fuzzy probability and also generalized it to possibility theory.More generally, fuzzy logic is one of many different extensions to classical logic intended to deal with issues of uncertainty outside of the scope of classical logic, the inapplicability of probability theory in many domains, and the paradoxes of Dempster-Shafer theory.