NATURE, PLACE AND USEFULNESS OF FUZZY LOGIC IN THE ANALYSIS OF HUMAN KNOWLEDGE

Fuzzy Logic is nowadays a very popular logic methodology. Different kinds of applications in cybernetics, in software programming and its growing use in medicine seems to make Fuzzy Logic a very important calculus in science and technology. Fuzzy logic is based on the fuzzy set theory (Zadeh, 1965). In the classical set theory the value of membership function of an element to a set is 0 or 1, while in the fuzzy set theory the membership function of an element to a set may have limited or infinite values that are between 0 and 1. Therefore in the fuzzy logic systems partially true premises provide partially true conclusions. The FL system is a simple model of fuzzy logic: connectives, inference rules and examples of inferences will be discussed. Is fuzzy logic against the principles of classical logic or is it an extension of classical logic? Probabilistic and fuzzy logic deals with uncertainty: is probabilistic logic reducible to fuzzy logic? What does it mean? Moreover, I will answer to the question whether Fuzzy logic is or is not the key of the formalization of natural language.