ABSTRACT
One paradigmatic change in science and mathematics this century concerns the concept of uncertainty. It was once thought science should strive for certainty and that uncertainty was regarded as unscientific. An alternate view now believes that uncertainty is essential to science. The publication of Lotfi A. Zadeh’s seminal paper, [23], introducing the concept of fuzzy set theory is an important work in the modern concept of uncertainty. Zadeh’s paper challenges both Aristotelian two-valued logic and probability theory as being the sole agent for uncertainty. Given a universal set X, a fuzzy subset µ of X is a function of X into the closed interval [0, 1]. For an element x in X, the statement that x is in µ is not necessarily true or false, but may be true to some degree. This degree is given by µ(x).
