In this work a comparison is attempted between the Aristotle’s traditional bivalent logic, which dominated for centuries on the human way of thinking, and the relatively recent Zadeh’s fuzzy logic, which has already found many and important applications to almost all sectors of the human activity. It is concluded that, although the enormous progress of science and technology owes a lot to bivalent logic, fuzzy logic which completes and extends it, fits much better to our everyday life situations and to the scientific way of thinking.