FUZZY LOGIC

Bart Kosko (“Making Everything Perfectly Fuzzy,” by Sheldon Teitelbaum, April 1) claims that “fuzziness refutes the traditional Aristotelian theory of absolutes” and that the Law of the Excluded Middle allows “no shades of gray, no concepts such as ‘partly’ or ‘mostly.’ ”

The Law of the Excluded Middle states that “the same attribute cannot at the same time belong and not belong to the same subject and in the same respect.” This means that Kosko’s fuzzy computer chip cannot at the same time be a computer chip and an African elephant.

Aristotle clearly recognized shades of gray: “Again, the intermediate . . . will be so either in the way in which gray is between black and white.” Furthermore, in his classification of animals, he clearly indicated the difficulties of classifying animals that differ by gradations into their respective groupings.

Kosko is attacking the distorted “logic” of 20th-Century philosophers such as Bertrand Russell and his followers, which, unfortunately, is often mistaken for Aristotelian logic.

Aristotelian logic is the foundation of all of science and of technology, and if it is abandoned, these fields are doomed.

RON M. KAGAN Los Angeles