The Fuzziness of Natural Thinking

Lotfi Zadeh, From Computing with Numbers to Computing with Words -- From Manipulation of Measurements to Manipulation of Perceptions (1999):

The depth of scientific tradition of respect for numbers and derision for words was reflected in the intensity of hostile reaction to my ideas by some of the prominent members of the scientific elite. In commenting on my first exposition of a linguistic variable in 1972, Rudolph Kalman had this to say:

I would like to comment briefly on Professor Zadeh's presentation. His proposals could be severely, ferociously, even brutally criticized from a technical point of view. This would be out of place here. But a blunt question remains: Is Professor Zadeh presenting important ideas or is he indulging in wishful thinking? No doubt Professor Zadeh's enthusiasm for fuzziness has been reinforced by the prevailing climate in the U.S. -- one of unprecedented permissiveness. "Fuzzification" is a kind of scientific permissiveness; it tends to result in socially appealing slogans unaccompanied by the discipline of hard scientific work and patient observation.

In a similar vein, my esteemed colleague Professor William Kahn -- a man with a brilliant mind -- offered this assessment in 1975:

"Fuzzy theory is wrong, wrong, and pernicious," says William Kahan, a professor of computer sciences and mathematics at Cal whose Evans Hall office is a few doors from Zadeh's. "I can not think of any problem that could not be solved better by ordinary logic." What we need is more logical thinking, not less. The danger of fuzzy theory is that it will encourage the sort of imprecise thinking that has brought us so much trouble."

What Lord Kelvin, Rudolph Kalman, and many other brilliant minds did not appreciate is the fundamental importance of the remarkable human capability to perform a wide variety of physical and mental tasks without any measurements and any computations. Familiar example of such tasks are parking a car; driving in heavy traffic; playing golf; understanding speech and summarizing a story.