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Lotfi Zadeh

      . . . father of Fuzzy Logic, Director of the Berkeley Initiative in Soft Computing (BISC). Since 1965, Dr. Zadeh has focused on the theory and applications of fuzzy sets, having earlier considered system theory and decision analysis. Dr. Zadeh is Professor in the Graduate School at the University of California - Berkeley, where he has been since 1959. He has been on the faculties of Columbia University, the Institute for Advanced Study, MIT, Stanford, and other distinguished research facilities. He is the recipient of a stunning array of awards and recognitions.



"Blue," "strong" and "lovely" are all imprecise, fuzzy concepts. They seem unlikely revolutionaries. But, in fact, exploiting our human tolerance for imprecision has spawned a revolution. Move over Aristotle. Lotfi Zadeh has arrived, armed with fuzzy logic. Fuzzy logic is "logic" only when used in its strictest sense, says Dr. Zadeh. In the wider sense, fuzzy logic is being applied, around the world, creating toasters and subways, concrete factories and washing machines. It's also making in-roads in chemistry. Even in that bastion of crisp distinctions -- mathematics.

Fuzzy logic is "logic" only when used in its strictest sense, says Dr. Zadeh. In the wider sense, fuzzy logic is being applied, around the world, creating toasters and subways, concrete factories and washing machines. It's also making in-roads in chemistry. Even in that bastion of crisp distinctions -- mathematics.

The real world is simply too complex for classical techniques of analysis, Dr. Zadeh found. They don't work, he says, when applied to psychology, artificial intelligence, philosophy, mathematical economics or any other field that presents problems that cannot be addressed if we insist on a high level of precision. Fuzzy logic, in contrast, builds on the virtues of imprecision.

Which brings us to the revolution. Professor Zadeh is convinced we are in the throes of not one but two! We can see the information revolution all around us but the less visible one is comparably important. It's the intelligent systems revolution. Fuzzy logic (in association with other methodologies including neural networks, genetic computing, and others) is increasing what Dr. Zadeh calls M-IQ -- machine IQ. As our machines get smarter, they will change our lives, he assures us.

It's not that fuzzy logic will make us happier when we read a newspaper, says Dr. Zadeh, or that it will help us decide whom to marry. The effect will be through the existence and development of all kinds of devices smart enough to affect the ways we live. Remember life before faxes, e-mail, the Internet, cell phones, answering systems and personal digital assistants?

Dr. Zadeh was himself steeped in the precise, rigorous, rational and quantitative tradition. A long-time professor at the University of California - Berkeley and now director of the Berkeley Initiative Soft Computing, even Dr. Zadeh did not imagine all the turns fuzzy logic has taken since he wrote his original paper on fuzzy sets in 1965. He first used the term "fuzzy logic" in 1974. It started as a theory of classes which do not have sharply-defined boundaries. He ended up fostering ways of thinking that he believes will one day dislodge the formal black and white ("crisp") distinctions we have come to think of as logic. Permanently.

How will all this look in 50 to 100 years? Dr. Zadeh is confident fuzzy logic will simply be taken for granted, much like Aristotle's ideas were -- until Lotfi Zadeh created the conceptual tools to deal with a fuzzy world.

[This Program was recorded September 17, 1996 in San Diego, California, US.]

Conversation 1

Professor Lotfi Zadeh establishes the predicates for his conversation with Paula Gordon Paula Gordon and Bill Russell, confident that we are in the throes of two revolutions -- the information revolution and the intelligent systems revolution. Fuzzy set theory -- "fuzzy logic" -- met with both great admiration and profound skepticism when Lotfi Zadeh introduced it in 1965. He recalls both and explains why critics never bothered him. He distinguishes people with closed minds from others and describes how the concept of fuzzy logic has evolved with time. He recalls deciding to use the word "fuzzy," anticipating both positive and negative connotations in various languages. Noting that work on fuzzy logic now goes on all over the world, Dr. Zadeh describes some of fuzzy logic's many facets. He describes what motivated him to come up with the concept of a fuzzy set and how the concept grew and matured. He distinguishes a narrow from a wide sense of fuzzy set theory. The challenge of language in introduced.


Conversation 2

Dr. Zadeh suggests the dimensions of the intellectual changes which accompany fuzzy logic, confident its full impact will take time. He elaborates on fuzzy logic's potential. He reminds us that he was once deeply committed to traditional thinking and recalls how he came to break with it, citing other orthodoxies that have fallen. Dr. Zadeh gives examples of areas where he believes the old logic will not work, adding a litany of thinkers who have had to lower their sights. Professor Zadeh explains why he believes theorems cannot be proven. He notes his own practical streak and states why he believes theorems in mathematical economics have no relevance to real-world economics. He expresses confidence that his perspective will be common place in 50 to 100 years.


Conversation 3

Early expectations Dr. Zadeh had for fuzzy logic were in humanistic systems, living systems and a variety of areas which he names. He defines fuzzy logic by example. He tells where he expected his ideas to be used and, in spite of his training in systems and control, his great surprise that fuzzy logic's largest monetary impact is in consumer products. He expands. Precision, he tells us, is expensive and he reminds us that a fundamental aspect of human behavior is a tolerance for imprecision. He has examples of how consumer products have exploited that tolerance.


Conversation 4

Noting that fuzzy logic has a vast number of applications, Dr. Zadeh expands on the implications of the dual revolutions through which we are living -- the very visible information revolution and the less visible intelligent systems one. He explains his concept of "MIQ" öö machine IQ -- listing machines that are getting smarter. He shows how fuzzy logic in combination with neural networks, genetic algorithms and other kinds of computing will affect our behavior as we use ever-smarter machines. He offers a series of examples. He reminds us that language is very, very fuzzy, making note of how cool the reception for his ideas has been among linguists . He describes when age is and is not on his side. He expresses surprise at how widely his ideas have been applied.


Conversation 5

Acknowledging dissenters, Professor Zadeh suggests what he feels confident are the dimensions of the true paradigm shift brought on by fuzzy logic. He assesses the contribution he believes he has made, confident that there are virtues to imprecision. He assures us that time is on his side.




Our thanks to David R. Russell for the photos he took in the course of our conversation with Professor Zadeh

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If you are interested in subscribing,contact: owner-bsic-group@EECS.Berkeley.EDU

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