DDJ: Is it possible that if you had patented this technology it would not have been so readily adopted?
LZ: It's difficult to predict what could have happened, because sometimes things evolve in [an] unpredictable fashion. Just to give you an example, the first consumer product [to use fuzzy logic] was a Panasonic showerhead which came out in 1987. If someone had asked me in 1986 what sort of applications would you expect, it wouldn't have occurred to me that there would be all these applications in the realm of consumer goods.
DDJ: What did you envision?
LZ: Industrial applications, yes. Industrial control, traffic control, applications in linguistics, yes. But not washing machines, not microwave ovens, none of those things would have occurred to me. So it shows that even a reasonably well-informed person in that field may find it very difficult to predict how things will evolve.
I could see that control was going to be an application, and in 1972 I wrote a paper called "A Rationale for Fuzzy Control." But my colleagues in the area of control didn't share that feeling, and to this day, most of the control-systems community is very antagonistic towards fuzzy logic, as is the AI community.
DDJ: I can understand the control-engineering community's wariness, which possibly is based on unfamiliarity, since in the classic control theory, proportional-integral derivative, and the like, so much time has been committed to working out these theories, and so much of the training of the people involved has dealt with this. You don't want to teach an old dog, in the form of a well-established school of engineering, new tricks.
In the AI field, I wonder if there is professional jealousy that AI didn't quite take off as a commercial proposition, whereas fuzzy logic has done so.
LZ: The issue is somewhat complex. Incidentally, many of the people within the AI community were very hostile toward fuzzy logic. Among them are good friends, so there is nothing personal about it.
I think that what happened is that, for historical reasons, AI embraced classical logic, classical predicate logic, symbolic logic. And so, the intellectual leaders of AI, who were deeply committed to that kind of logic, took the position of prescriptive logic, telling you "that is the way you should be reasoning." Since computers are symbol-manipulation machines, it appeared that computers could implement that kind of reasoning and go beyond what humans can do.
AI has hitched itself to symbol manipulation. As a result, most people in AI dislike numerical computation. They dislike not just fuzzy logic, but they dislike probability theory, neural networks, anything that involves numerical computations. Things are changing, and I think that gradually you'll find the number of people within AI who use numeric computations, [and] the number of papers at AI conferences in which numerical computations are used in one form or another, are increasing. It's a gradual process. If you go back five or ten years you will find that AI was almost entirely symbol-manipulation oriented.
Fuzzy logic is not symbol-manipulation oriented. It's computationally oriented. Because of that, it simply did not sit too well with the AI community.
Also, it's a human thing: You sit at a table and the pie is sliced, and the more people who sit at it, the smaller your slice of pie gets. It has happened in a number of fields. There is resistance to something that may result in a smaller piece of pie for yourself and perhaps, more importantly, may depreciate the value of your knowledge. This is what is happening in AI now, because many people will use neural networks; they use, to a lesser extent, fuzzy logic; they use things that were not in the mainstream of AI. Many people in AI see that as a threat. They see that as an intrusion of people whose thinking is different from their own.
In that respect, it's not very different from many of the sociological phenomena that we observe. Take the way people dress. People who are committed to a classical-logicalesque reasoning are people who dress very properly. They have a tie and a shirt and the colors match, shiny shoes, starched shirt, and so forth.
The fuzzy-logic people dress informally. Their shirt may have colors that don't match perfectly, they don't worry too much if the shoes are this kind or that kind. These people do have more traditional clothes somewhere in their closet, so that if they have to go to a party where that's what's expected, they have something to put on. But not the other way around! The traditional people would not have the other kinds of clothes in their closet, because they would never stoop to wearing such a thing.
People who dress very conservatively, when they look at people who dress very informally, they don't like it. They feel that "these people are not my people." And the people who dress very informally, when they look at people who dress formally, say, "these people are old-fashioned, they are not my people."
DDJ: So you subscribe to the theories advanced by Thomas Carlyle's fictional Herr Teufelsdroeck, who said in Sartor Resartus that clothes really do make the man.
LZ: (Laughs) So you do really have different philosophies. There is a defense mechanism that I have observed which is part of all of us, that if there is something that is unfamiliar to you, you convince yourself that it is not worth learning, because if that were not the case, then you would have to learn it. But if you convince yourself that it is garbage, or uninteresting, then that absolves you from the need.
DDJ: As long as we are on the subject of predisposition to certain viewpoints, may I ask you a personal question?
LZ: Sure.
