Gerald David Nordley	
1238 Prescott Avenue
Sunnyvale, CA 94089-2334
(408) 739-4032
gdnordley@aol.com
Book Review, about 800 words.

_Fuzzy Logic_ by Daniel McNeill and Paul Freiberger
Touchstone - Simon & Schuster, NY, 1994, $12

    Every now and then someone follows something that you knew all the time into new intellectual territory with such devastating clarity that you suddenly question everything you thought you knew.  Daniel McNeill and Paul Freiberger did this for me in _Fuzzy Logic_, a book that on one level explains how those smooth-running Japanese trains and unjittery video cameras work, and on another challenges the the formal logic foundations of western civilization.  This all is tied together by an engrossing human story of struggle and vindication which raises troubling questions about how the professional cultures in the United States handle new ideas.  It is a work which approaches, for me, the impact of Gleick's book on chaos.
    On one level, it follows the story of Lotfi Zadeh, the "father of fuzzy logic,"born in 1921 in Baku, through childhood under Stalin to a move to Iran during the communist-engineered Ukrainian famine and the intellectual whiplash of an American Presbyterian school in Teheran under a Shah that was "frogmarching his country into the future."  Zadeh eventually arrives as a mathematician in Berkeley with all the psychological armor needed to launch a revolution in the teeth of academic hostility and industrial indifference.  He starts with the theory of "fuzzy sets."
 	A "fuzzy set" is a set without sharp boundaries, one that has a fairly clear central idea but merges gradually into the other sets around it.  We use fuzzy sets all the time; they are simply generic nouns, such as "green" or "chair"  You know a chair when you see one, but what is the difference between a chair and a stool?  Classical logic treats each object as either a chair or a stool with an arbitrary "line in the sand" between the two.  Fuzzy logic asks not whether a thing is a chair or a stool, but rather how good a chair or a stool it is.  Thus a tall stool with a back, placed at a bar, might rate 0.8 as a stool and 0.3 as a chair, while the stump of a tree might rate about 0.3 in both categories.
	Note that fuzzy set membership is _not_ a probability.  Probabilities in such exercises add up to one, but fuzzy set memberships are under no such constraint.  The difference is described so clearly that most non-technical lay people should understand an issue that has apparently perplexed some highly-credentialed mathematicians and logicians.
	The name "fuzzy logic" seems like a hill that separates real thinkers from conformist wimps -- if you have enough intellectual integrity, you swallow the unfortunate connotations, climb over the hill, and deal with the subject itself.  Over the hill lies the aha! world where the question of "at what point does one thing become another" becomes irrelevant nonsense and longstanding conundrums vanish as one deals with continuous reality instead of categories. The authors avoid some obvious, but controversial, applications; they take on Aristotle, Kung Fu Tse (Confucius) and Russell, but not Marx, the pope, or political correctness.  
	The story of how yet another American idea became a Japanese commercial triumph is too painful to relate.  Would it really have mattered if Zadeh had called it something else?   The response to the name leads to a discussion of deeper problems within American industry and academia.  Here, the book takes a fascinating turn through the Tokugawa Shoganate and the non-Aristotelian pragmatism of the Japanese version of Buddhism, as illustrated in the yin-yang symbol that dominates the South Korean flag, as it attempts to account for the flowering of this idea in Japan.
	But this is a technology book as well.  Fuzzy logic control systems generate and add correction values in proportion to an error signal's membership in fuzzy sets like "close" and "changing slowly" and so generate smooth corrections without oscillations or solving a non-linear control equation.  They more the way you drive a car than the way you would solve an algebra problem.  Even highly complex systems can reach stability faster than with traditional control algorithms, but describing the behavior of and proving the stability of fuzzy controllers is problematical -- hence much of the resistance.  
	Yes, _Fuzzy Logic_ explains how fuzzy control systems get rid of those camera jitters, and raises hopes for devices that work faster, smoother, and cheaper and it may be a threshold technology for artificial intelligence.  But I think that the real revolution is still to come, as this concept makes its way into thinking about politics, tribalism, law, and our understanding of existence itself.  After ideas like fuzzy logic and chaos, the universe becomes a different, more natural, and perhaps more hopeful, place in which to live.  Read the book and think about it.   
ww780  October 1994