Monday, July 21, 2008

Vagueness and Fuzziness

Probability theorists tend to think that everything that fuzzy logic can do it (probability theory) can do better. But probability theory is a procedure for dealing with uncertainty. Perhaps some things are vague -- legal language, for example -- without being uncertain. So perhaps the question of the legitimacy of fuzzy logic boils down to the question of the existence or non-existence of vague objects that are not necessarily uncertain.

But perhaps fuzzy logic also legitimately applies to reasoning about uncertain propositions -- because perhaps some or much reasoning about uncertain propositions involves vague objects (concepts). Be that as it may, perhaps it is true that fuzzy logic will gain a greater measure of respectability among standard probability theorists if the distinction between uncertainty and vagueness is solidified.

N.B. It may be true that vague concepts -- e.g., vague legal concepts -- work in ways that are uncertain to some degree. But does it follow that such (vague) legal concepts are "uncertain" to some degree? This is perhaps a nice test question for logicians and legal theorists.

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Henceforth Criminal Defendants in Japan Will Be Allowed to Wear (Clip-On) Ties and (Fake) Shoes at Their Trials

Japan Times Online reports that criminal defendants will now be allowed to wear clip-on neckties and "and open-back slippers that look like leather shoes." These changes were precipitated by the advent of a new trial system in which lay judges as well as professional judges will preside in trials of serious criminal charges.

Thought is also being given to removing shackles and handcuffs from the accused before the accused enters the courtroom. In addition, under certain circumstances, the accused will be allowed to sit next to counsel, and not, as at present, between two police officers, with defense counsel sitting behind this trio. However, one of the police officers will plant a leg between the feet of the accused and defense counsel. In Japan justice may not be swift but it does have long and sturdy legs.

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Sunday, July 20, 2008

Fuzzy Logic -- Once Again

I keep returning to fuzzy logic. I do so plainly in part because I think fuzzy logic is an important key to human understanding of the world. But I also continue to revisit fuzzy logic because I firmly sense that the proper use of fuzzy logic in law remains to be worked out. (Indeed, I think this work has barely begun.)

When thinking about the implications of fuzzy logic for legal theory -- and for law in action --, I find it useful to consider, from time to time, the reception that has been given to fuzzy logic and how it has been used thus far. The following summary by Phil Serchuk in his 2005 honors thesis is quite useful in this regard:

Fuzzy logic is unique because it is a source of controversy not only in philosophy but in computer science as well, where it has been used in many successful applications. Yet despite its successes there are many compelling criticisms that fuzzy logic has yet to overcome. Both proponents and opponents of fuzzy logic tend to take extremist positions, a situation that makes fair accounts and criticisms of fuzzy logic difficult to come by. Engineers and computer scientists who use fuzzy logic vigorously defend their work and charge that their critics are conservatives who cannot see the fuzziness inherent to a given domain, a strong charge given the longstanding relationships many of the sciences have had with classical logic. Critics of fuzzy logic tend to take extreme positions as well: fuzzy logic has been described by Berkeley mathematician William Kahan as ‘the cocaine of science’ and as ‘pornography’ by Carnegie Mellon logician Dana Scott [Haa96, p. 230].

While the merits of infinitely-valued logics were being debated by philosophers, computer scientists had began building actual systems that used fuzzy logic. Early fuzzy expert systems and controllers were developed in the 1970’s and fuzzy logic’s ability to use linguistic rules were being explored and put into practice: steam generators and cement kilns were among the earliest applications of fuzzy control. Decision support systems were also being developed and one of the first commercial decision support systems to use fuzzy logic was developed by the INFORM Corporation in 1986 [vA95, p. 279]. Over the 1970’s and 1980’s Japanese researchers had begun to embrace fuzzy logic and by 1989 the Japanese government partnered with 49 companies to found the Laboratory for International Fuzzy Engineering Research (LIFE) [Ter95, p. 1]. LIFE’s six-year mandate was to develop new fuzzy technologies and applications in ‘human-friendly’ fields like robotics and expert systems. By 1990 fuzzy rice cookers, vacuum cleaners, refrigerators, and other electronics were yielding large profits for Japanese companies [LY99, p. 7]. The last part of the 1990’s saw many more concrete applications of fuzzy logic, particularly in computer systems designed to help humans make difficult and complex decisions. In addition to traditional applications in business and engineering, these applications were developed for many disciplines across the natural and social sciences as researchers in these fields slowly began to see the phenomenon of vagueness as being inherent to certain aspects of their work.

Like many other observers who are sympathetic to fuzzy logic, Serchuk stresses that it is important to distinguish uncertainty and vagueness.

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