Dear Rich,

Your interesting question stirred a lively discussion. Your question 
raised another question: Is the conceptual structure of probability 
theory an appropriate framework for formulating a definitive answer to 
your question? In my view, the answer is: No.

The problem is: probability theory does not differentiate between 
fuzziness and randomness or, concomitantly, between possibility and 
probability. Here is a simple example. I meet Valentina. I do not know 
how old she is. My perception is that she is about 40. In this instance, 
Valentina's age is a fuzzy variable and "about 40: is its fuzzy value. 
Next, suppose I am staying at a hotel and ask the doorman: How long will 
it take to get to the airport by taxi? His answer is: usually about 
thirty minutes. In this instance, travel time is a random variable. 
About thirty minutes is a fuzzy event, and usually is a fuzzy 
probability of this event.

Combinations of fuzzy variables and random variables are governed by 
different rules. As an illustration, suppose that I ask myself: If I 
leave the hotel at about 10 and usually it takes about thirty minutes to 
get to the airport, at what time will I arrive there? Try to answer this 
question using standard probability theory. A fuller discussion of 
fuzziness and randomness may be found in my paper, "Toward a generalized 
theory of uncertainty (GTU)—an outline," Information Sciences, Elsevier, 
Vol. 172, 1-40, 2005.

Warm regards to all,

Lotfi
-- 
Lotfi A. Zadeh
Professor in the Graduate School
Director, Berkeley Initiative in Soft Computing (BISC)
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