From: mmmirash@fury.ecn.uoknor.edu (Mandar M. Mirashi)
Subject: Re: Uniquely fuzzy
Date: Mon, 23 Nov 1992 21:08:30 GMT
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK, USA

In article <1992Nov23.180156.12399@waikato.ac.nz> maj@waikato.ac.nz writes:
>In article <By3F48.DpI@constellation.ecn.uoknor.edu>, mmmirash@banshee.ecn.uoknor.edu (Mandar M. Mirashi) writes:
>> In article <1992Nov20.090118.12334@waikato.ac.nz> maj@waikato.ac.nz writes:
>>>> 
>>>> The times of the clear "unique"/"not unique" distinction are over.
>>>> If there is fuzzy logic in every washing machine you can buy, why
>>>> shouldn't it be in the language as well? English couldn't survive
>>>> on the world market if it ignored the modern concepts.
>>>> 
>>>> And speakers will always (have to) adapt to their language. So it's
>>>> time for everyone to get fuzzy. Or should I say "quite fuzzy"?
>>>> 
>>>
>>>Both languages and washing machines would be far better without
>>>fuzzy logic. It's the wrong way to handle uncertainty about real
>>>events. Because it's purely formal and without any clear semantics
>>>I think it's probably the wrong way to handle conceptual vagueness
>>>as well.
>>>-- 
>> 
>>       That's the funniest thing I've heard today! :)  Even computers
>> have difficulty in representing events precisely. For example, take
>> the case of numbers. When you say "He's 5'10" ", when has the person
>> referred to ever been exactly 5'10" feet tall? He could be 5'9.99"
>> or 5'10.01" for that matter! Ambiguity always occurs in human speech
>> and this because each of us has a different notion about certain
>> concepts. Yes, there may be certain events which always result in a
>> simple "Yes" or "No" decision (binary for all you computer lingo
>> aficionados), but many events are conceived differently by different
>> persons. Let me relate the case of our fuzzy logic class. The professor
>> asked us to write down at what age a person was considered to be "young".
>> When the responses were tallied, they varied in the range from 5-30 years!
>> 
>>         Human beings will never be able to converse in precise terms,
>> however many milleniums may pass. 
>> 
>>                                                             Mandar.
>> 
>I am not saying that some concepts are not vague or fuzzy,
>I'm just saying that 'fuzzy logic' or 'fuzzy set theory'
>is the wrong way to handle them. The calculus of fuzzy logic 
>assigns numerical truth values between zero and one to 
>statements like 'Fred is old'. Deductions are made purely
>by calculating truth values for conclusions of logical
>rules purely as functions of the truth values of the
>premisses.
>
>This kind of theory cannot do justice to all the complex
>linkages that can exist between statements. To take
>your example if A and B are 'young' to the degree of
>0.6 what is the truth value of the statement 'Both
>A and B are young'?  But what if I tell you that A and B
>are twins?
>
>The proper way to handle uncertainty is through the theory
>of probability, which treats the important notions of 
>independence of events and conditioning on new information.
>
>-- 
>Murray A. Jorgensen [ maj@waikato.ac.nz ]    University of Waikato
>Department of Mathematics and Statistics     Hamilton, New Zealand      

I don't see why you separate fuzzy logic from probability theory. They
need not necessarily be distinct. The truth values you mentioned are
calculated on the basis of a membership function. This could be a
probability ditribution function!! Also, as far as the example 'Both A and 
B are young' is concerned, it is possible to construct a union of two
distinct truth values. I cannot remember the formula off-hand, however
I'll mail it to you in case you're interested. 

    Anyway, this  kind of a discussion belongs to a math newsgroup or
a fuzzy logic newsgroup, rather than to an english newsgroup. My apologies
to my fellow newsgroup readers.

                                            Thanks,
                                                             
                                                         Mandar.
-- 
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