Re: Humans think fuzzy?

From: Rich Shepard (rshepard@salmo.appl-ecosys.com)
Date: Thu May 17 2001 - 03:45:06 MET DST

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    On Tue, 01 May 2001 08:43:43 GMT, Cristian Fabbi <fabbic@galactica.it> wrote:
    >Soon I've read that neural system made with FL think like humans (i'm
    >summarizing).
    >Why do we say so? Have we got proofs that human brain works in a fuzzy way?

    Christian,

      Your confusion comes from the well-known problem associated with the term
    "fuzzy". When applied to fuzzy sets, fuzzy logic and fuzzy system models the
    term means "uncertainty". Let me back up and explain.

      When we measure something in the natural world (human or non-human), there
    are two sources of potential error: imprecision and uncertainty. Imprecision
    comes from our inability to measure something with absolute accuracy, for
    example, the temperature of soils or the intelligence of humans. On the
    other hand, we encounter uncertainty -- or fuzziness -- when describing soil
    temperatures or human intelligence.

      Consider what we mean by "warm", "cool", "smart" and "dumb". These terms
    describe a relative condition that is a function of what we are measuring,
    and they can mean different things to different people or under different
    circumstances. It is this latter situation -- uncertainty in the meaning of
    descriptive terms -- that we quantify in fuzzy sets, manipulate using fuzzy
    logic and apply to real-world problems with fuzzy system models.

      As Lotfi Zadeh explained, the term "fuzzy" is not the best to use, but was
    chosen for what seemed, at that time, to be a good reason. Think of it as
    the inherent "sloppyness" of a system, not of our measurements of the
    system.

      For your original question, the answer is "yes", humans think in fuzzy
    terms. We talk of "steep" slopes, "high speed" railroad systems, "tall" and
    "short" people. These are imprecise terms that describe characteristics of
    the system we're considering.

    HTH,

    Rich

    -- 
    Dr. Richard B. Shepard, President
    

    Applied Ecosystem Services, Inc. (TM) 2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A. + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard@appl-ecosys.com

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