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Re: Terminology Question

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  • J Wolfgang Goerlich
    Ugh. Bruce, you might have noticed that I sent _two_ responses to you. In the first one, I remarked on vertebrates versus invertebrates and listed a few links.
    Message 1 of 9 , Mar 2, 2004
      Ugh.

      Bruce, you might have noticed that I sent _two_ responses to you. In
      the first one, I remarked on vertebrates versus invertebrates and
      listed a few links. My reasoning was neither sound nor correct, and I
      ought not to have sent that one.

      Of course, the second response might not be correct, too. However,
      that was the one that I meant to send.

      Wolfgang

      "Coffee, where's the coffee ..."

      > Bruce replied:
      >> Both vertebrates and invertebrates have central nervous systems,
      >> so that doesn't enter into it.

      > I must respectfully disagree with you on this point.

      J Wolfgang Goerlich
    • Bruce Robinson
      Apologies for suddenly dropping out of several conversations. To catch up on one of them ... ... It s unfortunate that many BEAMers use terminology that is
      Message 2 of 9 , Mar 5, 2004
        Apologies for suddenly dropping out of several conversations. To catch
        up on one of them ...

        J Wolfgang Goerlich wrote:
        >
        > I agree; Hider has a spinal cord. My
        > problem is in wrapping my mind around
        > the many references on Beam web sites
        > to the 'core being called the spinal
        > cord. ...

        It's unfortunate that many BEAMers use terminology that is highly
        inaccurate (to say the least). Given the nature of the web, it's very
        difficult to correct this sort of thing retroactively. Usually the best
        we can do is try to use appropriate terminology ourselves and encourage
        others to do so. (And who, pray tell, dreamed up the ridiculous idea of
        a robot that eats the national sport of Japan :)

        > ... It is acting primarily as the CPG,
        > which in higher-level animals is thought
        > to be located within the spinal cord.
        > However, the CPG becomes more important
        > in lower-level animals that lack a spinal
        > cord or central processing altogether.

        Biological naming conventions are chosen because they are useful. The
        spinal cord is, by definition, a part of the central nervous system.
        Functionally it provides "lower level" processing. However, the main
        reason for giving it a special name is because it is a distinct physical
        entity. I used the term "spinal cord" to describe a portion of Hider's
        electronics (after a great deal of internal debate) because that
        sub-circuit ...

        - performed functions similar to a biological spinal cord.
        - was a disinct, easily identifiable, physical entitiy.
        - occupied an equivalent physical and functional position.

        It isn't especially useful to use biological terms for our robots when
        they don't convey similar meanings. In fact it's downright confusing.
        I'd call a central pattern generator just that -- a CPG. I wouldn't call
        it a "spinal cord" unless it bears some physical resemblance to a spinal
        cord.

        > Thus, my breaking point of "nervous system"
        > versus "central nervous system", and
        > "invertebrate" versus "vertebrate" robots.
        > It makes for an easy distinction and helps
        > me to understand the differences.

        My objection is this: "brain", "CNS", "spinal cord" are all terms
        relating to the nervous system (reasonably analogous to a robot's
        control system). "Vertebrate" and "invertebrate" are terms relating to a
        creature's skeletal structure, which is something else entirely.

        Consider the following definition of a spine: "A structure that joins
        two or more substructures and consists of two or more articulated
        elements." This fits the biological model nicely. But are there any
        robots that fall into this definition? Yes! 3-motor and 5-motor robots!
        Heads! We can legitimately call these robots vertebrates (assuming you
        accept my definition of a spine).

        The biological spinal cord got its name because it runs down the centre
        of the spine (which offers excellent protection for a such an important
        part of the nervous system). In a robot that protection may not be
        important -- the spinal cord and the spine can easily become distinct
        entities. You can very easily end up with a robot containing a spine but
        no spinal cord, or vice versa.

        What we need to keep in mind is that many of our robots have no
        biological equivalents. For example, I know of no biological creatures
        (that you can see without a microscope) that have wheels. Rather than
        trying to "force" inappropriate biological names on our robots, we
        should be thinking up a rational terminology that describes the robots
        we build. Where biological terms fit, by all means, let us use them.

        > What would you call a Beam robot that has a spinal cord?

        I called mine "Hider" :)

        Bruce
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