Re: Trying to define Surrogates
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 17 Aug 2006 16:43:26 GMT
Message-ID: <O01Fg.50713$pu3.588455_at_ursa-nb00s0.nbnet.nb.ca>
>
>
> That's a deep philosophical issue for William Kent to answer, and one
> which depends critically on formal definitions of "identity", "same",
> "equivalent", "equality", "distinguish," etc. Whether you assign a
> number (which may or may not be printed on the can), or an RFID, a
> database has no way to distinguish them unless you give it that
> artifical label. I agree the cans are distinct in the real world, and
> have identity. It makes no real difference for most of the data we care
> about. If I spill the pyramid of cans, and hand you an undented one,
> will you be able to determine whether it's the one you were eyeballing
> before I knocked them down? So when physical location changes, and you
> don't track it explicitly, identity is lost - still there, but unknown
> to us.
>
> A database is not the real world. Since a database concerns known
> facts, the limits of our knowledge (e.g. whether you can know which of
> the nearly-identical cans you want) are direcly reflected in our
> ability to design and maintain a database.
Date: Thu, 17 Aug 2006 16:43:26 GMT
Message-ID: <O01Fg.50713$pu3.588455_at_ursa-nb00s0.nbnet.nb.ca>
erk wrote:
> JOG wrote:
>
>>are you telling me that two Cans of Campbell's have no identity without >>an artificial label? If that were true you would not be able to >>distinguish them, yet you can. What, then, is that distinguishing >>property?
>
>
> That's a deep philosophical issue for William Kent to answer, and one
> which depends critically on formal definitions of "identity", "same",
> "equivalent", "equality", "distinguish," etc. Whether you assign a
> number (which may or may not be printed on the can), or an RFID, a
> database has no way to distinguish them unless you give it that
> artifical label. I agree the cans are distinct in the real world, and
> have identity. It makes no real difference for most of the data we care
> about. If I spill the pyramid of cans, and hand you an undented one,
> will you be able to determine whether it's the one you were eyeballing
> before I knocked them down? So when physical location changes, and you
> don't track it explicitly, identity is lost - still there, but unknown
> to us.
>
> A database is not the real world. Since a database concerns known
> facts, the limits of our knowledge (e.g. whether you can know which of
> the nearly-identical cans you want) are direcly reflected in our
> ability to design and maintain a database.
Not only the limits of our knowledge but the limits of our interest. Do we really care about the identity of individual cans of soup? Received on Thu Aug 17 2006 - 18:43:26 CEST