- From: Spork, Murray <murray.spork@sap.com>
- Date: Wed, 9 Feb 2005 19:00:16 +0800
- To: "Henry Story" <henry.story@bblfish.net>, <semantic-web@w3.org>
[Cc's trimmed] Hi Henry, I was going to point you towards a keynote speech at Extreme Markup Languages 2003 by Bill Kent on the "Unsolvable Identity Problem" but can't find it anywhere - the best I can find is [1]. Doesn anyone know if it's available online? I'm sure it used to be. Kent's book "Data and Reality" [2] is essential reading (and a little depressing for all of us interested in the "semantics" of data) - just as relevant now as it was in the 70s when written. [1] http://www.extrememarkup.com/extreme/2003/keynotes.asp [2] http://www.amazon.co.uk/exec/obidos/ASIN/1585009709/qid=1107946684/sr=1- 1/ref=sr_1_10_1/202-3816936-0235828 >-----Original Message----- >From: semantic-web-request@w3.org >[mailto:semantic-web-request@w3.org] On Behalf Of Henry Story >Sent: Wednesday,9 February 2005 7:42 PM >To: semantic-web@w3.org >Cc: Roy T. Fielding; Atom Syntax; bloged >Subject: Madonna > > >Just a point of clarification about identity. (I thought the example >is fun enough that it may be of interest) > >As we all know Madonna is a material girl, and she lives in a material >world [1]. > >Madonna is a US citizen also. Let us imagine the day she received her >social security card through the post. That day Madonna, the material >girl, had a very specific material constitution. Let us call the set >of cells, organic and inorganic material that composed Madonna that >moment M1. > >Now let us stipulate that two material things are equal if they are >made of exactly the same matter. > >That afternoon Madonna goes to the beauty salon where she gets her hair >cut and fingernails and toe nails clipped. The resulting material girl >call her M2 is no longer the same as M1, as M2 is M1 less some hair >and nail material. M2 may also contain a little more water (she was >drinking some beauty drink during the process). So M1 is not the same >material thing as M2. > >Both M1 and M2 are also girls, and have a functional relation to a >social security number. Ie M1 and M2 each only have 1 social security >number. There are in fact a very large number of such material Madonnas >Mx that have a functional relation to that same social security number. >So clearly the inverse relation (from social security to temporal >Material Madonnas) is not functional. > >Now let us think of the mereological fusion [2] of all of these >Material Madonnas, and let us call that MM. MM also has a functional >relation to the social security number. But it is also clear that >there is an inverse functional relation from social security number >to MM. > >So the social security number identifies madonna in two ways. > >1. via a functional relation > temporalId: temporal material madonnas --> social security number >2. via an inverse functional relation > fusionId: MM --> social security number > >Given a social security number we can via the fusionId relation >get a hold of the mereological fusion of that person, and from >the mereological fusion we can find the individual temporal parts, >each of which of course have a temporalId relation to the same social >security number. > >The above can probably be also put in terms of set theory, and >so in terms of rdf graphs. In which case it clearly shows how >rdf can speak about temporal and non temporal identity. > >Henry Story > >[1] http://www.lyricsfreak.com/m/madonna/86925.html > audio clip: http://tinyurl.com/5k9et >[2] http://plato.stanford.edu/entries/mereology/ > > >
Received on Wednesday, 9 February 2005 11:01:28 UTC