I seek some enlightenment:
Looking at this hierarchy, while it is questionable in many ways, I find it troubling that a place is a kind of thing, yet a date/time is a "data type," and not a kind of thing.
I sort of thought space-time was somehow unified. surely more than a datatype, such as number, which can be used to identify a location in space and time, and yet different from "things."
I can only hope there is some practical reason for this I do not understand, as I can more easily guess for many of the other classifiers and their otherwise dubious organization.
Wm
On Tue, Oct 23, 2012 at 5:58 PM, John F Sowa <sowa@xxxxxxxxxxx> wrote:
On 10/23/2012 2:27 PM, Deborah MacPherson wrote:
> Curious where this list of facilities came from and
> how they came to be organized this way.
I just selected a few random examples from the Schema.org hierarchy
to illustrate the discussion:
http://www.schema.org/docs/full.html
This hierarchy was defined by the consortium founded by Google,
Microsoft (Bing), and Yahoo.
R. V. Guha was the person from Google who presented a talk on Schema.org
in the Ontolog series. Guha had been the associate director of Cyc in
the early 1990s. He co-authored the book on Cyc with Doug Lenat (1991).
So Guha was certainly familiar with the methods used in Cyc, and he
made some major contributions to them. In particular, Guha's PhD
dissertation (for which John McCarthy was the thesis adviser and
Ed Feigenbaum was on the committee) was about reorganizing the Cyc
ontology in microtheories.
Guha later went to Apple and then to Netscape, where he worked
with Tim Bray to develop RDF. He also worked with Pat Hayes
to define the logic base (LBase) for RDF. He worked at IBM
research for a while in the early 2000s, and he is now at Google,
where he is working on Schema.org.
So I would assume that the current Schema.org hierarchy was at least
influenced by Guha. I don't know all the reasons why he would have
designed it that way, but I do know that one reason why Guha designed
RDF is that he believed that Cyc was too complex. He didn't want to
reject logic, but he wanted to find a simpler foundation that could
grow into a richer system.
And by the way, Guha said that he would have preferred LISP notation
for representing triples instead of XML notation. That may be one
reason why Google is emphasizing JSON for Schema.org -- JSON is
basically LISP with square brackets and curly braces.
John
PS: If I were forced to bet on a W3C design vs a Google design
as the likely direction for the future, I'd lean toward Google.
But Google has quite a few abandoned designs on their garbage
heap, and so does the W3C.
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