W3C home > Mailing lists > Public > semantic-web@w3.org > February 2009

Re: live meaning and dead languages

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Sun, 8 Feb 2009 14:19:49 +0000
To: Tim Berners-Lee <timbl@w3.org>, Jeremy Carroll <jeremy@topquadrant.com>
CC: "semantic-web@w3.org" <semantic-web@w3.org>
Message-ID: <EMEW,l17EK01509ad28a230acc7792c9c294c062e14,hg%ecs.soton.ac.uk,C5B49A85.29410%hg@ecs.soton.ac.uk>

Hi.
I expect it to be the case that meaning can seriously change, and there is an analogy with natural language.
(URIs based on formal groups such as WGS84 will always tend to be more stable, of course, just as words are.)
For example, if there had been a SW in the 1960s, there would have been a URI for the concept addressed by the word "hacker", say, http://dbpedia.org/resource/Hacker or even http://tmrc.mit.edu/dictionary.rdf#hacker.
However, once it had appeared in the metadata for TRON, and War Games, or whatever, in the 1980s, the URI http://dbpedia.org/resource/Hacker would have changed its meaning, with the most widespread meaning still being that usage today.
And no amount of pointing the world at dbpedia and other definitions would ever change that.
So "meaning as use" is not the basis of the design, but it is a reality we must face in the long term.
Of course, this is not just a problem - it is an exciting challenge!
And the fun is to work out how the SW can give us a better handle on all this.

<cod philosophy warning>
I consider that there is a great danger when designing systems that they get built for the way we would like the world to be, not the way it is. That way lies failure (cf the attitude to broken links in the old hypertext world already mentioned).
</cod philosophy warning>

Best
Hugh

On 08/02/2009 00:12, "Tim Berners-Lee" <timbl@w3.org> wrote:



Jeremy,

The Semantic Web is a system we design, not one we observe from the
sidelines as we do with Latin, say, or English.  It is simply a
different system. While analogies with natural languages are sometimes
useful they are often quit misleading. In particular, meaning as use
is not the basis of the design.

The design of HTTP space is that URIs -- terms in the language --  are
owned by particular agency -- people or communities of them.
The terms are defined well enough for a particular use.
The defining agency is often available to resolve the meaning n the
case of dispute.
The lifetime over which the terms are useful are the lifetime of the
application.

For example:

wgs84:lat is short for a URI defined by the international group WGS84.
The rdf property makes reference to a spec which has been implemented
thousands of times.
It is is well known as the numbers you get out of a GPS unit.
The term can only be used for positions on earth in a particular
projection.
If a new GPS system comes into play in the future which is much better
than the current, and uses a different projection, then new GPS
systems may be built to use new different terms by default.
The new terms will of course use a different URI, so there will be no
confusion.
But the relationships  between the projections will be well documented.
And the WGS84 system I would expect to have a very valuable life, huge
amounts of data being reliably exchanged using it, fro maybe
centuries, and I hope even in future millennia being a dead language
which is extremely well known by future librarians (human or not).

This stability of terms like this if very important for the systems we
are building.
You say you are an engineer not a philosopher.
I would, as you know, call you a philosophical engineer.  We are, in
the semantic web, building systems in which we engineer the philosophy
so that the system will have properties we desire.

Tim

On 2009-02 -05, at 22:34, Jeremy Carroll wrote:

>
>
> One of the occasional defects of people in SW is a tendency to arm
> chair philosophizing.
> I will indulge.[...]
Received on Sunday, 8 February 2009 14:20:43 UTC

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