W3C home > Mailing lists > Public > www-rdf-logic@w3.org > April 2001

Re: A plea for peace. was: RE: DAML+OIL (March 2001) released: a correction

From: pat hayes <phayes@ai.uwf.edu>
Date: Fri, 13 Apr 2001 10:45:47 -0500
Message-Id: <v04210104b6fcc9a0d83c@[]>
To: Aaron Swartz <aswartz@swartzfam.com>
Cc: www-rdf-logic@w3.org
>pat hayes <phayes@ai.uwf.edu> wrote:
> >>> All objects? There are objects which have no name in any human
> >>> language.
> >> That doesn't prevent you from giving them one.
> > That doesnt prevent it, but there might well be circumstances which
> > do prevent you from giving them one. Obviously we can, and often do,
> > refer to things that we cannot possibly give a name to (since we
> > cannot identify them), eg as when we say that a beach contains
> > hundreds of billions of grains of sand, each consisting largely of
> > silica. It is (literally) impossible to give a name to every grain.
>Is it really impossible? Hmm, how about we say that I define:
>where n is the number of the grain of sand on the shore of Lake Michigan,
>USA, numbered depth first, from top to bottom and left to write currently
>existing at the precise moment in time that I click send on this message.
>Now I've given them all names. Sure, it may be extremely, extremely
>difficult (I'm not sure that it is actually impossible) to go from one of
>these names to the actual grain of sand, but that does not mean that I have
>not given them all a name.

Yes, it does. I see what you mean (and I think agree with you), but 
you need to distinguish between *referring* to something and *naming* 
it. Thats my point: we can REFER to things like the nth grain of sand 
on a beach, but that isn't the same as giving that grain of sand a 
NAME. That requires that we have some way to distinguish the named 
thing from the other things like it.

> > (Similarly leaves of a tree, bacteria in a Petri dish, stars in a
> > remote galaxy, hydrogen atoms, etc. etc. .)
>Leaves of a tree are actually much easier to deal with, since they are large
>enough to write their URIs on. Others can be dealt with in a similar way to
>the sand, probably even more precisely, since they are commonly used in
>scientific work.

The science tells us why we can't give names to things like hydrogen 
atoms, in fact. And the stars-in-glaxies point is that no matter how 
good our telescopes get, we will always be able to see some galaxies 
whose stars we cannot see. We can talk about them, refer to them, but 
not name them.

> >> There is no authority to define the
> >> "meaning" of a word. However, it is clear who defines the meaning of a URI
> >> -- its "owner".
> > Ah, that is an interesting claim. Is it so clear?
>Well, it is clear that the owner holds the authority. However, I did not
>claim that it was clear who the owner was, or their definition was clear.
> > First, if the
> > "owner" is a human being, then maybe one could claim this; but even
> > then, how does anyone else find out what meaning the "owner" had in
> > mind (barring telepathy)?
>Well, we ask them, of course.

Which is fine is 'we' are the kind of thing that can ask such 
questions and understand the answers. But what if 'we' are a software 
agent trying to draw a conclusion?
And in any case, HOW do we ask them? I have no idea who owns most the 
URIs I see every day, or how to find out who they are.

>Now I admit, this is not an exact way of
>finding out the meaning, but I know of none better. I'm sure that if you
>have a better way of discovering meaning it could be worked in. Until then,
>we'll have to do with what we have.
> > And how do we know that the "owner" had a
> > single clear idea in mind? The owner may be confused about the
> > meaning, and if the word is part of a piece of natural language text
> > (eg inside HTML) then it is just as vague and nuanced in its meaning
> > as any other word in natural language.
>Well, it's not a word -- it's a URI. The meaning of the resource represented
>by the URI is defined by its owner. The owner may be confused, I admit, but
>at least we have limited our definition to a single person (at least I'm
>pretty sure it will be a person) who can give a definitive answer. This is
>better than some vague amorphous entity that depends on the ever-changing
>feelings of society at large (current natural language words).

So you think that because an English word appears on a web page it is 
somehow rendered more exact and clear in its meaning, and that 
meaning is somehow removed from society? I think the only thing I can 
say at this point is, get a life.

> Again, if
>you've got something better, please let us know. Until then, this system
>seems to work pretty well.

The system we are trying to create here doesnt work AT ALL yet. It 
doesnt even EXIST yet, except in small prototypes here and there.

> > And in any
> > case, what if the "owner" is, say, a refrigerator, or a file system?
> > Your use of scare quotes suggests that you are aware of such cases.
>The quotes I used were to ensure that it wasn't confused with some sort of
>legal definition of ownership, etc. I think it is unlikely within the near
>future that we will see refrigerators with advanced enough Artificial
>Intelligence that they will begin to create URIs of their own will.

Not of their own will, of course, but nothing turns on that notion. 
We will in the near future see refrigerators which have URIs and 
maintain up-to-date information on them about their (the 
refrigerator's) operating condition, dates of service, etc.. This is 
already routine for some more expensive pieces of equipment. Never 
mind about 'will'; the point is that the machine is the *source* of 
the information.

>If that
>happens, then I suppose we can simply ask the refrigerator, as we would ask
>any other person. In many cases however, a refrigerator is simply a machine
>carrying out work on behalf of its programmer, which often delegates
>responsibility to the owner of the machine.

But the whole point of doing this stuff is to NOT ask the owner of 
the refrigerator. The owner of the refrigerator probably hasnt a clue 
about the stuff on the fridge's website, and wouldnt understand it if 
they did. The programmer of this thing may have died already, and 
certainly has no further contact with this particular fridge. We are 
talking here about world where the machines are talking to each other 
independently of human beings. Better get used to that idea.

> >> This may not be a rigorously mathematical system, I admit, but it
> >> has worked well enough for the millions of users of the Web.
> > Sigh. This discussion seems to to constantly be going around this
> > particular loop, which is starting to get frustrating.
> >
> > Yes, of course. It works for the millions of HUMAN users of the Web.
> > This is not surprising, since names (not URI's, just plain names)
> > have worked for the hundreds of millions of human beings who have
> > been using language since before the Neolithic. (The Web hasnt added
> > anything to the human use of language; it has just enabled us all to
> > listen to more of it.) But this entire discussion on RDF is about how
> > to arrange things so that SOFTWARE AGENTS can use information on the
> > web, not human beings.
>Of course! But, to my knowledge, these SOFTWARE AGENTS are all programmed
>and run by HUMAN BEINGS (or at least, there is always a human at the top of
>the chain of command).

They are programmed by human beings (well, most of them are. Some may 
have evolved by themselves) but they are certainly not RUN by human 
beings, and they do not have human beings at the top of the chain of 
command. They operate autonomously; you know, like computers do?.

>The reason we seem to keep going in this loop is
>because I don't see what's better.

Its not a question of what is better: it is simply getting the facts 
of the case straight. Machines DO communicate with each other across 
the Web, and draw conclusions, take actions, etc., on their own 
initiatives and without consulting human beings. RDF and DAML+OIL are 
motivated by the need to have these machines convey useable 
information to one another and be able to draw, check and otherwise 
process conclusions from formally described information. No natural 
langauge is used, and no human thoughts intervene in this process.

>I know of no language that conveys
>"knowledge" to machines.

Read an AI textbook on 'knowledge representation' to come up to speed on this.

>Instead, the best we can do is use human language
>to invent a more rigorous one, and build up from there. But unless you know
>something I don't, there will always be human agreement and human language
>at the bottom. I simply don't see any other way.

See last comment.

>If I'm missing something, please tell me what this powerful language is. I'd
>love to get my hands on it.

It is broadly called 'formal logic', but it comes in many flavors.

Pat Hayes

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Received on Friday, 13 April 2001 13:43:36 UTC

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