Re: An intuition pump

>On Sunday, September 21, 2003, at 05:45  PM, pat hayes wrote:
>[snip]
>>>Now Molly comes along and notes the extreme chauvinism of Sally's 
>>>definition, excluding as it does (arguably) eunuchs, 
>>>hermaphrodites, intelligent programs, chimps, augmented chimps, 
>>>Martians and the like. Molly proposes an alternative ontology for 
>>>sally:Person.
>>>
>>>Now, if I understand the view as raised by tim in his issuing, 
>>>Molly and the Foafsters are pretty much stuck. sally:Person just 
>>>*means* whatever Sally wants it to mean.
>>
>>Well, it does mean that, but they are not stuck. Molly can 
>>introduce molly:person, a superClass of sally:person, tell people 
>>what it means, and then folk can use that. If enough people feel 
>>that this is the best definition, it will presumably get used more 
>>widely and will become the de facto new standard, maybe. More 
>>likely, two rival communities will emerge, the Mollyites and the 
>>Sallieties, with rather different views about what constitutes a 
>>person.
>
>There are at least two ways to express this rivalry: We have two 
>*terms* (molly:Person, and sally:Person) each with their own, rival, 
>definition, or we have two *definitions* for a single term which has 
>an associated concept which the definitions attempt to capture. Your 
>(and, I take it, Tim's) view is that we have multiple terms, 
>presumably at least one per definition.

Well, yes; at least, given that the term "definition" might be 
slightly misleading.

>  One thing I'm trying to get at is that people might reasonably take 
>Sally's term as *naming* a concept, a concept which she then says 
>false things about

I cannot make clear sense of this. I have no idea how to name a 
concept. Are you saying that there might be a real thing in the 
world, called a concept, that the assertions are about?

>, strictly analogous with Sally coining a URI for *me* and then 
>saying that I was born in 1887.

Not strictly analogous, because you are not a concept. Your date of 
birth is just a fact, which can be misrepresented by a falsehood. 
Concepts are not real things that have crisp edges beyond which 
falsehoods can be discerned. If I say that marriage means a social 
union between two consenting adults, and Joe says that marriage is a 
pact between a man and a woman made before God, do Joe and I disagree 
about a question of fact or about the meaning of the word "marriage"? 
I think the latter is the only option that makes sense.

Now, one might say that there is a concept OF you; but (1) that is 
not the same thing as you - for example, it doesn't have a weight or 
a date of birth - and more to the present point (2) if there is one 
of them, then there can be lots of them, eg your concept of you, your 
mother's concept of you, my concept of you , etc., all of which 
presumably differ slightly, or in some cases substantially from one 
another.

>Must people coin their own URI for me, in order to say true things 
>about me that are contrary to Sally's false statements?

No, of course not; though they might choose to use it in order to 
make a direct rebuttal.  But if they use *your* URI to refer to you, 
then your ownership of your URI means that their uses of it in any 
assertion have to be understood as de re in their reference to you.

>  I hope we all agree not.  So, what justifies the disanalogy?
>
>>What did you expect, that the entire world was going to agree about 
>>what words mean?? (Try 'marriage'.)
>
>In your view everyone DOES agree about what words/URIs mean. I'm 
>suggesting that people might disagree about what *sally:Person* 
>means.

The entire world has to allow the owner of a URI to say what its 
referent is supposed to be (if they want to do that: they are not 
obliged to). The same is true for coined words in English, in fact, 
at least initially.  Charles Dodgson said what "gyre" and "wabe" 
meant, and who is say that he was wrong? He invented the words, after 
all. So if Sally says that sally:Person means human beings, then 
that's what it means. If you use it intending to refer to something 
else, then you have made a  mistake, and what you actually said isn't 
what you meant to say. You should take more care when using other 
people's terminology, particularly when the terminology has got their 
bloody address written on it, like a dog tag.

Normal words aren't like that because they have no owner, obviously. 
Although it is interesting that there has been a kind of cultural war 
about something close to this issue in lexicography. Some 
dictionaries are prescriptive, some descriptive: the differences 
reflect deep-seated divergences about what it means for a word usage 
to be 'correct'.

>
>>The ontological reasoners have at least a chance of not getting 
>>confused, because they have names for both concepts and an idea of 
>>the relationship between them.
>
>I suspect that there will be some not so easily solved cases. 
>Perhaps my example was oversimple.

I agree there will be hard cases and I don't think this issue is 
going to just vanish away. But I think the TimB-L vision of URI 
ownership at least gets us started in the right general direction; 
whereas the idea that all meanings are globally determined simply by 
model theory is a non-starter.

>>  I don't see this as being a problematical kind of example; on the 
>>contrary, in fact: it shows (in a simplified caricature)
>
>Ah yes :) Deliberately so, for the record :)

Of course, that's OK.

>
>>  how a nuanced vocabulary can arise from people being obliged by 
>>the conventions of ownership to define relationships between 
>>concept meanings.
>
>How do I express that Sally *tried* to capture the concept that 
>planetOfTheApes:Person (only superchimps have rights) captures? (I 
>guess the common factor may come into play.)

I have no idea: but why should I care about that? If Sally said 
something she didn't mean to say, then she has screwed up, indeed, 
but I can hardly be expected to be telepathic. What matters to me is 
to grok the meaning of what Sally actually said. If there isn't a URI 
out there for her to use to express her concept then she has to use a 
new one, and then I may have to ask her what it means, or try to 
figure that out from whatever else she says using it, or maybe I 
don't really care as long as I get the inferences made well enough to 
do whatever I am trying to do.

Seems to me that in practice, this issue of 'but what were you trying 
to say?' will only come up when normal communication has broken down 
for some reason (eg when an inconsistency is detected where things 
should be consistent) and we are all in some kind of damage-control 
mode of trying to disentangle and re-align our concepts more exactly. 
One proven way to approach this kind of a snag is to use a kind of 
initial triage of making all the clashing concepts different, then 
trying carefully to see what happens when you re-merge them, using 
detected inconsistencies as a guide to how to split concepts into 
subcases, just like the Molly/Sally example where there are 
apparently two rather different notions of person being bandied 
about.  What this suggests is that the ability to trace URIs back to 
their owners, and the likely fine-tuning of concepts (my notion of 
person vs. your notion of person) is in fact a way of almost 
automating the initial stages of the damage-control process that 
would have to be done if we all tried to use the same URIs to express 
different meanings.

>
>>  Contrast this with the case where nobody can really say what a URI 
>>is supposed to mean,
>
>We have a way of saying what a URI actually means in a graph/document.

We do? How?

>What's at issue is what *else* we have to put in. For all its 
>issues, owl:imports vs. uri use gives you a way of specifying the 
>"extended" meaning of a URI on a fairly finegrained basis.

I fail to see how owl:imports helps with this matter at all.  All it 
does in effect is to create larger ontologies; it doesn't specify the 
meanings of URIs.  And I don't know what the 'vs.' is intended to 
suggest. Do you see some kind of methodological alternatives here? 
(That shared URI use is somehow a different way of doing importing?? )

>
>>  and when Molly used sally:person in a nonstandard way, that 
>>(mis?)use just kind of back-taints all the other uses, so that even 
>>Sally's ontology doesn't mean what she intended it to mean any more.
>
>I fail to see it. Explain?

Perhaps I have attributed too much to you here. I presume that if the 
owner of a URI is not an authority on its intended meaning, that the 
alternative view, which I thought you must be holding, is that the 
meaning of a URI is determined by (the model theory of) whatever 
assertions are made using the URI. In which case, if Molly uses 
Sally's URI and makes some assertions, then those assertions become 
part of what determines the meaning of the URI (in some sense the 
meaning is determined by the 'entire Web' at any given time) - after 
all, if you do not recognize ownership as important, then why is what 
Molly says any less determinate of meaning than what Sally says? - in 
which case, even if Molly's concept does not match with Sally's, what 
Molly *says* will affect the meaning of what Sally has published.

This seems kind of obvious, so if you don't see it then maybe I don't 
follow what you have been suggesting. The above "vs." suggests that I 
am not fully following you, indeed. Can you elaborate?

>
>>Now, *that* really is a recipe for world-wide confusion.
>
>I feel some fatuous statement coming one...must resist...can't: 
>"World-wide confusion is fine; local confusion isn't"

I have absolutely no idea what you are talking about.

>
>>>More interestingly, suppose Sally had just been a bit careless and 
>>>really was aiming at a more expansive notion of Person, just blew 
>>>it. However, before Molly detected the problem, Sally sold her now 
>>>very popular domain to People for a Very Narrow Sense of People in 
>>>Foaf Documents (PVNSPFD). They refuse to change sally:Person.
>>>
>>>Now, what concept does sally:Person identify? When? Does it matter?
>>
>>I would say : whatever PVNSPFD claims it does: because they own the 
>>URI (now). However, I doubt if they would have any motivation, 
>>having paid for the damn thing, to alter its meaning
>
>Of course not. They *like* the "mis"definition poor Sally gave for 
>it. They are trying to hijack her intentions (with, admittedly, what 
>she actually said).

Again, you seem to be seeing something underhand or nefarious in this 
(admittedly somewhat far-fetched) scenario that I do not perceive at 
all.  Why is Sally "poor Sally" at this point, exactly? Has she been 
cheated in some way? How? By whom?

[later, on re-reading: I think I may see the point. Sally *meant* to 
say A, but instead said B, and then sold her words to these bad guys 
who wanted to say B all along, so indeed just went on saying B; not 
thereby confusing anyone else, and not asserting anything false; but 
poor Sally, being either as thick as two short planks, or dyslexic, 
or maybe both, feels that she has been somehow misrepresented. Is 
that more or less right? Seems to me that if she got paid for saying 
something wrong, by people who are now saying something right, that 
she has very little cause to feel disgruntled.]

>They also seem free to change Sally's term any which way.

Well, the OWNER of a URI is I guess free to say anything they like 
using it, including change their mind about its meaning. I agree that 
if this happens a lot, things will get confusing. But in the absence 
of some kind of totalitarian control over Web usage, I see no way to 
guarantee that this can never happen.

However, I see no reason to worry about this unlikely scenario. It 
will become a serious problem only if one party has an economic stake 
in deliberately trying to confuse or sabotage the software used by 
the agents of other parties. I have never seen any suggestion of why 
or how this is likely to arise; on the contrary, in fact: most of the 
proposed uses of the SW , for example B2B and Service applications, 
clearly have all parties interests being served by everyone else 
grokking their intended meanings as accurately as possible. All the 
economic pressures on both sides converge towards increasing the 
convergence of meaning attached to URIs in mutual use. So I think 
this will just happen: the world will find ways to make it happen. 
All we have to do at this stage is to kind of point the way, and not 
to say anything too damn silly which might stop it happening. We 
don't have to make sure that the sky isn't falling.

>Er...meaning stabiltiy? World wide confusion? What if they 
>perversely *do* change it, can sally still publish/use her old 
>ontology?

She can publish whatever she likes, but if what she says contradicts 
what they say, then they are now the arbiters of the correct meaning. 
That is what ownership means.

This all seems clear as day and perfectly simple to me: what is the issue here?

>
>>  (or at least, not without widely disseminating this intended 
>>change) since to do so would only confuse their user base. So, it 
>>would likely retain its meaning. Yes, it does matter.
>>
>>>Is there anything Wrong with Molly (or *Sally*) putting out an 
>>>alternative ontology, and the Foaf x.x ontology switch its 
>>>owl:imports statement to point to the alt-ontology instead of the 
>>>(now owned by) PVNSPFD one.
>>
>>Ah, that indeed raises a nasty issue about 'versions' of ontologies 
>>and the real meaning of importing. But that issue just IS nasty: it 
>>is almost as nasty when phrased purely syntactically as when it is 
>>phrased semantically.  So think that is a red herring.
>
>Er.. I'm not yet seeing the sequitur. Lots of things are nasty both 
>syntactically and semantically. How does it make it a red herring?

In the context of this discussion, it isn't central to the issue of 
social MEANING.

>  Real meaning of importing? I thought importing was quite clear.

No, its not at all clear. Suppose ontology A imports B, using a URI 
to point to where B is published; and then suppose that the owners of 
B update the ontology at that URI. Has A changed, then? If so, have 
all other import-chains which include B also changed? What if a user 
of A had archived the imported ontology; is their version of A 
rendered out-of-date by the change made to B? Apparently, the owners 
of B can sabotage all ontologies which import their ontology, without 
the owners of those ontologies even being aware of it.

Now, one might reply: the Web is like that: there can be 404 errors, 
and so on. But an imports statement can have a much larger and more 
significant effect than a mere hyperlink in hypertext.  This raises a 
host of issues which have not been adequately addressed yet. The OWL 
semantics hedges around all this stuff by talking about an ontology 
being "consistent with the Web", but if we gave owl:imports a genuine 
model theory (which it emphatically has not been) then these issues 
would have to be made explicit.

>Could you separate out the issues a bit?

Hope the above gives an impression. There are others but its getting late.

Pat

>Cheers,
>Bijan Parsia.


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Received on Tuesday, 23 September 2003 00:02:09 UTC