- From: Danny Ayers <danny.ayers@gmail.com>
- Date: Wed, 13 Jun 2007 17:51:15 +0200
- To: "Tim Berners-Lee" <timbl@w3.org>
- Cc: "Pat Hayes" <phayes@ihmc.us>, "M.David Peterson" <m.david@xmlhacker.com>, r.j.koppes <rikkert@rikkertkoppes.com>, "Yuzhong Qu" <yzqu@seu.edu.cn>, "Sandro Hawke" <sandro@w3.org>, semantic-web@w3.org, swick@w3.org, "John Black" <JohnBlack@kashori.com>
give me a week dan, sorry i missed the original question but i'm pretty sure we know the answer a week at most, definitve reply, ok dear? On 13/06/07, Tim Berners-Lee <timbl@w3.org> wrote: > > > On 2007-06 -11, at 17:09, Pat Hayes wrote: > > > Tim, as this discussion gets to the heart of what Ive been trying > > to argue for several years, please take the comments below as > > intended in a spirit of analysis rather than just pins and angels. > > Ok. [takes a deep breath]. I'll go down this path with you. > > > > >> On 2007-06 -11, at 13:53, John Black wrote: > >> > >>> > >>> Tim Berners-Lee wrote > >>>> > >>>> > >>>> On 2007-06 -09, at 21:22, M. David Peterson wrote: > >>>> > >>>>> On Sat, 09 Jun 2007 07:13:52 -0600, Tim Berners-Lee <timbl@w3.org> > >>>>> wrote: > >>>>> > >>>>>> No. It cannot identify both a document and a person. > >>>>> > >>>>> Tim: Will all due respect... WTF? > >>>> > >>>> > >>>> I am using the 'identify' in the strict sense of 'denote'. > >>>> The semantic web is like a logic language in which URIs are > >>>> symbols. > >>> > >>> Do you believe that by claiming to use the strict, logical sense > >>> of the word 'denote' you thereby cause or require such > >>> denotations to be absolute and unambiguous? Where do think > >>> denotations (or identifications) come from? > >> > >> The architecture is that each URI is owned. > > > > OK > > > >> With HTTP URIs, this happens through the domain name system and > >> often delegation within a domain. Unlike a word, a URI has an > >> owner. The owner attempts to make enough information available > >> that the URI can be used by others without ambiguity in practical > >> situation. > > > > Well now, several points. First, do owners in fact do this? I havnt > > seen a great deal of such information-providing going on, myself. > > But OK, fair enough: perhaps you mean, they SHOULD make such > > information available. But second, more seriously, HOW would they > > do this? Take your example: > > > >> For example, W3C owns http://www.w3.org/People/Berners-Lee/card#i > >> and has delegated to me the right to say what that URI stands for. > > > > OK. So, what DOES that URI stand for? How will you tell someone > > what the referent is that you intend it to denote, so that they > > know what to use it for? Now of course, you and I being smart human > > native English speakers who are reasonably tech-savvy can look at > > this and figure out that it is probably meant to refer to you. But > > really, that does depend on us being this smart and savvy. > > Well, I put it in the Tabulator and I get out (among other stuff): > > Tim Berners-Lee > Assistant Amy van der Hiel > HomePage http://www.w3.org/People/Berners-Lee/ > Work > Address > City Cambridge > Country USA > PostalCode 02139 > Street 32 Vassar Street > Street2 MIT CSAIL Room 32-G524 > Phone tel:+1-617-253-5702 > Latitude 42.361860 > Longitude -71.091840 > Organization expandfetchWorld Wide Web Consortium > > which to many people gives a fairly lear indication of what is > identified. And in fact for non-english speakers, there are words to > the effect that "Sir Tim Berners-Lee is geboren in Londen in 1955. > Hij wordt gezien als de bedenker en grondlegger van het World Wide > Web (WWW), dat was geïnspireerd door HyperCard. Hij werkte hierin > samen met de Belg Robert Cailliau. Als directeur van het World Wide > Web Consortium houdt hij toezicht op de ontwikkeling van webtalen en - > protocollen als HTML, XML, CSS en HTTP. Berners-Lee schreef ook de > eerste webbrowser, net als het web World Wide Web genaamd, en de > eerste webserver." and > Sir Timothy "Tim" John Berners-Lee, KBE (TimBL o TBL). Nacido el 8 de > junio de 1955 en Londres Inglaterra, se licenció en Física en 1976 en > el Queen's College de la Universidad de Oxford. Sus padres eran > matemáticos. Trabajando como investigador en el Laboratorio Europeo > de Física de Partículas (CERN) de Ginebra, concibió la idea de un > proyecto de hipertexto global, que años más tarde se convertiría en > la world wide web."" > > > > It isn't absolutely obvious: and there are many, many web pages out > > there which I really have no idea what their owners would say they > > denote. > > (Web pages? Web pages are documents. I wouldn't say they denote > things. Symbols, like URIs, denote. > The URI <http://www.w3.org/People/Berners-Lee/card#i> denotes me, and > the URI <http://www.w3.org/People/Berners-Lee/card> denotes the web > page: an RDF one, but a web page. That web page describes mainly me > but also to an extent other people and things.) > > > > >> To use it for something else is an error. > > > > But surely if you make this ruling then it is up to you to tell me > > enough about what it is supposed to be used for, so that I can know > > when Im making an error. HOW?? > > Well, do you want the human way of the machine way? > - The human way is that you are tempted to use it to represent my car > but you see the stuff above, and you realize that for example, > people would be concerned about the weight property and so on. > - The machine way could be for example that you operate with an OWL > system which include the belief that foaf:Person and dot:Car are > distinct classes, which will flag an error. > > > And what about a URI that I own and wish it to denote, say, the > > planet Venus, or my pet cat? What do I do, to attach the URI to my > > intended referent for it? > > > >>> > >>> In my opinion to denote (or to identify) is a verb, something > >>> that is done by the users of a symbol. After all, symbols (URI) > >>> are not agents, they don't wake up and choose to denote this or > >>> that. > >> > >> They have wonders which create them for a specific purpose. > > > > wonders/owners I presume. > > yes > > > > > But the key question to me is, how can they communicate the purpose > > to the reader? How does one publish an intention? How does one > > indicate a referent, other than by describing it? How much > > description is enough? > > Experience shows. This is engineering. > That question is I suppose one agonized over by working groups all > the time. > Fortunately, there are social systems not only for announcing that a > UTI has been minted and describing what it denotes, but also for > getting feedback from people who don't understand it, or whose > machines are not able to process it. This feedback can lead to an > adjustment of the information out there, publication of tutorials, > and so on. > > > > > > >>> Nor do I think denotation is an attribute or property of a > >>> symbol, somehow built in or attached when the symbol is first > >>> conceived. It is more like a dance. I use a symbol to denote > >>> something expecting you to interpret it to denote the same thing. > >>> And this coordination, this synchrony of interpretation by both > >>> sender and receiver, is not always easy. It requires real effort > >>> to sustain it. The minter of a URI cannot make it happen by > >>> declaration, nor can a research group or a standards body just > >>> decree it so. > >> > >> In many cases, the URI is defined by connection to already well- > >> defined sets of things. In other cases, such as the terms in the > >> OWL ontology, there was a huge amount of effort and discussion > >> involved, and the current term is supported by a lot of ongoing > >> tutorials and so on. No one said it was easy. But it is a > >> different architecture from dance associated with natural language > >> words. > > > > The huge effort was for defining the meanings of the OWL reserved > > vocabulary, and that is indeed about as defined as a vocabulary can > > get. But if we just take some OWL ontology and ask how well it > > constrains the meanings of the new URIs that occur in it, this is > > *very* much like the word dance that John refers to. In fact in all > > essentials it seems to me to be pretty much the same game. I > > publish (say) some stuff which I intend to mean something, you read > > (hear) it and get some insight into my meaning. You draw some > > conclusions and if you send (tell) them to me I can check to see if > > I agree and if not try to send (say) some more to you to make your > > grasp of my intentions more firm. > > Yes, of course the game happens. But for example when I download my > OFX bank statements, > then my computer processes them. Millions of people do this. Very > very few of them worry about who > did the dance, or do the dance themselves. Actually, some people > from banks, Microsoft and Inituit etc did the dance. This is the > "total cost of ontologies" argument. > > > > > > It HAS to be similar, barring machine telepathy. There really isn't > > anything that either people or machines can do much beyond send > > symbols to one another: and symbols carry meaning only imperfectly, > > with inherent ambiguity. > > Yes. In theory, there is always a very small possibility that I > completely misunderstand the way you use a word, say "car", and a > moderate probability that in some small very rare corner case we > haven't come across yet, we in pedantic mode would disagree about its > meaning. > > The extent to which I can behave, and build systems, as though in > fact the terms had well-defied meanings depends on the amount of > dancing which has been done. As the dance is done, the structures > in my brain and those in yours, while never identical, become very > similar, specifically in that they develop an very strong association > between a class of real-world object (car) or concept > (TransitiveProperty). > Philosophy studies the dance. (Philosophy has ion the past been > distracted by a concern that you can't measure the brain's structure, > and you can't measure an external TranstiveProperty object. The fact > htat philsophers have found this difficult doesn't stop the fact that > it happens, and now we have fMRI machines we are even relieving some > of this angst. But I digress) > > > The important thing is that as the dance is done, the probability of > major disagreement, and the degree of pedantic disagreement, > decrease very dramatically, to become negligible for engineering > purposes. > > > >> > >> It is different by design. The semantic web is an engineered > >> system, not an observation of nature. > > > > But it is a real system, and so it has to obey laws of nature. And > > there are laws of meaning as well as of physics. > > You bring up physics. Indeed. As an engineer, I design my coffee mug > to stay in one place: with no wheels. Does it? It is a real system, > and so it has to obey laws of nature. Physics tells as that at any > time, there is a finite possibility that any object might just be > measured to be in a different place, such as a foot to the right and > no longer around my coffee. In fact if I study the construction of a > coffee mug from particles, all kinds of questions arise, as the first > few particles are very difficult to manage. I can't even build a > tool which will tell me where the stupid electron is, without my > being completely unaware of its momentum. Given that I can't > actually claim to have put an electron and proton together with any > degree of accuracy, how can I claim to be able to build a mug which > will stay in one place. Well, it turns out that as the number of > particles becomes larger, these effects, while still true, just > become ignorable for engineering purposes. > > The analogy is limited, of course. > > >>> The reason this matters is that since it requires this effort to > >>> create a denotation/identification in the first place, it is far > >>> more sensible, to me at least, to expect that the final > >>> disambiguation of a symbol be accomplished in the same way, by > >>> coordinated effort of the parties using the symbol, not by > >>> declaration of the W3C specifications that all URIs be absolutely > >>> unambiguous. > >>> This seems to me to be, as my grandfather used to say, a vain task. > >> > >> Your grandfather would perhaps have suggested that an attempt to > >> define the meaning of common words, as the Académie Française is > >> set up to do were a 'vain task'. Many would agree. But given > >> that his water came to him though pipes connected, possibly, by > >> half-inch British Standard pipe-thread connections, and he rode on > >> rails set a certain distance apart by some committee, and his TV > >> came for better or worse in 525 or 625 lines as decided by other > >> committees, he may have respected that the creation of standards > >> is a very valuable function, and an essential to progress. > >> > >> When people meet to define W3C specifications they are not doing > >> it out of vanity. They are performing coordinated effort of the > >> parties who would like to be able to use the symbol. They are, in > >> general, users and representatives of users of the symbol. They > >> come together to allow those who follow them to use it. They often > >> work long hours, receiving inadequate recognition for either > >> products shipped or papers published, the conventional metrics of > >> performance, so I would not call it vanity. > > > > The point surely is that URIs used to refer (not as in HTTP, but as > > in OWL) do *not* have a standardized meaning. Standards are > > certainly a chore to create, but they only go so far. OWL defines > > the meanings of the OWL namespace, but it does not define the > > meanings of the FOAF vocabulary, or the URIrefs used in, say, > > ontologies published by the NIH or by JPL. > > Ah, so you accept that the OWL working group has effectively given > meanings to the the terms in the OWL namespace, but you don't think > that the FOAF friends gave meaning to the FOAF namespace, or the NCBI > to its ontologies? How curious. OWL does indeed only go so far. > FOAF and OFX and so on go bit further, but also only so far. They > all create new terms which, modulo arguments afterward an so on, > become with time an increasingly stable foundation for communication > between parties. > > > > The only way those meanings can be specified is by writing > > ontologies: and finite ontologies do not - cannot possibly - nail > > down referents *uniquely*. No amount of authority-delegating or > > standard-setting is going to change this basic fact. > > Fortunately, the trains continue to run, and bank statements continue > to generate graphs and tax forms, more and more people say they > foaf:knows each other, despite the fact that none of them or the > relationships have been defined really completely precisely to the > complete mutual understanding of all parties. > > This seems to me to be a very important bridge between philosophy of > microscopic linguistic interactions of agents, and the large scale > world of communities with common terms which are 'good enough for > government work'. I suppose I am surprised it isn't in the textbooks. > > Tim > > > Pat > > > > > > > > -- > > --------------------------------------------------------------------- > > IHMC (850)434 8903 or (650)494 3973 home > > 40 South Alcaniz St. (850)202 4416 office > > Pensacola (850)202 4440 fax > > FL 32502 (850)291 0667 cell > > phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes > > > -- http://dannyayers.com
Received on Wednesday, 13 June 2007 15:51:32 UTC