- From: Sandro Hawke <sandro@w3.org>
- Date: Thu, 10 Oct 2013 09:11:50 -0400
- To: Pat Hayes <phayes@ihmc.us>,David Booth <david@dbooth.org>
- CC: Antoine Zimmermann <antoine.zimmermann@emse.fr>,www-archive <www-archive@w3.org>,"Peter F. Patel-Schneider" <pfpschneider@gmail.com>,Ivan Herman <ivan@w3.org>
Pat Hayes <phayes@ihmc.us> wrote: >Hi David > >This is NOT an official WG response, but only an informal note to >explain some of the background thinking and discussions behind some of >the decisions we took. Please don't copy this to the public comments >list. I added Sandro to the CC list as he seems interested in this >stuff. > >The 2004 semantics document tried to do (at least) two things at once. >It is a formal, normative description of the semantics, but it also >tried to be a "tutorial" in various places, including in the section >you refer to and the extended glossary. This introductory material has >gotten some good reviews (thanks) but also has gotten some criticism, >especially with regard to its appropriateness for inclusion in a >normative standard document. And for sure, it made the document a lot >longer than it would have been without it, and the sheer length of the >RDF specs has come in for a lot of criticism. And for some readers, it >is an irritating distraction. > >Early in this WG, after some extended discussions, we decided that the >public interest would be better served by separating the >explanatory/tutorial/introductory material from the formal technical >normative material, and moving the former to a different document, a >kind of introduction/tutorial/primer document that is yet to be >written, and thereby making the normative technical document shorter >and crisper. This sacrifices readability for precision and exactness, >but there was a consensus in the WG that at this time in the evolution >of RDF, precision and exactness (and comparative brevity) were more >important than introductory exposition, in the actual normative >specification. This is why the material that you now miss, is missing. >(You may also notice that the RDF1.1 Concepts document is also much >shorter and brisker than the 2004 version, for the same reasons.) As I >say, the plan was (and still is) to move this all to a 'primer' >document rather than abandon it entirely, but this is why its not in >the actual semantics document. > >The short "intuitive summary" section on which you commented earlier >represented an editorial lapse on my part when drafting the new >document, where my old teaching instincts overwhelmed my responsibility >as WG editor. Your comment made me realize the error of my ways. > >Pat > +1 - Sandro >On Oct 9, 2013, at 10:16 PM, David Booth wrote: > >> Hi Pat (and others), >> >> I would not raise an objection to deleting the Intuitive Summary, but >I think there would be a loss to the public in deleting it. I also >really liked the explanation of interpretations that you included in >the 2004 version, and miss it in the current draft. It really gave >very good insight into the concept. So personally, I think a better >solution would be to add back your explanation of interpretations and >tweak the Intuitive Summary section as needed. >> >> You mentioned this concern: >> [[ >> Consider: >> >> "An RDF graph is true under a given interpretation exactly when: >> > >> > > >> > > 1. the IRIs and literals in subject or object position in the >> > > graph all refer to things, >> >> But suppose that they refer to things that are not in the universe of >the given interpretation, then this is false. >> ]] >> >> But AFAICT that is impossible, because "refer" is defined in sec. 4 >to be relative to an interpretation: > >In the above sentence, I was using the word "refer" in its normal >English usage, informally. But in any case, the point still stands: >they might be referring to things in the universe of a different >interpretation. > >> http://www.w3.org/TR/2013/WD-rdf11-mt-20130723/#notation >> [[ >> The words denotes and refers to are used interchangeably as synonyms >for the relationship between an IRI or literal and what it refers to >> **in a given interpretation** . . . . >> ]] >> (my emphasis). And the wording that I suggested makes clear what >interpretation is intended > >I don't accept that it does make this clear. > >> , so the IRIs and literals *cannot* refer to things outside of that >interpretation's universe. >> >> Also, I don't know what you mean when you wrote: >> [[ >> No doubt David would respond, but readers should be *obliged* to >think about interpretations, and then my reply would be, OK, but if so >then this section is inappropriate in the first place, so let us delete >this section. >> ]] >> >> Why would that section be inappropriate if readers are obliged to >think about interpretations? It seems to me to give a fairly concise >summary of the formal approach taken. >> >> Finally, at the risk of restating the potentially obvious, I do not >see how anyone could possibly understand the formal semantics without >understanding the idea of interpretations, since they are so central to >the semantics. > >The notions of reference (what a name refers to, or denotes) and truth >are pre-theoretic. They are part of our ordinary understanding of the >world. Interpretations simply formalize (if one can call such a simple >construct a 'formalization") this intuition so that one can do some >mathematics with it. The idea of this section was to use the ordinary >English words "refer" and "interpret" to re-state the truth conditions, >just to show how mind-numbingly obvious they are, and hopefully to >indicate how the formal machinery corresponds closely to the >pre-theoretic ideas. However, this purpose is undermined if this >section is understood formally rather than intuitively. > >But, as I say, I now think that this idea, of trying to connect the >formal notions to an intuition, was probably a mistake in this document >and went against the spirit of a WG decision. > >Pat > ><<Other in-line responses, below, are part of our continuing, um, >debate, and are aside from discussions of the RDF documents.>> > >> > On Oct 4, 2013, at 10:51 AM, Peter Patel-Schneider wrote: >> > >> > > In my opinion the divergence boils down to Pat believing that >this informative section should be more informal and David believing >that it has to be more formal. >> >> I don't exactly think it has to be more formal, but just that: (a) it >needs to mention interpretations, because that concept is so central to >the formal semantics; and (b) the statement about the conditions under >which a graph is true *needs* to be scoped to an interpretation to make >any sense at all. > >That is exactly what it should *not* be, in order to convey the point >it was intended to be conveying. > >> If one talks about a graph being true, without mentioning an >interpretation, IMO the most sensible way to understand such a >statement is to take it as meaning that the graph is *satisfiable* > >No, that is not the right way to understand it. Truth and >satisfiability are not the same thing at all. (That pigs can fly, is >satisfiable.) To say that a graph (or any other assertion or sentence) >is true, is to say that when it is interpreted *in the actual world*, >its truth-value is true. That is the pre-theoretic, intuitive, notion. >Someone says something, you figure out *what* they are saying, and you >judge whether it - what they are saying - is true. Nothing in that >account mentions interpretations. It does mention, implicitly, the >truth conditions (section 5) and we could say that it *presumes* an >interpretation that the speaker and hearer have in common. And that is >where the naivitée of this naive account is displayed, of course, that >implicit assumption of a common interpretation; because when we have >the kind of distancing between publisher and reader that is inevitable >on the semantic web, and communicate using IRIs which have no assumed >common background of linguistic meaning, we cannot presume this common >shared interpretation, this "common ground" >(http://semantics.uchicago.edu/kennedy/classes/f07/pragmatics/stalnaker02.pdf, >or http://plato.stanford.edu/entries/discourse-representation-theory/.) >So this is where the interpretation idea comes in, because we have to, >as it were, survey the possible things you might mean when you publish >some RDF. We don't know what world you are talking in, so we have to >consider all *possible* worlds. Which is what interpretations are (the >thin, pale shadows of formalizations of). > >Long - very long - story short, the analysis of real linguistic >communication - including Web communication - between cognitive agents >(people, mostly) involves model-theoretic ideas, but it also involves a >*lot* more. RDF, indeed the entire semantic web, is a tiny part of this >larger picture, and can be fitted into it in one small corner. But in >order to be useful, it does need to be fitted into it accurately. > >> : that there *exists* an interpretation under which the graph is >true, and hence we can take the graph as being true. (Conversely, if >the graph is not satisfiable then we cannot take it as being true.) >OTOH, such a statement could be taken to mean that the graph is true >**in some unspecified interpretation** > >The one that is presumed when we talk (pre-theoretically) about what >people are referring to when they say "Everest" (for example), and when >we make judgements of the truth or otherwise of their utterances in the >actual, real, world we are all talking about. Yes, exactly. > >> . But that would be a very bad way to write > >Try telling that to linguists. Or to literary theorists, or historians, >or philosophers of language, or indeed pretty much anyone who uses >language professionally. Not only is this not a bad way to write, its >the ONLY way to write if we are trying to anchor model theory in an >intuitive description of how communication actually happens. Except, >calling the actual world "unspecified" seems a little strange. > >> , because the interpretation under which the graph is true would be >an implicit unbound variable, which as we all know is a big no-no. > >It is implicit, yes, but I don't know what kind of assumptions you are >appealing to by calling this a big no-no. Contexts are usually >implicit, right? > >> Instead, the problem can be easily solved by adding "under a given >interpretation" to the sentence. (Of course, the notion of an >interpretation should first be explained. But that is a different >omission that should be addressed anyway.) >> >> And regarding this: >> http://lists.w3.org/Archives/Public/public-rdf-wg/2013Oct/0079.html >> [[ >> I know, from extensive off-line email discussions with David, that he >does not properly understand the intuitive foundations of semantics in >any case, so I am not inclined to accept his rather condescending >advice. >> ]] >> (Wow, you're calling *me* condescending, after repeatedly telling me >to "go read a book"???) That's both: (a) quite a projection; and (b) >*really* unfair and unhelpful. Fortunately I'm thick skinned and I >have a good sense of humor. :) > >Well, you weren't meant to read that, obviously. But my dear fellow, >*have* you read the books, in fact? Is it really condescending for me >to suggest that you might want to read up something a little more >extensive than a few paragraphs that I wrote about RDF, before claiming >that you have discovered a new way to understand model theory, or >setting out to correct my misunderstanding of it, or telling me that my >perspective is too limited? I don't mean to pull rank on you here, but >I have been studying this stuff now, as well as teaching it, for about >40 years. For a few years, I invented new model theories for a living. >God knows there are a lot of things I don't fully understand, but >model-theoretic semantics is one topic I really do have pretty >thoroughly grokked. > > >> >> Thanks, >> David >> >> -------- Original Message -------- >> Subject: Re: RDF Semantics - Intuitive summary needs to be scoped to >interpretations (ISSUE-149) >> Date: Wed, 09 Oct 2013 15:06:19 -0700 >> From: Peter F. Patel-Schneider <pfpschneider@gmail.com> >> To: David Booth <david@dbooth.org> >> CC: public-rdf-comments <public-rdf-comments@w3.org> >> >> Greetings David: >> >> This is an official RDF working group response to your message >> >http://lists.w3.org/Archives/Public/public-rdf-comments/2013Oct/0010.html >> on Section 5.2, Intuitive Summary, of the RDF 1.1 Semantics document. >> The Working Group thanks you for your concerns on this aspect of the >RDF >> recommendations, which have been tracked as ISSUE-149. >> >> Section 5.2 is an informative section and was only put in as an >short, >> easier-to-understand gloss of some of the the preceeding more-formal >> section. Both your comment and the ensuing discussion have made it >clear >> that the section is not achieving its purpose. As there appears to >be no >> consensus on what changes, if any, should be made to the section, it >is the >> intent of the working group to just remove the entire section. >> >> Could you please respond to public-rdf-comments@w3.org as to whether >> removing this non-normative, non-formal section would satisfactorily >address >> your concern? If you are satisfied, then the section will be removed >from >> the document. >> >> Peter F. Patel-Schneider >> for the W3C RDF WG >> >> >> On 10/01/2013 10:15 PM, David Booth wrote: >>> https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html >>> >>> Section 5.2 Intuitive summary needs to be scoped to a particular >>> interpretation or set of interpretations. At present the >interpretations >>> are implicit, and this is misleading because it suggests that the >notion of >>> a graph being true is somehow independent of an interpretation, >whereas in >>> fact the truth of a graph critically depends on the interpretations >that are >>> chosen. >>> >>> I suggest rewording the first sentence of this section from: "An RDF >graph >>> is true exactly when: . . . " to: "An RDF graph is true exactly when >there >>> exists an interpretation such >>> that: . . . " >>> >>> Also, the verb "interpret" is being used in this clause: "2. there >is some >>> way to interpret all the blank nodes in the graph as referring to >things,", >>> but that causes confusion with the notion of an interpretation >(which is a >>> function). It would be better to use a different verb at this >point. >>> >>> Also point 4 mentions "these interpretations", but it isn't clear >what >>> interpretations are meant. Perhaps it means the results of the verb >>> "interpret" in item 2? In which case, a different word should be >used here >>> also. >>> >>> Thanks, >>> David >>> >>> >> >> >> >> >> >> >> > >------------------------------------------------------------ >IHMC (850)434 8903 home >40 South Alcaniz St. (850)202 4416 office >Pensacola (850)202 4440 fax >FL 32502 (850)291 0667 mobile >(preferred) >phayes@ihmc.us http://www.ihmc.us/users/phayes -- Sent from my Android phone with K-9 Mail. Please excuse my brevity.
Received on Thursday, 10 October 2013 13:11:53 UTC