- From: pat hayes <phayes@ai.uwf.edu>
- Date: Tue, 15 May 2001 17:52:17 -0500
- To: "Seth Russell" <seth@robustai.net>
- Cc: www-rdf-logic@w3.org, ora.lassila@research.nokia.com, swick@w3.org
>From: "pat hayes" <phayes@ai.uwf.edu> > > > First, note that quoting provides a character string, and reification > > in general provides at most a description of syntactic form, so such > > 'attribution' examples need to be taken with a pinch of salt. There > > is a world of difference between "X says 'statement Y'" and "X says > > that Y". Notice in the second case that the Y is NOT quoted; it is > > being used (to refer to its content), not mentioned. Reification does > > not provide access to content, only form. > >Apparently you are not using the word 'reification' in the same sense that >it is applied to the example below in the RDF specification; see [1]. > > Ralph Swick says that Ora Lassila is the creator > of the resource http://www.w3.org/Home/Lassila. > >[1] http://www.w3.org/TR/REC-rdf-syntax/#higherorder > No, I believe I am using it in that sense. The reference you cite says the following: -------------- For example, let us consider the sentence Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila. RDF would regard this sentence as a fact. If, instead, we write the sentence Ralph Swick says that Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila. we have said nothing about the resource http://www.w3.org/Home/Lassila; instead, we have expressed a fact about a statement Ralph has made. In order to express this fact to RDF, we have to model the original statement as a resource with four properties. This process is formally called reification in the Knowledge Representation community. A model of a statement is called a reified statement. ------------- Notice that this says that reification is used in the sense it is used in KRep, that a reified statement is a "model of" a statement, which I take it means that it refers to that other statement; and that the second fact is "about" the original statement. All of this is exactly what I mean by reification also. However, I think that the authors have used a slightly misleading example. Notice that if the second sentence is taken literally, what they say about it is not quite true. If understood in the most direct way, it *does* say something about the resource http://www.w3.org/Home/Lassila; it says, in fact, that Ralph Swick says that Ora Lassila is the creator of it. The fact that the authors claim that it says *nothing* about the resource suggests that they are understanding this sentence to mean something like a direct quotation, ie to mean something like: Ralph Swick uttered these words: "Ora Lassila is.....". Then, indeed, everything they say about the second sentence would be correct: it would say nothing about the resource, and it would be correctly modelled by reification. So, I am inclined to be charitable and assume that that this what they meant, even though it is not what they said. They were not writing a philosophical tract, after all. Pat Hayes --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Tuesday, 15 May 2001 18:52:19 UTC