Dear Conal, All,
Your arguments well taken, we are still obliged in formal ontologies to
have explicit semantics.
The use described by Robert, which fulfills a real need, appears here as
"emergent semantics"
from the community, which deviates fromthe W3C definition. I argue that
this can be formulated in quite
precise terms, similar to what Robert formulated, and then there will be
not need to talk about a lack of semantics.
I'd like to settle that until the end of the next meeting.
Let us distinguish
a) "values" which are points or areas in abstract mathematical spaces, from
b) symbolic objects in the form of linear sequences of
machine-encodeable symbols
c) things that cannot exist in a digital form.
For c) no "value" can be given. We have the classical Pierce's referent
and referree situation.
For those guys we use names, in particular identifiers.
Only objects of the form b) can reside on machines, if they have the
storage capacity. So, from all things
a formal ontology talks about, only for those we think of not only
talking about them in machines, but also
putting them into machines.
Then the question is: Is the identity-providing content in a Literal in
my database, in a digital file, or on a paper document?
For a) , only subsets in finite machine encodeable form can reside in
machines. In that case, the encoded form is not the a) guy itself, but a
guy of type b), which is interpreted not as a type b), but a type a) guy.
Names in particular, if their identity is given as DEFINED as a linear
sequences of machine-encodeable symbols, are type b) guys, but that does
not imply the type c) guy they may identify or not.
Therefore, if we distinguish the 3 cases, we can have perfect semantics,
and then talk about how to encode the cases.
Nothing mysterious, but we must understand the above distinctions, which
are not within a logical space, but between logical spaces and the world
around.
I hope this makes things clearer!
Comments welcome.
Best,
Martin
On 3/14/2018 12:01 PM, Conal Tuohy wrote:
On 9 March 2018 at 04:39, Martin Doerr <mar...@ics.forth.gr
<mailto:mar...@ics.forth.gr>> wrote:
I recommend NOT to recommend rdf:value, because RDFS 1.1 defines:
"5.4.3 rdf:value rdf:value is an instance of rdf:Property
<https://www.w3.org/TR/rdf-schema/#ch_property> that may be used
in describing structured values. rdf:value has no meaning on its
own. "
As CRM-SIG, we cannot recommend a property without meaning. We do
ontology here, so the must be a minimal ontological commitment.
Are there other opinions?
My opinion is that the real value of rdf:value is that it effectively
negates one of the weaknesses in the expressiveness of RDF, with
respect to the CRM.
In RDF, a literal value is a second-class citizen: it has no
identifier, which makes it ineligible to appear as the subject of a
triple, so it can't have properties of its own. It can't be woven into
the "Web of Data". It can't effectively function as an "access point"
(in the library science sense) without some additional context.
As Linked Data practitioners, we generally have literals like "Conal
Tuohy" as our source data for e.g. Appellations (and it's worth noting
that all of the formal examples of E41 Appellation are given as string
literals), but it's highly undesirable to encode an E41 Appellation
merely as a literal; such an encoding would make it impossible, either
for us, or for third parties, to annotate that name with properties of
its own ("A name of Irish origin ...").
So we must mint an identifier, either a local ("blank node")
identifier -- or better still, an HTTP URI -- for that name (e.g.
"_conal_tuohy"), so that we can then attach other properties to that
identifier. We are left, finally, with the residual problem of how to
associate the literal name value itself ("Conal Tuohy") with that
identifier. This is where rdf:value plays a valuable role of
effectively just equating the literal with identifier; it is described
as having "no meaning on its own" precisely because it really plays
only a syntactical role. This is why I think it would be a mistake to
critique the use of rdf:value on the basis of it "lacking meaning of
its own"; it would be equivalent to criticising a relational database
for having an Appellation table with a column named "value".
Regards
"Conal Tuohy"
Taken the above definition in RDFS 1.1, I question both, the
precise use and the emerging good practice,
until better evidence:-).
Do you have better evidence?
It is up to crm-sig to decide, I present only my opinion here.
Best,
martin
On 3/8/2018 6:28 PM, Robert Sanderson wrote:
Martin,
Could you clarify why you have changed your mind about rdf:value?
> I recommend NOT to recommend rdf:value
In particular, in the last week you said:
“CRM-SIG normally works reactively: When a good community
practice emerges, this is taken up.”
and
“Whatever the vast majority is and rdf:value does the job, I
have no objections to its use.
Just define precisely what you use it for. We can add that to our
guidelines. It is already standard rdf.”
Thanks,
Rob
--
--------------------------------------------------------------
Dr. Martin Doerr | Vox:+30(2810)391625 |
Research Director | Fax:+30(2810)391638 |
| Email:mar...@ics.forth.gr
<mailto:mar...@ics.forth.gr> |
|
Center for Cultural Informatics |
Information Systems Laboratory |
Institute of Computer Science |
Foundation for Research and Technology - Hellas (FORTH) |
|
N.Plastira 100, Vassilika Vouton, |
GR70013 Heraklion,Crete,Greece |
|
Web-site:http://www.ics.forth.gr/isl |
--------------------------------------------------------------
_______________________________________________
Crm-sig mailing list
Crm-sig@ics.forth.gr <mailto:Crm-sig@ics.forth.gr>
http://lists.ics.forth.gr/mailman/listinfo/crm-sig
<http://lists.ics.forth.gr/mailman/listinfo/crm-sig>
--
Conal Tuohy
http://conaltuohy.com/
@conal_tuohy
+61-466-324297
--
--------------------------------------------------------------
Dr. Martin Doerr | Vox:+30(2810)391625 |
Research Director | Fax:+30(2810)391638 |
| Email: mar...@ics.forth.gr |
|
Center for Cultural Informatics |
Information Systems Laboratory |
Institute of Computer Science |
Foundation for Research and Technology - Hellas (FORTH) |
|
N.Plastira 100, Vassilika Vouton, |
GR70013 Heraklion,Crete,Greece |
|
Web-site: http://www.ics.forth.gr/isl |
--------------------------------------------------------------
