Hi George,
On 5/8/2023 5:34 PM, George Bruseker wrote:
Hi Rob and Martin,
But the point is not to make assertions about the property class
itself but the instance of the property class.
of course😁
The instance of PC14 says Bob was the creator, Bob was a faker... it
is a regular abox assertion. And it has an identifier, necessarily.
The instances of PC classes are all already abox statements. They have
just been modelled in an odd way where we don't account for their
ontological substance. Being in a role is an ontological substance to
define.
Yes, we have discussed that in the past and in the OntoWeb project.
There are 3 kinds of roles. This is the "incidental role". There was a
classical paper about that. I'll search for it. Another role is the
life-long role. A third one is the "persona" or "office" role.
The point I made is the difference between ontological substance of
individuals versus that of relations, and the epistemic substance of
arguing about the world from a bird's perspective. I did not question
the substance of roles, but their nature as "entities" or "individuals"
in the narrower sense.
For me it is a big problem if there are statements in the CRM that can
be made (Bob was the builder) but can't be discussed. The abox
statement Bob was the builder is definitely in the domain of discourse
and for that reason should necessarily as a matter of principle be
referenceable.
I do not get the point. All statements, property instances, are
referenceable, by reification, Named Graphs, A13. Bob being in the role
of builder for that Activity can be formalized as specialication of the
P14 carried out by. What problem do you try to solve?
Otherwise, CRMbase cannot state the provenance for a piece of
knowledge like Da Vinci had the role of painter of Mona Lisa. It
becomes impossible. The abox information is in the PC14 instance.
Why not? Provenance of knowledge is an epistemic layer on top of any KB.
We have written in the introduction detailed explanations about that.
Reification
Yes we can use the partitioning pattern which is fine, but it remains
a question of technically what to do about PC classes and it seems
only half baked if they aren't instances of E1. They fit the
definition of instances of E1, "This class comprises all things in the
universe of discourse of the CIDOC Conceptual Reference Model." Being
in the role of the painter of Mona Lisa is, for me, a thing in the
universe of discourse of the CIDOC Conceptual Reference Model.
Well, then we have to refine the term "thing". Clearly, E1 is used
exclusively for individual entities. We did not model so far a "CRM
relation", in order to avoid that people instantiate an unqualified
relation.
Logically, I do not get the point why making PC classes instances of E1
does solve a problem, which reification, Named Graphs and E13 already
do? I mean, should we make an example? Could you be more specific why
the latter 3 mechanisms do not work for any CRM property and .1 property?😁
Best,
Martin
The main thing is this is a technical extension to a technical
extension to make things work and isn't a real ontological question to
my mind.
If we wanted to do the ontological discussions we would have to open
up the modelling box of worms, which is definitely another issue. I,
for example, would like to be able to talk about the timespan of the
property of something being part of something... but that's a broader
issue :)
G
On Mon, May 8, 2023 at 5:21 PM Robert Sanderson via Crm-sig
<crm-sig@ics.forth.gr> wrote:
Perhaps for the first time, I agree with Martin and not George!
The PC classes are part of the ontological layer -- we don't say
that classes or properties are descendants of E1. Or PC classes
are T box (terminology) and not A box (assertions using that
terminology).
(See - https://en.wikipedia.org/wiki/Abox)
I can see, however, that it would be useful to be able to refer to
assertions in CRMInf and perhaps in Activity templates ... but
then those assertions _are_ A box - the are the subject of the
discourse, not the language in which the discourse is taking
place. We have Attribute Assignment to talk about important
activities that assert relationships or properties. And if we
don't want to go to that layer of A box layer reification, then we
have the partitioning pattern -- to assert a role of a particular
individual in an activity, we can identify the part of that
activity that the person carried out and assert a role
classification on it via P2_has_type.
Rob
On Mon, May 8, 2023 at 9:44 AM Martin Doerr via Crm-sig
<crm-sig@ics.forth.gr> wrote:
Dear All,
I don't think it is correct to make the PC classes entities.
Even though formally an RDF class could be regarded as an
entity, ontologically we distinguish entities and
relationships. The E-R paradigm makes this distinction also
formally clear. We model the properties with .1 properties in
FOL as n-ary relationships, and not as individuals.
Making the PC classes CRM Entities is inconsistent with the
FOL definition, which is the proper formalization.
In other words, we would make a workaround for a missing
feature in RDFS an ontological argument. We are again in the
discussion to take RDFS as the definition of the CRM, and not
as an implementation.
As a first step, we could introduce an "E0 CRM Relation",
which would have as instances all properties and the PC
classes. The ontological distinction between relations and
entities is fundamental to the methodology of ontological
analysis.
As a second step, we can start to investigate to which degree
PC classes qualify as ontological individuals in their own
right. If we start declaring a priori all PC classes as
entities, we have later to justify and remove all those that
are relations in the true sense. For instance, I cannot
imagine the "being part of" a Physical Object for some time to
become an entity, because it needs a timespan.
Best,
Martin
On 5/8/2023 12:54 PM, George Bruseker via Crm-sig wrote:
Hi all,
I would argue that the safest thing to do is to make the PCs
a subclass of E1 and then see where we go from there. I agree
with Martin that it can't be an information object (because
everything would be then) but I imagine we would have a
debate about what each .1 actually ontologically is. What is
certain is that by virtue of the fact of being something said
in the universe of CIDOC CRM it is something sayable /
mentionable. This is what E1 gives us, the most vague point
of an object that can be pointed to and named, possibly
classified. The problem is right now that we have something
that is sayable in CIDOC CRM (PCxxx) but it is not
referenceable. But this is a logical contradiction.
Everything that can be said can be referenced and PCxxx can
definitely be said.
For example, if I say that Bob was involved in the Production
of Mona Lisa as Creator then this is something said / stated
that is important, that has a real world referent, which has
a definite meaning which is true or false etc. Ergo, it
requires provenance. The basic mechanism for provenance in
CRMbase is E13 and indicates that there was an agency behind
something being asserted of something else.
Here the thing we want to talk about is the role and the role
IS an instance of PC14. It's already an instance of a class
so it should be referenceable. (Also one might like to put a
bibliography for people who thought that Bob was Creator of
Mona Lisa etc.)
So I would go exactly for Paulos' modelling but with this change:
:painting_sistine_chapel
crm:P01i_is_domain_of
:role_of_michaelangeo_in_sistene_chapel_project
:role_of_michaelangeo_in_sistene_chapel_project
a crm:PC14_carried_out_by ;
crm:P02_has_range :Michelangelo ;
crm:P14.1_in_the_role_of :master_craftsman .
:attrAssign1
a crm:E13_Attribute_Assignment ;
crm:P140_assigned_attribute_to
:role_of_michaelangeo_in_sistene_chapel_project
... ... ...
On Mon, May 8, 2023 at 10:42 AM athinak
<athi...@ics.forth.gr> wrote:
Dear George, all,
I am not sure that the class PC0_Typed_CRM_Property
should be a
subclass of E1. In my understanding, this class implies a
situation
concluded in an epistemological context. I am also not
sure if the
provenance we are looking for in this set of statements
is a kind of
E13. I am just wondering.
BRs,
Athina
On 2023-03-29 16:36, George Bruseker via Crm-sig wrote:
> Dear all,
>
> When using the PC classes modelling structure we end up
with a class
> node for a property which we can then modify with
things like 'kinds'
> and 'modes' etc.
>
> Since such a statement has meaning and comes from
somewhere [e.g.:
> that someone did something in some capacity (PC14
carried out by ...
> P02 has range E39 + P14.1 in the role of E55)] one
sometimes needs to
> provenance this statement with an E13 attribute
assignment. Ie we want
> to ground who made this claim.
>
> In theory this would be done with E13 pointing to the
node in the
> typical fashion (p141, P140). However, the class
> PC0_Typed_CRM_Property is not declared as a subtype of
E1 CRM Entity
> in the PC extension file. As a result we cannot do this.
>
> https://cidoc-crm.org/rdfs/7.1.1/CIDOC_CRM_v7.1.1_PC.rdfs
>
> I would argue PC0_Typed_CRM_Property should be declared
a subclass of
> E1_CRM_Entity. Then it would be consistent with the
rest of the
> modelling.
>
> Opinions?
>
> Best,
>
> George
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------------------------------------
Dr. Martin Doerr
Honorary Head of the
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
Vox:+30(2810)391625
Email:mar...@ics.forth.gr
Web-site:http://www.ics.forth.gr/isl
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