Re: [ontolog-forum] Ontologies and individuals

[Nicola Guarino <guarino@xxxxxxxxxxxxxxx>]

Folks,

the point is not so much whether ontologies "contain" individuals, but whether they should include *facts* concerning specific individuals.

Of course ontologies are about individuals, in the sense that they tipically describe kinds of individuals, and the relationships among them. Such relationships are general facts which concern individuals, but usually not specific individuals.

Sometimes an ontology can include facts concerning a specific individual, but (here is the point) 

***only if such facts are intended to hold NECESSARILY in the underlying conceptualization ***

So, statements like "The United States are a country" or "The United States have a president" may perfectly go, say, in a eGov ontology. On the contrary, a statement like "The present president of United States is Barack Obama", should not go in an ontology (the Tbox), it rather goes to the Abox, simply because it doesn't hold necessarily.

Unfortunately current OWL theories often mix Tbox and Abox into something still called "ontology", but this is their problem ;-)

Nicola

On 11 Dec 2012, at 14:19, William Frank <williamf.frank@xxxxxxxxx> wrote:

On Tue, Dec 11, 2012 at 3:46 AM, Alex Shkotin <alex.shkotin@xxxxxxxxx> wrote:

William,

we need some physical actions (mostly algorithmic) to find a thing and to measure some properties of it (size, a form of surface...). As a result we get some simple ontological sentences (we call them factology, just for fun). And we put this sentences into domain ontology to get more about this particular individual. One of a derivation may be: yes, we have known this thing before. This is an identification.

About individuals. We have some 100 000 rock samples around the world collected by field geologists. Some of these samples are from the Moon. All of them are very important individuals of petrography ontology.

Great. Here you have supplied a great example of the absolute need for individual in a domain ontology in a big way.   The samples might also be serving as representative individuals, from which generalizations might be made.
 

By the way if we look inside Big Data, it is mostly facts about huge number of individuals;-)

Alex

2012/12/11 William Frank <williamf.frank@xxxxxxxxx>

On Mon, Dec 10, 2012 at 11:48 AM, Sandro Rama Fiorini <srfiorini@xxxxxxxxxxxx> wrote:

Hello all!

There is a question we have been discussing in our group for a long time, and we would be glad to have your opinions on it: Can ontologies really contain individuals?

I think that this question requires alot of precision, in order to usefully consider it. 

First of all, when somebody says

'really'

there is a suspicion that there is a philosophical axe in the background.  What is the supposed difference between

Can ontologies REALLY contain individuals?

        and

Can ontologies contain individuals?

?

I have always been bothered by that word, 'really'.  I was once told 'positions are not 'really' objects!'  (because the represent a relationships between an account and a financial instrument.)


Second,  

Ontologies

They 'contain' individuals of only a few kinds:  at least three kinds of individuals
  1. Structuring Rules
2.  The entries in the ontology that refer to things that exist outside the ontology (which may include   Identifiers, names, Definitions, etc. accordingto the structuring rules.)
  3.  Assertions about Relationships between entries

So,
I would phrase the question as:

can one of the categories of entry be an entry for an individual,

And, I would say this is one of the structuring rules for the ontology.
 

We know that many of the ontology representation languages provide constructs to represent individuals. However, an ontology is a theory about a conceptualization, which in turn could be loosely seen as a structure of generalizations about a given domain.

 

Generalizations usually refer to concepts; not to individuals.

 I would think that almost by definition, a 'generalization' is something that generalizes from a set of individuals.  So, I agree with Alex. OTOH, most of the entries in an ontology will be entries about classifiers of some kind, not individuals.

 

Thus, one might ask how a conceptualization can have individuals that could be specified.  

I think that individuals are generally **not** 'specified', but rather identified, often with some kind of locatability.  For example, Frege, "On Sense and Reference".  This is the real problem:  Individuals are identified by a set of features that let you know whether different experienced phenomina are experiences of the 'same' individual or a different one.  For physical things,  these features may include spatio-temporal contiguity.   We do not usually require continous movement through space time to determine whether a thing is of a certain 'kind'.  

Specifications can be tied to a temporal, spacial location, like a description of the Golden Gate Bridge, or, if the individual is abstract, such as the poem 'My Last Duchess'. the specification, by definition, has only one instance, and is not even distict from its one instance.
 

On the other hand, we also acknowledge the fact that including individuals in ontologies might be necessary in some cases, such as when a concept is defined in relation to specific particular (e.g. "Former US President", "Red Car"). 

 

Furthermore, there are some authors actually questioning this sharp distinction between universals and particulars (there some papers about this in FOIS 2010, I guess).

I think starting with Aristotle, Categories, through say Davidson Essays on Actions and Events, and many others who deal with individuals and concepts both, and try to show how they are related and continuous, and Hillary Putnam, 'Ethics Without Ontology' as well as those who focus one of the two,for example, Quine, "On what there Is" on the side of individual things, along with all 'nominalists' to Plato and  the OMG, who seem to think individuals are second class citizens, and other 'realists' who treat the concepts as the really real.

OTOH, many on this forum have pointed out that all this philosophical 'debate' should be avoided.   However, I personally think that there is an implicit, entirely pragmatic,  ordinary language ontology, sort of anti-philosophical ontology built into our practice.  And, in that world, there are obviously important individuals, and characterizations of types of individuals, and clubs that contain of individuals, which are themselves individuals, etc.   And, since all of these things exist, they are themselves individuals, for example, each individual type,  which has an identity as an individual, as well as applying to many other individuals.   The practical questions are things like: how to identify individuals, apart from a characterization of a type that just happens to have only one instance. 

 

Any thoughts on that?

Regards,
Sandro Rama Fiorini
inf.ufrgs.br/bdi

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