Re: discussion about meaning and senses

Dear Guido, all,

  I am not that sure we need a real distinction between *O*ntology and 
*o*ntology. I think that this distinction has been emphasized too much.

With the big *O* I refer to what you call an ontology in the 
philosophical sense as a theory of what exists in reality.

With a small *o* I refer to the formalization of the meanings of 
concepts in some logical theory with respect to some language (be it 
first-order, fuzzy logic, modal logic, OWL, DL, you name it).

Honestly, for me there is not much of a difference, for the following 
reasons:

1) There is  *O*ntology in every *o*ntology. When writing down a logical 
theory (*o*ntology), one has to think about what type of things exist in 
reality (*O*ntology) and decide how to model/represent their properties 
within some formal system. That means, there needs to be some 
conceptualization (in the sense of Guarino) as well as some ontological 
commitment of the logical theory.

2) There is also *O*ntology in any lexical resource. Every lexical 
resource makes choices with respect to the number, granularity etc. of 
meanings that a lexical entry is supped to have. These are *O*ntological 
choices essentially.

*o*ntologies and lexical resources differ in the formalism (language) 
they use to describe the meanings of symbols, i.e. some logical language 
vs. (say) natural language glosses or some atomic markers (in the line 
of preferential semantics).

An *o*ntology can be less or more axiomatized in the sense of reducing 
the possible models more or less. The more we axiomatize, the more we 
reduce the models. The more we axiomatize, the more a machine or 
computer will be able to infer or to verify whether symbols are used in 
the right way (i.e. according to their ontological commitment). The less 
we axiomatize, the more we rely on the intuition of people in using 
these symbols and the less we can check whether the symbols are used 
properly. This vagueness has clearly advantages in many respects, e.g. 
for the sake of interoperability where many people can (claim) to refer 
to the same vague concept ;-) This clearly undermines the idea of 
interoperability, i.e. we end up "agreeing on the fact that we agree on 
sth.".

Now clearly, which language and formalism is the best to represent the 
meaning of concepts (linguistic or non-linguistic, common sense or 
whatever) is a question that is clearly out of scope of this group and I 
will not make any statements about how to best express the concept of 
"baldness"  or any other concept for that matter. How many axioms and 
which type of axioms would be needed to represent the meaning of 
baldness  is also something that we should not be particularly concerned 
with. But I agree with you that the meaning of come concepts can be 
approximated in some logical language, while others are not formalized 
that easily (because they are inherently hard to define or because the 
logical language is not adequate).

Thus, for me there is not much of a difference between a concept, a 
category or a linguistic sense. In all cases we make fundamental 
*O*ntological choices about what exists and which meanings we wish to 
distinguish for some purpose. The crucial question is clearly how and to 
which extent and in which language we can specify and formalize the 
meaning of a symbol (or word for that matter), a question that is out of 
the scope of this working group.

For the sake of this group, I would propose that we assume that there 
are already resources that make basic *O*ntological choices, i.e. with 
respect to number and granularity of meanings as in any lexical resource 
or with respect to how many and which meaning distinctions are important 
for a certain domain/application (as done in any *o*ntology).

But before going on, I would like to understand a bit more what you mean 
with "pushing the sign upfront" and what you mean with a "native 
semiotic kind of modelling".

Apologies for the longer response. I hope that this all makes sense 
(Guido?).

And I welcome very much that we discuss these issues further. So thanks 
for your very valuable input Guido!

Regards,

Philipp.



Am 20.08.12 18:26, schrieb Guido Vetere:
> Philipp,
>
> thanks for your summary. Actually, there may be different visions on 
> fundamental aspects of our work; although we can get along with this 
> in a pragmatic way, I think that is worth discussing them a little bit 
> more, to see if we can get to an agreement, or at least to agree on 
> the nature of our disagreement :-)
>
> I think that we have to agree on the meaning of 'ontology', or at 
> least be aware of the polysemy of this term. Whereas philosophers have 
> mostly intended 'ontology' as a theory of what exists in the reality 
> (including 'socially constructed reality') independently of linguistic 
> habits, computer scientists, in general, use 'ontology' to refer to 
> any formalised conceptual schema, whether it contain common sense 
> notions (e.g. 'bald') or metaphysical ones (e.g. 'substance'). Of 
> course, in the latter sense, 'ontology' may be considered as a kind of 
> formal representation of linguistic meanings, hence there is obviously 
> a continuum from lexicons to ontologies.
>
> Sorting this continuum based on the 'degree of formalisation', may 
> help in the integration of different onto-lexicons, but it would be 
> quite difficult to find out a criterion to estimate the formality of 
> the representation of a linguistic sense. Pick up 'bald', for 
> instance. How many axioms would you need to formalise this concept? 
> Would a fuzzy logic provide a better formalisation than a typicality 
> logic? Who knows? From a 'normative' perspective, on the other hand, 
> we could tell people how to better organise their onto lexical content 
> on the Web. As you know, we experimented an approach where 'ontology' 
> is taken 'philosophically', hence the issue of distinguishing common 
> sense, linguistic (i.e. mostly vague) concepts from 'metaphysical' 
> categories is taken into account. This is achieved by implementing a 
> semiotic approach, i.e. pushing the 'sign' upfront, much in the line 
> of what Aldo says. Of course, I think that there are benefits in 
> adopting a 'native semiotic' kind of modelling, and we can discuss it, 
> but as a matter of facts most of the (so called) ontologies published 
> on the Web provide a mix of (what we consider as) categories, 
> linguistic senses, whatever.
>
> So, if the aim of this group is that of providing guidelines for 
> building new resources or restructuring existing ones, then we should 
> reach an agreement on whether there is a distinction between 
> ontological categories and linguistic senses. If, on the contrary, we 
> focus on integrating existing resources and practices, then we must 
> assume that such a distinction is just irrelevant. Which one is the case?
>
> Regards,
>
> Guido Vetere
> Manager, Center for Advanced Studies IBM Italia
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> Philipp Cimiano <cimiano@cit-ec.uni-bielefeld.de> wrote on 14/08/2012 
> 08:59:59:
>
> > Philipp Cimiano <cimiano@cit-ec.uni-bielefeld.de>
> > 14/08/2012 08:59
> >
> > To
> >
> > "public-ontolex@w3.org" <public-ontolex@w3.org>
> >
> > cc
> >
> > Subject
> >
> > Re: discussion about meaning and senses
> >
> > Dear Guido, Aldo, Piek
>
> > I have been following the discussion in silence so far as I have
> > been traveling and not found the time to summarize the current state
> > of the discussion.
> >
> > First of all, apologies for my misconception of what bald means ;-)
> >
> > But aisde from this misconception, my main point actually was that I
> > do not think that we need to strictly separate the ontological from
> > the 'ideal' or 'linguistic' meaning as Guido is advocating.
> > In fact, I like the point raised by Aldo that we could see lexicons
> > and ontologies not as opposites but rather as points along
> > a continuum where there can be more or less formalization (I hope I
> > got Aldo right, did I?)
> > So this means that meanings can be highly formalized or not
> > formalized at all. "Bald" would be a very vague concept along these
> > lines which would be possibly not axiomatized at all other than
> > saying sth. like $\forall x Bald(x) \rightarrow Human(x)$ which is
> > more or less
> > what in Senso Comune is expressed by the "characterizes Humans".
> > So I like the perspective that in principle we *can* formalize any
> > aspect of the meaning of words, but for pragmatic reasons we might
> > decide not to do it (because the effort is too high and it does not
> > pay off / the inferences we could draw and not particularly
> > interesting for applications, etc. or there is no agreement on how
> > to formalized). These are all pragmatic reasons, but no principled
> > ones again the formalization of the meaning of some lexical element.
>
> > So let me try to summarize the state of play of the discussion:
>
> > Guido (1): we clearly need senses as reified objects, reifying the
> > association between lexical entries and concepts.
> > This is necessary because we need to predicate over these
> > associations. For instance, many 'senses' come with specific
> > grammatical constraints, e.g. for nouns, plural is often used to
> > mean something different from a mere collection of individuals, as
> > in Italian 'acqua' (water) and 'acque' (thermal treatments).
> > => I fully agree with this and in fact such a reification is at the
> > core of our lemon model for the same reasons as mentioned by Guido.
>
> > Guido (2): Linguistic and ontological meanings should be clearly
> > distinguished. In Senso Comune 'meanings' are regarded in most cases
> > as vague and idealized meanings that are not properly formalized, so
> > that interpretation is subjective and can vary depending on the 
> context.
> > => I would not agree with this point and rather adhere to the
> > continuum views that Aldo has been putting forth.
> > The consequence of such a view is that there is in principle no
> > problem with what Aldo has called "the direct mapping" approach that
> > I was advocating.
>
> > Aldo (1): we should see lexicons and ontologies rather as a
> > continuum than as an opposition. If possible, and for the sake of
> > semantic interoperability and reasonability, concepts should be
> > axiomatized as far as possible, but if for pragmatic reasons such as
> > formalization is not provided, then a semi-formal definition as
> > provided in a lexicon (e.g. through a gloss or lexical
> > relationships) is better than nothing. In the long-term, such
> > "informal" meanings might be incorporated into the ontology by
> > axiomatizing them appropriately.
> > => I share this view.
>
> > Piek (1): was posing the question of whether there is any
> > fundamental line between what should be formalized and what not.
> > Clearly, I do not have a definite answer to this, but all those
> > lexical and linguistic properties that Piek mentions (morphology,
> > pronunciation, lexical relations) etc. should be definitely
> > modelled/represented at the lexical side (e.g. in OWL, which does
> > not mean that they are axiomatized along the lines of the argument
> > above). In this sense I do indeed advocate the two modular layers: a
> > lexical and a semantic/ontological one. Of course, the crucial
> > question is whether we have to model the semantic implications of
> > certain linguistic properties/distinctions. Take the word "dog" and
> > its plural "dogs". Clearly, they have different semantics, as "dog"
> > is used to refer to one element in the set of dogs, while "dogs" is
> > used to refer to a set of at least two elements in the set of dogs.
> > However, this is purely linguistic knowledge that is "systematic" in
> > the sense that it holds for all nouns. As such, it is questionable
> > whether this should be modelled in the lexicon-ontology interface.
> > But I agree that the interesting question is which aspects of the
> > meaning of lexical entries that touch the actual interface should be
> > formalized and how (one example is register).
>
> > By the way: both layers can support reasoning, but in a different
> > domain. In one layer, we reason about linguistic properties, while
> > in the ontological layer we would reason about (domain) concepts.
> >
> > So there are certain properties in the list of Piek that are purely
> > linguistic and do not touch the meaning layer at all (e.g
> > morphology, pronunciation, etc). while there are others that
> > modulate the meaning. The latter ones are the ones we should take
> > about in more detail.
> > In any case, I think it would be worth going through the bullet list
> > of Piek in our next telco to reach some consensus there.
>
> > Just my two cents for now.
> >
> > Best regards,
> > Philipp.
> > --
> > Prof. Dr. Philipp Cimiano
> > Semantic Computing Group
> > Excellence Cluster - Cognitive Interaction Technology (CITEC)
> > University of Bielefeld
> >
> > Phone: +49 521 106 12249
> > Fax: +49 521 106 12412
> > Mail: cimiano@cit-ec.uni-bielefeld.de
> >
> > Room H-127
> > Morgenbreede 39
> > 33615 Bielefeld
>
>
>
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-- 
Prof. Dr. Philipp Cimiano
Semantic Computing Group
Excellence Cluster - Cognitive Interaction Technology (CITEC)
University of Bielefeld

Phone: +49 521 106 12249
Fax: +49 521 106 12412
Mail: cimiano@cit-ec.uni-bielefeld.de

Room H-127
Morgenbreede 39
33615 Bielefeld