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