[Person-ontology] Methodology using an upper ontology

[Pat Hayes]

>All,
>
>It was posted (not sure by who):
>
>	"Construct an ontology. It almost does not matter exactly where
>you
>	start, but either the very top (most general) or the very bottom
>	(data) is not usually a good place."

Me (Pat Hayes). Though the advice comes originally from Doug Lenat.

>Question: Why not use an existing upper ontology?

Well, question back: Why use it? What would it be useful for? Here we 
are, say, trying to formalize a mid-level concept, say 'ocean wave' 
(Im making this up), using BOF, say. BOF requires us to classify 
ocean wave 'properly'. In particular, we must decide whether or not 
it is a continuant. Well, is it or isn't it? Do you know? I don't. 
Moreover, I don't CARE. Nothing turns on this decision other than 
making BOF happy. THe high-level upper ontology is just getting in 
the damn way, forcing me to make decisions I don't care about, are 
irrelevant to my concerns and that have no obvious answer. Suppose, 
moreover, I toss a coin and decide that my wave is indeed a 
continuant. Is this any help? No: all it does is make it harder for 
me to say some natural things (since continuants aren't allowed to 
have temporal parts).

Suppose instead I am using DOLCE and formalizing, say, the W3C TAG 
notion of a 'web resource', and I decide that a web resource is kind 
of like a 'place' where some information can be stored. So I look in 
DOLCE and I find a high-level notion of 'region'. The only way to 
decide whether or not I can put my notion under this heading is to go 
into the actual axioms of DOLCE (which is a bit like taking a bath in 
nitric acid, by the way) and see what it actually says about 
'regions', paying attention to detail and asking 'does this axiom 
apply to my idea'? And this is just writing axioms, only way slower.

>  Wouldn't it provide a
>good-enough top-down structure?  Wouldn't it also provide many (maybe
>half) of the needed concepts?

No, it almost certainly would not provide any of them in the form I 
am likely to need them, since the people who built it the upper 
ontology, no matter how smart or well-meaning they were, weren't 
thinking about the issues that arise at my level of detail: so 
whatever they put into the UO, its very unlikely to be anything more 
than a provisional sketch or draft of what I am going to need. 
Mereologists often take it as obvious that partOf is transitive, 
because they are thinking about lumps of clay: but if I'm making an 
ontology for a parts catalog, parthood isn't transitive. So for me, 
all that the UO has done is stolen the term 'part' and forced me to 
use a different term for my concept. Im going to have to write my own 
axioms for it anyway.

Upper ontologies, by and large, are no actual use to practical 
ontologizing at all. They warp intuitions and interfere with the 
process, like an exasperating micro-manager. They add nothing 
computationally useful, since almost nothing useful can be said at a 
very high level. They usually embody some a priori philosophical 
perspective which likely has no relevance to the actual topic under 
discussion. Whoever wrote them wasn't thinking about the topic, for 
sure.

>Of course, in parallel, gather
>requirements and work from the bottom up.

The danger is that these two parallel tracks might not actually meet 
anywhere. And the worse danger is that when this happens, the 
top-down track is usually treated as authoritative, since to change 
an entrenched 'upper' ontology is seen as harmful to interoperation. 
So we end up with a situation where the entire shape of the whole 
ontology has been formed by people who don't know squat about the 
actual subject-matter: kind of a pre-emptive Peter Principle at work.

Pat

>
>Jim Schoening
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>Person-ontology at idcommons.net
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