Orð og tunga - 01.06.2012, Síða 16

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Orð og tunga
English for a male horse which covers both castrated and uncastrated
varieties. WordNet sometimes fills this gap with multiword expres-
sions: in this case, the hypernym for stallion and gelding is given as
male horse, and it is male horse which is the co-hyponym of mare. At the
top of the hierarchy, are a number of abstract terms which root the
tree: so the top of the hierarchy for mare is not in fact animal but entity
(entity is in fact at the root of all noun hyponymy hierarchies).
animal
mammal reptile
pig horse
mare stallion
Figure 1. A (pnrtial) hyponymy hierarchy
Such hierarchies are therefore lexical ontologies, i.e. classifications of
the kinds of things that can be referred to in the language. Lexical on-
tologies must therefore confront the tension between scientific ontol-
ogies and folk ontologies, i.e. between the classification established as
objective by the natural sciences and the classification established by
popular usage and belief. A wordnet is often a compromise between
these two and not always a consistent one. So, for instance, WordNet
conforms to the scientific ontology for whale: it is given as a hyponym
of mammal and is glossed as "any of the larger cetacean mammals
having a streamlined body and breathing through a blowhole on the
head". However, tomato is given as a hyponym of vcgetable despite
biologically being a fruit; nevertheless the gloss acknowledges the sci-
entific classification and hints at the reason for the vegetable-classifica-
tion: "mildly acid red or yellow pulpy fruit eaten as a vegetable", i.e.
the hyponym relation is assigned on the basis of the use that is rnade
of the entity, rather than its biological status - this is a functional hy-
ponym not a nature-kind hyponym. It is important to stress here the
difference between WordNet and a traditional dictionary: the main
semantic information is the lexical semantic relation (hyponymy) and
not the gloss; a computer using WordNet to build a semantic repre-
sentation will treat tomato as a vegetable.