vdoc.pub_an-introduction-to-cognitive-linguistics

PROTOTYPES AND CATEGORIES 25
parrot
ostrich
A tropical bird with a curved beak and brightly coloured
feathers that can be taught to copy human speech.
(LDOCE4)
An ostrich is a large African bird that cannot fly. It has long
legs, a long neck, a small head and large soft feathers.
(COBUILD)
In terms of categorization, these dictionary definitions yield two types of information.
To start with, they supply the name of the category to which the
robin, the parrot and the ostrich belong (in this case BIRD). This category name
in turn suggests the properties which are shared by most birds: that they have
feathers, two legs, two wings and a beak, and that they lay eggs. The main
body of the dictionary entries lists properties which are specific to the item
in question. Thus the robin is characterized by small size, brownish colour
and red breast-feathers. These properties clearly set the robin apart from other
members of the category BIRD, such as parrots and ostriches. So robins, parrots
and ostriches have properties which serve to tie them to a common
category as well as properties which distinguish them from each other.
Collecting both the shared and the distinctive properties seems to provide a
feasible way of describing the internal structure of categories.
However, there are some problems. Dictionary definitions are written for
a practical purpose and not with a systematic linguistic and cognitive analysis
in mind. Lexicographers can afford to skip some properties that are to
be taken for granted, or they can modify their definitions by limiting
expressions or ‘hedges’, like usually (parrots ‘usually’ have brightly coloured
feathers). A more systematic linguistic approach not only has to fill in gaps,
e.g. by adding to the definition of robin that it chirps and to the definition
of ostrich that it can run very fast. A linguistic analysis will also have to clarify
the notion of property or attribute (to use the more technical term).
Regarding the attributes used in dictionary entries, it may be quite sufficient
to understand them in the rather vague sense of ‘characteristics’ or
‘typical aspects’. From a more theoretical stance, an additional question
must be asked: are attributes to be regarded as obligatory or not? This distinction
was first suggested by Aristotle, who contrasted the ‘essence’ of
things with the ‘accidence’. The notion of essence gave rise to what has
been called the ‘categorical view’ or ‘classical view’, a position which was
vigorously defended by structuralist and transformationalist linguists. 9
According to this view, a category is defined by a limited set of necessary
and sufficient conditions. These conditions are conceived as clear-cut, ‘discrete’
features (or essential features, as they will be called here), which