1.3.1 Categorial features
Another way to extend the system, which we will be making some use of, relies on the notion of underspecification of features. All the categories discussed above are fully specified for all the features, so each is associated with a plus or minus value for all three features. Underspecification is a situation in which one or more features is not specified for its value. Thus, we might propose a new category [+N, –V] which is not specified for the [±F] feature. This category would then be a noun which is neither functional, nor thematic. We will see that there is evidence that the [±F] feature can be left underspecified and hence there are a further four ‘non-functional’ categories. We will introduce these categories in the following sections. The important point for the moment is that the system of features restricts our ability to invent new categories ‘willy-nilly’.