Knowledge structures and language boundaries

I shall refer to such restrictions as preference restrictions, because of the way the present NLUS is already able to accept natural language that violates preferences, as (1) does (see recap in next section for more detail). Such usage as (s) will be referred to as extended, or preference violating, and these will serve instead of the more literary and philosophical term "metaphorical". It is an important assumption of this paper that such usage is the norm in ordinary everyday language use, and cannot be relegated to the realm of the exceptional, or the odd, and so dealt with by considerations of "performance". On the contrary it is, I would argue, central to our language capabilities, and any theory of language must have something concrete to say about it. Even if the newspaper usages above are "extended", I would suggest that anyone who could not grasp these extension could not be said to understand English properly (given adequate knowledge from which to extend, and we shall come to that.) It will be obvious already that the commitment to a norm implies a corresponding commitment to general everyday language as a proper topic for Al.