I attended a training event on Tuesday, and the other people there were from various humanities and social science disciplines, none of them linguistics. We each had to present a talk on our research, and then there were questions afterwards. One woman, doing a fine art creative practice PhD (in ceramics), asked me this:
Is it important that everything is put into one category or another?Typical creative type, you might think, not wanting things to be 'labelled'. She meant the labels like 'noun', 'verb', 'question particle' and so on. And it's a perfectly reasonable question to ask. Why do things have to be categorised? Without the categories, there's no problem to have to be solved.
Well, it's not just linguists doing it for the sake of it, because we like things to be rigid and ordered and follow the rules (though some of us do). These categories, although the labels are artificial, are natural classes. Consider the birds (as Brian didn't quite say).