Positing grammatical categories: linguists' vs. speakers' generalizations

Boye (2009) argues for a particular type of cross-linguistically valid grammatical categories, which he calls generic categories. Generic categories are categories encompassing conceptually related notions, e.g. present, past, and future, or epistemic and deontic. These can be described in terms of some more abstract notion that is used to define the category, such as tense or modality. Generic categories are standardly used in linguistic analysis, but a great deal of controversy exists about what generic categories exactly should be posited, for example about whether or not evidentiality can be regarded as a category in its own right. Boye argues that this is because proposals about generic categories are usually based on arbitrary notional criteria. Instead, generic categories should correspond to linguistically significant generalizations, that is, they should capture some organizing principle in the grammar of individual languages. In fact, Boye argues, generic categories are necessary in linguistic analysis exactly because they appear to play a role in a number of grammatical phenomena cross-linguistically. Claims about generic categories should be based on semantic maps, because the fact that the notions encompassed by a generic category cover a continuous region on a semantic map is evidence that the category corresponds to a linguistically significant, rather than a linguist's arbitrary generalization. The paper argues that Boye's proposal, along with much of the current literature on grammatical categories, does not distinguish between two possible senses of the notion of grammatical category, and that this distinction is essential to a proper understanding of what evidence can actually be used to posit individual categories, including evidence from semantic maps.