 In the acquisition process, however, the role of demonstrative identification may be unclear. Nevertheless, a similar argument against SK can be formulated as long as some kind of empirical knowledge is needed to acquire the water concept. Indeed, it is typically assumed that a person acquires a concept from experience—which already portends that acquisition depends on empirical knowledge. Yet if that’s right, then even knowledge of (2) has an empirical basis, since possession of the water concept does. Hence, knowledge of (2) does not qualify as purely apriori . 