 (a) are definitely mass by the grammatical criteria discussed above, and they refer to concrete entities. But, it is hard to see what import they would have for supporting a metaphysics of  stuff.[10]  These words are devices for speaking about distinct, discrete objects in a collective manner. In certain contexts, we seek to draw attention to a bunch of distinct individuals, not as such, but, for pragmatic reasons, as an undifferentiated mass or plurality of a certain kind.