 The Completeness Question: According to Hale’s epistemology of essence, we can come to know essentialist facts by deducing them from essentialist principles (like in the inference from  (H1)  and  (H2)  to  (H3)).  However, one might ask whether knowledge of the essentialist principle in (H1) is not itself already essentialist knowledge. In other words, it might be questioned whether such an account of essentialist knowledge can be complete (for discussion: Wallner forthcoming). Wallner (forthcoming) also points out that in order for us to successfully employ Hale’s distinction between pure and impure sortals that is supposed to differentiate essential from inessential properties, we might have to presuppose essentialist knowledge.