 The same procedure can be applied to evaluate the counterfactuals that figure in  (NEC)  and  (POS),  in order to gain modal knowledge. Based on the logical equivalence in (POS), we can come to know “\(\diamond A\)” by knowing “\(\neg(A \boxarrow \bot)\)”. And we know the latter through a counterfactual development, much like in the  (Rock)  example. For example, we might assess whether it is metaphysically possible for the rock to have ended in the lake, by using the logical equivalence (POS). The simple procedure will be to counterfactually suppose that the rock did end in the lake and check whether a contradiction would follow, as we develop that supposition in imagination as “realistically” as we can (2007: 142).