 Theory F(A)-Cond described in Fine 1982 licences P1, as well as the theory put forward in Zalta 1991 (cf. the supplementary document  Some Formal Theories in the Literature).  As we saw, Taylor (1985) has no modal theory of facts, but it seems that in a natural modal extension of his theory, P1 should hold. Notice that P1 is immediate on the view that facts are sets of worlds, and that all non-empty sets of worlds are facts (the view put forward in Restall 2004). For then, \(\ES(x) = x\) for any fact \(x\).