 On the alethic interpretation of the modality, this states that if necessarily, everything is \(A\), everything is necessarily \(A\). The proof is given, for example, in one of the supplements to the entry on the  possibilism-actualism debate.  But this provides another route to the necessity of being: since necessarily, everything is something, everything is necessarily something. In the presence of a further plausible modal principle, B, we may even prove the Barcan Formula. The Brouwerian principle, B, states that whatever is the case is necessarily, possibly the case: