Eternity is prior to all events. Events cook out of eternity. Their causal relations to each other cook out of their accidental forms, which are found originally in God. So Leibniz was right: the monads – the quanta of action which constitute the events of creaturely lives – don’t define themselves ab initio in terms of their own immediate relations to each other, but rather in terms of their relations to each other as mediated by the logically prior Divine omniscience of all compossibilities. They do see each other – they are not windowless – but only through God. God is their window.
To sin is to obscure that window and, so misled, almost inevitably, to begin to disagree with reality, both creaturely and divine.
In Paradise, our windows are immaculate, and we see God clearly, ipso facto seeing our fellows clearly. In the BV at the heart of Paradise, the windows are thrown open.
For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
— 1 Corinthians 13:12
 God is needed for this mediation, because the causal gap between any two causally related finite events is infinite. Only God could bridge it.