Arminians often regard the notion of divine permission in Calvinism as incoherent, given the Reformed doctrine of predestination. Here's a careful delineation of what the concept means:
As a preliminary to considering the first argument it is necessary to get clearer on the meaning of willing permission. God positively governs some acts by permitting them. Yet for such permission to be consistent with meticulous positive government, it has to be a particular kind of permission; it has to be willingly given, and it has to be permission of particular actions and not merely the permission of certain types of action. But doesn't introducing the idea of permission unacceptably modify the idea of divine positive government by introducing an element of conditionality? It does introduce an element of conditionality, but perhaps necessarily so. So far as God may ordain but not cause evil there is an element of conditionality about what happens, since what happens is conditioned upon what agents other than God do. Such conditionality is present in God's relations to all human actions, presumably. Nevertheless such conditionality is risk-free for God.
Divine permission is compatible with the absence of risk for God as long as there are types of actions which God can prevent but which he nevertheless cannot cause, even though he may be willing for them to occur. Then God controls an evil action by permitting it - by deciding not to prevent it - and the evil action occurs because it is caused by the natures and circumstances of those who perpetrate it. The evil action is then not caused by God although he willingly permits it as a necessary component part of some broader overall will. This leaves us with questions of why God has willingly permitted evil, and of exactly how evil comes about in a world created by an all-good God. Thankfully, attempting to answer these questions falls outside the scope of this paper.
So God may willingly permit an evil act; indeed since God cannot perform an evil act, if an evil act occurs, he must have permitted it and if his government of that action is positive, necessarily only permitted it, but willingly so.
So for S willingly to permit an action A is: for A to be the action of someone other than S; for S to ordain the occurrence of A and to have been able to prevent A; and for A not to be contrary to what S intends. On this conception God foreknows everything, and unconditionally governs everything, but does not causally determine everything in the sense that he is the efficient cause of everything. Nevertheless, nothing happens that God is unwilling should happen.
But it may still be insisted that if God willingly permits X, then God is the cause of X. It is tempting, but I believe crude and misleading, to assimilate the working of such permission to intramundane models of causation, and particularly to theories of physical determinism. Such permission has this in common with physical determinism, that what is physically determined and what is willingly permitted will each come to pass. But willingly to permit an action is not to cause that action in any straightforward sense of 'cause'. As part of his critique of the no-risk view John Saunders describes the Lord, in willingly permitting a rape, as himself a 'rapist'. Such ill-judged language is based on a thorough misunderstanding.
We can express some of the difference between willing permission and causation like this. While it seems clear that intramundane causation is transitive, that if (where A, B and C are mundane events) A causes B, and B causes C, then A causes C, there is no necessary transitivity in the case of the causal aspects or features of the divine willing permission. It is thus not necessarily the case that if God positively governs by willingly permitting some event B, and B causes C, then God causes C; rather God may will C by willingly permitting that B causes C.