Gregory MacDonald makes a note about “appeals to mystery”:
It may be that the traditionalist will appeal to mystery at this point. He may grant that he cannot see any way in which traditional punishment in hell can be defended but still maintain that it is just and good. “God, after all, is beyond our ken, and we should not presume to be able to understand everything about him. The fact of the matter,” he may say, “is that Scripture teaches everlasting hell, and so we must accept it. The things that have been revealed belong to us and to our children but the hidden things belong to the LORD and we must rest content with that.” I do have some sympathy with this position, but it is surely a last resort. The secret things may well belong to the Lord, but that which has been revealed can be known to be true; and it is on the basis of those revealed things that I have argued for universalism and against everlasting hell. The premises in my arguments all rely on traditional Christian claims about God, and it is those very claims that seem to conflict with traditional views of hell and yet fit so well with universalism. I would suggest that these arguments ought, at the very least, to make us wonder if we have not misunderstood certain biblical teachings on hell. Only if we are absolutely certain that have not done so would we appeal to mystery. I hope to show in the rest of this book that we have indeed misunderstood the implications of the Bible’s teachings on this subject. (The Evangelical Universalist, p. 33)
As I was reading this chapter I was thinking something along these lines. Saying that “God is beyond our understanding” is certainly true, but it is not a satisfactory defense of the traditional doctrine of hell. It sounds pious, but it seems to me to be an ill-informed approach to this doctrine with potentially eternal consequences. If mystery is the only basis we have for our doctrine of hell, we really don’t have a reason to believe it, do we? One could just as easily argue that God, in his mystery, will save everyone. None of that proves anything.