Prof. Joshua R. Brotherton (Professor of Theology at St. Mary's Seminary)
I propose that the much lesser-known speculative opinion of philosopher Jacques Maritain is a better way to approach the definitive reality of human freedom in relation to God's infinite love... Fundamentally, Maritain's hypothesis is that after the final judgment each of the damned may at some point be 'pardoned' by God in such a way as to receive a flow of natural love for God. This would induce a certain 'natural felicity' that in effect counteracts the subjective severity of both the pain of loss and the pain of sense... He proposes that perhaps all the condemned, humans and angels alike, are 'pardoned' at some point after the final judgment and are thereby restored to a state in which created nature is in harmony with its natural love for God. Although Maritain presupposes the existence of a limbus puerorum, which he nevertheless distinguishes from that other ('natural') state for which all the damned are destined (I have called it 'final limbo'), the essence of his conjecture is that God's will to be 'all in all' is fulfilled by an eternal hell that eventually functions in a way similar to the classical notion of limbo. Accordingly, divine justice and mercy are most manifest by an influx of natural love granted those who have eternally excluded themselves from the order of grace... resulting in an ever-increasing natural knowledge and love of God."
--Brotherton, Joshua R. "Presuppositions of Balthasar's Universalist Hope and Maritain's Alternative Eschatological Proposal." _Theological Studies_ 76.4 (2015): 718-741, at 719, 731, and 733-734.
A Reverie, by Jacques Maritain