In his excellent book The Great Divorce, C.S. Lewis depicts Hell and Purgatory as the same place, with the difference being whether people consent to leave or whether they decide to stay. Truth to tell, it’s a bit of timid description of purgatory because Lewis was trying to be non-denominational and so he was trying to avoid offending people who are rabidly anti-Catholic in their biases (possibly including himself—He was born in Belfast where anti-Catholicism was in the water). But it’s a very interesting idea which could really use a bit more development, especially with regard to the more fiery depictions of Hell and the more actively unpleasant depictions of Purgatory.

Purgatory is an oft-misunderstood doctrine, but its etymology is a good place to start understanding it. “Purgatory” comes from the same root as the word “purge,” as in “to clean” or “to make clean”. The doctrine of purgatory is a straightforward logical deduction from starting off sinful at death and being sinless in heaven. Something must happen between those two steps, and the thing that happens which cleanses people of their sins was called, very practically, “cleaning,” except it happened to come from the Latin rather than the German roots of English, and hence, “purge”→”Purgatory”.

If you consider how cleaning normally works, on physical objects, you do it by abrading the surface until all of the dirt is gone. If you want to do a thorough job, you often have to be rough with the thing being cleaned—which is why children do not like baths, especially baths which get them thoroughly clean, including, for example, under their fingernails. If we move from the physical to the spiritual, how much more invasive must the cleaning be which cleanses your soul from things like lust, greed, envy, hatred, etc?

From here, it’s a relatively short jump to the metaphor of using fire to purify metal. If you heat metal up roughly to its melting point, any organic contamination will burn away and you will be left with pure metal. (In practice, it will probably need a polishing afterwards, but this doesn’t matter to the metaphor.) And this metaphor for cleaning happens to work very well with the description of Hell as a burning grounds.

That Hell is a burning grounds with constant fire is taken to be metaphorical for the obvious reason that it can’t actually be completely literal. Quite apart from literal fire requiring the afterlife to be just more of the same, rather than different in important ways, if the fire consumes the damned, then they’re not there later be burnt anymore. If the fires don’t consume the damned, they’re not being burnt. It would be, at worst, like chili peppers—awful at first, but if you spend enough time with them you get used to them because you know the sensation doesn’t actually mean anything bad. Since orthodox Christians do not presume God to be incompetent, the fires must be, to some degree at least, metaphorical.

If you put these together, it produces an interesting version of C.S. Lewis’s presentation of Hell in The Great Divorce: if all of the souls go through something which is incompatible with sin, analogous to a bath or purifying metal with fire, and they let go of their sins, this is Purgatory, and they emerge from that process made fit for being perfectly happy being eternally in God’s presence. (Let me emphasize, due to the context of some odd heresies existing, that we are made clean entirely by God’s grace, and entirely by his power. This cleaning is purely receptive on our part and we merely cooperate with it.)

But if the person refuses to let go of their sin, this cleaning never finishes, and therefore becomes eternal—specifically, eternal punishment.

This actually goes quite well with the idea I saw somewhere (I think in G.K. Chesterton) that the fires of Hell are actually the burning love of God, rejected. Bishop Barron used the analogy of a person at a party who doesn’t want to be there, who hates everything that is making the people who do want to be there happy. But if we stick with the metaphor of fire, the light of God’s truth works quite well as a purifying fire that burns away all impurities, since all sin is some kind of lie, and light also heats. In the fullness of the light of God’s truth, unveiled, all lies will burn away, and if a person lets them go, they have been cleaned of the dirt of these lies. But if they will not let go, if they shield the dirt from the burning light of God with their own bodies, then they eternally are tormented by trying to do what they can’t—believe the lies.

This is all, of course, highly speculative metaphor. I’m not trying to say that this is exactly what will happen after we die. For one thing, I have no special revelation so I don’t know. For another, I doubt that any language we humans have on this side of death even contains the words needed to describe what actually happens after death. (The fact that our Lord never tried to tell us strongly suggests, to me, at least, that this is so.)

But I think that this does at least suggest an answer, or at least part of an answer, to the question of how eternal punishment can be just. The point isn’t really to identify the answer, though of course that would be nice. The point is to show that an answer is possible, and therefore any argument which relies on it being impossible is wrong.