Aquinas, following Augustine, wrote that, “This fire of Purgatory will be more severe than any pain that can be felt, seen or conceived in this world.” It is only worse since there will be the realization that the soul, in its suffering, is not in the presence of God–the very event that would relieve the soul of its terrible suffering. According to Aquinas, this suffering is “punishment by corporeal fire.”
Actually, there are two ‘pains’ that Aquinas describes in this part of the Summa. First, though, it’s necessary to state a caveat: this description of Purgatory is from the appendix to the supplement of the Summa Theologiae. It was not written by Thomas, so to speak; after his death, his colleagues compiled his (unfinished) discussion on penance, and added to them other things he had written elsewhere, and appended these to the Summa. So… ‘grain of salt’ time, if you want to say that this is Aquinas writing in the Summa, right?
OK, anyway: you seem to be conflating the two pains described here. One is, as you mention, the pain of the
coulda-shoulda-woulda recognition: it’s that pain of realizing that, but for our sins and the damage they did to us, we would be in heaven, in the presence of God,
right now!!!, but that we need to be cleansed of these imperfections before attaining to heaven. Think of Christmas morning, when you were a kid. You
knew there were toys from Santa down in the other room… you just
knew that they were there, just waiting for you! But… you weren’t allowed to get up and start opening them until Mom & Dad gave the ok. (Longest… morning… evar!!!) And so, you lay there in bed, wide awake, just dying inside until it was ok for you to go to the Christmas tree and start opening your presents. That’s the kind of pain Aquinas is talking about… just that it’s not
Christmas presents, it’s
eternal bliss that we’re missing out on.
There’s a second kind of pain, and that’s the one described as “punishment by corporeal fire.” There’s another name for this pain right there in the question you’re referencing: it’s the pain of
sense.
How the immaterial soul, without corporeal matter and form, could suffer from corporeal fire does seem mysterious.
Denise1957:
It is indeed mysterious how one (one’s soul in Purgatory) could suffer from corporal fire, even though the soul is immaterial… Somehow the soul can experience pain, but we may never really know why.
It’s really not all that mysterious. Time for an experiment: close your eyes and remember the greatest pain you ever felt: it might have been physical pain (giving birth, some sort of accident or illness) or emotional pain (the heartbreak of a relationship that ended). For just a minute, close your eyes and remember that pain… in fact, re-live it. Go ahead… I’ll wait.
OK – are you breaking out in a cold sweat right now? Is the memory of that pain so vivid that you were able to begin experiencing it all over? Good. 'Cause that’s what Aquinas is talking about here. It’s not that pain is, by definition, “flesh on fire.” Rather, pain is that
sensation that we have. That sensation is felt by our soul. So, the pain that the soul feels, Aquinas is asserting, is the
sensation of pain, as if by fire.
In q. 70 of the appendix, in speaking of the fires of hell, Aquinas asserts that it’s not just that the soul
sees the fire, and therefore feels pain, or even that it
perceives it as painful and therefore feels the pain that it thinks it should. Aquinas agrees that corporeal fire cannot ‘touch’ the soul. But, the fire is the agent of God’s punishment (that is, he’s talking about fires in hell, remember?), and the soul can be considered to be ‘located’ in the fires of hell, and from that location, experience the pain of the punishment of the fire.
If that still sounds mysterious, then consider it this way: your soul is not physical, and therefore, it does not exist in a given ‘place’ (after all, ‘place’ is a quality that only physical things have). But, your soul
is united to you; and so, your soul has that quality of being located ‘with’ you. (This being united to you, and therefore, sharing (in a sense) in your location, is what Aquinas is getting at: if your soul is ‘here’, united with you while your body is alive, then it can certainly be considered to be ‘there’, united with the fires of hell if you are damned to hell.
The same sort of argument applies to the ‘fires of Purgatory’, at least as far as the notion of the soul being ‘there’ and feeling their pain. It’s the pain of sense, not of physical sensation, and if it’s reasonable to think that our souls are united to us, then it’s reasonable to think that they can be caused to be united to the ‘fire of Purgatory’ or the ‘fire of hell’.
Fortunately, the works of Thomas Aquinas are not Scripture. They were written about eight-hundred years ago.
No, they’re not Scripture… but, they
are utilized, in various places and in various ways, to explain magisterial teaching – which, along with Scripture as part of the Deposit of the Faith, does
have the force of Scripture, so to speak.