Objection 1. It would seem that the separated soul cannot suffer from a bodily fire. For Augustine says (Gen. ad lit. xii): "The things that affect the soul well or ill after its separation from the body, are not corporeal but resemble corporeal things." Therefore the separated soul is not punished with a bodily fire.
Objection 2. Further, Augustine (Gen. ad lit. xii) says that "the agent is always more excellent than the patient." But it is impossible for any body to be more excellent than the separated soul. Therefore it cannot suffer from a body.
Objection 3. Further, according to the Philosopher (De Gener. i) and Boethius (De Duab. Natur.) only those things that agree in matter are active and passive in relation to one another. But the soul and corporeal fire do not agree in matter, since there is no matter common to spiritual and corporeal things: wherefore they cannot be changed into one another, as Boethius says (De Duab. Natur.). Therefore the separated soul does not suffer from a bodily fire.
Objection 4. Further, whatsoever is patient receives something from the agent. Therefore if the soul suffer from the bodily fire, it will receive something therefrom. Now whatsoever is received in a thing is received according to the mode of the recipient. Therefore that which is received in the soul from the fire, is in it not materially but spiritually. Now the forms of things existing spiritually in the soul are its perfections. Therefore though it be granted that the soul suffer from the bodily fire, this will not conduce to its punishment, but rather to its perfection.
Objection 5. Further, if it be said that the soul is punished merely by seeing the fire, as Gregory would seem to say (Dial. iv, 29).
On the contrary, if the soul sees the fire of hell, it cannot see it save by intellectual vision, since it has not the organs by which sensitive or imaginative vision is effected. But it would seem impossible for intellectual vision to be the cause of sorrow, since "there is no sorrow contrary to the pleasure of considering," according to the Philosopher (Topic. i, 13). Therefore the soul is not punished by that vision.
Objection 6. Further, if it be said that the soul suffers from the corporeal fire, through being held thereby, even as now it is held by the body while living in the body; on the contrary, the soul while living in the body is held by the body in so far as there results one thing from the soul and the body, as from form and matter. But the soul will not be the form of that corporeal fire. Therefore it cannot be held by the fire in the manner aforesaid.
Objection 7. Further, every bodily agent acts by contact. But a corporeal fire cannot be in contact with the soul, since contact is only between corporeal things whose bounds come together. Therefore the soul suffers not from that fire.
Objection 8. Further, an organic agent does not act on a remote object, except through acting on the intermediate objects; wherefore it is able to act at a fixed distance in proportion to its power. But souls, or at least the demons to whom this equally applies, are sometimes outside the place of hell, since sometimes they appear to men even in this world: and yet they are not then free from punishment, for just as the glory of the saints is never interrupted, so neither is the punishment of the damned. And yet we do not find that all the intermediate things suffer from the fire of hell: nor again is it credible that any corporeal thing of an elemental nature has such a power that its action can reach to such a distance. Therefore it does not seem that the pains suffered by the souls of the damned are inflicted by a corporeal fire.
On the contrary, The possibility of suffering from a corporeal fire is equally consistent with separated souls and with demons. Now demons suffer therefrom since they are punished by that fire into which the bodies of the damned will be cast after the resurrection, and which must needs be as corporeal fire. This is evident from the words of our Lord (Matthew 25:41), "Depart from Me, you cursed, into everlasting fire, which was prepared for the devil," etc. Therefore separated souls also can suffer from that fire.
Further, punishment should correspond to sin. Now in sinning the soul subjected itself to the body by sinful concupiscence. Therefore it is just that it should be punished by being made subject to a bodily thing by suffering therefrom.
Further, there is greater union between form and matter than between agent and patient. Now the diversity of spiritual and corporeal nature does not hinder the soul from being the form of the body. Therefore neither is it an obstacle to its suffering from a body.
I answer that, Given that the fire of hell is not so called metaphorically, nor an imaginary fire, but a real corporeal fire, we must needs say that the soul will suffer punishment from a corporeal fire, since our Lord said (Matthew 25:41) that this fire was prepared for the devil and his angels, who are incorporeal even as the soul. But how it is that they can thus suffer is explained in many ways.
For some have said that the mere fact that the soul sees the fire makes the soul suffer from the fire: wherefore Gregory (Dial. iv, 29) says: "The soul suffers from the fire by merely seeing it." But this does not seem sufficient, because whatever is seen, from the fact that it is seen, is a perfection of the seer. wherefore it cannot conduce to his punishment, as seen. Sometimes, however, it is of a penal or unpleasant nature accidentally, in so far, to wit, as it is apprehended as something hurtful, and consequently, besides the fact that the soul sees the fire, there must needs be some relation of the soul to the fire, according to which the fire is hurtful to the soul.
Hence others have said that although a corporeal fire cannot burn the soul, the soul nevertheless apprehends it as hurtful to itself, and in consequence of this apprehension is seized with fear and sorrow, in fulfillment of Psalm 13:5, "They have trembled for fear, where there was no fear." Hence Gregory says (Dial. iv, 29) that "the soul burns through seeing itself aflame." But this, again, seems insufficient, because in this case the soul would suffer from the fire, not in reality but only in apprehension: for although a real passion of sorrow or pain may result from a false imagination, as Augustine observes (Gen. ad lit. xii), it cannot be said in relation to that passion that one really suffers from the thing, but from the image of the thing that is present to one's fancy. Moreover, this kind of suffering would be more unlike real suffering than that which results from imaginary vision, since the latter is stated to result from real images of things, which images the soul carries about with it, whereas the former results from false fancies which the erring soul imagines: and furthermore, it is not probable that separated souls or demons, who are endowed with keen intelligence, would think it possible for a corporeal fire to hurt them, if they were nowise distressed thereby.
Hence others say that it is necessary to admit that the soul suffers even really from the corporeal fire: wherefore Gregory says (Dial. iv, 29): "We can gather from the words of the Gospel, that the soul suffers from the fire not only by seeing it, but also by feeling it." They explain the possibility of this as follows. They say that this corporeal fire can be considered in two ways. First, as a corporeal thing, and thus it has not the power to act on the soul. Secondly, as the instrument of the vengeance of Divine justice. For the order of Divine justice demands that the soul which by sinning subjected itself to corporeal things should be subjected to them also in punishment. Now an instrument acts not only in virtue of its own nature, but also in virtue of the principal agent: wherefore it is not unreasonable if that fire, seeing that it acts in virtue of a spiritual agent, should act on the spirit of a man or demon, in the same way as we have explained the sanctification of the soul by the sacraments (III, 62, 1,4).
But, again, this does not seem to suffice, since every instrument, in acting on that on which it is used instrumentally, has its own connatural action besides the action whereby it acts in virtue of the principal agent: in fact it is by fulfilling the former that it effects the latter action, even as, in Baptism, it is by laving the body that water sanctifies the soul, and the saw by cutting wood produces the shape of a house.
Hence we must allow the fire to exercise on the soul an action connatural to the fire, in order that it may be the instrument of Divine justice in the punishment of sin: and for this reason we must say that a body cannot naturally act on a spirit, nor in any way be hurtful or distressful to it, except in so far as the latter is in some way united to a body: for thus we observe that "the corruptible body is a load upon the soul" (Wisdom 9:15). Now a spirit is united to a body in two ways. In one way as form to matter, so that from their union there results one thing simply: and the spirit that is thus united to a body both quickens the body and is somewhat burdened by the body: but it is not thus that the spirit of man or demon is united to the corporeal fire. In another way as the mover is united to the things moved, or as a thing placed is united to place, even as incorporeal things are in a place. In this way created incorporeal spirits are confined to a place, being in one place in such a way as not to be in another. Now although of its nature a corporeal thing is able to confine an incorporeal spirit to a place, it is not able of its nature to detain an incorporeal spirit in the place to which it is confined, and so to tie it to that place that it be unable to seek another, since a spirit is not by nature in a place so as to be subject to place. But the corporeal fire is enabled as the instrument of the vengeance of Divine justice thus to detain a spirit; and thus it has a penal effect on it, by hindering it from fulfilling its own will, that is by hindering it from acting where it will and as it will.
This way is asserted by Gregory (Dial. iv, 29). For in explaining how the soul can suffer from that fire by feeling it, he expresses himself as follows: "Since Truth declares the rich sinner to be condemned to fire, will any wise man deny that the souls of the wicked are imprisoned in flames?" Julian [Bishop of Toledo, Prognostic ii, 17] says the same as quoted by the Master (Sent. iv, D, 44): "If the incorporeal spirit of a living man is held by the body, why shall it not be held after death by a corporeal fire?" and Augustine says (De Civ. Dei xxi, 10) that "just as, although the soul is spiritual and the body corporeal, man is so fashioned that the soul is united to the body as giving it life, and on account of this union conceives a great love for its body, so it is chained to the fire, as receiving punishment therefrom, and from this union conceives a loathing."
Accordingly we must unite all the aforesaid modes together, in order to understand perfectly how the soul suffers from a corporeal fire: so as to say that the fire of its nature is able to have an incorporeal spirit united to it as a thing placed is united to a place; that as the instrument of Divine justice it is enabled to detain it enchained as it were, and in this respect this fire is really hurtful to the spirit, and thus the soul seeing the fire as something hurtful to it is tormented by the fire. Hence Gregory (Dial. iv, 29) mentions all these in order, as may be seen from the above quotations.
Reply to Objection 1. Augustine speaks there as one inquiring: wherefore he expresses himself otherwise when deciding the point, as quoted above (De Civ. Dei xxi). Or we may reply that Augustine means to say that the things which are the proximate occasion of the soul's pain or sorrow are spiritual, since it would not be distressed unless it apprehended the fire as hurtful to it: wherefore the fire as apprehended is the proximate cause of its distress, whereas the corporeal fire which exists outside the soul is the remote cause of its distress.
Reply to Objection 2. Although the soul is simply more excellent than the fire, the fire is relatively more excellent than the soul, in so far, to wit, as it is the instrument of Divine justice.
Reply to Objection 3. The Philosopher and Boethius are speaking of the action whereby the patient is changed into the nature of the agent. Such is not the action of the fire on the soul: and consequently the argument is not conclusive.
Reply to Objection 4. By acting on the soul the fire bestows nothing on it but detains it, as stated above. Hence the argument is not to the point.
Reply to Objection 5. In intellectual vision sorrow is not caused by the fact that something is seen, since the thing seen as such can nowise be contrary to the intellect. But in the sensible vision the thing seen, by its very action on the sight so as to be seen, there may be accidentally something corruptive of the sight, in so far as it destroys the harmony of the organ Nevertheless, intellectual vision may cause sorrow, in so far as the thing seen is apprehended as hurtful, not that it hurts through being seen, but in some other way no matter which. It is thus that the soul in seeing the fire is distressed.
Reply to Objection 6. The comparison does not hold in every respect, but it does in some, as explained above.
Reply to Objection 7. Although there is no bodily contact between the soul and body, there is a certain spiritual contact between them (even as the mover of the heaven, being spiritual, touches the heaven, when it moves it, with a spiritual contact) in the same way as a "painful object is said to touch," as stated in De Gener. i. This mode of contact is sufficient for action.
Reply to Objection 8. The souls of the damned are never outside hell, except by Divine permission, either for the instruction or for the trial of the elect. And wherever they are outside hell they nevertheless always see the fire thereof as prepared for their punishment. Wherefore, since this vision is the immediate cause of their distress, as stated above, wherever they are, they suffer from hell-fire. Even so prisoners, though outside the prison, suffer somewhat from the prison, seeing themselves condemned thereto. Hence just as the glory of the elect is not diminished, neither as to the essential, nor as to the accidental reward, if they happen to be outside the empyrean, in fact this somewhat conduces to their glory, so the punishment of the damned is nowise diminished, if by God's permission they happen to be outside hell for a time. A gloss on James 3:6, "inflameth the wheel of our nativity," etc., is in agreement with this, for it is worded thus: "The devil, wherever he is, whether in the air or under the earth, drags with him the torments of his flames." But the objection argues as though the corporeal fire tortured the spirit immediately in the same way as it torments bodies.
Source: Summa Theologica (New Advent)