I answer that, There have been many opinions about the fire of hell. For some philosophers, as Avicenna, disbelieving in the resurrection, thought that the soul alone would be punished after death. And as they considered it impossible for the soul, being incorporeal, to be punished with a corporeal fire, they denied that the fire whereby the wicked are punished is corporeal, and pretended that all statements as to souls being punished in future after death by any corporeal means are to be taken metaphorically. For just as the joy and happiness of good souls will not be about any corporeal object, but about something spiritual, namely the attainment of their end, so will the torment of the wicked be merely spiritual, in that they will be grieved at being separated from their end, the desire whereof is in them by nature. Wherefore, just as all descriptions of the soul's delight after death that seem to denote bodily pleasure---for instance, that they are refreshed, that they smile, and so forth---must be taken metaphorically, so also are all such descriptions of the soul's suffering as seem to imply bodily punishment---for instance, that they burn in fire, or suffer from the stench, and so forth. For as spiritual pleasure and pain are unknown to the majority, these things need to be declared under the figure of corporeal pleasures and pains, in order that men may be moved the more to the desire or fear thereof. Since, however, in the punishment of the damned there will be not only pain of loss corresponding to the aversion that was in their sin, but also pain of sense corresponding to the conversion, it follows that it is not enough to hold the above manner of punishment. For this reason Avicenna himself (Met. ix) added another explanation, by saying that the souls of the wicked are punished after death, not by bodies but by images of bodies; just as in a dream it seems to a man that he is suffering various pains on account of such like images being in his imagination. Even Augustine seems to hold this kind of punishment (Gen. ad lit. xii, 32), as is clear from the text. But this would seem an unreasonable statement. For the imagination is a power that makes use of a bodily organ: so that it is impossible for such visions of the imagination to occur in the soul separated from the body, as in the soul of the dreamer. Wherefore Avicenna also that he might avoid this difficulty, said that the soul separated from the body uses as an organ some part of the heavenly body, to which the human body needs to be conformed, in order to be perfected by the rational soul, which is like the movers of the heavenly body---thus following somewhat the opinion of certain philosophers of old, who maintained that souls return to the stars that are their compeers. But this is absolutely absurd according to the Philosopher's teaching, since the soul uses a definite bodily organ, even as art uses definite instruments, so that it cannot pass from one body to another, as Pythagoras is stated (De Anima i, text. 53) to have maintained. As to the statement of Augustine we shall say below how it is to be answered (ad 2). However, whatever we may say of the fire that torments the separated souls, we must admit that the fire which will torment the bodies of the damned after the resurrection is corporeal, since one cannot fittingly apply a punishment to a body unless that punishment itself be bodily. Wherefore Gregory (Dial. iv) proves the fire of hell to be corporeal from the very fact that the wicked will be cast thither after the resurrection. Again Augustine, as quoted in the text of Sentent. iv, D, 44, clearly admits (De Civ. Dei xxi, 10) that the fire by which the bodies are tormented is corporeal. And this is the point at issue for the present. We have said elsewhere (Q[70], A[3]) how the souls of the damned are punished by this corporeal fire.
Reply to Objection 1: Damascene does not absolutely deny that this fire is material, but that it is material as our fire, since it differs from ours in some of its properties. We may also reply that since that fire does not alter bodies as to their matter, but acts on them for their punishment by a kind of spiritual action, it is for this reason that it is stated not to be material, not as regards its substance, but as to its punitive effect on bodies and, still more, on souls.
Reply to Objection 2: The assertion of Augustine may be taken in this way, that the place whither souls are conveyed after death be described as incorporeal, in so far as the soul is there, not corporeally, i.e. as bodies are in a place, but in some other spiritual way, as angels are in a place. Or we may reply that Augustine is expressing an opinion without deciding the point, as he often does in those books.
Reply to Objection 3: That fire will be the instrument of Divine justice inflicting punishment. Now an instrument acts not only by its own power and in its own way, but also by the power of the principal agent, and as directed thereby. Wherefore although fire is not able, of its own power, to torture certain persons more or less, according to the measure of sin, it is able to do so nevertheless in so far as its action is regulated by the ordering of Divine justice: even so the fire of the furnace is regulated by the forethought of the smith, according as the effect of his art requires.
Whether the fire of hell is of the same species as ours?
Objection 1: It would seem that this fire is not of the same species as the corporeal fire which we see. For Augustine says (De Civ. Dei xx, 16): "In my opinion no man knows of what kind is the everlasting fire, unless the Spirit of God has revealed it to anyone." But all or nearly all know the nature of this fire of ours. Therefore that fire is not of the same species as this.
Objection 2: Further, Gregory commenting on Job 10:26, "A fire that is not kindled shall devour him," says (Moral. xv): "Bodily fire needs bodily fuel in order to become fire; neither can it be except by being kindled, nor live unless it be renewed. On the other hand the fire of hell, since it is a bodily fire, and burns in a bodily way the wicked cast therein, is neither kindled by human endeavor, nor kept alive with fuel, but once created endures unquenchably; at one and the same time it needs no kindling, and lacks not heat." Therefore it is not of the same nature as the fire that we see.
Objection 3: Further, the everlasting and the corruptible differ essentially, since they agree not even in genus, according to the Philosopher (Metaph. x). But this fire of ours is corruptible, whereas the other is everlasting: "Depart from Me, you cursed, into everlasting fire" ( Mat. 25:41 ). Therefore they are not of the same nature.
Objection 4: Further, it belongs to the nature of this fire of ours to give light. But the fire of hell gives no light, hence the saying of Job 18:5 : "Shall not the light of the wicked be extinguished?" Therefore . . . as above.
On the contrary, According to the Philosopher (Topic. i, 6), "every water is of the same species as every other water." Therefore in like manner every fire is of the same species as every other fire.
Further, it is written ( Wis. 11:17 ): "By what things a man sinneth by the same also he is tormented." Now men sin by the sensible things of this world. Therefore it is just that they should be punished by those same things.
I answer that, As stated in Meteor. iv, 1 fire has other bodies for its matter, for the reason that of all the elements it has the greatest power of action. Hence fire is found under two conditions: in its own matter, as existing in its own sphere, and in a strange matter, whether of earth, as in burning coal, or of air as in the flame. Under whatever conditions however fire be found, it is always of the same species, so far as the nature of fire is concerned, but there may be a difference of species as to the bodies which are the matter of fire. Wherefore flame and burning coal differ specifically, and likewise burning wood and red-hot iron; nor does it signify, as to this particular point, whether they be kindled by force, as in the case of iron, or by a natural intrinsic principle, as happens with sulphur. Accordingly it is clear that the fire of hell is of the same species as the fire we have, so far as the nature of fire is concerned. But whether that fire subsists in its proper matter, or if it subsists in a strange matter, what that matter may be, we know not. And in this way it may differ specifically from the fire we have, considered materially. It has, however, certain properties differing from our fire, for instance that it needs no kindling, nor is kept alive by fuel. But the differences do not argue a difference of species as regards the nature of the fire.
Reply to Objection 1: Augustine is speaking of that fire with regard to its matter, and not with regard to its nature.
Reply to Objection 2: This fire of ours is kept alive with fuel, and is kindled by man, because it is introduced into a foreign matter by art and force. But that other fire needs no fuel to keep it alive, because either it subsists in its own matter, or is in a foreign matter, not by force but by nature from an intrinsic principle. Wherefore it is kindled not by man but by God, Who fashioned its nature. This is the meaning of the words of Isaias (30:33): "The breath of the Lord is as a torrent of brimstone kindling it."
Reply to Objection 3: Even as the bodies of the damned will be of the same species as now, although now they are corruptible, whereas then they will be incorruptible, both by the ordering of Divine justice, and on account of the cessation of the heavenly movement, so is it with the fire of hell whereby those bodies will be punished.
Reply to Objection 4: To give light does not belong to fire according to any mode of existence, since in its own matter it gives no light; wherefore it does not shine in its own sphere according to the philosophers: and in like manner in certain foreign matters it does not shine, as when it is in an opaque earthly substance such as sulphur. The same happens also when its brightness is obscured by thick smoke. Wherefore that the fire of hell gives no light is not sufficient proof of its being of a different species.
Whether the fire of hell is beneath the earth?
Objection 1: It would seem that this fire is not beneath the earth. For it is said of the damned ( Job 18:18 ), "And God shall remove him out of the globe [Douay: 'world']." Therefore the fire whereby the damned will be punished is not beneath the earth but outside the globe.
Objection 2: Further, nothing violent or accidental can be everlasting. But this fire will be in hell for ever. Therefore it will be there, not by force but naturally. Now fire cannot be under the earth save by violence. Therefore the fire of hell is not beneath the earth.
Objection 3: Further, after the day of judgment the bodies of all the damned will be tormented in hell. Now those bodies will fill a place. Consequently, since the multitude of the damned will be exceeding great, for "the number of fools is infinite" ( Eccles. 1:15 ), the space containing that fire must also be exceeding great. But it would seem unreasonable to say that there is so great a hollow within the earth, since all the parts of the earth naturally tend to the center. Therefore that fire will not be beneath the earth.
Objection 4: Further, "By what things a man sinneth, by the same also he is tormented" ( Wis. 11:17 ). But the wicked have sinned on the earth. Therefore the fire that punishes them should not be under the earth.
On the contrary, It is written ( Is. 14:9 ): "Hell below was in an uproar to meet Thee at Thy coming." Therefore the fire of hell is beneath us.
Further, Gregory says (Dial. iv): "I see not what hinders us from believing that hell is beneath the earth."
Further, a gloss on Jonah 2:4, "Thou hast cast me forth . . . into the heart of the sea," says, "i.e. into hell," and in the Gospel ( Mat. 12:40 ) the words "in the heart of the earth" have the same sense, for as the heart is in the middle of an animal, so is hell supposed to be in the middle of the earth.
I answer that, As Augustine says (De Civ. Dei xv, 16), "I am of opinion that no one knows in what part of the world hell is situated, unless the Spirit of God has revealed this to some one." Wherefore Gregory (Dial. iv) having been questioned on this point answers: "About this matter I dare not give a rash decision. For some have deemed hell to be in some part of the earth's surface; others think it to be beneath the earth." He shows the latter opinion to be the more probable for two reasons. First from the very meaning of the word. These are his words: "If we call it the nether regions (infernus [*The Latin for 'hell']), for the reason that it is beneath us [inferius], what earth is in relation to heaven, such should be hell in relation to earth." Secondly, from the words of Apoc. 5:3 : "No man was able, neither in heaven, nor on earth, nor under the earth, to open the book": where the words "in heaven" refer to the angels, "on earth" to men living in the body, and "under the earth" to souls in hell. Augustine too (Gen. ad lit. xii, 34) seems to indicate two reasons for the congruity of hell being under the earth. One is that "whereas the souls of the departed sinned through love of the flesh, they should be treated as the dead flesh is wont to be treated, by being buried beneath the earth." The other is that heaviness is to the body what sorrow is to the spirit, and joy (of spirit) is as lightness (of body). Wherefore "just as in reference to the body, all the heavier things are beneath the others, if they be placed in order of gravity, so in reference to the spirit, the lower place is occupied by whatever is more sorrowful"; and thus even as the empyrean is a fitting place for the joy of the elect, so the lowest part of the earth is a fitting place for the sorrow of the damned. Nor does it signify that Augustine (De Civ. Dei xv, 16) says that "hell is stated or believed to be under the earth," because he withdraws this (Retract. ii, 29) where he says: "Methinks I should have said that hell is beneath the earth, rather than have given the reason why it is stated or believed to be under the earth." However, some philosophers have maintained that hell is situated beneath the terrestrial orb, but above the surface of the earth, on that part which is opposite to us. This seems to have been the meaning of Isidore when he asserted that "the sun and the moon will stop in the place wherein they were created, lest the wicked should enjoy this light in the midst of their torments." But this is no argument, if we assert that hell is under the earth. We have already stated how these words may be explained (Q[91] , A[2]).