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 (Question [70], Article [3]) how the souls of the damned are punished by this corporeal fire.