1 Objection 1: It would seem that the angels are not incorruptible; for Damascene, speaking of the angel, says De Fide Orth. ii, 3) that he is an intellectual substance, partaking of immortality by favor, and not by nature.
1 Ad quintum sic proceditur. Videtur quod Angeli non sint incorruptibiles. Dicit enim Damascenus de Angelo, quod est substantia intellectualis, gratia et non natura immortalitatem suscipiens.
2 Objection 2: Further, Plato says in the Timaeus: O gods of gods, whose maker and father am I: You are indeed my works, dissoluble by nature, yet indissoluble because I so will it. But gods such as these can only be understood to be the angels. Therefore the angels are corruptible by their nature
2 Praeterea, Plato dicit, in Timaeo, o dii deorum, quorum opifex idem paterque ego, opera siquidem vos mea, dissolubilia natura, me tamen ita volente indissolubilia. Hos autem deos non aliud quam Angelos intelligere potest. Ergo Angeli natura sua sunt corruptibiles.
3 Objection 3: Further, according to Gregory Moral. xvi), all things would tend towards nothing, unless the hand of the Almighty preserved them. But what can be brought to nothing is corruptible. Therefore, since the angels were made by God, it would appear that they are corruptible of their own nature.
3 Praeterea, secundum Gregorium, omnia in nihilum deciderent, nisi ea manus omnipotentis conservaret. Sed quod in nihilum redigi potest, est corruptibile. Ergo, cum Angeli sint a Deo facti, videtur quod sint corruptibiles secundum suam naturam.
4 On the contrary, Dionysius says Div. Nom. iv) that the intellectual substances have unfailing life, being free from all corruption, death, matter, and generation.
4 Sed contra est quod Dionysius dicit, IV cap. de Div. Nom., quod intellectuales substantiae vitam habent indeficientem, ab universa corruptione, morte et materia et generatione mundae existentes.
5 I answer that, It must necessarily be maintained that the angels are incorruptible of their own nature. The reason for this is, that nothing is corrupted except by its form being separated from the matter. Hence, since an angel is a subsisting form, as is clear from what was said above Article 2), it is impossible for its substance to be corruptible. For what belongs to anything considered in itself can never be separated from it; but what belongs to a thing, considered in relation to something else, can be separated, when that something else is taken away, in view of which it belonged to it.
Roundness can never be taken from the circle, because it belongs to it of itself; but a bronze circle can lose roundness, if the bronze be deprived of its circular shape. Now to be belongs to a form considered in itself; for everything is an actual being according to its form: whereas matter is an actual being by the form. Consequently a subject composed of matter and form ceases to be actually when the form is separated from the matter.
But if the form subsists in its own being, as happens in the angels, as was said above Article 2), it cannot lose its being. Therefore, the angel's immateriality is the cause why it is incorruptible by its own nature. A token of this incorruptibility can be gathered from its intellectual operation; for since everything acts according as it is actual, the operation of a thing indicates its mode of being. Now the species and nature of the operation is understood from the object. But an intelligible object, being above time, is everlasting. Hence every intellectual substance is incorruptible of its own nature.
5 Respondeo dicendum quod necesse est dicere Angelos secundum suam naturam esse incorruptibiles. Cuius ratio est, quia nihil corrumpitur nisi per hoc, quod forma eius a materia separatur, unde, cum Angelus sit ipsa forma subsistens, ut ex dictis patet, impossibile est quod eius substantia sit corruptibilis. Quod enim convenit alicui secundum se, nunquam ab eo separari potest, ab eo autem cui convenit per aliud, potest separari, separato eo secundum quod ei conveniebat. Rotunditas enim a circulo separari non potest, quia convenit ei secundum seipsum, sed aeneus circulus potest amittere rotunditatem per hoc, quod circularis figura separatur ab aere. Esse autem secundum se competit formae, unumquodque enim est ens actu secundum quod habet formam. Materia vero est ens actu per formam. Compositum igitur ex materia et forma desinit esse actu per hoc, quod forma separatur a materia. Sed si ipsa forma subsistat in suo esse, sicut est in Angelis, ut dictum est, non potest amittere esse. Ipsa igitur immaterialitas Angeli est ratio quare Angelus est incorruptibilis secundum suam naturam. Et huius incorruptibilitatis signum accipi potest ex eius intellectuali operatione, quia enim unumquodque operatur secundum quod est actu, operatio rei indicat modum esse ipsius. Species autem et ratio operationis ex obiecto comprehenditur. Obiectum autem intelligibile, cum sit supra tempus, est sempiternum. Unde omnis substantia intellectualis est incorruptibilis secundum suam naturam.
6 Reply to Objection 1: Damascene is dealing with perfect immortality, which includes complete immutability; since every change is a kind of death, as Augustine says Contra Maxim. iii). The angels obtain perfect immutability only by favor, as will appear later Question 62).
6 Ad primum ergo dicendum quod Damascenus accipit immortalitatem perfectam, quae includit omnimodam immutabilitatem, quia omnis mutatio est quaedam mors, ut Augustinus dicit. Perfectam autem immutabilitatem Angeli non nisi per gratiam assequuntur, ut infra patebit.
7 Reply to Objection 2: By the expression gods' Plato understands the heavenly bodies, which he supposed to be made up of elements, and therefore dissoluble of their own nature; yet they are for ever preserved in existence by the Divine will.
7 Ad secundum dicendum quod Plato per deos intelligit corpora caelestia, quae existimabat esse ex elementis composita, et ideo secundum suam naturam dissolubilia, sed voluntate divina semper conservantur in esse.
8 Reply to Objection 3: As was observed above Question 44, Article 1) there is a kind of necessary thing which has a cause of its necessity. Hence it is not repugnant to a necessary or incorruptible being to depend for its existence on another as its cause. Therefore, when it is said that all things, even the angels, would lapse into nothing, unless preserved by God, it is not to be gathered therefrom that there is any principle of corruption in the angels; but that the nature of the angels is dependent upon God as its cause. For a thing is said to be corruptible not merely because God can reduce it to non-existence, by withdrawing His act of preservation; but also because it has some principle of corruption within itself, or some contrariety, or at least the potentiality of matter.
8 Ad tertium dicendum quod, sicut supra dictum est, quoddam necessarium est quod habet causam suae necessitatis. Unde non repugnat necessario nec incorruptibili, quod esse eius dependeat ab alio sicut a causa. Per hoc ergo quod dicitur quod omnia deciderent in nihilum nisi continerentur a Deo, et etiam Angeli, non datur intelligi quod in Angelis sit aliquod corruptionis principium, sed quod esse Angeli dependeat a Deo sicut a causa. Non autem dicitur aliquid esse corruptibile, per hoc quod Deus possit illud in non esse redigere, subtrahendo suam conservationem, sed per hoc quod in seipso aliquod principium corruptionis habet, vel contrarietatem vel saltem potentiam materiae.