Summa contra Gentiles2.55 Chapter LV. That intellectual substances are incorruptible

F'rom the foregoing it is clearly shown that every intellectual substance is incorruptible.

For all corruption consists in separation of form from matter: simple corruption, from separation of the substantial form, relative corruption from separation of an accidental form. Because so long as the form remains, the thing must exist, since by the form the substance is made the proper recipient of being. But where there is not composition of form and matter, there can be no separation of the same: wherefore neither can there be corruption. Now it has been proved that no intellectual substance is composed of matter and form. Therefore no intellectual substance is corruptible.

Moreover. That which belongs to a thing per se, is necessarily in it always and inseparably: thus roundness is per se in a circle and accidentally in a coin, wherefore it is possible for a coin to be made not round, whereas it is impossible for a circle not to be round. Now, being is a per se consequence of form, for per se means according as it is suchf and a thing has being according as it has a form. Hence substances that are not themselves forms, can be deprived of being, in so far as they lose a form, just as a coin is deprived of roundness according as it ceases to be round. "Whereas substances that are themselves forms can never be deprived of being: thus if a substance were a circle, it could never be made not round. Now, it was shown above that intellectual substances are themselves subsistent forms, therefore they cannot possibly cease to exist: and consequently they are incorruptible.

Further. In every corruption potentiality remains after the removal of act: for a thing is not corrupted into nonbeing, just as neither is a thing generated from absolute Ch. 1. I Poster, iv. 9.

non-being. But in intellectual substances, as we have proved, the act is being itself, while the substance is by way of potentiality. Consequently if an intellectual substance were corrupted, it will remain after its corruption: which is utterly impossible. Therefore every intellectual substance is incorruptible.

Again. In every thing that is corrupted there must be potentiality to non-being. Wherefore if there be a thing wherein there is not potentiality to non-being, such a thing is not corruptible. Now there is no potentiality to nonbeing in an intellectual substance. For it is clear from what we have said that a complete substance is the proper recipient of being. But the proper recipient of an act is compared as potentiality to that act in such a way that it is nowise in potentiality to the opposite: thus fire is compared to heat in such a way that it is nowise in potentiality to cold. Consequently neither in corruptible substances is there potentiality to non-being in the complete substance except by reason of the matter. But there is no matter in intellectual substances, for they are complete simple substances. Hence there is no potentiality to non-being in them. Therefore they are incorruptible.

Further. In whatsoever things there is composition of potentiality and act, that which holds the place of first potentiality, or of first subject, is incorruptible: wherefore even in corruptible substances primary matter is incorruptible. Now in intellectual substances that which holds the place of first potentiality and subject, is their complete substance. Therefore their substance is itself incorruptible. But nothing is corruptible except through its substance being corruptible. Therefore all intellectual natures are corruptible.

Moreover. Whatsoever is corrupted, is corrupted either per se or accidentally. But intellectual substances cannot be corrupted per se. Because all corruption is by a contrary, for an agent, since it acts according as it is an actual being, always brings something into actual being by its action.

Consequently, if by this same actual being, something is corrupted through ceasing from actual being, this must result from their mutual contrariety, since contraries are things which exclude one another. Hence whatsoever is corrupted per se must either have a contrary, or be composed of contraries. But neither of these can be said of intellectual substances. A sign of this is that in the intellect things even of contrary nature cease to be contraries: for white and black are not contraries in the intellect, since they do not exclude one another, in fact rather do they follow from one another, seeing that by understanding the one we understand the other. Therefore intellectual substances are not corruptible per se. Moreover, neither are they corrupted accidentally. For thus accidents and non-subsistent forms are corrupted. Now it was shown above that intellectual substances are subsistent. Therefore they are altogether incorruptible.

Further. Corruption is a kind of change: and change must needs be the term of a movement, as is proved in the Physics. Consequently whatsoever is corrupted must be moved. Now it was proved in the Physics that whatsoever is moved is a body. Hence it follows that whatsoever is corrupted is moved,—if it be corrupted per se,—or else that it is a form or a bodily force dependent on a body, if it be corrupted accidentally. But intellectual substances are neither bodies, nor forces or forms dependent on a body. Therefore they are not corrupted either per se or accidentally: and consequently they are altogether incorruptible.

Again. Whatsoever is corrupted, is corrupted through being passive to something, since to be corrupted is itself to be passive. Now no intellectual substance can be passive with such a passion as leads to corruption. Because to be passive is to be receptive: and that which is received into an intellectual substance, must needs be received according to the mode thereof, namely intelligibly. Now that which S, i-is thus received into an intellectual substance, perfects the intellectual substance and does not corrupt it, since the intelligible is the perfection of the intelligent. Therefore an intelligent substance is incorruptible.

Further. Just as the sensible is the object of sense, so the intelligible is the object of the intellect. But the sense is not corrupted by a proper corruption except through being excelled by its object, for instance the sight by very brilliant objects, and the hearing by very loud sounds, and so on. And I say by proper corruption: because the sense is corrupted also accidentally on account of its subject being corrupted. This kind of corruption, however, cannot happen to the intellect, since it is not the act of any body, as depending on the body, as we have proved above. And it is clear that it is not corrupted through being excelled by its object, because he who understands very intelligible things, understands things less intelligible not less but more. Therefore the intellect is nowise corruptible.

Moreover. The intelligible is the proper perfection of the intellect: hence the intellect in act and the intelligible in act are one. Accordingly, whatever is applicable to the intelligible, as such, must be applicable to the intellect, as such, since perfection and perfectible belong to the one genus. Now the intelligible, as such, is necessary and incorruptible, for necessary things are perfectly knowable by the intellect: whereas contingent things, as such, are only deficiently knowable, because about them we have not science but opinion, so that the intellect has science about corruptibles in so far as they are incorruptible, that is, according as they are universal. Therefore it follows that the intellect is incorruptible.

Again. A thing is perfected according to the mode of its substance. Consequently, we can gather the mode of a thing’s substance from the mode of its perfection. Now the intellect is not perfected by movement, but by the fact of its being outside movement: for we are perfected, as regards the intellective soul, by science and prudence, when the movement both of the body and of the soul’s passions are subdued, as the Philosopher states (7 Phys.). Hence the mode of an intelligent substance is that its being is superior to movement, and consequently superior to time: whereas the being of every corruptible thing is subject to movement and time. Therefore it is impossible that an intelligent substance be corruptible.

Further. It is impossible for a natural desire to be vain: since nature does nothing vainly. Now every intelligent being naturally desires everlasting being, and to be everlastingly not merely in its species, but also in the individual. This is proved as follows. The natural appetite, in some, results from apprehension: thus the wolf naturally desires the slaying of the animals on which it feeds, and man naturally desires happiness. In some it results without apprehension from the sole inclination of their natural principles, which inclination is, in some, called the natural appetite; thus a heavy body desires to be below. In both ways things have a natural desire for being: a sign of which is that not only things devoid of knowledge resist corruptives according to the power of their natural principles, but also those which have knowledge resist the same according to the mode of their knowledge. Consequently those things lacking knowledge in whose principles there is a power of perpetuating their being, so that they remain ever the same as to individual identity, naturally desire to be perpetuated even in their individual identity: whereas those whose principles contain no such power, but only the power of perpetuating their being in the same species, desire also to be perpetuated in this way. Hence we must observe this same difference in those things which have a desire of being, together with knowledge, so that, to wit, those who have no knowledge of being except as now, desire to be as now, but not to be always, because they do not apprehend perpetual being. Yet they desire perpetuity of the species, albeit without knowledge, because the generative power, which conduces to this effect, is a preamble and hi. 7. 2 De Calo xi.

not a subject of knowledge. Wherefore those things which know and apprehend perpetual being, desire it with the natural desire. Now this applies to all intelligent substances. Therefore all intelligent substances, by their natural appetite, desire to be always: and consequently it is impossible that they cease to be.

Further. Whatsoever things begin to be, and cease, have both through the same potentiality: because the same potentiality regards being and not being. Now intelligent substances could not begin to be except through the potentiality of the first agent: since they are not made out of matter that could exist before them, as we have proved. Consequently there is no potentiality in respect of their not being, except in the first agent, inasmuch as He is able not to pour being into them. But nothing can be said to be corruptible by reason of this potentiality alone:—both because things are said to be necessary and contingent according to a potentiality that is in them, and not according to God’s potentiality, as we proved above—and because God, the Author of nature, does not lake from things that which is proper to their respective natures; and it was shown above that perpetual being is a property of intellectual natures, wherefore God will not take this from them. Therefore intellectual substances are in every way incorruptible.

Hence in the psalm, Praise ye the Lord from the heavens, after mentioning together the angels and heavenly bodies, the text continues: He hath established them for ever and for ages of ages, thus designating the perpetuity of the aforesaid.

Dionysius also (Div. Nom. iv.) says that on account of the rays of the divine goodness the intelligible and intellectual substances subsist, are, and live: and their life never fails nor diminishes, for they are free from the universal corruption, knowing neither generation nor death, and they are raised above restless and ever-flowing change.