The questions from last week are resolved today. This is a long and deep one, my friends.
1 Now, toward a solution of these difficulties this consideration is required: God, as was said, above, when He established human nature, granted the human body something over and above that which was its due in its natural principles: a kind of incorruptibility, namely, by which it was suitably adapted to its form, with the result that, as the life of the soul is perpetual, so the body could live perpetually by the soul.
2 And this sort of incorruptibility, although not, of course, natural in its active principle, was somehow natural in its order to the end; namely, as matter would be ordered to its natural form, which is the end of the matter.
3 When the soul, then, outside the order of its nature, was turned away from God, that disposition was lost which had been divinely bestowed on the soul’s body to make it proportionally responsive to the soul; and death followed. Death, therefore, is something added as an accident, so to say, to man through sin, if one considers the establishment of human nature.
4 But this accident was taken away by Christ, who by the merit of His passion our “death by dying did destroy.” From this, then, it follows that by the divine power which gave the body incorruption the body may once again be restored from death to life.
5 In this way, then, one must answer the first argument that the power of nature fails the divine power, as the power of an instrument fails the principal agent. Granted, then, that the operation of nature cannot bring it about that a corrupted body be restored to life, the divine power can bring it about. The reason nature is unable to do this is that nature always operates by a form. But what has a form, already is.
When it was corrupted, of course, it lost the form which was able to be the principle of the action. Hence, by natures operation, what was corrupted cannot be restored with a numerical identity. But the divine power which produced things in being operates by nature in such wise that it can without nature produce natures effect, as was previously shown. Hence since the divine power remains the same even when things are corrupted, it can restore the corrupted to integrity.
Notes In other words, a miracle. If God can create the universe, constructing a new body for you is nothing.
6 What is stated in the second objection, however, cannot be an obstacle to man’s ability to rise with numerical identity. For none of man’s essential principles yields entirely to nothingness in death, for the rational soul which is man’s form remains after death, as was shown above; the matter, also, which was subject to such a form remains in the same dimensions which made it able to be the individual matter. Therefore, by conjunction to a soul numerically the same the man will be restored to matter numerically the same.
7 Corporeity, however, can be taken in two ways. In one way, it can be taken as the substantial form of a body as it is located in the genus of substance. Thus, the corporeity of any body is nothing else but its substantial form; in accord with this it is fixed in genus and species, and to this the bodily thing owes its having three dimensions. For there are not different substantial forms in one and the same thing, by one of which it is placed in the supreme genus—substance, say; by another in its proximate genus—body or animal, say; and by another in its species—say man or horse.
Since, if the first form were to make the being substance, the following forms would be accruing to that which already is actually a definite something (hoc aliquid), and subsisting in nature; thus, the later forms would not make a definite something, but would be in the subject which is a definite something as accidental forms.
Therefore, corporeity, as the substantial form in man, cannot be other than the rational soul, which requires in its own matter the possession of three dimensions, for the soul is the act of a body. Another way of taking corporeity is as an accidental form; in accord with this one says a body is in the genus of quantity. And corporeity thus is nothing other than the three dimensions which constitute the character of body. Therefore, although this corporeity yields to nothingness when the human body is corrupted, it cannot, for all that, be an obstacle to the body’s rising with numerical identity; the reason is that corporeity taken in the first way does not yield to nothingness, but remains the same.
8 In the same fashion, also, the form of a compound can be taken in two ways. In one way it is so taken that by form of a compound one understands the substantial form of the compound body. And thus, since there is not in man any other substantial form than the rational soul, as was shown, one will not be able to say that the form of the compound, as it is the substantial form, yields to nothingness when man dies. Taken in a second way, a form of the compound is called that certain quality which is composed and balanced from the mixture of the simple qualities, and stands to the substantial form of the compound body as the simple quality stands to the substantial form of the simple body. Hence, although the form of the compounding when thus stated yields to nothingness, this is not prejudicial to the unity of the body arising.
9 Thus, also, must one speak of the nutritive part and the sensitive part. For, if by sensitive part and nutritive part one understands those very capacities which are the natural properties of the soul, or, better, of the composite, then, when the body is corrupted, they are corrupted; nonetheless, this is no obstacle to the unity of the one arising. But, if by the parts mentioned the very substance of the sensitive and nutritive soul is understood, each of those parts is identified with the rational soul. For there are not three souls in man, but only one, as was shown in Book II.
10 But, in speaking of humanity, one should not understand it as a kind of form coming forth from the union of the form to the matter, as though it were, really other than each of the two, because, since by the form the matter is made this actual something, as De anima II  says, that third form following would be not substantial, but accidental.
Of course, some say that the form of the part is the same as the form of the whole: it is called form of the part in that it makes the matter actual being, but it is called form of the whole in that it completes the species essentially. In this way, humanity is not really other than the rational soul. Hence, clearly, when the body is corrupted it does not yield to nothingness.
But humanity is the essence of man. The essence of a thing, of course, is, what the definition signifies; and the definition of a natural thing does not signify the form alone, but the form and the matter. Therefore, necessarily, humanity signifies something composite of matter and form, just as “man” does. Differently, nevertheless; for “humanity” signifies the essential principles of the species, both formal and material, prescinding from the individual principles.
Humanity is used so far as one is a man; one is not a man by reason of having the individual principles, but only by having the essential principles of the species. Humanity, therefore, signifies only the essential principles of the species. Hence, it is signified in the way in which a part is signified. “Man” truly signifies the essential principles of the species, but does not exclude the individuating principles from .its signification, for he is called man who has humanity, and this does not shut out the ability to have other things. For this reason, man is signified as a whole is, for it signifies the essential principles actually, but the individuating principles potentially.
“Socrates,” however, signifies each set of principles actually, just as the genus contains the difference in potency, but the species contains it actually. Hence, it is clear that man returns numerically the same both by reason of the permanence of the rational soul and by reason of the unity of matter.
11 However, what is said in the third argument—that being is not one because it is not continuous—rests on a false foundation. For, clearly, the being of matter and form is one; matter has no actual being except by form. Nonetheless, in this respect the rational soul differs from other forms. For there is no being of other forms except in their concrete union with matter, since they exceed matter neither in being nor in operation. But the rational soul plainly exceeds matter in its operation, for it has an operation in which no bodily organ takes part; namely, the act of understanding. Hence, its being, also, is not merely in its concrete union with matter. Its being, therefore, which is that of the composite, remains in the soul even when the body is dissolved; when the body is restored in the resurrection, it is returned to the same being which persisted in the soul.
12 The fourth objection, also, fails to remove the unity of the one who rises. For what is no obstacle to a man’s numerical unity while he continues to live manifestly cannot be an obstacle to the unity of one who rises. But in the body of man, so long as he is alive, it is not with respect to matter that he has the same parts, but with respect to his species. In respect to matter, of course, the parts are in flux, but this is not an obstacle to his being numerically one from the beginning of his life to the end of it.
An example of this can be taken from fire: While it continues to burn, it is called numerically one because its species persists, yet wood is consumed and new wood is applied. It is also like this in the human body, for the form and species of its single parts remain continuously through a whole life; the matter of the parts is not only resolved by the action of the natural heat, but is replenished anew by nourishment.
Man is not, therefore, numerically different according to his different ages, although not everything which is in him materially in one state is also there in another. In this way, then, this is not a requirement of man’s arising with numerical identity: that he should assume again whatever has been in him during the whole time of his life; but he need assume from that matter only what suffices to complete the quantity due, and that especially must be resumed which was more perfectly consistent with the form and species of humanity.
But, if something was wanting to the fulfillment of the quantity due, either because one was overtaken by death before nature could bring him to the quantity due or because mutilation perhaps deprived him of some member, the divine power will supply this from another source. This, however, will be no obstacle to the unity of the body of the one rising, for even the work of nature adds to what a boy has from some other source to bring him to his perfect quantity. And this addition does not make him numerically other, for the man is the same in number whether he is boy or adult.
Notes The ship of Thesus paradox resolved.
13 From this it is clear, also, that there is no obstacle to faith in the resurrection—even in the fact that some men eat human flesh, as the fifth objection was maintaining. For it is not necessary, as has just been shown, that whatever has been in man materially rise in him; further, if something is lacking, it can be supplied by the power of God.
Therefore, the flesh consumed will rise in him in whom it was first perfected by the rational soul. But in the second man, if he ate not only human flesh, but other food as well, only that will rise in him which came to him materially from the other food, and which will be necessary to restore the quantity due his body. But if he ate human flesh only, what rises in him will be that which he drew from those who generated him, and what is wanting will be supplied by the Creator’s omnipotence.
But let it be that the parents, too, have eaten only human flesh, and that as a result their seed—which is the superfluity of nourishment—has been generated from the flesh of others; the seed, indeed, will rise in him who was generated from the seed, and in its place there will be supplied in him whose flesh was eaten something from another source. For in the resurrection this situation will obtain: If something was materially present in many men, it will rise in him to whose perfection it belonged more intimately.
Accordingly, if something was in one man as the radical seed from which he was generated, and in another as the superfluity of nourishment, it will rise in him who was generated therefrom as from seed. If something was in one as pertinent to the perfection of the individual, but in another as assigned to the perfection of the species, it will rise in him to whom it belonged as perfection of the individual. Accordingly, seed will arise in the begotten, not in his generator; the rib of Adam will arise in Eve, not in Adam in whom it was present as in a principle of nature. But, if something was in both in the same degree of perfection, it will rise in him in whom it was the first time.
14 Now, however, what is said in the sixth objection can be answered from what has been said. Resurrection is natural if one considers its purpose, for it is natural that the soul be united to the body. But the principle of resurrection is not natural. It is caused by the divine power alone.
15 Nor must one deny that there will be a resurrection of all, although not all cleave to Christ by faith, and are not imbued with His mysteries. For the Son of God assumed human nature to restore it. Therefore, what is a defect of nature will be restored in all, and so all will return from)death to life. But the failure of the person will not be restored except in those who have adhered to Christ; either by their own act, believing in Him; or at least through the sacrament of faith.