The first of these occurs in four ways. Either the two things can be joined in one thing that is the same in number: thus the two arms are joined in the chest, or two branches that touch only in the one trunk. Or they may be one in virtue of their species, as Socrates and Plato are joined in man. Or they may be one in genus, as man and donkey are joined in animal. Or they may be one by analogy or proportion, as substance and quality are joined in being; for just as substance is related to the existence appropriate to it, so also is quality related to that existence suitable to its genus. Now, things that are joined to each other in some one thing constituted from their union are like matter and form; for form is joined to matter as its perfection, and both are joined together in their common nature. Similarly, the parts of continuous quantity are joined to each other in such a way that a certain whole arises from them, in which the two parts share. And those things that are united to each other but not in some one thing are like an accident and its subject. What is produced out of these is not something one through itself, of which the subject and its accident could be called parts, as is proved in the Metaphysics 8.¹

Now, because there is no comparison of earthly things to God, as Hilary says in On the Trinity I,¹ nor will human reason furnish a parallel adequate to divine things. It must be known that none of these modes is entirely suitable to the ineffable union by which God has been united to man. Nonetheless, some of these modes do represent that mode of union in a certain respect. Therefore, one should know that the middle mode by which things are united to each other—such that from them some third thing results—does not belong to God in any way. For two things that are joined together in this way relate to the third as its parts, but the notion of a part, like that of the imperfect, is altogether remote from God.

The first and third ways, however, can belong to God in a certain respect. For on the part of the one assuming, two things can be considered in the Incarnation—namely, the person and the nature. Now, if we consider the person who is assuming, then it is united to the human nature being assumed according to the third mode of being joined; for the divine person does become a person of this human nature, but no third thing arises from these two things. Likewise in the case of Socrates, no third thing arises out of his person and nature, but rather his person subsists in his human nature. However, if we consider the nature of the one assuming, then its union to human nature is according to the first way of being united, inasmuch as the two natures come together in one person, while in their natural properties they are nevertheless distinct. This is why the Incarnation is compared to grafting. For just as, in grafting, in the same trunk where there was one branch by nature another branch is grafted, likewise, in the same person in whom the divine nature existed naturally, a human nature exists by union. However, it is impossible for God and a created thing to share in one genus or species, but it is possible by analogy. But this was the case from the time that created things began to be, and therefore this is not relevant to the present question.

This is how it is in the point at issue. For the Creator can be referred to the thing created only insofar as the thing created, in which the relation really exists, is referred to him, as was said in Book I, Distinction 30.¹ For this reason, God is said to be united not through a change of himself, but through a change in that to which he is being united. And likewise, when he is said to be capable of union, this is not said on account of any passive power existing in God, but on account of a power in the creature such that it can be united to him.

Or it could be said that the expression “capable of union” does not mean a passive power, but an active one. Yet this response is unsuitable for two reasons. First, from the very signification of the expression, since “capable of union” signifies what is able to be united, whereas “unitive” signifies what is able to unite. Second, because a power belongs to whatever performs the action, so, because the action of uniting belongs to the whole Trinity without distinction, then if “capable of union” indicates an active power of uniting, it will belong to the whole Trinity without distinction, and will not belong more to the Son, as it says in the text.¹

Furthermore, James 4:6 says, God opposes the proud. But it is through pride that the devil, being envious of man, resolved to make him his slave, and held him in servitude unjustly, since man was created for the service of God. Therefore it was becoming that almighty God oppose the wickedness of the devil, so that not only would he snatch man from the devil’s power, but would also effect a reversal, establishing man as the lord of the devil. But since nothing created is above the angelic nature, which the devil has, this could not be unless the man who did this were lord of the angels—which belongs to God alone. Therefore it was becoming that God become man, so that thus, at the name of Jesus every knee should bow, in heaven and on earth and under the earth (Phil 2:10).

Therefore one should know that, given the fall of human nature, the suitability of the Incarnation is apparent from three things: the fullness of divine mercy, the unchangeability of God’s justice, and the order befitting his wisdom. Therefore, because God is supremely good and merciful, it was becoming that he not deny to anything what lay in its capacity. Therefore, since human nature had fallen and yet was capable of being restored, it was becoming that he should restore it. Also, because his justice, whose law has ordained that sin is never forgiven without making satisfaction, is unchangeable, it was becoming that he establish in human nature one who was able to make satisfaction—for a mere man was not able to do so by himself, as will be said below.¹ But because he is supremely wise, he should go to the most suitable mode of restoration, whereas the most suitable mode is that nature be restored integrally, and that man should be able to attain easily what he had lost. Now, if he had restored man through an angel, the restoration would not be integral, for then man would always be indebted for his salvation to the angel, and thus could not be made equal to the angel in beatitude. Yet man would have attained this if he had not sinned, just as men do so now through the grace of restoration, so that they are like angels in heaven (Matt 22:30). And for this reason, it was fitting that God himself, rather than an angel, restore man. Likewise, so that there would be an easy way of ascending to God, it was fitting that man rise to God from the things that are known to him in virtue of both his understanding and his affections. And because it is connatural to man, according to his present state of misery, to receive knowledge from visible things and to have affection for them, God fittingly became visible by assuming human nature, so that we might be caught up out of visible things into the love and knowledge of invisible things.²

The first proceeds from the natural powers of each. In regard to the cognitive power, the angel understands in a full light, through his godlike intellect, so he is able to consider all that pertains to the choice of something, without investigation. As such, the angel has no excuse on account of ignorance, as man does, who only knows the things that should be done by deliberating through his reason, which is, as it were, a certain of dimness of understanding, as Isaac says in the book On Definitions.¹ In regard to the affective power, it is because after making its choice, the will of the angel cannot turn back—for the will of the angel is below the divine will, which cannot turn back either before or after, and above the human will, which can turn both before and after. Therefore, the angel adheres unchangeably to the evil that he desired by sinning.

A second reason is taken from the nature of each. For unlike human nature, the nature of the angels is not propagated from one of them, from whom it contracts sin. And therefore neither is it fitting that the angelic nature be restored through one of the angels. This is what the Apostle seems to say in Romans 5:12: as sin came into the world through one man and death through sin, and so death spread to all men because all men sinned.

A third is taken from the sin of each. First, with respect to the kind of sin: because man was arrogant in his appetite for a knowledge that a created nature is capable of, but the angel’s arrogance arose from an appetite for a power that a created nature cannot receive as perfectly as it receives knowledge. It is also for this reason that omniscience, but not omnipotence, was communicated to Christ’s soul. And second, with respect to the circumstance of the sin: because in sinning, man also thought about the possibility of forbearance, and was also deceived in a certain respect, as stated in Book II.¹ But this was not the case when the angel sinned. And likewise, with respect to the occasion of the sin, wherein the man sinned at the suggestion of another, but the angel did not.

A fourth reason is taken from the divine justice. For all of those to whom the corruption of the first man’s sin was due come did not yet exist in act, but only in power. Thus it was not fitting that, before they existed, they should receive their final damnation like all of the angels who, existing in act, sinned by their own choice.

A fifth reason is taken from the divine mercy. For the entire human nature fell in the one parent, but the entire angelic nature did not fall. For this reason, it was more unbecoming that the entirety of human nature should be abandoned to damnation than that this should happen to the angelic nature, which had not been ruined as a whole.

The sixth and chief reason proceeds from the state of each. For man did not sin at the end of his way as the angel did, for whom the state of being “on the way” ended at his own choice. And this argument harmonizes with Damascene’s statement that what the fall is for the angels, so is death for men,¹ as was said in Book II.²

Now, as was said above, the action of the one making satisfaction is proportioned to the magnitude of the fault in respect of the good that is corrupted through that fault. And since every action belongs to a person, since acts belong to individuals, in order to make satisfaction for an actual sin, the act of any man whatsoever, together with divine grace, would suffice. However, this would not suffice to make satisfaction for original sin—unless the action of that man were of a greater value than the whole good of human nature. And this could not be the case if he were a mere man. And therefore the one who was to make satisfaction for original sin needed to be God and man.

Or it should be said that, according to some,¹ a mere man is not sufficient to make satisfaction even for actual sin unless the satisfaction made by Christ is presupposed, whose suffering gave efficacy even to the satisfaction made by the patriarchs, who were saved through faith in him.

First, everything created is in debt to God for all that it is capable of; whence, this leaves to it no capacity for making satisfaction on behalf of another.

Second, in making satisfaction, the one who makes satisfaction must give back something that outweighs, or is at least equal to, what was taken away through the offense. Now, although there is a created nature which is or can be better than human nature, nonetheless no nature in any person considered as created can equal the goodness of the whole of human nature. For the good of the human nature is in a certain way infinite in comparison to supposits,¹ inasmuch as human nature is, through generation, endlessly communicable. However, the good of any created nature whatsoever is both finite in itself, and is rendered finite insofar as it is considered in one determinate supposit. And therefore, since acts belong to supposits, it cannot be that the activity of any created thing is of as great a value as the whole good of human nature, such that it could be a worthy satisfaction for the restoration of that nature.

The third reason is that, as was said in Book II,¹ human nature in its original condition received certain things through which it was elevated above the state befitting its proper principles—such as a certain immortality that proceeded from grace, not nature, as well as other such things bestowed upon it by the sheer generosity of God—and it lost these through sin. Whence, to restore this nature he elevated it to that loftier level wherein he had previously established it. However, raising any nature to a higher level is only possible to the one who established the natures and ordained their levels; and thus only God was able to restore human nature.

Furthermore, 1 Timothy 1:15 reads, Christ Jesus came into the world to save sinners. Here Augustine’s gloss says that the only cause of Christ’s coming was to save sinners: take away wounds, take away diseases, and there is no cause for medicine.¹ But if the cause is removed, so too is the effect. Therefore if there had been no sin, the Son of God would not have been incarnate.

But others say that, since what was accomplished through the Incarnation of the Son of God was not only liberation from sin, but the exaltation of human nature and the consummation of the whole universe, there would have been an Incarnation for these reasons, even if there had been no sin. This position can also be maintained with probability.

Reply Sed Contra: As for the arguments to the contrary, it could be answered that, according to the second opinion mentioned in the main response, those authorities are speaking of his coming into flesh that is able to suffer for the sake of redemption (for there would have been no redemption unless the servitude to sin had preceded it), and not of his coming into flesh simply speaking.

The first is that, because man had sinned through pride, it was necessary that he be restored through humility, and this required him to recognize his own lack in power and knowledge. Now, the deficiency of his knowledge was made known to man in the time of nature’s law, in which many fell into the worst errors of idolatry and into the most abominable deeds without the light of natural reason making any opposition. Furthermore, the deficiency of his power, properly speaking, was made known to man in the time of the written law. For at that time, although instructed by the law, he was not yet able to shake off the yoke of sin. And therefore it was necessary that God become man after these two periods of preparation, as it were, so that he might place his hope of salvation in God alone.

The second reason is that the natural order is to go from the imperfect to the perfect. But the most perfect among God’s works is the Incarnation itself, through which a created thing is united to God in the unity of a person. For this reason, it was necessary that this work come to fufilment not at the beginning of the human race but later, towards the end of all time; thus what was animal would come first, and then what was spiritual, as it says in 1 Corinthians 15:44. Augustine assigns this reason in his On 83 Questions, where he says, it would be absurd if one were to wish that young adulthood be the only age of man, for he would thus abolish the excellences which manifest their succession and order in the other ages. In like manner, it would be absurd to desire a single age for the entire human race. For the race too lives through its own ages, just as one single man does. Nor was it necessary that the divine teacher, by imitating whom the human race might be formed in the most excellent mores, come in every age but only in the age of its young adulthood.¹ And for this reason the Apostle says in Galatians 3:23 that under the law people were like little children in the custody of a tutor, until the one who had been promised through the prophets came.

The third reason is that a greater distance from the beginning weakens its effect. This is also why certain things are unable to last so as to remain forever the same in number: because they are far distant from the beginning. Therefore, if that greatest of remedies, the Incarnation, had taken place at the beginning of all time, its effect would, with the passing of time, have been less prized among men as their love grew cold. For this reason, from the beginning of the human race the natural law was implanted in men’s minds, through which law men might be subject to God; but afterwards, as the habit of sinning grew strong, the natural law was, for the majority of men, darkened to such a point that it seemed insufficient for governing the human race. That is why another remedy was added then: the Old Law and the things pertaining to it. And when this, too, grew weak in men’s hearts with the lapse of time, it was necessary that another, more perfect remedy be applied through the Incarnation, until that time when the love of many will grow cold. Then, through the Second Coming, faith will give way to vision, and the present state of the Church to the state of glory. Accordingly, Dionysius says in the Celestial Hierarchy, that the hierarchy of the law is related to our hierarchy just as ours is related to the heavenly one.¹

Furthermore, the Incarnation includes in its understanding being sent, as it says in the text.¹ But for one divine person to be sent, it does not follow that all would be sent. Therefore one person can be incarnate without the others.

Therefore, I say that the three persons are indeed distinguished in personhood, but they come together in their nature. For this reason whatever might be united to the Son in his nature, of necessity would be united to the Father. However, if something were united to the Son in his person, it is not necessary that it be united to the Father. For we do not hold the Incarnation of the Son to exist in such a way that the union happened within the nature, but only within the person. And therefore it need not be that we consider the Father to be incarnate, just as it need not be that if the visual power were an act of the body, the intellect would be an act of the body, although they come together in the soul’s essence.

Furthermore, according to the Philosopher,¹ what is first in any genus is the cause of those things that come after. But sonship is found first in the Son of God, just as fatherhood is first in God the Father, from whom all fatherhood in heaven and on earth is named (Eph 3:15).² Therefore the Son of God became incarnate most fittingly, so that through him we might receive adoption as sons of God.

Now, four things can be considered proper to him: namely, that he is a Son, that he is a Word, that he is an image, and that he is the middle person within the Trinity.

However, insofar as he is an image, he has an affinity with the one who needed to be restored—that is, man, who was made according to the image of God (Gen 1:27). And so it was becoming that the uncreated image assume the created image.

Moreover, insofar as he is a Son, he was suited to the mode of reparation, which was fulfilled by the mysteries of the Incarnation and Passion. For insofar as he is from another, which of course is common both to him and to the Holy Spirit, the Father’s authority relative to him is indicated. This is why also prayer, satisfaction, and other things like this that show the authority of the Father befit him in relative to the Father. But insofar as we understand in the Son a determinate mode of origin, it befits him to be born, so that the one who is the Son of God in divinity might be the Son of the Virgin in his humanity—such that there would not be several sons within the Trinity. It also befits him as a natural son, such that through him whose inheritance is natural, others would be adopted as sons and become co-heirs.

But insofar he is the Word, the Incarnation has a certain congruence with the office of preaching and teaching. For a word makes known the one speaking, and he himself has made known the Father: I have manifested thy name to the men whom thou gavest me (John 17:6).

And insofar as he is the middle person in the Trinity, it fits with the ultimate effect, which is the reconciliation of man with God. For it is becoming that the one who is in the middle also to be a mediator.

In addition, four things are found to have been appropriated to the Son: namely, wisdom and power—by the Apostle: Christ the power of God and the wisdom of God (1 Cor 1:24)—equality, by Augustine,¹ and splendor and beauty, by Hilary.²

Now, insofar as he is wisdom, he is suited for our restoration, for it is becoming that what was made in wisdom be restored by wisdom. Also, man had fallen into the slavery from which he needed to be freed by a kind of seduction, so it was becoming that he should be freed from the seducer by wisdom. Also, man himself sinned through his desire for knowledge, and so he was to be freed through wisdom.

However, insofar as he is the power and arm of the Father, he is suited to seizing the victory from the enemy: he has shown strength with his arm (Luke 1:51).

But insofar as he is equality, he also corresponds to the sickness that was to be healed. For both man and the devil had sinned by seeking equality, the former in knowledge, the latter in power.

And insofar as he is splendor and beauty, he is suited to restoration, so that the disfiguring of the image through sin might be undone through him himself. But being incarnate does not befit the Father, especially because of his property of innascibility; for it is not becoming that he who is the Father in the Godhead should be a son in humanity. For then the Son of God the Father would be the grandson of the Virgin, if the Virgin herself were the mother of God the Father. Likewise, this also does not befit the Holy Spirit, otherwise the name “son” should be applicable to more than one divine person.

Furthermore, the joining of things equally distant is equally possible. But human nature is equally distant from the three persons, being at an infinite distance from every one of them. Therefore, if the Son was able to assume flesh, so is the Father.

Therefore, since his absolute power is infinite, everything that is something in itself and that does not tend toward a lack of power must of necessity be attributed to it. Now, I say “something in itself,” because the joining of an affirmation and a negation is nothing, and neither is any understanding produced when “man” and “not-man” are said to be taken together, as though by the force of a single expression. This is why God’s power does not extend as far as allowing an affirmation and a negation to exist together; and the same is true of all things that involve a contradiction. However, I call "tending toward the lack of power” those things that imply that the power’s suffering. For it happens from an active power’s lack of resistance that something is corrupted, or divided, or something of this sort. So too softness is said to be a natural powerlessness because of being easily divisible. And it is for this reason that we do not say that God, in the nature of his Godhead, has the power to suffer, or die, or anything of this sort, just as we do not say that he has the power of being powerless.

Now, when something that he wills to do and which his wisdom holds that he do is attributed to this power considered absolutely, then he is said to be capable of it in virtue of his ordained power. However, when his power, in respect of itself, extends to what is attributed to it, even though his wisdom and will do not hold that it be done in this way, then he is said to be able from his absolute power only. In the latter case, however, one must make a distinction. For among these things, some are inseparably joined to something that is in itself repugnant to the divine wisdom and goodness, such as sinning, lying, and such; these we also say that God is not able to do. But there are certain others that are in no way unfitting to the divine wisdom of themselves, but merely do not befit some ordination of his foreknowledge, which God, according to his own will, has established or foreseen; for example: that man’s head should be his lowest part. God is able to do this, since he is able to establish a different order in things, in virtue of which what now is seen to be unfitting, according to the order now present in things, would then be fitting.

Therefore, in this way there are four distinctions or orders among things that can attributed to the divine power. For certain things are not attributed to that very power absolutely; whence these things he is, simply speaking, not able to do—to suffer, for example, and to make contradictories coexist. But certain others are opposed to his wisdom and goodness in themselves, and we do not say that God is able to do them, except under a condition—namely, if he should will it. For it is not unfitting that the antecedent of a true conditional be impossible. And also certain others are not repugnant in themselves, but only because of something external to them, and it must be conceded absolutely that God is able to do such things from his absolute power; nor should they be denied [from his power] except under a condition—namely, it might be said that he is not able to do this if it is opposed to his will. Finally, there are certain things that are attributed to his power such that they conform to his will and wisdom; and these God must be said to be able to do simply speaking, and to be in no way unable to do them.

Therefore we should say that the Father becoming incarnate is not among those things that are not subject to the absolute power of God, since it neither implies a contradiction, nor does it assert any defect in the incarnate person—for the Father and the Son are of the same dignity, and the same account of personhood belongs to both. Nor is it among those things which of themselves involve something unfitting. Rather, it is among those things that involve unfittingness on account of another ordination established by God’s wisdom. But that the Son be incarnate belongs to the fourth order. And therefore it must be conceded without qualification that the Father was able—speaking of his absolute power—to assume flesh, and the Holy Spirit likewise.

But that the nature assumed by the three persons might be one by the unity of an individual nature is not impossible, if we are speaking about his absolute power—although it would not be fitting according to the order of divine wisdom, since one person’s becoming incarnate would suffice for the restoration of a thousand worlds. However, I call it a “unity of an individual nature” if one body is assumed with one soul united to it, and one humanity resulted from this union, such that the three persons could share in one assumed nature just as they share in their eternal nature. But on the other hand, some people hold the opposite opinion, and the objections can be answered according to either.

Reply Sed Contra: To the things said to the contrary, one can respond, according to the others, that a unity of supposit would in a certain way follow on the unity of the nature, according to them. And this cannot be.¹

The fullness of time.¹ One should note that the time of the Incarnation is called “the fullness of time” for many reasons. First, it is so called on account of the perfection of the universe; for when all created things returned to their beginning in man by a human nature having been assumed by God, then the universe came to its greatest completion. So it is said in Ephesians 1:10, as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth. Second, it is called this on account of the abundance of the grace that was poured forth at that time, as it says in John 1:16: and from his fullness have we all received, grace upon grace. Third, on account of the fulfillment of the law, as Matthew 5:17: I have come not to abolish them but to fulfill them. Fourth, on account of the magnitude of that which happened in that time, for in that time the Lord of time was born, and thus something greater than time was made, something that fulfilled time. Fifth, because at that time was fulfilled what God foresaw from eternity, and what he foretold through his prophets, according to Romans 1:2.

Made of a woman.¹ On the contrary, in the Creed we say, begotten, not made. Furthermore, a woman implies a corruption, but Christ was born of the most uncorrupted Virgin, so it was not fittingly said that he was made of a woman. But it should be said to the first point that, in reference to his divine nature, the Son of God was in no way made; rather, he was begotten. But in reference to the human nature that he assumed, he is something created. Nevertheless, Christ cannot be said to be “made” simply speaking, but the Son of God is said to be “made man.” To the second point it should be said that the woman is noted here to designate a sex, not to designate any corruption, just as the rib taken from Adam is said to have been formed into a woman, although Eve at that time was made as a virgin.

Made under the law.¹ On the contrary, 1 Timothy 1:9 says that the law is not laid down for the just but for the lawless, whereas Christ was most just, so he was not made under the law. But it should be said that something is said to be “under the law” in three ways. First, it is under it as its mover; and in this way those who keep the precepts of the law out of fear of the penalty that the law inflicts, as though burdened and coerced by it. And in this way the just man is not under the law, because he acts out of love of justice, even if there is no law, as is said in Romans 2:14–15. In another way, someone is said to be under the law as regards his cause; and in this way all born in sin are under the law, because the sacraments of the law were instituted to take away sin. In another way, someone is said to be under the law as regards the observance of the law; and in this way Christ was made under the law, for he fulfilled the sacraments and precepts of the law—not by any necessity, as do others, but only by his will.

So as to redeem those who were under the law.¹ On the contrary, 1 Timothy 2:4 says he desires all men to be saved, and thus he came to redeem not only the Jews, who were under the law, but also for others. But it should be said that although he came to redeem the entire human race, still in a specific way he did this for the redemption of the sons of Israel, because he preached to them in person; whence Matthew 15:24 says, I was sent only to the lost sheep of the house of Israel. And through them the word of life was poured out among the nations; whence Isaiah 27:6 says, Jacob shall take root, Israel shall blossom and put forth shoots, and fill the whole world with fruit. This is the evangelizing woman spoken of in Luke 15:8–10. Note also that divine wisdom is called a woman not on account of any weakness, but on account of its fertility, as in Sirach 24:19, eat your fill of my produce.

Nor that the same Trinity descended over Jesus in the form of a dove.¹ On the contrary, in that dove there was nothing that would not be common to the whole Trinity, since it was not assumed into a unity of any person, since the whole Trinity did this with a shared operation; and the whole Trinity was in it the way it is in all created things, through its essence, presence, and power. And thus it appears that it pertained to the whole Trinity.

But it should be said that that dove can be considered in two ways. For it can be considered insofar as it is real thing, whether it was the animal or only something bearing the likeness of the animal; and in this way it pertains to the whole Trinity as its common effect. Or it can be considered insofar as it is a sign; and in this way it pertains only to the Holy Spirit, whose invisible sending forth is indicated through the arrival of the dove. About this visible sending and others we have spoken in Book I.¹

But the power of God can be considered in two ways: either as absolute, or as ordained. How this should be understood is evident from what was said in Distinction 1.¹ Now, speaking about God’s absolute power, God can assume any created thing he wants. Whence, in this respect, no created thing is more assumable than any another. However, in speaking of his ordained power, he is able to assume the created thing that it is suitable that he assume, given the order of his wisdom. This is why the created thing in which such a suitability is found is said to be assumable. However, this suitability is found in the human nature above others in virtue of three things that are required in the assumption.

First, in virtue of the likeness of the things united. For a more express divine likeness is found in human nature than is found in any irrational created thing. For man, insofar as he has a mind, is said to be made according to the image of God, while in irrational created things there is found only the likeness of a trace. And in certain respects, the divine likeness is even more in human nature than in the angelic nature, as will be said below.

Second, in virtue of the endpoint of the assumption. For the assumption terminates in the unity of the person; but personhood is not found in irrational natures, since a person is an individual substance of a rational nature, as Boethius says.¹ In the angels there are persons, of course, but not persons distinct according to their origin, since one angel does not draw its origin from another, whereas in human nature the persons are distinct according to their origin. Therefore, human nature is most fittingly assumed into the unity of a divine person—which persons are distinguished according to the relation of origin.

Third, in virtue of the end of the assumption. For if the perfection of the universe is said to be the principal end of the assumption, as some say, then no particular nature could have been assumed through which the universe could be perfected as much as it is perfected through the assumption of a human nature. This is so, first, because man is the last of created things, as though created at the limit, and when his nature is assumed, the last is conjoined to the first beginning in the manner of a circle, which is a perfect figure insofar as it admits no addition. And second, this is so also because in a certain way all natures flow together in man, since he holds something in common with all created things, as Gregory says.¹ Therefore, by man being united to God, every created thing is in a certain manner also united to God.

But if liberation from sin is set forth as the end of the assumption, then in this way as well human nature alone was able to be suitably assumed. For there was no sin in anything irrational that was created. There was sin, of course, in the angelic nature, but it was irredeemable, as is evident from what was said.¹ But in man sin was redeemable, and therefore it was fitting to assume human nature alone. And having restored it in this way, so too is restored irrational creation, which is said to have deteriorated in a certain way on account of man’s sin, insofar as it yields to man’s use.

To the first question, I answer that, concerning his absolute power, God was able to assume an irrational created thing. Nor is this impeded by the fact that an irrational created thing has no personhood, because personhood is not owed even to the assumed human nature, by reason of itself, as will be clear below in Distinction 6,¹ but only by reason of the one assuming it; this is why here there is only the uncreated personhood. Furthermore, even though a person is not found in an irrational nature, still a hypostasis, and supposit, is found in it, whereas the union is made not only in the person, but in the hypostasis and supposit as well. But it was not fitting that it be assumed, and especially so because the assumed nature is beatified to the highest degree, as is said in Psalm 65:4, blessed is he whom you have chosen and assumed.² But the irrational created thing cannot partake of beatitude, which consists in an act of the mind.

To the second question, it should be said that when speaking of his absolute power, God was able to assume an angelic nature. But the angelic nature did not have any suitability for being assumed, chiefly for two reasons: first, because its sin was incurable, and second, because it is not becoming that God take away any perfection of a created thing by assuming it, and personhood is a perfection of a created thing. But if the nature assumed were to have its own proper personhodd after its assumption, there could not be a union in the person, because there would be two persons. Whence, it was necessary that what was assumed not have personhood, yet it has a birth. Now, in an angelic nature there is found no potency for personhood without the act, since it does not come into existence through generation. And so it was not suitable that an angelic nature be assumed.

To the third question, it should be said that something can belong to some whole in two ways: either by reason of its part, as a man might be called gray on account of his hair; or by reason of itself—that is, it belongs primarily to the whole itself—and what belongs to the whole also belongs to all its parts, as is proved in the Physics 6.¹ Therefore the universe can be assumed in two ways: either by reason of its part—and in this way it was assumable, and was assumed when human nature was assumed—or by reason of itself—and in this way it could not be assumed, because not all its parts were assumable, as is clear from what has been said.

We concede the fourth objection.

To the second question, it should be said that it was not becoming that the Son of God assume human nature from any source other than the lineage of Adam, and this chiefly for three reasons. First, to uphold the justice of satisfaction, for if it had not been from the race of Adam, it would not pertain to the Son of God to make satisfaction for the sin of Adam. Second, for the perfect reintegration of the dignity of Adam, who had it such that he himself and his race needed no other creature to save or sustain them. And this would not have returned to his race if he would have been redeemed through someone who did not belong to his race. Third, to preserve the dignity specifically of Adam himself, who in a certain way uniquely possessed the image of God: just as God, as the first being, is the principle of all beings through creation, so too Adam, as the first man, is the principle of all men through generation. If Christ had not become a man from his race, Adam would have lost this.

We concede the third objection.

To the third question, it should be said that it was in no way becoming that the Son of God assume the human nature in Adam himself, and this for two reasons. First, because Adam was complete by his own proper personhood; whence, he could not be assumed into the unity of the divine person unless his own personhood were destroyed—which was not fitting, as was said above of the angels.¹ Second, because through the assumption a communication of properties arises, such that whatever is said of the man would be said of God, it would follow that one might say, “God sinned,” because Adam sinned—which is absurd.

We concede the third objection.

Therefore, since Christ was of the same species as other men—otherwise he would not have been a true man, but would have been called a “man” equivocally, nor could he have suitably made satisfaction for men—all the things that are essential to man must have been present in Christ: a body, a vegetative, sensible, and rational soul, and ultimately the form of the whole that results from the joining of the body and soul, which is called humanity. And because natural properties are caused by essential principles, all the natural properties consequent on the human species must have been present in Christ.

However, as concerns other properties accidentally consequent on the human species, whether they be defects or perfections, they will be discussed later in their proper place.

To the first question, I answer that there were two errors about this matter.

One was that of the Manichees, who said that Christ did not have a true body, but only an apparitional one. And the reason for this position seems to have been that they held that the devil was the author of all visible things, and therefore nothing visible was in Christ in truth, over whom the prince of this world had no power.¹

Now, it is clear that this position is false, both with respect to the position’s root—because faith holds and reason demonstrates that God is the Creator of all things visible and invisible, since all beings must be from a first being, as is evident in the Metaphysics 2¹—and also the position is in itself false, because it destroys the truth of his humanity, as is evident from what has been said; for that would be to find some falsity or deceit in the one who says of himself, in John 14:6, I am the way, the truth, and the life.

The other error was that of the Marcionites, who said that Christ had not assumed a body from the Virgin, but that he had brought it from heaven. This perhaps arose from the opinion of Platonists, who said that an earthly body is to be in all ways fled, so that blessedness could be obtained. For they did not believe that it could be the case that a soul could become blessed while united to an earthly body. Nevertheless, they did assert that souls that are united to heavenly bodies, such that the sun, the stars, and the moon, are blessed, as Augustine notes in the City of God;¹ therefore they thought that Christ’s soul, which was blessed in the highest degree, was united to a heavenly body, and not to an earthly body.

But this position also takes away the truth of his humanity. For every natural form requires a determinate matter; and therefore the human soul makes a man not by perfecting any matter whatsoever, but inasmuch as it is the form of a body of a certain kind, one made up of the elements and in a duly proportioned combination. Therefore, if Christ did not have an earthly body, he was not a true man. Moreover, the same error takes hold among these thinkers as occurred among the ancient philosophers, who in speaking about the soul said nothing about the body, opining that any given soul can be adapted to any given body, as is said in On the Soul 1.¹ But this cannot be, since there is a proper matter corresponding to a proper form, and for each agent there are determinate instruments.

And therefore the Catholic faith, which confesses that Christ is a true man, holds firmly that he had a body composed of the four elements, just as we do.

Reply Sed Contra 4–5: We concede the fourth and fifth arguments.

To the second question, it should be said that there were two errors about this matter as well. One was that of Arius and Eunomius, who said that the Son of God assumed flesh without a soul, because they were of the opinion that the divinity gave life to his body without a soul. The other error was that of Appollinarius, who said that in Christ the body had already been animated with a soul, but one lacking sense and intellect. Each error derogates from the truth of his humanity and the dignity of Christ’s body.

For no matter can be perfected in any existence unless it be through something that is its form. Whence, since God could in no way be the form of a body—because he would then have to be a part, and not immaterial to the highest degree—it follows that Christ’s body, if it lacked a soul in all ways, would be as a non-living body. And if it were to lack a sensitive and rational soul, it would be as the body of a plant; whence it would be much less noble than our body. Likewise also, since it is of the notion of a man that he have a rational soul, if Christ had lacked one, he would not have been a true man.

Now, this appears to have seized them because they believed that the soul was not united to the body as a form, but rather as a kind of covering, as Plato says, according to what Gregory of Nyssa relates.¹ If God were united to a body in this way, he would not be called a man, especially if it were asserted, as some have said, that the soul is of the substance of God—all of which contain manifest falsity.

Therefore, the error of these and the others already mentioned is excluded in the book of Gennadius, Of Church Doctrine, chapter 2: the Son of God was born of man, but not through man—that is, through a man’s intercourse, as Ebion says; but drawing flesh from the Virgin, not conveying it from heaven, as Marcion affirms; nor in an apparition—that is, without flesh, as Valentius said; but a true body, not only flesh from flesh, as Martianus says; but true God and true man, in Godhead, the Word of the Father and God, in man, soul and flesh; not without sense and reason, as Appolinarius asserted; nor in flesh without a soul, as Eunomius said; nor was he born of the Virgin in such a way that before he was born of the Virgin he was not God, as Antemon and Marcellus said.¹

Reply Sed Contra 4–6: We concede the other three arguments.

To the third question, it should be said that some have asserted that God assumed a soul and a body, but not in such a way that any humanity resulted from their conjunction. And this opinion similarly takes away the truth of Christ’s humanity and the dignity of Christ’s body. For Christ could not have been a true man, nor could his body be truly alive, unless the soul had been united to the body as its form, in such a way that something one was produced from them. But we will speak about this opinion below.¹ Whence it must be said that just as there was a true body and a true soul in Christ, so too there was a true humanity, that is, a true human nature, resulting from their being joined together.

Reply Sed Contra 4–5: We concede the other two arguments.

A medium of suitability is what makes for a becoming joining together of extremes, which nonetheless could be made without this. For example, beauty makes for the becoming joining together of marriage, yet without this the marriage is not thereby destroyed.

However, a medium of necessity is one without which the joining together of the extremes cannot occur, such as light being joined to the air by the mediation of transparency. Yet this happens in two ways, for either it is the cause of the joining together, or it is consequent on the joining together. The cause of the conjoining is a medium the way water and air are in vision, since the visible species is borne through the air to vision itself. But a medium consequent on the conjoining is what is caused by the disposition of the things joined together, the way air or water is a medium in touch; on account of this the extremities of bodies touching each other must be moist, and thus a certain moisture must be intermediate. Now, a medium that is the cause of the joining together is of two sorts: for either it joins them together by effecting it, the way a man who reconciles enemies is called a “medium” between them, or it joins them together as a form, the way that love joins friends together, as a certain “medium” between them. But each of these happens in two ways, since a necessary medium is either the cause of an actual joining together, as is clear in cords by which certain things are bound together, or it is cause of their joinability, as dryness in wood is the cause of its joinability with a fire.

To the first question, therefore, having seen these things, it should be said that the soul is in a certain way the medium by which the body is united to the divinity. But it should be notes that if the soul is compared to actual union, it is only a congruent medium. For it is not becoming that the divinity be united to the body unless it has a soul, because it is closer to God; because it is in more ways unitable to God than is the body, since it is even unitable to him through grace and glory; and because it is united to the body for the sake of the soul’s restoration. But if it the soul is compared to unitability, in this way it is a necessary medium, as formally causing the unitability in the body, for the body, while maintaining its order to the end of the union—insofar as the rational creature was said to be more assumable than the other creatures—cannot be united [to God] except through its partaking in God’s image by the mediation of the soul. Whence inanimate bodies are cannot be united [to God].

To the second question, it should be said that, according to Augustine,¹ “spirit” is said in many ways. In one way, it is a subtle body, like air. In another way, a body wholly subject to the soul, as the bodies of the saints in the resurrection (1 Corinthians 15:44–49). In a third way, any soul of the beasts: who knows whether . . . the spirit of the beast goes down to the earth? (Eccl 3:21). In a fourth, the imaginary power: I will sing with the spirit and I will sing with the mind also (1 Cor 14:15). In a fifth, the very mind of a man or angel: be renewed in the spirit of your minds (Eph 4:23). Sixth, the divine substance itself: God is spirit (John 4:24). Now, however, we are speaking of spirit insofar as one means the mind. Whence it should be said that the divinity assumed the soul by the mediation of the spirit, just as it assumed the body by the mediation of the soul. For just as the body cannot be assumed except through its having a soul, so the soul cannot be assumed except through there being a mind in it, through which it has the image of God.

Reply Sed Contra: We concede the other two arguments.

To the third question, it should be said that parts are prior in origin to the whole, as what constitute it. However, in completion the whole is prior to the parts, because the notion of the complete nature is found in the whole itself first, and it reaches its parts by the mediation of the whole,¹ insofar as they are its parts. This is also why they are in a genus through a reduction. And therefore it should be said that in a certain way he assumed the whole by the mediation of the parts—namely, insofar as the parts constituted the human nature as its origin, to which nature the assumption was owed through itself. However, in a certain way he assumed the parts by the mediation of the whole, insofar as the notion of a human nature, which is assumable through itself, is found in the whole first, and through this, in the parts.

To the first question, I answer that, as the Master says in Book II,¹ “grace” is spoken of in two ways: in one way, as meaning God himself giving gratuitously, or his gratuitous will, and in another way, as that gift that is given gratuitously. Therefore in the first way of taking “grace,” grace is the medium of the union as causing the union as effecting it, for by his gratuitous will, without any preceding merits, he assumed flesh. In the second way of taking “grace,” no habitual gift falls as a medium there, as something formally causing the union; rather, it is only as a medium of congruence, as is also knowledge and the perfection of the body and things of this sort that it is becoming for the nature not to lack. Unless perhaps the union itself is called a “grace,” which is a certain gift given gratuitously. This is a medium in a certain way, as will be explained below.

To the second question, it should be said that the Holy Spirit cannot be called the medium in that union, except as one causing the union as effecting it. However, this is the effect of the whole Trinity, though it is appropriated to the Holy Spirit—as will be explained in Distinction 4.¹

To the third question, it should be said that, between the human and divine natures it is necessary that there fall a middle union, not as cause, but as an effect following the joining together of the natures. For it is the nature of a relation in other kinds of things that it have a cause, since it holds the minimum of the nature of a being, as the Commentator says in the Metaphysics 12.¹ Whence, although a relation is not through itself there terminus of a motion, since there is no motion into being toward-something, as is shown in the Physics 5,² still because motion is through itself terminated at some being, some relation follows it of necessity. For example, from a motion of alteration being terminated at whiteness, the relation of likeness toward all white things follows; and likewise, from a motion of generation being terminated at a form, the relation in virtue of which the matter is said to be under the form follows. So too then, from the motion of the assumption of human nature being terminated at the person, this relation called “union” follows. Whence the union is a medium not as something causing the union, but rather as something following on it. This is just as we also said above that water in the medium in touch from the fact that touching things must be moistened.

And therefore none of the following three things are possible: that the flesh be conceived first and assumed after; that the soul was created first and assumed after; and that the man was constituted from his parts first, and assumed after. Now, as is clear from things said, the body has its assumability from the soul, and likewise, essential parts have their assumability from the notion, of which they are the parts of the nature. Whence also both of the following is impossible: that the soul was created and assumed first and joined to the body after; and that the flesh was conceived and assumed first and united to the soul after. Rather, it is necessary that these four happened simultaneously: the conception of the flesh, the creation of the soul, the joining together of both, and the union to the Godhead.

The response to the first question is clear from this, for it is not possible that the flesh was conceived first and later assumed. For were it to have been conceived before the assumption, it would have its own proper hypostasis, and then after the assumption either that hypostasis would have remained—and thus, there could not have arisen a union in the [divine] hypostasis—or it would not have remained, and this could occur without the prior corruption of the conceived flesh—for the notion of a hypostasis is not accidental to a thing, such that it could be one in number while the other hypostasis still remains.

To the second question, the response is clear, from things said before. For it is not possible that the flesh was assumed first and animated later, for two reasons: first, because it has its assumability from the soul, which the soul cannot confer on it before it is united to it; and second, because parts have their assumability from the whole, as was said before.

To the third question, the response is clear from the foregoing. For the soul could not have been assumed before it was united to the flesh, since it is assumable through its being a part of human nature.

Jerome teaches clearly that by the term human nature or humanity are to be understood soul and flesh.¹ One should not understand the soul and the body by “humanity,” as though it could be said properly that humanity is the soul and the body. Rather, it should be understood the way parts are understood in the whole, as the walls and roof are in the house and yet they are not predicated of the whole. This is also why in the authority of Jerome is added, the humanity, which is comprised of the soul and the body.² He does not say, “which is the soul and the body.”

And so they are in error who contend that, whenever Christ’s humanity is recalled, it is not the substance that is understood by the term humanity, but some property by which he is called a man.¹ By this property, which they call “humanity,” can be understood the form following the composition of the parts—namely, of the soul and body, in which form all the individuals share as in their common nature.

For perhaps those who asserted this had a taste of Plato’s opinion, who asserted that universal forms have actual existence in nature outside of matter. For in this way, according to him, as the Philosopher says in the Metaphysics 1,¹ the form of man existed without flesh and bones and without its other parts, and they asserted that such a humanity without body and soul was assumed. And against this Damascene says: he did not assume the nature as considered in bare contemplation; for then it would not be an incarnation but a deception and feigning of incarnation.²

Or, as some say, this touches on the opinion of those who said Christ, insofar as he is a man, is not a thing, but one bearing himself a certain way. This will be touched upon below, in Distinction 6.

The same John clearly shows this.¹ Note that the Master here is taking up John Damascene’s words, but not their meaning. For Damascene brings in these words to refute the error of those who said that there is only one nature in Christ—one that is, as it were, put together from the divinity and the humanity, as some one nature is put together from soul and body. This is indicated when it is said that all men are of the same nature—not such that in each of them the soul and the body are of one nature compared to each other, but rather, because one nature is put together from these two, in which nature all men agree. But it is not the case in Christ that one common nature results from his humanity and divinity, as though it were a common species that could be predicated of many who might have divinity and humanity together.

However, the Master takes up these words to fight against the position of those who said what was as assumed was a property that is called “humanity.” For humanity, if it is being considered as common, is a species that is found in many, in which way it is said that there is one nature of all men. However, in this way the common species of humanity is not in Christ, for Christ’s humanity is not actually common, but is a single humanity.

For another such was never made, nor is made now, nor ever will be made.¹ It appears that this proof is invalid, for there are many species that are predicated of only one individual, such as the soul and the moon. But to this it should be said that it is easy to respond following the Master’s intention. For every species that is participated in by many individuals is predicated of all of them; whence if the human species, insofar as it is common, were something subsisting outside the singulars, it would be predicated of all of them. Whence if Christ had assumed such a humanity, the man who is Christ would be predicated of all men.

But following Damascene’s intention, one should answer differently, saying that every common nature as such can be found in many, but if there is some species that is in only one individual, this is for the sake of something else that is not of the understanding of that nature; this is why it is possible to understand many suns. But a singular has incommunicability through what belongs to its notion—namely, through matter, which is part of its definition, if it were to be defined, as is clear from the Metaphysics 8.¹ Whence it is not possible to understand this man being predicated of many. So it is clear that what neither actually nor in its understanding can be said of many is singular. However, Christ is of this sort; whence the name “Christ” does not signify one common nature resulting from the union of the divinity and humanity, but one hypostasis subsisting in each nature.

The Word of God took on all things which he had planted in our nature.¹ This should be understood of the things that belong to the notion of human nature as its essential principles, or even of the things that follow on the essential principles as natural properties. Whence there is no obstacle of immortality, which was given to the first man gratuitously.

And yet they preach that our visible sun spreads its rays over all manner of offal, but keeps them clean and pure.¹ But why is the sun not infected by the fact that it shines its rays over feces. The answer is that it does not share with other bodies in their matter, such that the agent would suffer at the same time, just as happens in things that share in matter: when they act, they are acted upon, as is said in On Generation and Corruption 1.² Now, the soul does share in matter with the body, though not as though the body were that from which the soul comes to be, but as that in which it comes to be, and therefore it is infected from its being joined to the body. However, the divinity does not share with the body either as in matter from which it comes to be—since it is wholly immaterial—nor as the matter in which it comes to be—since it is not united to the body as its form.

To the first question, it should be said that there is no way she could have been sanctified in her parents, nor even in the very act of her conception.

For a specific person’s condition does not pass from the parents into their offspring unless it pertains to their bodily nature; for example, the father’s knowledge of grammar does not pass into his son, for it is a personal perfection. This is also why the sanctification of her parents could not be transferred to the Blessed Virgin, unless not only what pertains to the person were healed in them, but also what pertains to their nature as such; this God could certainly have done, but it would not have been fitting. For the perfect healing of a nature pertains to the perfection of glory. And therefore her parents would not have been healed while in the wayfaring state in such a way that they would be able to conceive their child without original sin. And therefore the Blessed Virgin was conceived in original sin, because of which Blessed Bernard wrote to Lyon that her conception was not to be celebrated,¹ although it may be celebrated in some churches out of devotion, not considering it as her conception but rather as her sanctification, for it is uncertain exactly when that took place.

To the second question, it should be said that the Blessed Virgin’s sanctification could not have occurred in a becoming way before the infusion of her soul, because she was not yet capable of grace, but also not in the very instant of its infusion, such that by grace infused into her at that time she would be preserved from incurring original sin. For Christ was unique in the human race in not needing redemption, for he is our head, but all share in needing to be redeemed through him. Now, this could not be if any other soul were found that had never been infected by the original stain. And therefore this was not granted to the Blessed Virgin or anyone other than Christ.

To the third question, it should be said that the Blessed Virgin was sanctified before her birth from the womb, which can be gathered from the fact that she above all the other saints was most pure from sin, as the text states,¹ as the chosen mother of divine Wisdom, in which no defilement occurs, as it says in Wisdom 7:22. Whence, since this purity may be found to have existed in some people such that they were cleansed before their birth from the womb—such as John the Baptist, of whom we read in Luke 1:15, he will be filled with the Holy Spirit, even from his mother’s womb; and Jeremiah, of whom it says, before I formed you in the womb I knew you, and before you were born I consecrated you (Jer 1:5)—one should not doubt that this was bestowed on the Mother of God in a much more excellent way.

For in the first, as is commonly held by everyone, she was purified of original sin both as to its stain and as to its guilt. But there are several opinions about her cleansing from the fomes, or tinder of sin.

For some people say that by the first sanctification the fomes was completely taken away, which contradicts what is said in the text, based on the words of Damascene,¹ that in the second sanctification the Holy Spirit came upon her to purify her. This can only be understood about a purification from the fomes, for she had never committed actual sin, as Augustine says.²

And therefore others say that in her first sanctification she was in a certain respect purified from the fomes, but in another respect the fomes still remained. And there are several ways of making this distinction.

For some say that it was taken away as to the inclination toward evil, but it remained in presenting the difficulty of accomplishing the good—which are the two effects of the fomes that the Apostle mentions in Romans 7:19: for I do not do the good I want, but the evil I do not want is what I do.

Now, this does not seem to stand, for that due to which there is a proneness to one contrary, in the same respect presents a difficulty toward the other—whether it be a certain habit or form, as heaviness draws things downward and causes difficulty in their going upward, or even if it be a privation or lack, as weakness in the power of moving causes a proneness to fall, as well as a difficulty in going forward. This is why the fomes cannot be taken away insofar as it inclines one to evil and yet remain insofar as it causes difficulty toward attaining the good.

And therefore others say that the fomes is a corruption of the person, insofar as it impels one to evil and insofar as it makes the good difficult; and in this way it was thoroughly taken away from the Blessed Virgin in her first sanctification. It is also a corruption of the nature, by reason of which the infection of original sin passes to the child through the act of nature; and in this way it remained after the first sanctification, but then she was purified in the second such that she could conceive children without any original sin.

But this also does not seem to be fitting, for as was said in Book II,¹ the original corruption did pass to children from their father as pertained to guilt, but as pertains only to punishment it is like bodily susceptibilities, passing to children from their mother, who supplies the matter. For this reason it does not seem that the cause of Christ’s being conceived without original sin was the purification of his mother from the fomes insofar as it infected her nature, but more so because he was born without relations with a man, which is the cause that Anselm assigns in his book On the Virginal Conception.² Now, he did not assume penal defects by necessity, but voluntarily.

And furthermore, since it is essentially the same fomes that is the corruption of the nature and of the person, if it remained as the corruption of the nature, the fomes that corrupts the person cannot essentially be taken away.

Whence, what is left, as others say, is that the fomes remained in its essence after her first sanctification, but it was impeded by sanctifying grace from either inclining toward sin or withdrawing from the good. For it happens sometimes that a habit is hampered from being able to go into act, as knowledge can be by drunkenness, as the Philosopher says.¹ But in the second sanctification, that fomes was taken away.

To the second question, it should be said that just as in the first sanctification there was a certain beginning of cleansing, when original sin was removed as regards the fault, and the fomes was bound, so too there was a certain beginning of confirmation. For by sanctifying grace she acquired immunity from sin thereafter. And this immunity was caused by three things: namely, from the binding of the fomes, which did not incite her toward evil; from the inclination of grace, which ordered her toward the good, although her free decision was not yet firmly established on the last end, as it is in the blessed, who have attained the end of life; and lastly, from the preservation of divine providence, which guarded her untouched by any sin, just as it also had protected man from anything harmful in his first state.

Reply Sed Contra: We grant the other two arguments.

To the third question, it should be said that in her second sanctification, both her cleansing and her confirmation in the good were in a certain way completed, according to the perfection of life on the way. But in her glorious Assumption these were completed according to the perfection of the heavenly homeland, which is evident in this way. For in the first sanctification the inclination of the fomes was removed, although its essence did remain. But in the second sanctification the fomes itself was extinguished in its essence, while certain penalties caused by sin did remain; from these she was fully freed by the glory of the Assumption. Likewise this is also the case from the other side: in her first sanctification, grace was bestowed efficaciously inclining her free decision toward the good, although not enough to remove her decision’s ability to bend toward evil, which even man in his first state had. But in the second sanctification an additional grace was added that so filled the power of her free decision that she could not bend toward evil—not by removing the nature of the free decision, but by removing its defect, just as the matter of the heavens, because it subsists under a form that excludes all privation from it, is not in potency to corruption. But in the Virgin’s third exaltation, she was joined to the end through a perfect grace drawing her into glory, which causes a perfect immobility.

For some say that in Christ’s conception, his mother was at work actively; and some of these hold that this would have been by a natural mode, while some others say it was by a supernatural gift. For since the Blessed Virgin is believed to be Christ’s true mother, we must attribute to her all that belongs to a mother. Now, they judge that it pertains to a mother’s office to supply a certain active principle in the conception, and not only a material one.

However, this is held in different ways. For some hold that in the matter that the mother supplies there is chiefly an active power, both because they think the conception happens from the intermingling of seeds, such that the woman’s seed is just as active as the man’s seed in generation, although in her there is not as much efficacy for acting; and also because they believe the child conceived becomes sentient and vegetative through the mother’s soul, so that in this way the mother is also found to be more important in generation than the father.

Now, the Philosopher rejects this in On the Generation of Animals 15.¹ For in things that have a perfect life, the agent and the patient are distinguished in generation for the sake of the generation being brought to perfection within them; in plants, on the other hand, which have an imperfect life, both powers—that is, the active and the passive—are in the same thing, although perhaps in one plant the active power dominates, while in another the passive power does, which is also why one plant is called “male” and another “female.” Therefore, since it is impossible for what is determined as the patient to have an active power in the same respect, the female must not be the agent in conception, but only the patient.

And for this reason, others say that what the mother supplies stands as the natural matter in generation. Now, in natural matter there is not merely a passive potentiality (otherwise generation would be violent, not natural), but the matter’s very form, which is brought out through generation must be present in potency, and as incomplete existence. And therefore it does not have a perfect power of acting but merely an imperfect one; and thus it cannot act through itself unless it is incited in some way by an external agent, and then it cooperates with it.

However, this cannot stand. For it is impossible for the same thing to be what changes and what is changed; this is why it cannot be that the form that is in a certain matter acts on it, whether be a perfect or an imperfect form. For a form that does not exist through itself does not act, nor is its matter acted upon, properly speaking; rather, the composite acts by reason of the form, and it is acted upon by reason of its matter. And therefore it is not possible that some imperfect form cooperate with an external agent in acting.

And furthermore, if it belonged to a mother necessarily to participate actively in generation, the Blessed Virgin could not be called a mother. For since that conception happened all at once, it could not occur through any created active power. Therefore the Blessed Virgin could not participate actively in the conception; and so she would not have had what pertains to a mother, and so she would not have been a mother. Nor can it be said that she only cooperated in the introduction of the substantial form, which is instilled in an instant even according to nature. For instilling a form is nobler than preparing matter by alteration, and in this way what is less would be attributed to the Holy Spirit, and what is of greater dignity would be attributed to the Virgin. And furthermore, the substantial form at which the conception terminates in is the soul, which is the act of the whole and of all its parts. For this reason, if it were removed, the bone could not be called ‘bone,’ nor the flesh ‘flesh’, except equivocally. However, it is certain that the Blessed Virgin did not actively cooperate for [the creation of] Christ’s soul.

And therefore others say that the Blessed Virgin had something more than other mothers by a supernatural power. For the matter that is supplied by other mothers cannot bring itself totally into act unless there is an external agent. But the matter for Christ’s body, which the Blessed Virgin supplied, by divine gift was able to form itself by a power added over and above the nature. But this could not happen in an instant. And therefore, since it was becoming that this conception would happen in an instant, the Holy Spirit came first, completing the formation of Christ’s body immediately, which nevertheless would have been completed otherwise, albeit successively.

However, this theory does not seem fitting. First, because if that power did not cooperate toward the formation of Christ’s body, then it was bestowed in vain, which does not happen in nature’s works, and much less in miraculous ones. Second, because the Blessed Virgin was not chosen to be both father and mother to Christ, but only mother, and so it was not fitting that in the matter that the Virgin supplied there should be included what in others comes from the father and the mother. Third, because no one is called father or mother in virtue of the active or passive potency for generating, but insofar as this potency goes into act. Whence, if in the matter that the Virgin supplied, the active potency required for father and mother existed without that power working, she would be called neither father nor mother, or by the same reasoning father and mother, which is absurd—unless perhaps merely supplying the matter were enough to be the mother, which is not enough to be the father, and because of this she is called mother and not father. And indeed this seems to be the case according to the Philosopher’s intent, and in this way the mother’s virginity and her true motherhood are preserved most perfectly. And so it is also most in harmony with the faith.

Therefore, by keeping to this path, it seems we should say that there are three kinds of action found in a child’s conception. One which is principal—namely, the forming and organizing of the body—and with respect to this action, the agent is only the father, while the mother merely supplies the matter. Another action precedes this action and is preparatory to it, for since natural generation is from a determinate matter, in that every act comes to be in its proper matter, as the Philosopher says in On the Soul 2,¹ it is necessary that formation of the child happen from its appropriate matter, not just any matter. Therefore there must be some acting power, by which the matter is prepared for conception. Now, as the Philosopher says,² the art or skill that works the form rules over and commands the one that prepares the matter, as the art of constructing a ship is related to that of sanding the wood. Therefore, the power that prepares the matter for the child to be conceived is incomplete relative to the power that forms the child from the prepared matter. However, this preparing power is the mother’s, and is incomplete with respect to the active power that is in the father, which is why the Philosopher says that a woman is like a little boy who cannot yet generate.³ The third action is concomitant, or following the principal action. For just as the location conduces toward the goodness of a generation, so too does the good disposition of the womb work toward the good disposition of the offspring, as though furnishing the kindling; and this is what Avicenna says in the chapter on floods: the womb only improves what is conceived.

Therefore, following this, I say that in the principal action of the formation of Christ’s body, there was nothing active on the Blessed Virgin; rather, what the Blessed Virgin supplied was related purely materially to this action, while divine power did everything that in other conceptions happens by the power of the seed from the father. Thus Damascene says divine power was, as it were, a divine seed, as we have in the text.¹ But in the second and third actions, the Blessed Mother was actively working, like other mothers; and thus she was also truly a mother.

For any generation that is called natural must be arise from the agent naturally, and out of natural matter proportioned to this. However, if any of these are lacking, the generation cannot be called natural, but miraculous, if it was done by supernatural power. Now, since a natural agent is of finite power, cannot produce its effect from matter that is not naturally proportioned, whereas a supernatural agent, which is of infinite power, can work from both kinds of matter, natural and non-natural. And therefore it can be miraculous in these two ways: in one way, when neither the agent is natural nor is the matter naturally proportioned to that form, as is clear in man’s formation from the slime of the earth; and in the other way, when the matter is natural, but the agent is supernatural, as when someone is miraculously cured of a fever, for a human body is the natural matter of the health that is conferred on it by a supernatural agent. And it was like this in the conception of Christ the man. For the matter that the Virgin supplied was matter from which a human body could naturally be formed, but the power forming it was divine. Therefore it should be said that that conception was simply speaking miraculous, but also natural in a certain respect; and for this reason Christ is called the natural son of the Virgin, because she prepared the natural matter for his conception.

To the second question, it should be said that it is most appropriate that the Annunciation was made through a physical vision. First, so that the Annunciation would be more certain, for we are less deceived about things that we visibly perceive. Second, because, as Dionysius says in his ninth Letter to Titus,¹ this is the reason that divine things are set before us in physical figures, so that each kind of human life may be illuminated by divine knowledge according to its own properties: the life of the senses by the images of figures, and the life of the intellect by the contemplation of spiritual truth. In the same way, it was also seemly that the Virgin’s perspective should be ennobled in both ways: the interior sight by the revelation of so great a mystery, and the external sight by the physical vision of an angel. Third, because the Annunciation should be proportioned to what it announced. Now, what it announced was the visible sending of the Son of God into the world, so the announcing angel appeared in a physical vision.

To the second question, it should be said that the announcing angel was not from the highest nor from the middle hierarchy, but from the lowest; nor was he from the first order of that hierarchy, but from the middle, which is the order of archangels. Many reasons for this are clear. First because, since Christ was born in order to repair the insubordination that happened among the angels, it was fitting that in his own conception that ordering of the heavenly hierarchy, in which the highest angels illuminate men by means of the lowest, should most be preserved. Second, so that their ministry would be shared more. For since the lowest angels act according to what they receive from the higher ones, and not vice versa, when the lower angels announce something, the annunciation is explicated by the higher ones to the lower ones, which would not be the case if the higher ones announced it directly. Third, because in this way the properties of the orders are preserved, as was said in Book II.¹ For the lowest hierarchy has the office of directing humans according to a certain limitation, either of one province, like the order of principalities, or of one man, like the orders of angels and archangels. But they differ, because it belongs to angels to direct someone in the actions that pertain to him alone, and so they are said to make known the least things. But it pertains to archangels to direct someone in those actions that redound on the whole multitude; this is also why archangels are intermediaries between principalities and angels, which their name also shows, for they are called “archangels,” as though “ruling angels.”

Therefore, since the Blessed Virgin’s consent, which was being sought in the Annunciation, was an act of an individual person that redounded to the salvation of the multitude—or rather, of the whole human race—the angel who brought the news had to be of the order of archangels, and the highest among them.

The power of the Most High will overshadow you.¹ The power of the Most High, according to the subsequent explanation of John Damascene, is understood as the Son, about whom it says, Christ, the power of God and the wisdom of God (1 Cor 1:24). This is how the angel’s words foretell the coming of the two divine persons into the Virgin: the Holy Spirit to purify and furnish the reproductive power, and the Son to assume flesh. And this is why he says, the power . . . will overshadow you. For the power of the Most High was overshadowed by accepting our weakness. Or it could be said that it will overshadow you, means the blotting out of any form of the fomes. For by the Son’s coming into her all traces of the fomes had been uprooted from her; and this uprooting is called “overshadowing,” just as the fomes is called a “fire,” for shadow offers a coolness against the heat.

Like a divine seed.¹ He does not simply say seed, so as to avoid the error of the Apollinarists, who held that the Holy Spirit came into the Virgin’s womb truly as a seed. However, there is a likeness to a seed insofar as a seed is active in generation, and so too the Holy Spirit in Christ’s conception, or the Son, whom he calls the power of the Most High.

Of our ancient mixture:¹ not as to the antiquity of the fault, but of the punishment.

Created through the Holy Spirit.¹ To the contrary, to create means to make something out of nothing. But Christ’s body was formed from matter. Therefore it was not created by the Holy Spirit. But one should say to this that “creation” here is being taken broadly for any supernatural activity that can be only from God himself.

If we said that we have no sin, we deceive ourselves (1 John 1:8).¹ The baptized child and the adult who had just been to confession seem to be obstacles to this claim. But it should be said that the apostle’s statement can be taken in two ways so that it has truth for all men. In one way, “sin” is understood not only as the stain and guilt of sin, but also as the cause and results of sin. For in the baptized child and in the penitent adult the fomes inciting them to sin remains, as are certain dispositions left behind by actual sin. But in Christ there were neither of these, for his flesh was conceived without the corruption of the fomes; and since he did not commit any sin, the traces of sin were not in him. Similarly, they were not in the Blessed Virgin, who was free from actual sin. However, although the fomes remained in her in its essence after her first sanctification, still it remained bound and not inciting to sin, as was said.² The other way it can be held as true is if it is understood also as referring to actual sin in its guilt and stain. For even if a human being could be without actual sin for a short time, he cannot persevere that way so long that he does not fall into venial sin at least. Then the verb we have conveys an indefinite present tense, not a precise one. But in Christ and his mother, actual sin had no place at all, whether mortal or venial.

One is the heresy of those who said that Christ’s body was not formed from the same thing as what other human flesh is formed from, but rather, that the Son of God brought a heavenly body with him, and in this way he passed through the Virgin’s womb while assuming nothing from her. Now, this is heretical in two respects. First, because it detracts from the truth of scripture, which says that Christ was formed and born of a woman. For he would not be said to be formed from her unless he had drawn something from her that his flesh could arise from in a material way. Also in that case the Blessed Virgin could not be called the Mother of God. Second, because it detracts from the truth of Christ’s humanity. For since every form requires a determinate matter, if Christ’s body were formed from some other kind of matter than the matter from which other human bodies are formed, it would not be a body of the same species with other human bodies. And then he would be called a ‘man’ equivocally, since this matter is an essential part of a man.

The other error belongs to those who say that Christ’s flesh, as it existed in his ancestors, was not infected. For they say that when Adam sinned, God kept something in him uncorrupted and not infected, by which human nature might be healed, and this was passed down without any infection all the way to the Blessed Virgin, and from it Christ’s body was formed. Now, this is judged to be erroneous particularly because of two things. First, because according to this position Christ was not truly the son of the Virgin, nor is he truly from the stock of any of his forefathers except Adam alone. For that part that remained uncorrupted in human nature in other men, coming from Adam, would have been almost like something extraneous to them, while it would be connatural only to Adam according to his first state. Second, because the fitting order of making satisfaction is destroyed. For just as it was not seemly that anyone should make satisfaction for Adam and his corrupt posterity who was not from that race, in the same way it would also not be fitting that the Son of God should heal our infected nature by making satisfaction for it unless he had assumed the very thing that beforehand had been infected.

And therefore it should be said that the flesh of Christ, insofar as it existed in his forebears as well as in the Blessed Virgin herself, was infected by sin before it was assumed. But in the assumption itself it was purified from all infection of sin, so that insofar as it is actually Christ’s flesh no blemish would be found in it.

One opinion says that the flesh of Christ, and of every other human, existed in Adam as determinate matter in such a way that there was some part of Adam’s body from which the bodies of all men were formed by a certain of multiplication, either without the admixture of anything foreign, as some say, or with something mixed in with that matter that had been converted from food: and in Book II it was discussed how improbable this would seem to be.¹

The other opinion, which seems more probable, is that other men did not exist in the first parent except according to original matter; and in this way, Christ did exist in our first parents. But there is a difference in that other men existed in our first parent according to their seedlike principle, but Christ did not.¹

This fact can be seen in this way. In those who are begotten through physical intimacy, two things have to come together for the formation of the body: an active principle, which is in the seed, and is called the “seedlike principle," but the other is the matter from which the body is formed, which the mother supplies. Now, both of these things can be originally traced back to the first parent. For whatever may be the power active in the father’s seed for the conception of the human body exists by the power of human nature, which the father of children to be brought forth received from his own father, and he from his father, and so on back to Adam. And in this way it is clear that the seedlike principle of those conceived from a man’s seed descends from Adam originally. In the same way, also the matter that the mother supplies must be prepared by her reproductive power, for the begetting of a natural thing requires a proper and determinate matter. Now, the reproductive power of the mother herself descended originally from Adam, just as did the man’s reproductive power. And thus those who are begotten from male and female are descended from Adam originally both according to the seedlike principle and according to the matter; and since one mode of being-in something is the way an effect is said to be in its efficient cause, as it says in the Physics 4,¹ for this reason men so conceived are said to have existed in Adam both in virtue of their seedlike principle and in virtue of their original matter.

However, in Christ’s conception only the Holy Spirit was the active power, while the matter was supplied by the Virgin, having been prepared in the appropriate way. Accordingly, it is clear that the matter of Christ’s body was originally descended from Adam, but no active principle in his conception was descended originally from Adam. And thus Christ existed in Adam according to original matter, but not according to a seedlike principle.

For it is a moral act insofar as a certain part of the fruits of the land and of other things was brought together for the use of God’s ministers and the poor, so that there would be food in the house of the Lord, as is said in Malachi 3:10.

However, it is a figurative act insofar as it is a figure of imperfection, in that one who gives a tithe hopes for perfection from the one to whom he gives it. For in the number ten there is certain notion of perfection insofar as it is a certain threshold; this is why nine signifies imperfection, inasmuch as it falls short of ten. And therefore one who gives a tenth, insofar as he holds on to nine tenths and gives the other that tenth confesses that he is imperfect, and hopes for perfection from the other. And this is why also paying a tithe is in a certain way a sacramental act, insofar as a real spoken confession proceeded from faith in the mediator, through whose perfection the imperfection of the human race due to original sin has been removed. For this tithing prefigured the remedy that was offered against original sin by way of the sacrament.

Therefore that tithing by which Abraham give the tithe, showing himself to need a liberator, pertains only to those descending from his line who drew the imperfection of original sin from him, such that in the same way they hoped for liberation by another, just as he did. Now, only those who descended from him through physical intimacy drew original sin from him, for only these ones received human nature from him as from an active principle. This is also why they are said to have been in him according to their seminal principle, and on account of this also they at the same time as the nature contracted the nature’s wound from Adam and Abraham. However, although he did not descend from Adam or Abraham through physical intimacy, Christ had the matter of human nature from them, which matter was formed into a human nature by the power of the Holy Spirit. And therefore he did not contract original sin, so he could not be prefigured as having imperfection and being in need of a liberator. And on account of this he was not tithed in Abraham.

Reply Sed Contra 4–5: We grant the fourth and fifth arguments.

To the second question, it should be said that Christ was in no way tithed in Abraham, and the reason for this is evident from what has been said.

Reply Sed Contra 4–5: We grant the other two arguments.

Now, the Philosopher refuted this in many ways in On the Generation of Animals 15,¹ where he showed that what comes from the man is not the matter for the human body, but only its active principle, both by reason and by sensory indications, which latter most of all cause conviction in natural matters. This is evident to anyone who examines his words. Likewise, he also shows that the woman’s seed does nothing toward generation, which is why some women even conceive without supplying any seed. But the blood that is called menstrual discharge is in women in place of the seed that is in men.

And following this, the opinion of the Philosopher, the Virgin’s giving birth can be most fittingly safeguarded if only a woman’s blood is materially required for conceiving a human body. For it is not to be believed that the matter of Christ’s body, which was conceived without the seed of a man, should be lacking anything that is materially required for the formation of a human body. To all who believe in his mother’s virginity, it is also clear that this conception was brought about without any human seed. And therefore the matter from which the body is formed, both in Christ and in other human beings, is the blood prepared by the mother’s reproductive power. For that blood in women is like the seed in men, which is also why the latter begins to form in men and the former in women at the same time, namely, with the appearance of hair and the other happenings that are signs of puberty. But since in women the heat serving the reproductive power is less than the man’s heat, in women the surplus of ingested food is not as thoroughly digested as it is in men, and this is why it remains in the form of blood, as falling short of the complete digestion of seed. This is why it happens that someone who has intercourse too frequently may produce blood in place of seed, as it says in On the Generation of Animals 15,¹ as though nature were not sufficient to digest as much seed as the incontinence demands.

Now, in others these things occur successively, such that a male child’s conception is not completed until the fortieth day, or a female’s until the ninetieth, as the Philosopher says in History of Animals 9.¹ But in the completion of the male body Augustine seems to add six days, which are distinguished as follows, according to him in his Letter to Jerome.² For the first six days the seed has a likeness resembling milk; in the next nine days it changes to blood; then in twelve days it solidifies; in eighteen days it is formed to the complete lines of the members; and from then on the rest of the time until the time of delivery it grows in size. Thus the verse: Six days as milk, three times three as blood, two times six forms the flesh, three times six the members. However, in Christ’s conception, the matter that the Virgin supplied immediately took the form and figure of the human body, as well as the soul, and was assumed into the unity of the divine person.

Therefore it could have been that Christ’s body, perfectly formed in the first instant of his conception, would have had the sufficient size for his species, while being smaller than he should have been at the beginning of his humanity if he had been naturally conceived, relative to the size that he had in the full phase of life, proportionally with other men. In this way, by growing until the fortieth or forty-sixth day, he reached the size that in him should have been the smallest in proportion to other people, and from then on he grew as other people grow. In this way, the whole time that he was in his mother’s womb was given to growth, while in others it is given to conversion of matter, formation, infusion of the soul, and growth.

For example, if something moves from being black to being white, in the last instant of time measuring that movement, whiteness is present in the thing changing, and indeed, the last terminus of the time corresponds to the last terminus of the motion. But in all the time before the last instant, the thing changing is distant from whiteness. Now, before the last instant of time, no second-to-last instant can be taken, since between any two instants there is a middle time, as is proved in the Physics 6.¹ That is why we cannot take a last instant in which what is becoming white is not white. And it is the same way in changes that, although they are not motions, nevertheless follow upon a certain motion, as generation follows change, and illumination follows the sun’s local movement. For there cannot be a last instant in which what is becoming fire is not fire, nor an instant in which air that is being illuminated is dark, because the beginning terminus in those changes is in the changed thing for the whole time measuring the motion, to which the change is united as a terminus, only in the last instant of that time.

Therefore, I say that although Christ’s conception is not a motion—because it does not happen successively— nevertheless, it is joined to a kind of motion, at least to the local motion of material blood to the place of generation, where it is collected from everywhere. And in the final terminus of that motion the matter was under the species of Christ’s body, and this is how we take the first instant that Christ’s body existed. But in all the time that preceded this instant, it was still blood, so we cannot take a last instant that the blood existed, but only a last time. Now, a time is continued from an instant without any middle falling in between them, just as neither is there some middle falling between a line and a point. For this reason the form of the blood and the form of Christ’s body succeed each other continuously in that matter; nor is it necessary to think there was any middle time that would make the conception seem to have happened successively.

From being holy it can happen again in two ways. One way is from being less holy to being more holy, as it says in John 17:17: Father, sanctify them in truth. For at that time the apostles were holy. Or it can happen according to a continuation of holiness maintained in the same amount, and in this way Christ can be sanctified, just as he himself says, and for their sake I consecrate myself (John 17:19), because a successive continuation has a measure of sanctification. But this manner of speaking does not seem customary, which is why we do not speak of sanctification this way.

From not being holy, too, someone can become holy in two ways. One way is from not being holy, being the contrary or lacking, as a sinner is said to be sanctified by grace. And in this way Christ cannot be said to be sanctified, because no defect in sanctity can be taken to have existed in him with a consistent subject, for he was a man and a holy man at the same time. The other way is from not being holy negatively, and then a distinction still needs to be made, for someone can become holy from not being holy either by reason of a created holiness, which belongs to a human being, and then Christ is said to have become holy just as he became man; or by reason of an uncreated holiness, and then he is said to become holy by the mode in which the man is said to become God—which is either false, or less appropriate than the first way, namely, God became man, as will be clear below in Distinction 7.¹ And this is how it can be granted that in a some sense Christ was sanctified.

That flesh . . . would have been in bondage to sin in Mary.¹ But to the contrary: what does not exist cannot be in bondage to sin. But Christ’s flesh did not exist except in himself. Therefore it is false to say this. It should be said that although Christ’s flesh did not exist except in himself, nevertheless, it did exist materially in the Blessed Virgin, and in others, but in a different way. For in the Blessed Virgin that matter pre-existed in its essence, but in the others who went before, it existed only in its origin, as was said. And according to the mode that it existed in each of them, it was in bondage to sin.

So too was the Levitical order.¹ It seems that the Apostle’s argument will not hold up. For it can happen that the Pope’s father paid tithes to some simple priest, but the Pope would not be less than that priest because of this. And so it does not seem to follow that if Abraham paid tithes to Melchizedek, the Levitical order was less than Melchizedek because of it. But it should be said, according to some, that the Apostle is proceeding from the supposition that Abraham was greater than all his posterity. This is why, if Melchizedek had been greater than Abraham, he would have consequently been greater than Levi or Aaron. But since this supposition is either doubtful or false, at least because of the Blessed Virgin, it is therefore better to say that the Apostle did not intend to prove that Melchizedek was personally greater than Aaron, but that the priesthood of Christ represented by the priesthood of Melchizedek is greater than the priesthood of Aaron. So the strength of the Apostle’s argument is founded upon a figure, for Abraham giving tithes to Melchizedek represented that he, along with his whole posterity, was less than the priesthood of Christ, represented by Melchizedek.

Levi was there according to that seminal reason.¹ A seed, as the Philosopher says in the Physics 2,² is in the genus of efficient causes. This is why it is said that those who were conceived by the active power originally descended from Abraham existed in Abraham according to a “seminal” principle. But this cannot be said of Christ, as is clear from what has been said.

His mother conceived him through grace, and not through concupiscence.¹ This can be understood in two ways. Either “concupiscence” and “grace” could be in the nominative case, and then concupiscence is being called the “mother” of those who are born through concupiscence, and grace is being called Christ’s “mother,” since he was born through grace. Or it can be understood that they are in the ablative case, so that we understand that Christ’s mother did not bear him through concupiscence, but through grace, and then this statement is proper and plain.

Because, as the natural philosophers say, the form of the human body is completed in as many days.¹ This can be explained in another way than the Master explains it afterward, so that the completion of the human body is understood not only as to shape, but also as to due size, and by these forty-six days the whole time until birth is understood. For if forty-six is multiplied by six, which is a perfect number, the result is 276 days, and all the days are counted from the octave of the first of April, when Christ was conceived, until the octave of the first of January, when Christ was born, and this is accepted by Augustine.²

However, each divine activity is can be appropriated to one person more than another insofar as the attribute that is appropriated to that person is more manifest in him. Now, divine goodness is manifest in God’s activity when, without any need of his own, he communicates what is his to his creation; and to the degree that those are communicated, the less they are owed to the creature; and to the degree that they are proper to God, the more God’s goodness is displayed thereby. For example, there are things that are gratuitously added to nature, and because of this graces are attributed to the Holy Spirit, to whom goodness is appropriated.

Therefore, since it is especially above the condition of human nature that it be assumed into the unity of a divine person, this work should particularly be appropriated to the Holy Spirit.

We grant the third objection.

To the second question, it should be said that what should be appropriated to the Father are those divine activities that especially manifest power; this is why the work of creation is appropriated to the Father. For the Father’s power is found at work in the production of an effect, but goodness is in the generous bestowal of it. Therefore, in the work of creation, things are produced in existence, but nothing is bestowed on them at that time beyond what the account of their nature requires, as it is in the work of re-creation, in which things are not entirely produced out of non-existence, but something is bestowed on them above their condition. And thus the things that pertain to re-creation are appropriated to the Holy Spirit, and not the Father.

To the third question, it should be said that as the Philosopher says in the Metaphysics 1,¹ it belongs to wisdom to order things. For this reason, those divine actions that pertain to God’s ordering, such as governance and the like, are attributed to the Son, to whom wisdom is appropriated. However, in the work of the Incarnation we find a certain gratuitous bestowal by which to be assumed into the unity of a divine person was given to a human nature, both to be filled with every grace, as the first thing, and even the carrying out of that gift, as the second—which pertain to God’s ordering. And this is why it belongs to the Holy Spirit to be the one who brings about the Incarnation, but to carry out the mystery of the Incarnation belongs to the Son.

We grant the third objection.

To the fourth question, it should be said that, by the reason already mentioned the effecting of the Incarnation is appropriated to the Holy Spirit, and therefore it can be said that Christ was conceived of the Holy Spirit, whether this preposition “of” names the relationship of an efficient cause, or even designates the reason for doing it; for the very reason for accomplishing the Incarnation is the goodness appropriated to the Holy Spirit.

We grant the third objection.

For some deny this not as simply false, but as unfittingly said, inasmuch as it presents an occasion for error—both about the Son’s eternal generation, in which a certain confusion of the relations would result if the Son were said to be his own son, and the Holy Spirit’s—and about his generation in time, lest the Holy Spirit would seem to have generated Christ as man out of his own substance if he were called his father. And just as he cannot be called the son of the Trinity simply speaking, neither can he be called that through his creation, in order to avoid the error of Arius, who said that Christ was merely something created; nor through his grace, in order to avoid the error of Nestorius, who said that there were two persons in Christ, and that the union of divinity to Christ the man was only by grace, not at the level of the person.

Yet some grant that it can be said, “this man is the son of the Trinity through his creation,” if the “this man” refers to the supposit or individual of the man, not the person of the Son of God. Nonetheless, the Son of God can in no way be called the son of the Trinity because of the repugnance of the relations.

They also grant that, in reference to the habitual grace by which the whole Trinity dwells in Christ’s soul, it can be said, “this man is the Son of God,” even insofar as he is a man. But he cannot be called the son of the Trinity, for in virtue of this [grace] he does not have the relationship to the relations by which the Trinity is distinguished. But in reference to the grace of the union, [they grant that] he is called the natural Son only of the Father.

But this opinion does not fit with the things said by Augustine, who simply denies that Christ can be said to be son of the Trinity, or of the Holy Spirit. For this cannot be for the sake of avoiding a confusion of the relations. For, since confusion is from an inordinate mixing of things, no confusion would follow if, in virtue of the different natures, we were to attribute opposed relations to the Son, or to the Holy Spirit by reason of different things. For without any unfittingness even contraries may be predicated of the Son, by reason of his different natures, such as that he is able to suffer and also unable to suffer, and even opposite relations, such as that he is less than and equal to the Father, and even greater and less than himself. Nor do they even deny this in order to avoid an error that could follow; for it does not support the error of Arius more if it be said that he is the son of the Trinity through his creation, than when it is said that insofar as he is a man he is created, which is granted anyway. And it is similar with the other errors.

Likewise too, that Christ is not related, through his habitual grace, to the relations distinguishing the divine persons does not seem to be a reason that he could not be called the son of the Trinity. For we are called sons of the Trinity through grace, and yet the grace that is in us is an effect of the divine essence, not something having reference to the distinction of the persons.

And therefore it should be said instead, with others, that Augustine denies this as simply false and impossible. For sonship is the relation consequent upon generation, while generation is the way to existence. Now, existence is something the supposit has from its form or nature. For this reason, since sonship, according to Damascene,¹ is determinative of the supposit, or hypostasis, someone cannot be said to be someone’s son unless he receives existence from him. However, Christ’s existence is one—at least according to the second opinion, as will be said later.² But Christ does not have this existence from any divine person other than the Father. Therefore he can only be called the Son of the Father.

In a similar way also, it cannot be said that he is the son of the Trinity, whether through creation or grace, because when the perfect account of any name is found in someone, in no way is that name received by him with a determination that diminishes it, as is clear from Augustine’s words in the text. For instance, a plant is called an imperfect living thing, on account of its vegetative soul, since it does not have existence with a sensitive soul, whereas although an animal has the same soul, it is not called an imperfect living thing, because it possesses it with a sensitive soul. Now, Christ has the true account of sonship toward God. Therefore he is not to be called “son” through his creation or through grace, for by this is meant an imperfect sonship toward God, which only is sonship in a certain respect, and not simply speaking.

Reply Sed Contra 4–5: We grant the fourth and fifth arguments.

To the second question, the response is evident from what has been said.

Reply Sed Contra 4–5: We grant the other objections.

And by this the answers to the others are evident.

But habitual grace can also be said to be natural in Christ in two ways. In one way, because it is stands according to the mode of natural properties, which are inseparably consequent on their subject. In the other way, because it is caused by one of his natures—that is, the divine nature, not the human one.

To what is further asked about, it should be said that there are three ways the fullness of divinity is said to dwell in Christ bodily.

In the first way, because the Godhead was united not only to his soul, but also to his flesh.

Second, by a likeness to the three dimensions of his body, because the divinity is in Christ in three ways. One way is in general, as it exists in all created things: by its essence, presence, and power; and in this it subsists like length. Another way is specific, as it exists in the saints by grace, by which the wideness of charity exists. The third way is proper to the Son, namely, by union; in him, there is sublimity and depth.

Third, something is said to dwell bodily from a likeness to a body as opposed to a [mere] shadow. For in the sacraments of the Old Law it existed as though in shadows and signs: the law had but a shadow of the good things to come (Heb 10:1), whereas in Christ it existed according to the reality and the truth—and this is how Christ is related to those figures as a body is to a shadow.

When one of the three is named . . . the Trinity is understood.¹ Against this: we say the Son of God was incarnate, which is not understood of the Father and the Holy Spirit. It should be said to this that this statement should be understood as being about things that pertain to the [divine] essence, wherein if something is said about only one person, it must be understood of the others.

But it is not to be granted that whatever is born of some thing is necessarily to be called the son of that thing.¹ Therefore, it must be noted that this preposition “of” or “from” denotes efficient or material cause. Now, for something born from something else materially to receive the name “sonship,” it must be produced in a likeness of species with what it was born from, just as a son is born from a mother. And this is why hair and stomach worms are not called the “sons” of the person they materially arise from. Also, for someone actively born from another to be called his “son,” he must be produced from the substance of the agent, and also in a likeness of the same species, and it must not be an instrumental agent, but a principal one. However, the first two conditions are lacking in the Holy Spirit, which is why Christ cannot be called his “son.” Moreover, the second and third conditions are lacking in the case of water, since someone spiritually reborn does not assume the likeness of water, but the likeness of God; and water is the instrument of divine power working in him. Nevertheless, in the Ecclesiastical Hierarchy, Dionysius calls the water of baptism the “mother of filiality”;² but he is not speaking properly.

Some are even called sons of hell. ¹ Notice that this is said according to the customary mode of speaking in Scripture, where what has a great affinity for another may be called its son, as Isaiah 5:1 says: on a hill, son of oil,² that is, on a mountain top where oil was abundant; and similarly, David said of Abner that he would be the “son of death,” because he greatly deserved death (1 Sam 26:16).

Conceived and born of the Holy Spirit.¹ Although either of these could be said of both the Holy Spirit and of his mother, nevertheless, “conceived” is said more properly of the Holy Spirit because conception was brought about in an instant by the Holy Spirit; while “born” is said more properly of the mother, who brought him forth from her womb. This is why we say in the Creed, conceived of the Holy Spirit, born of the Virgin Mary.

Made from the seed of David (Rom 1:3).¹ To the contrary: Damascene says, not as by seed, but as by something made by the Holy Spirit.² To this it should be said that Damascene is speaking about the proximate generation of Christ from the Virgin, while the words of the Apostle should be understood as about his remote ancestors, from whom Christ’s mother proceeded by seed.

Even though to be made is one thing, and to be born another.¹ To the contrary: being made seems to be common to every act of producing in which something begins to exist. It should be said to this that this is true of “making” as it is taken commonly, but if “to make” is taken properly, it is to exercise any action in outward matter; in this way the Philosopher says, in the Ethics 6,² that an art is the right account of things that can be made. Therefore, the Apostle says “made” to show that Christ’s conception is from an external acting principle, not one acting naturally, as it is in our conception—although he can also be said to be born and conceived on the part of his mother.

To the second question, it should be said that this union can be considered under two aspects: either as to what the union happens in, or as to the things that are united. If the first way, since the union happens in the divine person, which is the most one and simple, then this is the greatest union after the union of essence in the three divine persons. For, although the person is as simple and one as the essence, nevertheless, any of the three persons is the same thing as the essence itself, in which they are united. However, the two natures in Christ are not the same thing as the divine person, although one of his natures, the divine one, is entirely the same thing as it. Thus the union of persons in one essence is greater than the union of the natures in one person. If we look at it in the second way, then it is not the greatest union. But the first consideration is of the union in itself, because according to this it is one thing, whereas the latter is not the consideration of the union insofar as it is a union. And therefore it should be said that the union is the greatest, simply speaking, although it is not the greatest in a certain respect.

To the third question, it should be said that the first difference between assumption and union is that assumption is either an action or a being-acted-upon, while union is only a relation, although uniting is also an action. The second difference is that “assumption” is said in relation to the terminus from which it is being separated, or it is taken as what is to be united; but “union” is said in relation to the terminus or effect of the uniting, which is being one. And from here we can take a third difference, that the one uniting is also united; for “united” is signified insofar as it has already become one, while “assumed” insofar as it is on its way toward this. And so the one assuming is not the assumed. A fourth difference is that assumption determines what the uniting is done to, just as we say “assumption” as in, “taken to oneself.” But this is not the case with union, and so whoever causes the joining can be said to unite, but he cannot be said to assume unless he joins the thing to himself. Thus, the Father united human nature with the divine nature, but he did not assume human nature. A fifth difference is that union, in itself, has to do with both extremes equally, but assumption does not, but rather it requires something fixed and stationary in the one, which the other is drawn into. And for this reason the divine nature can be said to be united to human nature in the person, but it cannot be said to be assumed.

However, aside from the significations by which form and matter are called “substance,” “substance” is said in two ways, according to the Philosopher in the Metaphysics 5.¹ In one way, the subject itself that is called a "this-something" and is not predicated of another (like “this man”), insofar as a substance is signified by the word “hypostasis.” And according to this signification, a substance is called a “nature” insofar as a nature is what can act or be acted upon, as Boethius says in the book mentioned.² In another way, we call the substance the “what it was to be”—that is, the “what-ness” and essence that the definition of anything whatsoever signifies, as is signified by the name ousia. And this is also how substance is called the “nature,” as when Boethius says that the nature is what informs each thing with its specific difference,³ because the last difference is the one that completes the definition.

Therefore, leaving aside all other meanings of the word “nature,” we are asking whether there is one nature in Christ or several according to this last signification alone. Now, if there is only one, it is either one of the two, or it is a composite of both.

But if there is only one of the two, there are two ways this would be the case. In one way, by no intervening joining of one to the other, and then, if it were in the divine nature, nothing new would happen in the Word becoming flesh, and the Incarnation would be nothing. But if it were in the human nature alone, Christ would not be different from other people, and the Incarnation would be lost. In the other way, one of the natures would pass into the other. And this cannot be, for things that do not share in matter cannot pass into one another. Now, the divine nature is entirely immaterial, and still less could it share in matter with the human nature. Furthermore, if divine nature passed into the human nature, the simplicity and immutability of divine nature would be destroyed. But if the human nature changed into the divine nature, the truth of the Passion and all the things that Christ did physically would be destroyed.

However, if it were one nature composed out of the two, there are two ways that this could be the case. In one way, if the third nature were composed out of two natures that do not remain, like a combination composed out of the four elements. And according to this, the divine nature would be considered material and capable of suffering, because a combination happens only of things that share in matter and are naturally apt to act and be acted upon by each other. And the faith that confesses that Christ is true God and true man would be destroyed. In the other way, it would be composed out of two natures that did remain, and this could happen two ways. One, according to a commensurateness of continuity or contiguity, and following this we would be holding that the divine nature is bodily, because continuity and contact have to do with bodies. In the other way, it could happen as an internal formation, just as one thing is made from the soul and the body. And this also cannot be the case, because in this way one thing is made not from two acts nor from two potencies, but from act and potency, according to the Philosopher,¹ but divine and human natures are each a being in act. Furthermore, divine nature does not have anything of potentiality, nor can it be an act entering into the composition of anything, since it is the infinite first existence subsisting through itself. Therefore, it is clear that in any way that one nature is posited in Christ results in an error. And that is why Eutyches, who did hold this, was condemned as a heretic.

Therefore, it should be known that in certain things the nature and the person differ according to reality, but in other things they differ only according to their notion. For a nature, as we are speaking of it here, is the “whatness” of a thing that its definition designates, while a person is this something that subsists in that nature. Now, in simple things that lack matter, as Avicenna says,¹ the simple thing itself is its own whatness. But the whatness of a composite thing is not the composite thing itself, for humanity is not a man. The reason for this is that within the signification of “humanity,” either of its whatness or of its nature, are contained only the essential principles of man, in virtue of which he is a man, but not those things that pertain to the determination of the matter, by which the nature is individuated—these are contained only in the signification of “Socrates,” because by these Socrates is this man, and is divided from other men. And so, since humanity does not include in its signification the whole that is in the thing subsisting in the nature, since it is, as it were, just a part, it is not predicated of it. And because only what is composite subsists, and the part is possessed by its whole, therefore the soul does not subsist, but rather Socrates does, and he is the one who has humanity. Now, “man” signifies both the essentials and the individuating principles, but in different ways; for it signifies the essentials determinately, but the individuating principles indeterminately, these ones or those ones. And thus “man,” since it is the whole, can be predicated of Socrates, and can mean “someone having humanity.” But because being indistinct is incomplete, as a being in potency, this is why “man” does not subsist, but only this man, to whom belongs the account of “person.” Therefore the account of “person” is of a distinct subsisting thing and it includes everything that is in the thing, whereas “nature” includes only the essentials. Now, in simple things the nature and the person do not differ in reality, because nature is not received in any matter by which it is individuated; rather, it is subsisting through itself. Nevertheless, inasmuch as the essentials of the thing are considered, we say there is a nature there; but insofar as is found there something subsisting, we say there is a person there.

Therefore it is evident from the account of “person”—that it comprehends everything that there is in the thing—that if there is something that is beyond what “person” includes, then this is not united to the thing, unless perhaps in virtue of a likeness in genus, or in species, or accidentally. And this is why, as Boethius says,¹ if there is not one person in Christ, no union was made between divinity and humanity, except according to a likeness of grace, which Nestorius also held. And this is neither something new, nor proper to Christ; nor could our redemption have been accomplished by him, nor would he have been the true God, but only by participation, just like the other saints. Therefore, it should simply be granted that there was one person in Christ.

The divinity of Christ is not alien to the Father’s nature . . . nor is his humanity alien to his mother’s nature.¹ To the contrary: Christ shares with the Father in a nature that is one in number, but this is not the case with his mother, so it is not a direct likeness. To this it must be said that there need not be a likeness in all things; rather, it suffices that it be there in some respect.

When you hear of Christ that he was in the form of God, it is necessary that you acknowledge and hold most firmly that in the term ‘form,’ the fullness of nature is to be understood.¹ It should be known that the divine nature is called a “form” not because it is the act of any nature, but because it does not have its nature as a part of itself, nor anything of potentiality in itself. But human nature is called a “form” not because it includes only formal principles (for it does include both form and matter), but by the mode in which the whatness of a composite thing is called the form of the whole.

The Trinity itself made the Word alone flesh.¹ Here the part is being taken for the whole, because “flesh” is being taken for the man. And it puts forth the weaker [part], of which it is seen to be the lesser, so that it may be seen that our whole nature was assumed, and even the defects of human nature, which it adorned.

The whole [omnem] and perfect nature of the divinity.¹ To the contrary: "whole/all" is a distributive sign, but the divine nature is undivided. To this it should be said that "whole/all" is used here to mean “whole,” insofar as what lacks nothing is called “whole,” and not in the way that a "all/whole" is compared to its parts, because the divine nature does not have parts.

And so the divine nature is not said to be man or to have been made man, in the same way as the Son of God is.¹ To the contrary: anything that the Son of God is predicated of, a man is predicated of; but the divine nature is the Son of God; therefore it is a man. It should be said that there is a difference between substantive nouns and adjectives. For substantives signify not only the form, but also the supposit of the form, and so they can be predicated by reason of either. And when they are predicated by reason of the supposit, it is called a predication by identity; but when it is by reason of the form, it is called a predication by denomination, or informing. And this is the more proper predication, because the termini in the predicate are held as forms. However, adjectives signify only the form, and so they can be predicated only as informing. This is why it is false to say, “the essence is the one generating,” although this is true: “the essence is the Father.” Therefore, when we say, “the Son of God is a man,” it is a predication by informing and identity; but when we say, “the divine essence is a man,” it is a predication by identity, because it is the same thing in reality as a supposit of “man,” but it is not a predication by informing, because the divine nature is not signified as a supposit subsisting in human nature. And this is why the Master said that the one is not as true as the other, but he also does not say that it is simply false.

But because accidents follow upon a nature, every name designating a particular in reference to its properties also designates it in reference to its common nature. This can happen in two ways: either by a name of a first imposition—and in this way “hypostasis” is common to all substances, but “person” to all rational substances—or by a name of a second imposition—and in this way something is an “individual“ insofar as in itself it is not divided, but a “singular“ insofar as it is divided from others. This is why the “singular“ is the same thing as the “divided.”

We should also notice another difference between such words. For some of these words signify the particular commonly, as under any genus at all, such as “particular,” “individual,” and “singular.” But some signify the particular only in the genus of substance, such as a “thing of a nature,” “supposit,” “hypostasis,” and “person.”

But because the notion of substance is of what subsists through itself, these things are said only of a complete thing subsisting through itself. Whence they are said neither of a part nor of an accident, even though the other names found in all genera can be said of them. For although this whiteness or this hand might be called an “individual” or a “singular,” still it cannot be called a “hypostasis,” or a “supposit,” or a “reality of a nature.”

However, if there be present two things, each of which subsists through itself, then it is impossible that the one is the other. For they differ insofar as they are numbered, since difference is the cause of number, and they are not predicated of each other except insofar as they are one.

Whence since a divine person is a thing subsisting through itself, if there is also present one complete thing subsisting through itself composed of soul and flesh, which is a man, or this man, then the one cannot be predicated of the other, as when one says, “the Son of God is this man.” And because the first opinion does assert this, this is why it is not held by anyone now.

But according to this, being composed only of soul and flesh does not indicate that it is something subsisting; rather, it indicates that it is a human nature, in which a divine person subsists. Therefore, following this opinion, it should be said that all names that signify a particular in whatever genus can be said to be two in Christ. For just as this hand is called an “individual,” or “singular,” or “particular,” so too the human nature in Christ is an “individual,” “singular,” or “particular.”

Also, since the human nature is not the divine nature, nor is it the divine person, nothing prevents one from saying, “in Christ there are two individuals,” or “two singulars” or “two particulars,” or even “several,” according to the number of the parts of Christ’s body, each of which can be called an “individual”—unless one is forced to say that names of this sort are not properly found in the divine. Nonetheless these several individuals are not predicated of Christ, since the human nature is not predicated of him, nor are its parts. However, one cannot say that in Christ there are two hypostases, or things of a nature, or supposits. For the human nature in Christ is not a thing of a nature, or a supposit; rather, it is a nature itself. For no composite nature is a thing or supposit of its very self. Likewise, it is not a "hypostasis," but an ousia.

Nonetheless, just as we say the union is accomplished in the person, so too we say it is accomplished in the hypostasis, supposit, thing of the nature, individual, singular, or particular. For although these last three can be said of things that do not subsist through themselves, still they are also said of things that do subsist through themselves. For we do say that a hypostasis is an individual. Whence insofar as the union is accomplished in the hypostasis, it is also accomplished in the individual. And in this way we can say that Christ is one individual, and yet also in him there are two or several individuals, just as also happens with any other man. And the account of the singular and the particular is the same.

Reply Sed Contra: We grant the things objected on the contrary. Yet one should know that the first opinion, although it asserts that there are two hypostases, still does not assert that there are different persons. For because a person is an individual of a rational nature—which is most complete and where the entire breadth of the nature is present—it follows that “person” signifies the most complete thing at a final completion, one beyond which there is no further completion. Whence when it asserts that a man is assumed united to the Word, it was not granting it the notion of being a person, though it did grant it the notion of being a hypostasis, insofar as it was subsistent. Yet neither did it assert that this man was united to the divine person as its accident, since then it would not say that [the word “man”] would predicate what he is, but it would say it is united to it accidentally—as the third opinion says. Rather, it asserted that the person of the Word was that hypostasis. Nevertheless, this is not intelligible, as one of the two distinct things would be predicated of the other, as was said before.

To the second question, it should be said that in Christ there is only one supposit, for the reason already stated—unless one means that it is just a supposit of speech, but in this sense anything about which one can speak is a supposit.

To the third question, it should be said that in Christ there are two individuals, yet not individuals subsisting through themselves; and Christ himself is one subsisting individual, as was said.

To the fourth question, it should be said that in Christ there are not two things of a nature, but rather that he himself is one thing of two natures.

Nonetheless it should be known that the first opinion did not assert any of the stated modes of union, so it is not heretical. But it did assert that the union was brought about in this respect: that the person of the Word did begin to be that substance. But it is not intelligible that of two things one would become the other unless by one turning into the other. Indeed, this is impossible, as was said before, and therefore it is not upheld.

Therefore according to the second opinion, which is what we are treating now, the something that is the assumed nature is not predicated of Christ. For it does not have the notion of a man, but of humanity. Therefore when “something” is predicated of Christ, it signifies not only a nature, but also a supposit of the nature. And because a plural multiplies a singular, thus Christ cannot be called “somethings” unless there are in him two supposits of a nature—which the second opinion denies, as does the third. And therefore both opinions say that Christ is one [thing], though the second says that he is one [thing] through himself, but the third says he is one [thing] accidentally, as is a white man. But the first opinion says that the thing assumed has not only the notion of humanity, but also the notion of a man; and yet it cannot be called “someone,” since it is joined to something else of greater dignity, though it is said to be “something” and that something is predicated of the person assuming it.

And therefore it follows that Christ is someone, namely the one doing the assuming, and he is something, namely the thing assumed, and that he is two things taken in the neuter, but not in the masculine.

Therefore, when speaking about existence insofar as it is the act of a being, in this way I say that according to the second opinion one must assert there is only one existence, but according to the others one must assert there are two existences. For a subsisting being is what has existence as of that which exists, although it is of a nature or form as of that by which it exists. Whence neither a thing’s nature nor its parts are properly said “to be,” if “to be” is being taken in the aforesaid mode; likewise, neither are its accidents. But the complete supposit, which exists in virtue of all the others, is [properly said “to be”]. Whence also the Philosopher says in the Metaphysics 2,¹ that an accident is more properly of a being than a being.

Therefore the first opinion, which asserts there are two subsistences, asserts two substantial existences; likewise the third opinion, since it claims that the parts of human nature come to the divine person accidentally, asserts two existences: one substantial and the other accidental. But the second opinion, since it asserts that there is one subsistence, and also asserts that the humanity does not come to the divine person accidentally, must assert one existence. For it is impossible that something one have two substantial existences, since the one is founded on being. So if there were many existences, each in virtue of which something is called a “being” simply, it is impossible that he would be called “one.” But it is not a problem that one subsistence’s existence be in reference to many things, just as Peter’s existence is one though it has reference to the diverse principles that make him up. Likewise also, in its own way Christ’s one existence has two references, one to the human nature and the other to the divine.

However, according to the third and first opinions, neither of these are found in Christ. For the first opinion says that this man has his own proper existence, so the divine person’s existence does not belong to him. Likewise the third opinion says that there is an existence added accidentally to the divine person’s existence; so the soul and the body are not said to be the person’s parts, just as neither are accidents a subject’s parts. Whence neither asserts that the person of the Word is composite.

But the second opinion asserts that there is one existence in Christ, which is why the divine person’s existence belongs to both natures. Nevertheless, that existence is not caused by the joining of the natures, the way that the existence of a composite is caused by the joining of its components. This is why, according to this opinion, the [person of Christ after the Incarnation can in some way be called “composite,” inasmuch as a certain condition of composites is preserved here; still, the true notion of composition is not here, because the other condition is lacking. This is also why calling the person “composite” is not customary among contemporaries who hold this opinion.

Nor should one say that he is called “composite” only according to the interpretation of the name as meaning, as it were, “placed with another.” For this way the first and third opinions would assert that the person is composite in the same way the second does.

Reply Sed Contra 6: This binding-together is taken according to a likeness with number, but not according to a likeness with whole and part.

Reply Sed Contra 7: This likeness is in a certain respect, not in all respects, as is clear from the things said.

Reply Sed Contra 8: A whole has something in its notion over and above being composed of parts: namely, that it is lacking none of the things it should have. And it is being taken by Damascene in reference to this.

Nonetheless, this opinion appears to have proceeded from the same spring as the first, namely: they believed that every composite of soul and body has the notion of a man, and therefore, since the first opinion asserted that a united soul and body was assumed, it was forced to assert that a man was assumed, and that Christ is two things. However, to deny this, this opinion asserted that the soul and body were assumed without being united. But the second opinion avoids this, as has been said.