Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the Son of God did not assume flesh through the medium of the soul. For the mode in which the Son of God is united to human nature and its parts, is more perfect than the mode whereby He is in all creatures. But He is in all creatures immediately by essence, power and presence. Much more, therefore, is the Son of God united to flesh without the medium of the soul.

Objection 2: Further, the soul and flesh are united to the Word of God in unity of hypostasis or person. But the body pertains immediately to the human hypostasis or person, even as the soul. Indeed, the human body, since it is matter, would rather seem to be nearer the hypostasis than the soul, which is a form, since the principle of individuation, which is implied in the word "hypostasis," would seem to be matter. Hence the Son of God did not assume flesh through the medium of the soul.

Objection 3: Further, take away the medium and you separate what were joined by the medium; for example, if the superficies be removed color would leave the body, since it adheres to the body through the medium of the superficies. But though the soul was separated from the body by death, yet there still remained the union of the Word to the flesh, as will be shown (Question 50, Articles 2,3). Hence the Word was not joined to flesh through the medium of the soul.

On the contrary, Augustine says (Ep. ad Volusianum cxxxvi): "The greatness of the Divine power fitted to itself a rational soul, and through it a human body, so as to raise the whole man to something higher."

I answer that, A medium is in reference to a beginning and an end. Hence as beginning and end imply order, so also does a medium. Now there is a twofold order: one, of time; the other, of nature. But in the mystery of the Incarnation nothing is said to be a medium in the order of time, for the Word of God united the whole human nature to Himself at the same time, as will appear (Question 30, Article 3). An order of nature between things may be taken in two ways: first, as regards rank of dignity, as we say the angels are midway between man and God; secondly, as regards the idea of causality, as we say a cause is midway between the first cause and the last effect. And this second order follows the first to some extent; for as Dionysius says (Coel. Hier. xiii), God acts upon the more remote substances through the less remote. Hence if we consider the rank of dignity, the soul is found to be midway between God and flesh; and in this way it may be said that the Son of God united flesh to Himself, through the medium of the soul. But even as regards the second order of causality the soul is to some extent the cause of flesh being united to the Son of God. For the flesh would not have been assumable, except by its relation to the rational soul, through which it becomes human flesh. For it was said above (Question 4, Article 1) that human nature was assumable before all others.

Reply to Objection 1: We may consider a twofold order between creatures and God: the first is by reason of creatures being caused by God and depending on Him as on the principle of their being; and thus on account of the infinitude of His power God touches each thing immediately, by causing and preserving it, and so it is that God is in all things by essence, presence and power. But the second order is by reason of things being directed to God as to their end; and it is here that there is a medium between the creature and God, since lower creatures are directed to God by higher, as Dionysius says (Eccl. Hier. v); and to this order pertains the assumption of human nature by the Word of God, Who is the term of the assumption; and hence it is united to flesh through the soul.

Reply to Objection 2: If the hypostasis of the Word of God were constituted simply by human nature, it would follow that the body was nearest to it, since it is matter which is the principle of individuation; even as the soul, being the specific form, would be nearer the human nature. But because the hypostasis of the Word is prior to and more exalted than the human nature, the more exalted any part of the human nature is, the nearer it is to the hypostasis of the Word. And hence the soul is nearer the Word of God than the body is.

Reply to Objection 3: Nothing prevents one thing being the cause of the aptitude and congruity of another, and yet if it be taken away the other remains; because although a thing's becoming may depend on another, yet when it is in being it no longer depends on it, just as a friendship brought about by some other may endure when the latter has gone; or as a woman is taken in marriage on account of her beauty, which makes a woman's fittingness for the marriage tie, yet when her beauty passes away, the marriage tie still remains. So likewise, when the soul was separated, the union of the Word with flesh still endured.

Articulus 1

Argumentum 1

Ad primum sic proceditur. Videtur quod filius dei non assumpserit carnem mediante anima. Perfectior enim est modus quo filius dei unitur humanae naturae et partibus eius, quam quo est in omnibus creaturis. Sed in creaturis est immediate per essentiam, praesentiam et potentiam. Ergo multo magis filius dei unitur carni, et non mediante anima.

Argumentum 2

Praeterea, anima et caro unita sunt dei verbo in unitate hypostasis seu personae. Sed corpus immediate pertinet ad personam sive hypostasim hominis, sicut et anima. Quinimmo magis videtur se de propinquo habere ad hypostasim hominis corpus, quod est materia quam anima, quae est forma, quia principium individuationis, quae importatur in nomine hypostasis, videtur esse materia.

Ergo filius dei non assumpsit carnem mediante anima.

Argumentum 3

Praeterea, remoto medio, separantur ea quae per medium coniunguntur, sicut, remota superficie, cessaret color a corpore, qui inest corpori per superficiem. Sed, separata per mortem anima, adhuc remanet unio verbi ad carnem, quod infra patebit.

Ergo verbum non coniungitur carni mediante anima.

Sed Contra

Sed contra est quod Augustinus dicit, in epistola ad volusianum, ipsa magnitudo divinae virtutis animam sibi rationalem, et per eandem corpus humanum, totumque omnino hominem, in melius mutandum, coaptavit.

Corpus

Respondeo dicendum quod medium dicitur respectu principii et finis. Unde, sicut principium et finis important ordinem, ita et medium. Est autem duplex ordo, unus quidem temporis; alius autem naturae. Secundum autem ordinem temporis, non dicitur in mysterio incarnationis aliquid medium, quia totam naturam humanam simul sibi dei verbum univit, ut infra patebit.

Ordo autem naturae inter aliqua potest attendi dupliciter, uno modo, secundum dignitatis gradum, sicut dicimus Angelos esse medios inter homines et deum; alio modo, secundum rationem causalitatis, sicut dicimus mediam causam existere inter primam causam et ultimum effectum. Et hic secundus ordo aliquo modo consequitur primum, sicut enim dicit dionysius, XIII cap. Cael. Hier., deus per substantias magis propinquas agit in ea quae sunt magis remota.

Si ergo attendamus gradum dignitatis, anima media invenitur inter deum et carnem. Et secundum hoc, potest dici quod filius dei univit sibi carnem mediante anima. Sed secundum ordinem causalitatis, ipsa anima est aliqualiter causa carnis uniendae filio dei. Non enim esset assumptibilis nisi per ordinem quem habet ad animam rationalem, secundum quam habet quod sit caro humana, dictum est enim supra quod natura humana prae ceteris est assumptibilis.

Ad 1

Ad primum ergo dicendum quod duplex ordo considerari potest inter creaturam et deum. Unus quidem, secundum quod creaturae causantur a deo et dependent ab ipso sicut a principio sui esse.

Et sic, propter infinitatem suae virtutis, deus immediate attingit quamlibet rem, causando et conservando. Et ad hoc pertinet quod deus immediate est in omnibus per essentiam, potentiam et praesentiam. Alius autem ordo est secundum quod res reducuntur in deum sicut in finem. Et quantum ad hoc, invenitur medium inter creaturam et deum, quia inferiores creaturae reducuntur in deum per superiores, ut dicit dionysius, in libro caelest. Hier..

Et ad hunc ordinem pertinet assumptio humanae naturae a verbo dei quod est terminus assumptionis. Et ideo per animam unitur carni.

Ad 2

Ad secundum dicendum quod, si hypostasis verbi dei constitueretur simpliciter per naturam humanam, sequeretur quod corpus esset ei vicinius, cum sit materia, quae est individuationis principium, sicut et anima, quae est forma specifica, propinquius se habet ad naturam humanam. Sed quia hypostasis est prior et altior quam humana natura, tanto id quod est in humana natura propinquius se habet, quanto est altius. Et ideo propinquior est verbo dei anima quam corpus.

Ad 3

Ad tertium dicendum quod nihil prohibet aliquid esse causam alicuius quantum ad aptitudinem et congruitatem, quo tamen remoto, id non tollitur, quia, etsi fieri alicuius dependeat ex aliquo, postquam tamen est in facto esse, ab eo non dependet. Sicut, si inter aliquos amicitia causaretur aliquo mediante, eo recedente adhuc amicitia remanet, et si aliqua in matrimonium ducitur propter pulchritudinem, quae facit congruitatem in muliere ad copulam coniugalem, tamen, cessante pulchritudine, adhuc durat copula coniugalis. Et similiter, separata anima, remanet unio verbi dei ad carnem.