Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the union of the Incarnate Word did not take place in the person. For the Person of God is not distinct from His Nature, as we said (1, Question 39, Article 1). If, therefore, the union did not take place in the nature, it follows that it did not take place in the person.

Objection 2: Further, Christ's human nature has no less dignity than ours. But personality belongs to dignity, as was stated above (1, Question 29, Article 3, ad 2). Hence, since our human nature has its proper personality, much more reason was there that Christ's should have its proper personality.

Objection 3: Further, as Boethius says (De Duab. Nat.), a person is an individual substance of rational nature. But the Word of God assumed an individual human nature, for "universal human nature does not exist of itself, but is the object of pure thought," as Damascene says (De Fide Orth. iii, 11). Therefore the human nature of Christ has its personality. Hence it does not seem that the union took place in the person.

On the contrary, We read in the Synod of Chalcedon (Part ii, act. 5): "We confess that our Lord Jesus Christ is not parted or divided into two persons, but is one and the same only-Begotten Son and Word of God." Therefore the union took place in the person.

I answer that, Person has a different meaning from "nature." For nature, as has been said (Article 1), designates the specific essence which is signified by the definition. And if nothing was found to be added to what belongs to the notion of the species, there would be no need to distinguish the nature from the suppositum of the nature (which is the individual subsisting in this nature), because every individual subsisting in a nature would be altogether one with its nature. Now in certain subsisting things we happen to find what does not belong to the notion of the species, viz. accidents and individuating principles, which appears chiefly in such as are composed of matter and form. Hence in such as these the nature and the suppositum really differ; not indeed as if they were wholly separate, but because the suppositum includes the nature, and in addition certain other things outside the notion of the species. Hence the suppositum is taken to be a whole which has the nature as its formal part to perfect it; and consequently in such as are composed of matter and form the nature is not predicated of the suppositum, for we do not say that this man is his manhood. But if there is a thing in which there is nothing outside the species or its nature (as in God), the suppositum and the nature are not really distinct in it, but only in our way of thinking, inasmuch it is called "nature" as it is an essence, and a "suppositum" as it is subsisting. And what is said of a suppositum is to be applied to a person in rational or intellectual creatures; for a person is nothing else than "an individual substance of rational nature," according to Boethius. Therefore, whatever adheres to a person is united to it in person, whether it belongs to its nature or not. Hence, if the human nature is not united to God the Word in person, it is nowise united to Him; and thus belief in the Incarnation is altogether done away with, and Christian faith wholly overturned. Therefore, inasmuch as the Word has a human nature united to Him, which does not belong to His Divine Nature, it follows that the union took place in the Person of the Word, and not in the nature.

Reply to Objection 1: Although in God Nature and Person are not really distinct, yet they have distinct meanings, as was said above, inasmuch as person signifies after the manner of something subsisting. And because human nature is united to the Word, so that the Word subsists in it, and not so that His Nature receives therefrom any addition or change, it follows that the union of human nature to the Word of God took place in the person, and not in the nature.

Reply to Objection 2: Personality pertains of necessity to the dignity of a thing, and to its perfection so far as it pertains to the dignity and perfection of that thing to exist by itself (which is understood by the word "person"). Now it is a greater dignity to exist in something nobler than oneself than to exist by oneself. Hence the human nature of Christ has a greater dignity than ours, from this very fact that in us, being existent by itself, it has its own personality, but in Christ it exists in the Person of the Word. Thus to perfect the species belongs to the dignity of a form, yet the sensitive part in man, on account of its union with the nobler form which perfects the species, is more noble than in brutes, where it is itself the form which perfects.

Reply to Objection 3: The Word of God "did not assume human nature in general, but 'in atomo'"---that is, in an individual---as Damascene says (De Fide Orth. iii, 11) otherwise every man would be the Word of God, even as Christ was. Yet we must bear in mind that not every individual in the genus of substance, even in rational nature, is a person, but that alone which exists by itself, and not that which exists in some more perfect thing. Hence the hand of Socrates, although it is a kind of individual, is not a person, because it does not exist by itself, but in something more perfect, viz. in the whole. And hence, too, this is signified by a "person" being defined as "an individual substance," for the hand is not a complete substance, but part of a substance. Therefore, although this human nature is a kind of individual in the genus of substance, it has not its own personality, because it does not exist separately, but in something more perfect, viz. in the Person of the Word. Therefore the union took place in the person.

Articulus 2

Argumentum 1

Ad secundum sic proceditur. Videtur quod unio verbi incarnati non sit facta in persona. Persona enim dei non est aliud a natura ipsius, ut habitum est in primo.

Si ergo unio non est in natura, sequitur quod non sit facta in persona.

Argumentum 2

Praeterea, natura humana non est minoris dignitatis in christo quam in nobis. Personalitas autem ad dignitatem pertinet, ut in primo habitum est.

Cum ergo natura humana in nobis propriam personalitatem habeat, multo magis habuit propriam personalitatem in christo.

Argumentum 3

Praeterea, sicut boetius dicit, in libro de duabus naturis, persona est rationalis naturae individua substantia.

Sed verbum dei assumpsit naturam humanam individuam, natura enim universalis non sistit secundum se, sed in nuda contemplatione consideratur, ut Damascenus dicit.

Ergo humana natura habet suam personalitatem.

Non ergo videtur quod sit facta unio in persona.

Sed Contra

Sed contra est quod in chalcedonensi synodo legitur, non in duas personas partitum aut divisum, sed unum et eundem filium unigenitum dominum nostrum iesum christum confitemur.

Ergo facta est unio verbi in persona.

Corpus

Respondeo dicendum quod persona aliud significat quam natura. Natura enim significat essentiam speciei, quam significat definitio.

Et si quidem his quae ad rationem speciei pertinent nihil aliud adiunctum inveniri posset, nulla necessitas esset distinguendi naturam a supposito naturae, quod est individuum subsistens in natura illa, quia unumquodque individuum subsistens in natura aliqua esset omnino idem cum sua natura. Contingit autem in quibusdam rebus subsistentibus inveniri aliquid quod non pertinet ad rationem speciei, scilicet accidentia et principia individuantia, sicut maxime apparet in his quae sunt ex materia et forma composita. Et ideo in talibus etiam secundum rem differt natura et suppositum, non quasi omnino aliqua separata, sed quia in supposito includitur ipsa natura speciei, et superadduntur quaedam alia quae sunt praeter rationem speciei. Unde suppositum significatur ut totum, habens naturam sicut partem formalem et perfectivam sui. Et propter hoc in compositis ex materia et forma natura non praedicatur de supposito, non enim dicimus quod hic homo sit sua humanitas. Si qua vero res est in qua omnino nihil est aliud praeter rationem speciei vel naturae suae, sicut est in deo, ibi non est aliud secundum rem suppositum et natura, sed solum secundum rationem intelligendi, quia natura dicitur secundum quod est essentia quaedam; eadem vero dicitur suppositum secundum quod est subsistens. Et quod est dictum de supposito, intelligendum est de persona in creatura rationali vel intellectuali, quia nihil aliud est persona quam rationalis naturae individua substantia, secundum boetium.

Omne igitur quod inest alicui personae, sive pertineat ad naturam eius sive non, unitur ei in persona. Si ergo humana natura verbo dei non unitur in persona, nullo modo ei unitur. Et sic totaliter tollitur incarnationis fides, quod est subruere totam fidem christianam. Quia igitur verbum habet naturam humanam sibi unitam, non autem ad suam naturam divinam pertinentem consequens est quod unio sit facta in persona verbi, non autem in natura.

Ad 1

Ad primum ergo dicendum quod, licet in deo non sit aliud secundum rem natura et persona, differt tamen secundum modum significandi, sicut dictum est, quia persona significat per modum subsistentis.

Et quia natura humana sic unitur verbo ut verbum in ea subsistat, non autem ut aliquid addatur ei ad rationem suae naturae, vel ut eius natura in aliquid transmutetur, ideo unio facta est in persona, non in natura.

Ad 2

Ad secundum dicendum quod personalitas necessario intantum pertinet ad dignitatem alicuius rei et perfectionem, inquantum ad dignitatem et perfectionem eius pertinet quod per se existat, quod in nomine personae intelligitur. Dignius autem est alicui quod existat in aliquo se digniori, quam quod existat per se. Et ideo ex hoc ipso humana natura dignior est in christo quam in nobis, quia in nobis, quasi per se existens, propriam personalitatem habet in christo autem existit in persona verbi. Sicut etiam esse completivum speciei pertinet ad dignitatem formae, tamen sensitivum nobilius est in homine, propter coniunctionem ad nobiliorem formam completivam, quam sit in bruto animali, in quo est forma completiva.

Ad 3

Ad tertium dicendum quod dei verbum non assumpsit naturam humanam in universali, sed in atomo, idest in individuo, sicut Damascenus dicit, alioquin oporteret quod cuilibet homini conveniret esse dei verbum, sicut convenit christo. Sciendum est tamen quod non quodlibet individuum in genere substantiae, etiam in rationali natura, habet rationem personae, sed solum illud quod per se existit, non autem illud quod existit in alio perfectiori. Unde manus socratis, quamvis sit quoddam individuum, non est tamen persona, quia non per se existit, sed in quodam perfectiori, scilicet in suo toto. Et hoc etiam potest significari in hoc quod persona dicitur substantia individua, non enim manus est substantia completa, sed pars substantiae. Licet igitur humana natura sit individuum quoddam in genere substantiae, quia tamen non per se separatim existit, sed in quodam perfectiori, scilicet in persona dei verbi, consequens est quod non habeat personalitatem propriam. Et ideo facta est unio in persona.