1 Objection 1: It would seem that in God the essence is not the same as person. For whenever essence is the same as person or suppositum, there can be only one suppositum of one nature, as is clear in the case of all separate substances. For in those things which are really one and the same, one cannot be multiplied apart from the other. But in God there is one essence and three persons, as is clear from what is above expounded Question 28, Article 3; Question 30, Article 2). Therefore essence is not the same as person.
1 Ad primum sic proceditur. Videtur quod in divinis essentia non sit idem quod persona. In quibuscumque enim essentia est idem quod persona seu suppositum, oportet quod sit tantum unum suppositum unius naturae, ut patet in omnibus substantiis separatis, eorum enim quae sunt idem re, unum multiplicari non potest, quin multiplicetur et reliquum. Sed in divinis est una essentia et tres personae, ut ex supra dictis patet. Ergo essentia non est idem quod persona.
2 Objection 2: Further, simultaneous affirmation and negation of the same things in the same respect cannot be true. But affirmation and negation are true of essence and of person. For person is distinct, whereas essence is not. Therefore person and essence are not the same.
2 Praeterea, affirmatio et negatio simul et semel non verificantur de eodem. Sed affirmatio et negatio verificantur de essentia et persona, nam persona est distincta, essentia vero non est distincta. Ergo persona et essentia non sunt idem.
3 Objection 3: Further, nothing can be subject to itself. But person is subject to essence; whence it is called suppositum or hypostasis. Therefore person is not the same as essence.
3 Praeterea, nihil subiicitur sibi ipsi. Sed persona subiicitur essentiae, unde suppositum vel hypostasis nominatur. Ergo persona non est idem quod essentia.
4 On the contrary, Augustine says De Trin. vi, 7): When we say the person of the Father we mean nothing else but the substance of the Father.
4 Sed contra est quod Augustinus dicit, VII de Trin., cum dicimus personam patris, non aliud dicimus quam substantiam patris.
5 I answer that, The truth of this question is quite clear if we consider the divine simplicity. For it was shown above Question 3, Article 3) that the divine simplicity requires that in God essence is the same as suppositum, which in intellectual substances is nothing else than person. But a difficulty seems to arise from the fact that while the divine persons are multiplied, the essence nevertheless retains its unity. And because, as Boethius says De Trin. i), relation multiplies the Trinity of persons, some have thought that in God essence and person differ, forasmuch as they held the relations to be adjacent; considering only in the relations the idea of reference to another, and not the relations as realities. But as it was shown above Question 28, Article 2) in creatures relations are accidental, whereas in God they are the divine essence itself. Thence it follows that in God essence is not really distinct from person; and yet that the persons are really distinguished from each other. For person, as above stated Question 29, Article 4), signifies relation as subsisting in the divine nature. But relation as referred to the essence does not differ therefrom really, but only in our way of thinking; while as referred to an opposite relation, it has a real distinction by virtue of that opposition. Thus there are one essence and three persons.
5 Respondeo dicendum quod considerantibus divinam simplicitatem, quaestio ista in manifesto habet veritatem. Ostensum est enim supra quod divina simplicitas hoc requirit, quod in Deo sit idem essentia et suppositum; quod in substantiis intellectualibus nihil est aliud quam persona. Sed difficultatem videtur ingerere quod, multiplicatis personis divinis, essentia retinet unitatem. Et quia, ut Boetius dicit, relatio multiplicat personarum Trinitatem, posuerunt aliqui hoc modo in divinis differre essentiam et personam, quo et relationes dicebant esse assistentes, considerantes in relationibus solum quod ad alterum sunt, et non quod res sunt. Sed, sicut supra ostensum est, sicut relationes in rebus creatis accidentaliter insunt, ita in Deo sunt ipsa essentia divina. Ex quo sequitur quod in Deo non sit aliud essentia quam persona secundum rem; et tamen quod personae realiter ab invicem distinguantur. Persona enim, ut dictum est supra, significat relationem, prout est subsistens in natura divina. Relatio autem, ad essentiam comparata, non differt re, sed ratione tantum, comparata autem ad oppositam relationem, habet, virtute oppositionis, realem distinctionem. Et sic remanet una essentia, et tres personae.
6 Reply to Objection 1: There cannot be a distinction of suppositum in creatures by means of relations, but only by essential principles; because in creatures relations are not subsistent. But in God relations are subsistent, and so by reason of the opposition between them they distinguish the supposita; and yet the essence is not distinguished, because the relations themselves are not distinguished from each other so far as they are identified with the essence.
6 Ad primum ergo dicendum quod in creaturis non potest esse distinctio suppositorum per relationes, sed oportet quod sit per essentialia principia, quia relationes non sunt subsistentes in creaturis. In divinis autem relationes sunt subsistentes, et ideo, secundum quod habent oppositionem ad invicem, possunt distinguere supposita. Neque tamen distinguitur essentia, quia relationes ipsae non distinguuntur ab invicem secundum quod sunt realiter idem cum essentia.
7 Reply to Objection 2: As essence and person in God differ in our way of thinking, it follows that something can be denied of the one and affirmed of the other; and therefore, when we suppose the one, we need not suppose the other.
7 Ad secundum dicendum quod, inquantum essentia et persona in divinis differunt secundum intelligentiae rationem, sequitur quod aliquid possit affirmari de uno, quod negatur de altero, et per consequens quod, supposito uno, non supponatur alterum.
8 Reply to Objection 3: Divine things are named by us after the way of created things, as above explained Question 13, Articles 1, 3). And since created natures are individualized by matter which is the subject of the specific nature, it follows that individuals are called subjects, supposita, or hypostases. So the divine persons are named supposita or hypostases, but not as if there really existed any real supposition or subjection.
8 Ad tertium dicendum quod rebus divinis nomina imponimus secundum modum rerum creatarum, ut supra dictum est. Et quia naturae rerum creatarum individuantur per materiam, quae subiicitur naturae speciei, inde est quod individua dicuntur subiecta, vel supposita, vel hypostases. Et propter hoc etiam divinae personae supposita vel hypostases nominantur, non quod ibi sit aliqua suppositio vel subiectio secundum rem.