Accordingly those predicates which do not denote the essential nature of a thing cannot alter, change, or disturb its nature in any way. Wherefore if Father and Son are predicates of relation, and, as we have said, have no other difference but that of relation, and if relation is not asserted of its subject as though it were the subject itself and its substantial quality, it will effect no real difference in its subject, but, in a phrase which aims at interpreting what we can hardly understand, a difference of persons. For it is a canon of absolute truth that distinctions in incorporeal things are established by differences and not by spatial separation. It cannot be said that God became Father by the addition to His substance of some accident; for he never began to be Father, since the begetting of the Son belongs to His very substance; however, the predicate father, as such, is relative. And if we bear in mind all the propositions made concerning God in the previous discussion, we shall admit that God the Son proceeded from God the Father, and the Holy Ghost from both, and that They cannot possibly be spatially different, since They are incorporeal. But since the Father is God, the Son is God, and the Holy Spirit is God, and since there are in God no points of difference distinguishing Him from God, He differs from none of the Others. But where there are no differences there is no plurality; where is no plurality there is Unity. Again, nothing but God can be begotten of God, and lastly, in concrete enumerations the repetition of units does not produce plurality. Thus the Unity of the Three is suitably established.
[23] Dominus and seruus are similarly used as illustration, In Cat. (Migne, P.L. lxiv. 217).
[24] i.e. which is external to the master.
[25] i.e. which is external to the whitened thing.
VI.
Sed quoniam nulla relatio ad se ipsum referri potest, idcirco quod ea secundum se ipsum est praedicatio quae relatione caret, facta quidem est trinitatis numerositas in eo quod est praedicatio relationis, seruata uero unitas in eo quod est indifferentia uel substantiae uel operationis uel omnino eius quae secundum se dicitur praedicationis. Ita igitur substantia continet unitatem, relatio multiplicat trinitatem; atque ideo sola singillatim proferuntur atque separatim quae relationis sunt. Nam idem pater qui filius non est nec idem uterque qui spiritus sanctus. Idem tamen deus est pater et filius et spiritus sanctus, idem iustus idem bonus idem magnus idem omnia quae secundum se poterunt praedicari. Sane sciendum est non semper talem esse relatiuam praedicationem, ut semper ad differens praedicetur, ut est seruus ad dominum; differunt enim. Nam omne aequale aequali aequale est et simile simili simile est et idem ei quod est idem idem est; et similis est relatio in trinitate patris ad filium et utriusque ad spiritum sanctum ut eius quod est idem ad id quod est idem. Quod si id in cunctis aliis rebus non potest inueniri, facit hoc cognata caducis rebus alteritas. Nos uero nulla imaginatione diduci sed simplici intellectu erigi et ut quidque intellegi potest ita aggredi etiam intellectu oportet.
Sed de proposita quaestione satis dictum est. Nunc uestri normam iudicii exspectat subtilitas quaestionis; quae utrum recte decursa sit an minime, uestrae statuet pronuntiationis auctoritas. Quod si sententiae fidei fundamentis sponte firmissimae opitulante gratia diuina idonea argumentorum adiumenta praestitimus, illuc perfecti operis laetitia remeabit unde uenit effectus. Quod si ultra se humanitas nequiuit ascendere, quantum inbecillitas subtrahit uota supplebunt.
VI.
But since no relation can be affirmed of one subject alone, since a predication referring to one substance is a predication without relation, the manifoldness of the Trinity is secured through the category of relation, and the Unity is maintained through the fact that there is no difference of substance, or operation, or generally of any substantial predicate. So then, the category of substance preserves the Unity, that of relation brings about the Trinity. Hence only terms belonging to relation may be applied singly to Each. For the Father is not the same as the Son, nor is either of Them the same as the Holy Spirit. Yet Father, Son, and Holy Spirit are each the same God, the same in justice, in goodness, in greatness, and in everything that can be predicated of substance. One must not forget that predicates of relativity do not always involve relation to something other than the subject, as slave involves master, where the two terms are different. For equals are equal, like are like, identicals are identical, each with other, and the relation of Father to Son, and of both to Holy Spirit is a relation of identicals. A relation of this kind is not to be found in created things, but that is because of the difference which we know attaches to transient objects. We must not in speaking of God let imagination lead us astray; we must let the Faculty of pure Knowledge lift us up and teach us to know all things as far as they may be known.[26]
I have now finished the investigation which I proposed. The exactness of my reasoning awaits the standard of your judgment; your authority will pronounce whether I have seen a straight path to the goal. If, God helping me, I have furnished some support in argument to an article which stands by itself on the firm foundation of Faith, I shall render joyous praise for the finished work to Him from whom the invitation comes. But if human nature has failed to reach beyond its limits, whatever is lost through my infirmity must be made good by my intention.