S. Gregory's own doctrine, indeed, has seemed to some critics to be open to the charge of tritheism. But even if his doctrine were entirely expressed in the single illustration of which we have spoken, it does not seem that the charge would hold good, when we consider the light in which the illustration would present itself to him. The conception of the unity of human nature is with him a thing intensely vivid: it underlies much of his system, and he brings it prominently forward more than once in his more philosophical writings [54] . We cannot, in fairness, leave his realism out of account when we are estimating the force of his illustration: and therefore, while admitting that the illustration was one not unlikely to produce misconceptions of his teaching, we may fairly acquit him of any personal bias towards tritheism such as might appear to be involved in the unqualified adoption of the same illustration by a writer of our own time, or such as might have been attributed to theologians of the period of S. Gregory who adopted the illustration without the qualification of a realism as determined as his own [55] . But the illustration does not stand alone: we must not consider that it is the only one of those to be found in the treatise, De Diff. Essen. et Hypost., which he would have felt justified in employing. Even if the illustration of the rainbow, set forth in that treatise, was not actually his own (as Dorner, ascribing the treatise to him, considers it to have been), it was at all events (on the other theory of the authorship), included in the teaching he had received from his "master:" it would be present to his mind, although in his undisputed writings, where he is dealing with objections brought against the particular illustration from human relations, he naturally confines himself to the particular illustration from which an erroneous inference was being drawn. In our estimate of his teaching the one illustration must be allowed to some extent to qualify the effect produced by the other. And, further, we must remember that his argument from human relations is professedly only an illustration. It points to an analogy, to a resemblance, not to an identity of relations; so much he is careful in his reply to state. Even if it were true, he implies, that we are warranted in speaking, in the given case, of the three human persons as "three men," it would not follow that we should be warranted thereby in speaking of the three Divine Persons as "three Gods." For the human personalities stand contrasted with the Divine, at once as regards their being and as regards their operation. The various human prosopa draw their being from many other prosopa, one from one, another from another, not, as the Divine, from One, unchangeably the same: they operate, each in his own way, severally and independently, not, as the Divine, inseparably: they are contemplated each by himself, in his own limited sphere, kat' idian perigraphen, not, as the Divine, in mutual essential connexion, differentiated one from the other only by a certain mutual relation. And from this it follows that the human prosopa are capable of enumeration in a sense in which number cannot be considered applicable to the Divine Persons. Here we find S. Gregory's teaching brought once more into harmony with his "master's:" if he has been willing to carry the use of numerical terms rather further than S. Basil was prepared to do, he yet is content in the last resort to say that number is not in strictness applicable to the Divine hupostaseis, in that they cannot be contemplated kat' idian perigraphen, and therefore cannot be enumerated by way of addition. Still the distraction of the hupostaseis remains; and if there is no other way (as he seems to have considered there was none), of making full acknowledgment of their distinct though inseparable existence than to speak of them as "three," he holds that that use of numerical language is justifiable, so long as we do not transfer the idea of number from the hupostaseis to the ousia, to that Nature of God which is Itself beyond our conception, and which we can only express by terms suggested to us by what we know of Its operation.
Such, in brief, is the teaching of S. Gregory on the doctrine of the Holy Trinity, as expressed in the treatises in which he developed and defended those positions in which S. Basil appeared to diverge from the older Nicene theologians. That the terminology of the subject gained clearness and definiteness from his exposition, in that he rendered it plain that the adoption of the Eastern phraseology was a thing perfectly consistent with the Faith confessed alike by East and West in varying terms, seems beyond doubt. It was to him, probably, rather than to S. Basil, that this work was due; for he cleared up the points which S. Basil's illustration had left doubtful; yet in so doing he was using throughout the weapons which his "master" had placed in his hands, and arguing in favour of his "master's" statements, in language, it may be, less guarded than S. Basil himself would have employed, but in accordance throughout with the principles which S. Basil had followed. Each bore his own part in the common work: to one, perhaps, is due the credit of greater originality; to the other it was given to carry on and to extend what his brother had begun: neither, we may well believe, would have desired to claim that the work which their joint teaching effected should be imputed to himself alone.
So far, we have especially had in view those minor treatises of S. Gregory which illustrate such variations from Athanasian modes of expression as are to be found in the writers of the "Neo-Nicene" school. These are perhaps his most characteristic works upon the subject. But the doctrine of the Trinity, as he held it, is further set forth and enforced in other treatises which are, from another point of view, much more important than those with which we have been dealing--in his Oratio Catechetica, and his more directly polemical treatises against Eunomius. In both these sections of his writings, when allowance is made for the difference of terminology already discussed, we are less struck by the divergencies from S. Athanasius' presentment of the doctrine than by the substantial identity of S. Gregory's reasoning with that of S. Athanasius, as the latter is displayed, for example, in the "Orations against the Arians."
There are, of course, many points in which S. Gregory falls short of his great predecessor; but of these some may perhaps be accounted for by the different aspect of the Arian controversy as it presented itself to the two champions of the Faith. The later school of Arianism may indeed be regarded as a perfectly legitimate and rigidly logical development of the doctrines taught by Arius himself; but in some ways the task of S. Gregory was a different task from that of S. Athanasius, and was the less formidable of the two. His antagonist was, by his own greater definiteness of statement, placed at a disadvantage: the consequences which S. Athanasius had to extract from the Arian statements were by Eunomius and the Anomoeans either openly asserted or tacitly admitted: and it was thus an easier matter for S. Gregory to show the real tendency of Anomoean doctrine than it had been for S. Athanasius to point out the real tendency of the earlier Arianism. Further, it may be said that by the time of S. Basil, still more by the time when S. Gregory succeeded to his brother's place in the controversy, the victory over Arianism was assured. It was not possible for S. Athanasius, even had it been in his nature to do so, to treat the earlier Arianism with the same sort of contemptuous criticism with which Eunomius is frequently met by S. Gregory. For S. Gregory, on the other hand, it was not necessary to refrain from such criticism lest he should thereby detract from the force of his protest against error. The crisis in his day was not one which demanded the same sustained effort for which the contest called in the days of S. Athanasius. Now and then, certainly, S. Gregory also rises to a white heat of indignation against his adversary: but it is hardly too much to say that his work appears to lack just those qualities which seem, in the writings of S. Athanasius, to have been called forth by the author's sense of the weight of the force opposed to him, and of the "life and death" character of the contest. S. Gregory does not under-estimate the momentous nature of the questions at issue: but when he wrote, he might feel that to those questions the answer of Christendom had been already given, that the conflict was already won, and that any attempt at developing the Arian doctrine on Anomoean lines was the adoption of an untenable position,--even of a position manifestly and evidently untenable: the doctrine had but to be stated in clear terms to be recognized as incompatible with Christianity, and, that fact once recognized, he had no more to do. Thus much of his treatises against Eunomius consists not of constructive argument in support of his own position, but of a detailed examination of Eunomius' own statements, while a further portion of the contents of these books, by no means inconsiderable in amount, is devoted not so much to the defence of the Faith as to the refutation of certain misrepresentations of S. Basil's arguments which had been set forth by Eunomius.
Even in the more distinctly constructive portion of these polemical writings, however, it may be said that S. Gregory does not show marked originality of thought either in his general argument, or in his mode of handling disputed texts. Within the limits of an introductory essay like the present, anything like detailed comparison on these points is of course impossible; but any one who will take the trouble to compare the discourses of S. Gregory against Eunomius with the "Orations" of S. Athanasius against the Arians,--the Athanasian writing, perhaps, most closely corresponding in character to these books of S. Gregory,--either as regards the specific passages of Scripture cited in support of the doctrine maintained, and the mode of interpreting them, or as to the methods of explanation applied to the texts alleged by the Arian writers in favour of their own opinions, can hardly fail to be struck by the number and the closeness of the resemblances which he will be able to trace between the earlier and the later representatives of the Nicene School. A somewhat similar relation to the Athanasian position, as regards the basis of belief, and (allowing for the difference of terminology) as regards the definition of doctrine, may be observed in the Oratio Catechetica.
Such originality, in fact, as S. Gregory may claim to possess (so far as his treatment of this subject is concerned) is rather the originality of the tactician than that of the strategist: he deals rather with his particular opponent, and keeps in view the particular point in discussion more than the general area over which the war extends. S. Athanasius, on the other hand (partly, no doubt, because he was dealing with a less fully developed form of error), seems to have more force left in reserve. He presents his arguments in a more concise form, and is sometimes content to suggest an inference where S. Gregory proceeds to draw out conclusions in detail, and where thereby the latter, while possibly strengthening his presentment of the truth as against his own particular adversary,--against the Anomoean or the polytheist on the one side, or against the Sabellian or the Judaizer on the other,--renders his argument, when considered per se as a defence of the orthodox position, frequently more diffuse and sometimes less forcible. Yet, even here, originality of a certain kind does belong to S. Gregory, and it seems only fair to him to say that in these treatises also he did good service in defence of the Faith touching the Holy Trinity. He shows that alike by way of formal statement of doctrine, as in the Oratio Catechetica, and by way of polemical argument, the forces at the command of the defenders of the Faith could be organized to meet varied forms of error, without abandoning, either for a more original theology like that or Marcellus of Ancyra, or for the compromise which the Homoean or Semi-Arian school were in danger of being led to accept, the weapons with which S. Athanasius had conquered at Nicæa.
[39] See Dorner, Doctrine of the Person of Christ, Div. I. vol. ii. p. 314 (English Trans.).
[40] It is to be noted further that the use of the terms "Persona" and prosopon by those who avoided the phrase treis hupostaseis no doubt assisted in the formation of this suspicion. At the same time the Nicene anathema favoured the sense of hupostasis as equivalent to ousia, and so appeared to condemn the Eastern use.