Orthodoxos and Eranistes.
Orth.— Better were it for us to agree and abide by the apostolic doctrine in its purity. But since, I know not how, you have broken the harmony, and are now offering us new doctrines, let us, if you please, with no kind of quarrel, investigate the truth.
Eran.— We need no investigation, for we exactly hold the truth.
Orth.— This is what every heretic supposes. Aye, even Jews and Pagans reckon that they are defending the doctrines of the truth; and so also do not only the followers of Plato and Pythagoras, but Epicureans too, and they that are wholly without God or belief. It becomes us, however, not to be the slaves of a priori assumption, but to search for the knowledge of the truth.
Eran.— I admit the force of what you say and am ready to act on your suggestion.
Orth.— Since then you have made no difficulty in yielding to this my preliminary exhortation, I ask you in the next place not to suffer the investigation of the truth to depend on the reasonings of men, but to track the footprints of the apostles and prophets, and saints who followed them. For so wayfarers when they wander from the high-road are wont to consider well the pathways, if haply they show any prints of men or horses or asses or mules going this way or that, and when they find any such they trace the tracks as dogs do and leave them not till once more they are in the right road.
Eran.— So let us do. Lead on yourself, as you began the discussion.
Orth— Let us, therefore, first make careful and thorough investigation into the divine names—I mean substance, and essences, and persons and proprieties, and let us learn and define how they differ the one from the other. Then let us thus handle afterwards what follows.
Eran.— You give us a very admirable and proper introduction to our argument. When these points are clear, our discussion will go forward without let or obstacle.
Orth.— Since we have decided then that this must be our course of procedure, tell me, my friend, do we acknowledge one substance of God, alike of Father and of the only begotten Son and of the Holy Ghost, as we have been taught by Holy Scripture, both Old and New, and by the Fathers in Council in Nicæa, or do we follow the blasphemy of Arius?
Eran.— We confess one substance of the Holy Trinity.
Orth.— And do we reckon hypostasis to signify anything else than substance, or do we take it for another name of substance?
Eran.— Is there any difference between substance and hypostasis?
Orth— In extra Christian philosophy there is not, for οὐσία signifies τὸ ὄν, that which is, and ὑ πόστασις that which subsists. But according to the doctrine of the Fathers there is the same difference between οὐσία and ὑ πόστασις as between the common and the particular, and the species and the individual.
Eran.— Tell me more clearly what is meant by race or kind, and species and individual.
Orth.— We speak of race or kind with regard to the animal, for it means many things at once. It indicates both the rational and the irrational; and again there are many species of irrational, creatures that fly, creatures that are amphibious, creatures that go on foot, and creatures that swim. And of these species each is marked by many subdivisions; of creatures that go on foot there is the lion, the leopard, the bull, and countless others. So, too, of flying creatures and the rest there are many species; yet all of them, though the species are the aforesaid, belong to one and the same animal race. Similarly the name man is the common name of mankind; for it means the Roman, the Athenian, the Persian, the Sauromatian, the Egyptian, and, in a word, all who are human, but the name Paulus or Petrus does not signify what is common to the kind but some particular man; for no one on hearing of Paul turns in thought to Adam or Abraham or Jacob, but thinks of him alone whose name he has heard. But if he hears the word man simply, he does not fix his mind on the individual, but bethinks him of the Indian, the Scythian, and the Massagete, and of all the race of men together, and we learn this not only from nature, but also from Holy Scripture, for God said, we read, “I will destroy man from the face of the earth,” and this he spoke of countless multitudes, and when more than two thousand and two hundred years had gone by after Adam, he brought universal destruction on men through the flood, and so the blessed David says: “Man that is in honour and understands not,” accusing not one here nor one there, but all men in common. A thousand similar examples might be found, but we must not be tedious.
Eran.— The difference between the common and the proper is showed clearly. Now let us return to discussion about οὐσία and ὑ πόστασις
Orth.— As then the name man is common to human nature, so we understand the divine substance to indicate the Holy Trinity; but the hypostasis denotes any person, as the Father, the Son and the Holy Ghost; for, following the definitions of the Holy Fathers, we say that hypostasis and individuality mean the same thing.
Eran.— We agree that this is so.
Orth.— Whatever then is predicated of the divine nature is common both to the Father, to the Son, and to the Holy Ghost, as for instance “God,” “Lord,” “Creator,” “Almighty,” and so forth.
Eran.— Without question these words are common to the Trinity.
Orth.— But all that naturally denotes the hypostasis ceases to be common to the Holy Trinity, and denotes the hypostasis to which it is proper, as, for instance, the names “Father,” “Unbegotten,” are peculiar to the Father; while again the names “Son,” “Only Begotten,” “God the Word,” do not denote the Father, nor yet the Holy Ghost, but the Son, and the words “Holy Ghost,” “Paraclete,” naturally denote the hypostasis of the Spirit.
Eran.— But does not Holy Scripture call both the Father and the Son “Spirit”?
Orth.— Yes, it calls both the Father and the Son “Spirit,” signifying by this term the incorporeal illimitable character of the divine nature. The Holy Scripture only calls the hypostasis of the Spirit “Holy Ghost.”
Eran.— This is indisputable.
Orth.— Since then we assert that some terms are common to the Holy Trinity, and some peculiar to each hypostasis, do we assert the term “immutable” to be common to the substance or peculiar to any hypostasis?
Eran.— The term “immutable” is common to the Trinity, for it is impossible for part of the substance to be mutable and part immutable.
Orth.— You have well said, for as the term mortal is common to mankind, so are “immutable” and “invariable” to the Holy Trinity. So the only-begotten Son is immutable, as are both the Father that begot Him and the Holy Ghost.
Eran.— Immutable.
Orth.— How then do you advance the statement in the gospel “the word became flesh,” and predicate mutation of the immutable nature?
Eran.— We assert Him to have been made flesh not by mutation, but as He Himself knows.
Orth.— If He is not said to have become flesh by taking flesh, one of two things must be asserted, either that he underwent the mutation into flesh, or was only so seen in appearance, and in reality was God without flesh.
Eran.— This is the doctrine of the disciples of Valentinus, Marcion, and of the Manichees, but we have been taught without dispute that the divine Word was made flesh.
Orth.— But in what sense do you mean “was made flesh”? “Took flesh,” or “was changed into flesh”?
Eran.— As we have heard the evangelist say, “the word was made flesh.”
Orth.— In what sense do you understand “was made”?
Eran.— He who underwent mutation into flesh was made flesh, and, as I said just now, as He knows. But we know that with Him all things are possible, for He changed the water of the Nile into blood, and day into night, and made the sea dry land, and filled the dry wilderness with water, and we hear the prophet saying “Whatsoever the Lord pleased that did He in heaven, and in earth, in the seas and all deep places.”
Source: Dialogues ("Eranistes" or "Polymorphus") (New Advent)