As I read the first part of To Ablabius, On Not Three Gods by Gregory of Nyssa I cannot help but pause because it sounds so Tritheistic! I may be misunderstanding what he is trying to say but it seems that his introductory argument follows as such:
(1) Peter, James, and John are three individuals.
(2) Peter, James, and John are all men.
(3) We can speak of Peter, James, and John as being three persons sharing one substance, namely “humanity”
(4) The error of language is speaking of men as “many men” rather than “humanity”.
(4) The error of language is speaking of the Trinity as “Gods” rather than “God”.
(3) We can speak of the Father, Son, and Holy Spirit are being three person sharing one substance, namely God/Divinity.
(2) The Father, Son, and Spirit are all God.
(1) The Father, Son, and Spirit are all individuals.
If you are unfamiliar with his argument you can read it here and here. If you are familiar with it, please explain!
the archives near Emmaus 
Brian,
When Gregory of Nyssa is discussing Peter, James, and John, he is referring to the argument that Alblabius has been making, not his own arguments.
Alblabius apparently understands the Trinity to be somehow represented by the authority figures of Peter, James, and John. I do not know how he gets there, but he does.
In addition,
I understand his argument– just as there are many apostles within the ONE apostolic tradition, there are three persons within the Godhead. The apostles have the same mission and the same Spirit; the Trinity, Father, Son, and Holy Spirit have the same substance.
That would make better sense of things. I must have missed the transition from his quoting Alblabius into his own argument because it felt like he was almost adopting his argument as his own. I need to read more carefully!
@Brian,
I believe Gregory makes his own arguments starting with “The question is, as I said, very difficult to deal with…..”
This is the line that seems to make the most sense of Gregory’s own argument: “every operation which extends from God to the Creation, and is named according to our variable conceptions of it, has its origin from the Father, and proceeds through the Son, and is perfected in the Holy Spirit.”
I think he is trying to say that the “persons” thing cannot be taken too far to the point where we think of Peter, James, and John as humans b/c, for instance, if Peter, James, and John were all eating the action of Peter cannot be shared by James nor John (as in the same action). But when the Spirit does something it originated from the Father, proceeded through the Son, and is perfected by the Spirit. Therefore, the Triune God does all actions as Trinity.
Am I reading this correctly?
This is the stuff that social trinitarianism is made of! In fact St. Gregory of Nyssa is the champion of the social trinitarians although Sarah Coakley argues persuasively that they’ve misread him.[1] There’s a few things to keep in mind here:
*This isn’t Gregory’s only analogy of the Trinity.
*This analogy must be read in light of Gregory’s distinctly apophatic theology (which he explicates shortly after the analogy).[2]
*Modern conceptions of personhood (= individualism) need to be avoided at all costs when reading Gregory’s reference.[3]
[1] See her “‘Persons’ in the ‘Social’ Doctrine of the Trinity: A Critique of Current Analytic Discussion,” in The Trinity: An Interdisciplinary Symposium on the Trinity (eds. Stephen T. Davis, et al.; Oxford: Oxford University Press, 1999): 123-44; “Re–thinking Gregory of Nyssa: Introduction—Gender, Trinitarian Analogies, and the Pedagogy of The Song,” ModTheol 18/4 (2002): 431-43 [esp. 432-35]; reprinted as pages 1-13 of Re-Thinking Gregory of Nyssa (ed., Sarah Coakley; Malden, MA: Blackwell, 2003), in fact you’d do well to read the entire volume.
[2] See the first new paragraph in the second column on the page shown in the second link you provide (or NPNF2 5.332); or Christology of the Later Fathers (ed., Edward R. Hardy; Philadelphia: Westminster Press, 1954; Repr., Louisville, KY: Westminster John Knox, 2006), 259.
[3] As Lewis Ayres notes, “Gregory makes no extended attempt—and rarely any attempt—to explain what the divine prosopa or hypostases are by attributing to each the sorts of mental and psychological characteristics we use to define a distinct human person.” (“Not Three People: The Fundamental Themes of Gregory of Nyssa’s Trinitarian Theology as Seen in To Ablabius: On Not Three Gods,” in ModTheol 18/4 [2002]: 445-74 [here 446-47]; reprinted as pages 15-44 of Re-Thinking Gregory of Nyssa (ed., Sarah Coakley; Malden, MA: Blackwell, 2003). Cf. Ayres’ Nicaea and Its Legacy: An Approach to Fourth Century Trinitarian Theology (Oxford: Oxford University Press, 2006), 344-63.
From the links that you gave us,
Gregory of Nyssa is arguing this:
Peter is named Peter as an individual.
James is named James as an individual.
Luke is named Luke as an individual.
Stephen is named Stephen as an individual.
But God is one and has one name, as Gregory says, for that name is Godhead, as the Shema says in Deuteronomy 6, Here Oh Israel, the Lord God is One Lord.
Godhead is the special name (Gregory’s words) that we are given from Scripture toward the conclusion of the second link you posted. There is only one name for God; because Peter and James and Stephen have different names, they cannot be one person, so it is erroneous to argue to begin with that they are the trinity somehow.
Rod: You’re correct that Gregory is recounting Ablabius’ argument, but he also grants it for the sake of his apologetic/polemic.
Nick,
I agree. but contextually, Nyssa is making a point of departure, talking about the names of the apostles and the one name of the Godhead according to the Shema.
This shows how thin and blurred is the line between Trinity and polytheism. I say it’s explicitly Polytheism.
NIck Norelli is right—he actually grants Ablabius’ logic, but goes on to say that when we call Peter, James, and John “men” in the plural, it is actually a “customary abuse of language.”