I am arguing that the NT does not have enough information to say definitively, because I agree the two key terms can be used in a variety of ways--though the ways you are arguing forare the exceptions, not the rule.
I am also noting that it is really only the later tradition that would make the view of perpetual virginity "plausible", because that is where it is spelled out, and by a number of promoters.
But even then they have to address the texts in the gospels that might call it into question for some.
Yes, I agree. And it is primarily on the basis of later tradition. But that later tradition does not agree in the particulars of the actual history. They only agree on the end-point, and have different ways of getting there.
If two father promote two views, one of children from a prior marriage, and another that of cousins, that is not a unified history that all have passed down, straight from the apostles.
Those are two different explanations of how the currently predominant view--perpetual virginity--can be found to match up with the NT text. And even some modern protestant groups who hold to perpetual virginity do not settle on one or the other necessarily, but say both are--plausible. Because the NT is not definitive, and the tradition passed down by fathers is varied.
Note, I am certainly not arguing that the gospel writers were inspired to make statements that either view is acceptable, as though there could be two truths simultaneously There is a truth behind it. I just don't know what it is. I see inspiration as communicating a true reality.
But in the NT I don't think they addressed the question of perpetual virginity, which is why later commentators are trying to understand what they might say on that point, based on what they did say on other points more crucial to their argument at the time.
In Matthew's account the point is clearly that Jesus was born of a virgin--it was miraculous. It was not a normal birth. It was of God.
If the point was to assert perpetual virginity of Mary, I am sure it could have been spelled out beyond any doubt. I think we are asking a question regarding the text of the NT that it was not meant to answer. And we are asking it because of later views. Those later views may have stemmed from other knowledge, present in apostolic times. Or it may not have. I don't really know.
Yes, it is a fair argument that early sources, spread out across a large area, suggest a tradition going back earlier than those sources. I have no axe to grind on the point, because I am open to any of the views.
Agreed, but he notes in that very section that some do not have heresies regarding the nature of Christ, the Spirit. etc. but do teach grave error in regards to Mary. So he still considers it heresy, and that they are very misguided, and prey to one of the various winds of doctrine plaguing their generation, but not all those he wrote to were on the same order of those who rejected the Trinity, etc.
But he also notes they trace their view back to an earlier figure (who was more definitively condemned, but for a different reason). And Epiphanius himself is not sure whether it is really true that they trace it back to an earlier time, or whether it just an innovation, and they claim to trace it back from that figure.
Epiphanius claimed to be addressing those who had an orthodox view of the Trinity, but very flawed Mariology. Obviously, the view of Mary's perpetual virginity was predominant by that point, and any works of critics would have been unlikely to be preserved. But we still see echoes of them in the works themselves, criticizing those views. You, of course, would consider them non-Christian. But the issue came up multiple times in that century because it was not fully settled, however you see that coming about.
Bishop of Sardica, a heretic in the latter part of the fourth century
www.newadvent.org
For instance, Bonosus, a bishop, was brought before a regional council, which deferred on the question to other leaders, and eventually the pope.