Can a coherentism hold?

The Eastern Orthodox view of the Patrum Consensus, and of the evaluating of theological claims, presupposes some form of coherentism.  Briefly defined, coherentism is the belief the essence of truth (or better, a true particular) is whether belief x properly coheres within a system.  Bertrand Russell explains it “forms part of the completely rounded system of truth” (Russell 1964, 122).  As Alvin Plantinga notes, “It is a relation that holds just among beliefs” (Plantinga 1993, 179).  

We see something similar with Eastern Orthodoxy.  How can we evaluate a particular teaching of a church father?  Here is a clear example (and also a response to yours truly).  Summarizing Vincent of Lerins,

This approach examines a doctrine by asking three questions: (1) Was this doctrine held by early Christians? (the test of antiquity); (2) Was this doctrine widely held among early Christians? (the test of ubiquity); and (3) Was this doctrine affirmed by the church as a whole? (the test of catholicity).

Explained another way:

The solution to this problem is to read Scripture not individually, but corporately in solidarity with the Church.  The early Church viewed Scripture and Tradition (T¹) not in tension with each other but as congruent.

Practical Problem 1: So let’s flesh this out.  Father Z advances teaching x. How do we know x is right?  We judge it in light of the teaching of the church (x*).  How then do we know that x* is right?  

When you evaluate a later father in light of earlier teachings, this isn’t a problem.  When you evaluate fathers contemporaneous with one another, then it gets problematic.  Let’s assume Fathers Y and X minister around the same time and leave a corpus of work.  Further, let’s assume they write about an issue that had not yet been decisively solved.  

Back to (PP1).  Let’s say that x* is indeed the inherited tradition of the church.  It is Truth.  It is what has been always taught.  Said this way, it sounds like a standard to compare other teachings--and indeed it can (and sometimes should) be used that way.  Here’s the problem, though:  some of the terms that constitute x* were themselves not yet part of x*.  We will call these terms x*...m, n, p...z.  Examples would be later ecumenical councils, later fathers, different liturgies, etc.  Orthodox love to say that “their view of tradition isn’t static.”  Indeed, it is not.  The question is how to know whether x*...n is part of tradition.

I suggest that this problem is best seen in a logical fallacy.  In other words,

p ⊃ q

q

---

p

This is the fallacy of asserting the consequent

“If this, then that.”
That,

Therefore, this.

If (T¹) is true, then x*...n

x*...n

Therefore, an unbroken T¹.

If (T¹), then the Dormition of Mary.

The Dormition of Mary is celebrated as tradition.

Therefore, T¹.  

Stated less formally, the Orthodox must prove that the current instantiation of tradition, be it the Dormition of Mary or whatever, is already within p from the beginning.  This has not been done.  

Back to Coherentism

Does a doctrine like the Dormition of Mary cohere within Orthodox Tradition?  I actually think it does.  But that’s not good enough for truth.  All coherence can demonstrate is consistency.  To be good enough for warrant it must demonstrate a correspondence with an external standard.  Any such standard, either the Scriptures or the earliest (i.e., writings contemporary with the Apostles) Christian writings, must bear witness to it.

There is a possible rejoinder: one can demonstrate that x*...n is compatible with such a standard.  That is certainly possible, but it does not demonstrate the historical evidence of x*...n from the earliest days.  Therefore, the Evangelical is warranted in not practicing x*...n.  

Difficulties with a Patristic-Prism Hermeneutics

This piece by Keener is golden.  I'll just highlight a few points.   
Some writers have expressed the conviction that any legitimate interpretation of a passage should already appear in the church fathers, and questioned any interpretation that does not.

On many issues, there was no universal patristic view, and everyone who studies the church fathers recognizes that they often differed among themselves. For example, many early interpreters, such as Papias, appear to have been premillennial. By the time of Eusebius, however, premillennialists were viewed as schismatics; amillennialism prevailed by this period.

Second, their ancient setting was not always the decisive advantage we wish it to be, since it was not the same as the settings in which the biblical books were written. For some examples: whereas the Hebrew Bible addresses various ancient Near Eastern settings and the New Testament presupposes a Jewish context (most thoroughly in the Gospels and Revelation), only a few of the church fathers (such as Jerome) knew the Jewish context well. Many, in fact, were unfortunately decisively anti-Jewish (including Chrysostom, otherwise one of my favorite commentators).

Likewise, even Greek culture changed. Stoicism was the dominant philosophy for the milieu addressed in Paul’s letters, but Platonism dominated the patristic period. Most church fathers wrote after the second sophistic, a different rhetorical situation than prevailed among the biblical writers. (Indeed, some of the best-known church fathers were more homileticians than exegetes, their homilies marked by efforts to communicate in their context and not just explaining texts’ meanings.)

 Once some Fathers used biblical texts polemically against Gnostics or Manicheans, sometimes in understandable ways in their settings, subsequent interpreters sometimes applied these texts only to these settings, as if these were the texts’ original settings.