It is significant that at this point Gregory appeals to the identity of the Spirit’s work with the work of God–that is, the doctrine of identical operations among the persons of the Trinity–not as a fundamental argument for the Spirit’s divinity but as an element of spiritual exegesis, based on baptismal deification. Despite the common scholarly view that Nicene theologicans established the unity of the Trinity on the basis of the common activity of the three persons, or the presence of this argument, for example, in Gregory of Nyssa, Gregory of Nazianzus does not establish his Trinitarian doctrine in this way, because he recognizes that any argument from the identity of activities depends on a prior question–namely, how do we know that God does not do divine things through nondivine or semidivine intermediaries? In his argument for the divinity of the Son an d the Spirit, particularly in the Theological Orations, Gregory squarely bases his position on the soteriological principles of divinization through the divine economy and the corresponding spiritual exegesis of Scripture. In this respect, it must be admitted that a different understanding of salvation, or even a different baptismal practice, could yield a different doctrinal understanding, for the two go hand in hand. For this reason the argument from identical activities cannot suffice to establish the doctrine of the Trinity without the more primary soteriological approach that it assumes and represents. We might compare Gregory’s approach to Ludwig Wittgenstein’s argument that learning the language game of naming involves not simply learning what to call specific objects, or “ostensive definition,” but more fundamentally learning the human activity of naming, which includes all sorts of mental, bodily, and social practices. For Gregory it is the Christian’s actual knowledge of God through the presence of the Holy Spirit within the life of the Church that enables him or her to identify the Spirit as God in the biblical text, and to practice theology at all. The Spirit’s divinity, and consequently the knowledge of God in Christ, is thus shown directly in and through the lived process of Christian growth, and it is this fuller sense of knowing that is epistemically foundational. In Gregory’s system, the Bible, we might say, necessarily connects with Christian theological experience (without losing its authority or canonical force), just as Christians undergo the sanctification that is attested in Scripture and typified definitively in the person of Christ. By integrating all of these themes, Gregory completes the rhetorical chiasmus that he began with the question of the witness of Scripture (31.1), that reader’s sense of expectation is fulfilled at last.”
-Christopher A. Beeley, Gregory of Nazianzus on the Trinity and the Knowledge of God (Oxford: OUP, 2008), 182-183.
If this is an accurate representation of Gregory’s thought, I am at one time both excited and frustrated. Excited because I’ve had a sneaking suspicion that arguing for the Trinity on the basis of “identical activities” left the question open (as pointed out above) as to the use of nondivine intermediaries. If God can use creatures without necessarily implying their divinity, then the Holy Spirit (or even Jesus) could then be found to ultimately be a creature. That seems like a poor way to argue for the Trinity. On the other hand, I am frustrated because his solution (as described by Beeley), also leaves open the question of (what I will call) subjectivity. That is, if the foundation or rational of believing that “A” is true or has certain characteristics, etc… is my own individual experience of it, then what basis does one have for criticizing anyone else’s beliefs? To put it more bluntly, I fear that such methodology (if it can be called that) commits the Tom Cruise fallacy: “If you knew what I knew, you’d know.” Maybe I’m too much of a rationalist, but I want something more “objective.” There is much I like in Beeley’s description, but it also seems to open some doors I’m not ready to in just yet.