It is not easy reading, but at times I struggle to see why it all matters.
Here are a few rambling reflections.
Gunton mentions that the struggle to put something as profound at the Trinity into words can be constructive. It stretches and clarifies our thinking. But it pushes the words and concepts to their limits.
Yet, it can also be dangerous. First, we can delude ourselves that we actually fully understand something. Second, it can become unnecessarily divisive. History has certainly shown this to be the case. The words can mean different things to different people. Different emphases and balances take different priorities to others. Pride and misunderstanding can lead to confusion, conflict, and hostility.
After struggling through the opening chapters of the book I found it helpful to re-read the chapter on the Trinity in Alister McGrath's textbook Christian Theology: An Introduction.
Here are a few details I found helpful, particularly in understanding some of the key terminology.
homoousios vs. homoiosious
same substance vs. similar substance
The Father and the Son are of the same [similar] substance.
The former was adopted in the Nicene Creed [325 A.D.] after much debate.
Aside: The two terms only differ by an "i" or "iota", the smallest object in the Greek alphabet. Amusingly, this may be the origin of the phrase, "it makes not one iota of difference."
Filioque [and from the Son]. There was controversy about whether the Holy Spirit proceeds from the Father or from the Father and the Son.
This is one of the main differences between the Eastern vs. Western conceptions of the Trinity.
perichoresis. This describes the relation between each person of the Trinity.
The Economic Trinity. I tend to think "economic" means frugal or minimalist, but here it means "how the different parts relate to and interact with one another", just like economic/business relations between individuals, societies, and companies. It relates to the acts of the different persons of God in creation, redemption, salvation, and the personal experiences of believers.
It is the manner "in which we experience the diversity and unity of God's self disclosure in history".
The immanent trinity reflects the unity and diversity of God as it is in God.
The Cappodocians played a key role in the acceptance of the full divinity of the Holy Spirit, which was formally endorsed in AD 381 by the Council of Constantinople.
Karl Barth was influential in stimulating renewed interest in the twentieth century in the Doctrine of the Trinity. He placed it at the beginning of his Magnus Opus, Church Dogmatics. He argued that it "undergirds and guarantees the actuality of divine revelation to sinful humanity."
Karl Rahner also played a key role, with the axiom, "The economic trinity is the immanent trinity, and the immanent trinity is the economic trinity.
I still don't really understand this.
It is all about balance. [page 79].
As in all theology, we are on a knife edge, or, we might say, a narrow path with precipices on each side. On one side, we deny the unity of God, and make it appear that there are three gods; on the other, we cause the distinctions of the three to disappear into some underlying undifferentiated deity.What is the relation between God and the world? On the one hand God is sovereign and ruler of everything. All creation is completely sustained by God and completely dependent. Yet, on the other hand, human agents seem to be autonomous and can act independently. And the material world [ostensibly the creation] can be described and understood scientifically without reference to God. Is there a tension and/or contradiction? Gunton responds to the interaction of Robert Jenson [his Ph.D supervisor] with Jonathan Edwards. [page 95]
in connection with Jenson's query to Edwards' theology of Creation. `T[o] say that "God himself, in the immediate exercise of his power" is the creature' sole support and coherence, were we to take the proposition without trinitarian differentiation would cursedly threaten the distinct reality of creation' [Systematic Theology 2, page 41] The reason is that an authentically Christian theology must make two affirmations which so easily slip into contradiction of one another: that, First, God is the sole creator, and indeed, sole lord of what happens within that creations' history subsequent to its creation; and that, second, as creator and redeemer he is at the same time the one who gives to that creation its ... relative independence, ....Thus, a Trinitarian theology allows one to at the same time affirm the complete sovereignty of God the Creator and the independence of the creation.
It is one reason of the modern world's rejection of the gospel that it has come to the conclusion that this is indeed the case. To affirm the world, and especially to establish the freedom of the human agent with in that world, it is has been thought necessary to deny God. That is almost an axiom of modern atheism, and indeed of much that affects to be a Chrsitain response to it.
Why does it matter? Should we care? Is it just word games?
Gunton has helped me see there are practical implications that do matter.
First, who are we? What is the meaning of a human person?
"God is one who has his being in communion" [page 15], following John Zizioulas. Similarly, with many careful qualifications, we only have our true being as persons in relation to others, in community. We do have a distinct individual identity but that cannot be defined or meaningful out of the context of relationships.
Second, the Trinity is all about balance. Father, Son, and Holy Spirit are of equal importance. Yet in the church today things tend to bifurcate to extremes. [page 79]
Conservative Reformed types barely mention the Holy Spirit, and focus solely on the Son, particularly on his redemptive death.
At the other extreme are Pentecostals, who are preoccupied with the Holy Spirit, often with little reference to the Son.