A solution, not an explanation

The Shack is an allegory that depicts the persons of the Trinity. Collin Hansen responds to the book in "The Trinity: So What?" by noting: "When authors experiment with allegory, they risk only failure and ridicule. Christian history, on the other hand, is littered with theologians who experimented with new conceptions of the Trinity. All they got for their efforts was the lousy title of heretic." He goes on to provide a very good concise explanation of the development of the doctrine:

What is the orthodox Trinitarian doctrine of God? Along with the Hebrews, Christians believe that God is one (Deut. 6:4, James 2:19). Yet Christians also teach that God is three persons: Father, Son, and Holy Spirit (Phil. 2:6, Heb. 1, Acts 5:3-4). Finally, Christians affirm that each of these three persons is God (Matt. 28:19-20, 2 Cor. 13:14). The Council of Nicea in 325 was especially crucial for the church's understanding of the Trinity. Meeting in what is now Turkey, church bishops rejected Arianism, which compromised Jesus' full divinity by teaching that God created him. The subsequent Council of Constantinople in 381 solidified what we now recite as the Nicene Creed. This includes these famous lines about Jesus: "begotten of the Father before all the ages, Light of Light, true God of true God, begotten not made, of one substance with the Father, through whom all things were made."

Modalism, an earlier challenge to Trinitarian doctrine, actually upheld both the unity of God and the divinity of Jesus. But modalism, popularized in the early third century by Sabellius, taught that the one God reveals himself in successive modes as Father, Son, and Holy Spirit. These are not three distinct persons but rather three different names or functions for the one God. One common but mistaken analogy of the orthodox Trinity depicts modalism. The same bucket of water may appear as ice, liquid, or steam. But that water cannot simultaneously exist in every mode. God, on the other hand, exists simultaneously as Father, Son, and Holy Spirit.

Dionysius, bishop of Rome from 259 to 268, attacked modalism as heretical. Modalism twists Jesus' words and makes him out to be deceptive or even a liar. After all, the Gospels, especially seen from John's perspective, recount the relationship Jesus shares with the Father. If God is not three at once, then how could Jesus pray to the Father? And what about Jesus' baptism, when the Holy Spirit descends on him like a dove and the Father says, "This is my beloved Son, with whom I am well pleased" (Matt. 3:16-17). Furthermore, modalism erred in teaching that the Father suffered with Christ as one and the same person. It also ran afoul of the leading Greek philosophies of the age, especially divine impassibility, the idea that God cannot suffer.

Given the doctrine's complexity, it's no surprise that we turn to analogies for help. But every analogy breaks down. "Most analogies drawn from the physical realm tend to be either tritheistic or modalistic in their implications," Millard Erickson writes in Christian Theology. Following Augustine's lead, Erickson therefore opts for analogies drawn from human relationships, though he admits that they, too, fail to convey the deep beauty of this central Christian confession.

"We do not hold the doctrine of the Trinity because it is self-evident or logically cogent," Erickson writes. "We hold it because God has revealed that this is what he is like."

This should be enough to answer our "So what?" question. We care about the Trinity because this is how God has shown himself to us in the Bible, even if we have to put the puzzle pieces together. [more]

When God provides us with information about Himself that seems contradictory, the course of wisdom is to doubt our ability to understand.

The Trinity: So What? | Christianity Today | A Magazine of Evangelical Conviction