Altizer began with a fairly traditional view of God somewhat along these lines, accepting the idea of a transcendent-immanent divinity. And he also accepted the Incarnation as a historic fact: God manifesting himself in the world in the flesh of Jesus.
For years, however, he brooded upon the full significance of this event. He immersed himself in a study of Eastern mysticism, Nietzsche, Hegel, William Blake—and he thought hard about the Incarnation. Then, one day while he was reading, it came to him. It all fell in place.
The Incarnation happened.
So did the Crucifixion.
But not the Resurrection!
This idea is the essence of Altizer’s theology. God had incarnated himself in the body of Jesus; but when Jesus died, God did not “jump back up into heaven.” He remained in the world. He is in the world now. What God did, said Altizer, was “empty himself of transcendence.” He became totally immanent in the universe. He became part of the universe. But he did not, immediately, become all of the universe.
At first he was immanent only in Jesus. Since the death of Jesus he has continued to embed himself deeper and deeper into the fabric of the universe. No longer transcendent in any sense, he is in the process even now of becoming ever more immanent.

(…)

The God of the East is “very real,” he said, and “infinitely more realistic” than the traditional Western God. One could opt for this God, he said. But there is one important sense in which Altizer would distinguish his position from the Eastern view, and we shall return to this point in a later chapter. Briefly, for now, Altizer’s theology suggests that the cosmic process is evolutionary—that it is leading up to something—while Eastern metaphysics supposedly rejects the evolutionary hypothesis. The East “looks backward to a primordial totality” (according to Altizer), and Altizer on the other hand “looks forward” to an eschatological totality which is utterly transformed and aware of itself.

(…)

Q. Let me see if I understand your viewpoint correctly, from what you said the other night. You believe, do you not, that there once was a transcendent God?
A. Yes.
Q. Was this God wholly transcendent, or was he also immanent in the world?
A. Both transcendent and immanent.
Q. Did he create the world?
A. This gets more difficult theologically. I do not believe in a literal creation or creation story. Frankly, I haven’t worked this out. It’s merely tentative. But I think in terms of a kind of evolution of the cosmos. There was an original totality in which all things were one—no separation between nature, man, and God. And out of this totality there evolved the world or the cosmos as a distinct entity—and also God. I think in a certain sense God appears as creator in conjunction with the world’s coming to exist apart from God.
Q. As I understand it, you believe God emptied himself of transcendence and became immanent in the world—that he incarnated himself in the person of Jesus. That sounds orthodox, to a point. But you stop with the Incarnation. You reject the Resurrection. You say, “God did not jump back up into heaven.” You say he stayed right here in the world after the Crucifixion. Is that correct?
A. Correct. I believe the fullness, the totality of God passed into Christ, moving ever more deeply and fully and comprehensively into the world, flesh, consciousness, and experience.
Q. Why did God decide to do this?
A. He didn’t decide. I understand the Incarnation as implicit and essential in the whole process of cosmic movement. There was no arbitrary point where a decision was reached.
Q. So God is no longer transcendent but is immanent right now in the world?
A. That’s right….