If God is immutable (or unchangeable), we have a couple of problems worth considering.
For one, nothing we do contributes to the greatness of God; if God is unchangeable. "So, why exactly do we serve God," Hartshore asked?
This idea of unchangeability also contradicts the concept of infinity, he pointed out. In an infinite universe we might expect that things are always changing for the better with no upper limit.
In modern philosophy there are six interpretations of God's relationship with nature; exclusion, acceptance, identity, two forms on inclusion, and rejection. Process Theology is an inclusion interpretation. Hartshorne saw it as Panentheism while Wieman usually saw it as Naturalistic theism.
Exclusion: Monistic theism -- God is real but nature is a reflection of reality. This is a philosophical interpretation not observed by many religions today.
Acceptance: Dualistic theism or classical transcendent theism -- God created nature but exists separately and beyond it. There are natural and supernatural powers in the universe.
Inclusion: Panentheism (Everything is within God) -- Hartshorne's reasoning that the universe is a network of natural powers unified by God. Instead of divine intervention, we have divine interaction.
Identity: Pantheism (God is everywhere) -- God is nature. All power in the universe is essentially supernatural.
Inclusion: Naturalistic theism -- Nature includes God, which is the influence for good in the universe.
Rejection: Atheism -- Nature is real but God is a theoretical idea. Atheistic Humanism seeks fulfillment of human ideals.
Theologian James Luther Adams, a colleague of Hartshorne's, drew a memorable distinction between faith and God. He saw faith as our understanding of things we cannot know based on scientific facts. Faith is essentially part of life, he noted. Our experiences have shown us that we cannot make all of our decisions based on scientific facts alone.
Even an atheist has faith, Adams said. He has faith in his beliefs about the nature of the universe. For others, God is the object of faith.