By way of brief overview, open theism is a contemporary mode of theological discourse that is more consonant with our present scientific descriptions of reality, as well as the central theme of divine love that permeates both the Hebrew and Christian scriptures. Open theism, in other words, offers a logical and coherent metaphysical system that engages with the best science of our age—one that breathes new life into the biblical text in order that it might adequately address our spiritual needs.
Governed by a static and hierarchically ordered worldview, classical theism addresses the question of God’s nature, especially as it relates to the world, through the lens of Aristotelian philosophy. As a keen observer of the natural world, Thomas Aquinas notably synthesized the doctrinal propositions of Christianity and Aristotelian metaphysics, a brilliantly conceived theological construct that nicely fit the Ptolemaic description of the cosmos.
His system of thought came to be known as “analogical theology,” whereby a perfect and eternal God (“the unmoved mover”) who stands above and outside of creation cannot possibly be affected by the world or its creatures. Aquinas writes: “A real relation of God to creatures is not a reality in God.” Whatever happens “in time,” in other words, is only related to God externally and makes no difference to the identity or internal life of God. Put bluntly, the only real relation of God to the world exists in our imaginations.
While Aquinas’ metaphysics of being was inherently consistent with the cosmology of his time, the insights of twentieth-century science have furnished us with a picture of the cosmos that is radically different from previous centuries. We now understand reality as a “relational process,” an open, dynamic, energetic, and complexifying web of interconnectedness that can be traced all the way down to the quantum level of life. Steeped in the philosophical writings of Alfred North Whitehead who developed a new metaphysical system based on the deeper implications of modern science, and Charles Hartshorne who developed the emergent theological and philosophical issues of Whitehead’s speculative thesis, open theism decidedly heeds Aquinas’ admonishment that “a mistake in our thinking about nature is a mistake in our thinking about God” and so gives us a view of God more reflective of our experiences and reality.
In contrast with classical theism, therefore, open theism portrays God as dynamically involved in all things, both in nature and in human history. In an open and relational world, God is understood as Absolute Future: the supremely personal and unbounded lure of love in the creative advance of endless possibilities. Unlike classical theism, open theism invites us to embrace a God who is organically and intimately related to the world and all its events; it invites us to actively share in the process of bringing the world one step closer to the completion of God’s vision for it. No longer spared from the spoils of time, God shows true love and care for the world by truly acting along with it and being affected by it.
Not incidentally, this dynamic and developing God-world relationship is directly reflective of many biblical accounts. In the biblical imagery of the Pentateuch, for instance, God is neither a fixed, immovable Being, nor has human history been foreordained. Rather, Israel’s free response continually alters not only its destiny but the very nature of God. In his classic work The Suffering of God, Hebrew bible scholar Terence Fretheim offers a helpful explication: “God is absolute only in regard to divine love for people, which remains forever and is foundational to all other actions, even wrath. God becomes angry with people only because God first loved them so very much. God is absolute in regard to love, but in terms of the various aspects of the relationship with humanity, God changes in response to the myriad of human decisions.” By being related to humanity in the flow of events, God does not know the future, but God and humanity co-creatively construct the events that give rise to the future. According to Fretheim, the application of the language of past, present, and future actions and feelings to God is meaningful only if God changes in that relationship with creation and humanity.
In summary, all of our theologizing is done within a worldview. As a result, open theism, not unlike what Aquinas did in the thirteenth century, seeks to integrate the philosophical shifts ushered in by modern science in order to offer us a more coherent discourse about the God-world relationship. In addition to its faithfulness to biblical thought, open theism provides a truly effective form of religious expression by creatively and responsibly “resynthesizing” our inherited theological beliefs for the purpose of adequately addressing present spiritual challenges.
 Terence Fretheim, The Suffering of God: An Old Testament Perspective (Philadelphia: Fortress Press, 1984), 124.