Charles Hartshorne (1897–2000) wrote over 20 books dedicated to developing the theological side of Whitehead’s philosophy. Hartshorne posited a dynamic form of evolution that included human events, time, history, and God. God is “di-polar.” He has an abstract pole and a concrete one. Hartshorne thought that the necessity of God’s existence could be proved in his version of St. Anselm of Canterbury’s ontological argument. Hartshorne believed that Anselm was mistaken in attempting to prove the existence of God from thought, but that what can be proved is the necessity of God’s existence.

Hartshorne’s major works are Beyond Humanism: Essays in the New Philosophy of Nature (1968), The Logic of Perfection and Other Essays in Neoclassical Metaphysics (1962; revised, 1973), Anselm’s Discovery (1965), A Natural Theology for Our Time (1967; revised, 1992), The Philosophy and Psychology of Sensation (1968), Creative Synthesis and Philosophic Method (1970), Reality as Social Process (1971), Omnipotence and Other Theological Mistakes (1984), and Born to Sing: An Interpretation and World Survey of Bird Song (1992).