Classical theism

Classical theism is not a single doctrine but a package of interconnected commitments that emerged from the interaction of Abrahamic monotheism with Greek (and later Arabic-Islamic) philosophy. The core claims: God is simple (no parts); immutable (cannot change); atemporal or eternal (not located in time); impassible (cannot be affected by creatures); omnipotent, omniscient, and perfectly good; and exists a se (from himself). Each of these attributes is supposed to follow from the others in a tight web of philosophical reasoning, and removing any one tends to compromise the rest.

The picture is sometimes called "perfect being theology" — it starts from the idea that God is the greatest conceivable being and works out which properties that entails. Anselm's Proslogion is the canonical early statement of the method. Aquinas's Summa Theologiae is the canonical systematic development. The dominant forms of Christian, Jewish, and Islamic philosophical theology from the Middle Ages through the early modern period were all versions of classical theism.

In contemporary philosophy of religion, classical theism has come under pressure from several directions. Process theologians (Whitehead, Hartshorne) argue that the immutable and impassible God cannot have meaningful relationships with creatures or be affected by their suffering — and a God who cannot be moved by a child's tears is not the God of biblical religion. Open theists argue that immutability is incompatible with genuine divine responsiveness. Panentheists argue that the classical picture is too transcendent to be the ground of the ordinary religious experience of divine presence. And naturalist critics argue that classical theism is so metaphysically austere that it bears little resemblance to what most believers actually hold.

Defenders reply that classical theism is the only view that preserves divine perfection without collapsing into anthropomorphism. A God who can change, be affected, and exist in time is a finite being — impressive, perhaps, but not the ultimate reality that the cosmological argument was supposed to reach. The classical theist accepts the philosophical austerity as the price of preserving what it actually means to say God is ultimate.

For a secular reader, knowing classical theism lets you distinguish the specific philosophical target of most academic natural theology from the more anthropomorphic God of popular religion. When a contemporary apologist like Edward Feser defends "the theism philosophers have always defended," they mean this specific package — not the God of most churchgoers.