Summa of the Summa

This work presents a carefully curated selection from Thomas Aquinas's Summa Theologica with extensive contemporary commentary, making medieval scholastic arguments for God's existence accessible to modern readers. Kreeft selects those portions of the Summa most relevant to contemporary philosophical and theological debates, particularly focusing on Aquinas's natural theology, his Five Ways of demonstrating God's existence, and his treatment of divine attributes.

The commentary serves multiple functions: it clarifies technical scholastic terminology, explains the Aristotelian metaphysical framework underlying Aquinas's arguments, and addresses common modern objections to Thomistic reasoning. Kreeft particularly emphasizes how Aquinas's arguments differ from later rationalist proofs, showing that the Five Ways begin from empirical observations about change, causation, contingency, gradation, and teleology in nature rather than from pure concepts. The work demonstrates how each argument moves from observable phenomena to the necessity of a first cause possessing the attributes traditionally ascribed to God.

Kreeft engages with contemporary critics of natural theology, particularly those influenced by Hume and Kant, defending the validity of causal reasoning beyond the empirical realm. He argues that modern rejections of Aquinas often rest on misunderstandings of scholastic metaphysics, particularly the distinction between essence and existence and the analogical nature of theological language. The commentary addresses why Aquinas's God is not merely a "god of the gaps" but a metaphysical necessity given certain features of reality.

The work's significance lies in its bridging function between medieval and contemporary philosophy of religion. Kreeft shows how Thomistic arguments remain relevant to current debates about cosmological and teleological arguments, the relationship between faith and reason, and the logical coherence of classical theism. He demonstrates that Aquinas's synthesis of Aristotelian philosophy and Christian theology offers resources for responding to both scientific materialism and fideistic rejections of rational theology.

By making Aquinas's technical arguments accessible without oversimplification, Kreeft enables contemporary readers to engage with one of the most sophisticated attempts to demonstrate God's existence through natural reason. The work serves as both an introduction to Thomistic thought and a defense of its perennial relevance to questions about ultimate reality, causation, and the rational grounds for theistic belief.