Proceedings of the American Catholic Philosophical Association

Volume 78, 2004

Reckoning with the Tradition

Thomas’s Elusive Proof
A Reconstruction of the “Existential Argument” for the Existence of God

This paper presents a reconstruction of the “existential argument” for the existence of God that seems implicit, if somewhat elusive, in the writings of Thomas Aquinas. The reconstructed argument corresponds to no single passage of Thomas’s but gathers and synthesizes arguments used by him throughout his writings. The paper then attempts to evaluate the argument’s soundness against the background of Thomas’s metaphysical principles. There is ample motivation for desiring such an evaluation. John Haldane has recently described the existential argument as perhaps Thomas’s “most original contribution to the search for theistic proofs.” Yet, ironically, several prominent Thomistic philosophers have denied the soundness, and indeed the very possibility, of any such existential argument, leveling criticisms based on textual issues in Thomas’s works, the limitations of apriori reasoning, and perceptions of circular reasoning. The paper will attempt to show that the criticisms formulated by these critics are unfounded.