Ross and Scotus on the Existence of God: Two Proofs from Possibility

Abstract

In his Philosophical Theology James Ross claims to have uncovered an assumption essential to the proof of God’s existence advanced by Duns Scotus: the equivalence of logical and real possibility. Ross argues that the omission is reparable, and that Scotus’s proof is ultimately satisfactory. In this paper I examine his claim and determine that while Scotus may have believed there to be a significant connection between these two concepts, his proof of God does not depend on it. Ross’s attempt to rework the Scotist demonstration merits consideration on its own terms, however. In calling attention to the relation between real and metaphysical possibility, Ross has hit on a way of circumventing one of the major impediments to the acceptability of Scotus’s original proof: the infinite regress of causes. Since Scotus argues against the possibility of the infinite regress in copious detail, we must wonder whether he could have countenanced the alternate route suggested by Ross. While I shall argue that indeed Ross’s gambit is flawed in a way that Scotus may have foreseen, his proof nevertheless deserves recognition as an original and noteworthy contribution to the literature.