Abstract: Contrary to received opinion, Descartes' view on the merits of the ontological proof may actually agree with that of Thomas Aquinas, whose rejection of the a priori existence proof has stocked the armories of anti-Anselmians ever since. In a rarely noted passage of the First Replies, Descartes claims not to differ in any respect from Thomas on the proof, a claim that gains sense in light of recent work on the Fifth Meditation. That work in turn reveals a well-founded, (...) if surprising, understanding of the Cartesian proof and of Cartesianism's true relation to Thomism. (shrink)

Contrary to received opinion, Descartes’ view on the merits of the ontological proof may actually agree with that of Thomas Aquinas, whose rejection of the a priori existence proof has stocked the armories of anti‐Anselmians ever since. In a rarely noted passage of the First Replies, Descartes claims not to differ in any respect from Thomas on the proof, a claim that gains sense in light of recent work on the Fifth Meditation. That work in turn reveals a well‐founded, if (...) surprising, understanding of the Cartesian proof and of Cartesianism's true relation to Thomism. (shrink)

In the fifth of his Meditations on First Philosophy, Descartes offers a version of the ontological proof for the existence of God. As Caterus argues in the First Objections, however, it seems that if this argument were valid, then so also would be any number of absurd arguments, for insofar as Descartes infers that God exists from the fact that existence belongs to His essence, we should also be able to infer that other objects---the fictitious existing lion, say---exist on similar (...) grounds. Descartes's lone defense against this objection is to distinguish true and immutable essences from fictitious ones , a distinction that, in its details, seems to imply a realistic view of essences. Such a view of essences, though, conflicts with Descartes's explicit rejection of Platonism in the Principles of Philosophy , among other places. ;In this dissertation, I offer an interpretation of the Fifth Meditation that resolves this problem by treating true and immutable natures as nothing more than ideas, and I argue that, by a careful reading of several crucial yet rarely noticed texts, we can bring Descartes's cryptic and confusing Fifth Meditation claims under an anti-Platonic rubric. As an upshot of this interpretation, I propose an unusual reading of Descartes's ontological proof, one that draws it much closer to the proof of the Third Meditation and one that, in the end, forces us to reevaluate Descartes's connection to three great figures in the tradition of the ontological proof. St. Anselm, St. Thomas, and Kant. (shrink)