The Ontological Argument from Descartes to Hegel (review)

Kevin Harrelson's book commences with the following words:

This book provides a philosophical analysis of the several debates concerning the "ontological argument" from the middle of the seventeenth to the beginning of the nineteenth century. My aim in writing it was twofold. First, I wished to provide a detailed and comprehensive account of the history of these debates, which I perceived to be lacking in the scholarly literature. Second, I wanted also to pursue a more philosophically interesting question concerning the apparent unassailability of ontological arguments. In pursuit of this latter problem, the driving question that my account addresses is "why has this argument, or kind of argument, been such a constant in otherwise diverse philosophical contexts and periods?"

(9)

I think that there is no doubt that Harrelson succeeds in the first of these aims. He has, indeed, produced a detailed scholarly account of the history of debates about ontological arguments from the middle of the seventeenth century to the beginning of the nineteenth. His history is engaging and interesting, covering a wide range of authors with diverse philosophical orientations: Descartes, Arnauld, Caterus, Gassendi, Hobbes, Mersenne, More, Geulincx, Cudworth, Locke, Clarke, Malebranche, Huet, Spinoza, Leibniz, Wolff, Baumgarten, Eberhard, Crusius, Kant, Mendelssohn, and Hegel, among others. It seems to me that anyone who works on the treatment of ontological arguments in this period is bound to profit from Harrelson's study.

I think that it is less clear that Harrelson succeeds in the second of his aims. Indeed, it is not clear to me that he ever really succeeds in properly clarifying it. While this brief review is hardly the place to set out detailed considerations, perhaps I can point to just one of the difficulties I find in Harrelson's discussion, a difficulty that arises in connection with the various ways in which he talks about "argument," "demonstration," and "proof."

Harrelson tells us, for example, that "the ontological arguments of Descartes, Hegel, et al. stand and fall with a fairly well-defined set of metaphysical, psychological and theological claims to which the arguments are wedded" (19), that "acceptance or rejection of [Spinoza's] ontological argument involves the acceptance or rejection of an entire philosophy" (135), and that "Hegel cannot demonstrate the existence of God in any sense of 'demonstrate' that involves convincing someone who initially rejects the conclusion" (220).

I wonder whether there is any acceptable sense of 'argument' that can accommodate these—and many similar—claims. There are various places where Harrelson clearly supposes that particular syllogisms are examples of ontological arguments. For instance, he represents the argument from the First Replies as follows:

Premise 1: That which we clearly understand to belong to the true and immutable nature, or essence, or form of something, can be truly asserted of that thing.

Premise 2: But once we have made a sufficiently careful investigation into what God is, we clearly and distinctly understand that (necessary) existence belongs to his true and immutable nature.

Conclusion: Hence we can now truly assert of God that he does exist.

(22)

But, if—as seems evidently correct—this is the kind of thing that is properly called an "ontological argument," then it is hard to understand how it could be correct to say that it is the kind of thing that could "stand and fall with a fairly well-defined set of metaphysical, psychological and theological claims," etc. Perhaps it is true that the premises of this argument stand and fall with a fairly well-defined set of metaphysical, psychological, and theological claims, etc.—but the same is no less true of the following argument:

Premise: God exists.

Conclusion: God exists.

What is missing here—and what I find myself unable to supply—is some sense in which the argumentative virtues of things like the First Replies syllogism depend upon an entire philosophy, stand and fall with particular metaphysical, psychological, and theological claims, and so forth. Surely, one is tempted to think, if the premises...