Does the ontological argument beg the question? (response to William F. Vallicella , Religious Studies, vol. 29, p. 97, 1993)

In his paper |Has the Ontological Argument Bun Refuted?' (Religious Studies, 29 (1993), 97-110) William F. Vallicella argues that my attempt to show that the Ontological Argument begs the question is unsuccessful.(1) I believe he is wrong about this, but before endeavouring to vindicate my position I must first make clear what precisely is the point at issue between us. The Ontological Argument is not a single argument, but a family of arguments. Newly devised formulations of the argument are frequently put forward by philosophers in an effort to avoid difficulties that have been pointed out in previous versions. As a consequence there is no possibility of a conclusive proof that every form of the argument embodies the same fallacy. Nevertheless, one can, I believe, prove that all the standard versions of the argument embody a certain fallacy and that, given the nature of the argument, it is therefore unlikely that the argument can be formulated in such a way as to avoid this difficulty. What I tried to show in my paper is that the six best-known versions of the argument (the non-model versions of Anselm, Descartes and Leibniz and the modal versions of Malcolm, Hartshorne and Plantinga) all beg the question and that they do so at the same point in the argument, namely when it is asserted that it is possible,that an absolutely perfect being exists. It is difficult to see how an ontological argument could be formulated without, including this claim as one of its premises, since the distinguishing badge of the argument is the inference from the possibility of an absolutely perfect being to its actuality. It must be unlikely then, if my criticism of these six versions is correct, that there is any way of formulating the argument that avoids this fallacy.

Vallicella does not contest this reasoning, but he thinks that I am wrong in claiming that every form of the ontological argument begs the question. To establish this point he considers the following version. (I retain his numbering.)

(4) If the concept of an x is internally coherent, then an x exists in some possible world.

(5) The concept of a greatest conceivable being (hereafter: GCB) is internally coherent.

(6) Therefore, the GCB exists in some possible world. (4, 5)

(7) Either the GCB …