Mackie’s responses to the Ontological ArgumentJ.L. Mackie – The Miracle of Theism, chapter 3: Ontological Arguments -Ontological arguments “purport to show that once we even entertain the relevant notion of a god we cannot deny his real existence.” According to Descartes’ terms, God has formal (actual) and not just objective (representative) reality. They make “very strong claims” about rational cogency that should be possible to settle definitely one way or the other. The Earliest ontological argument put forward by Anselm (11thC).

Mackie starts with Descartes’ argument. He outlines his argument: the term ‘God’ refers to something that exists, therefore the statement that God doesn’t exist is equivalent to the statement, ‘the thing that exists does not exist’, which is contradictory, so one must reject the statement and affirm that God does exist.

Mackie then raises the objection that one could imagine anything as having existence in its essence – he uses the example of a ‘Remartian’, a Martian whose existence is essential. Descartes’ own reply to objections of this form is that God’s perfect qualities are united in such a way that they cannot be fully realised independently of each other, whereas a being such as a chimera is artificial and arbitrarily composed of traits which are not connected in the same way that God’s are.

So in defending his argument from this objection, Descartes reveals a further assumption in his argument: that there is an objective necessity which binds all of God’s divine perfections into an indissoluble whole.Kant’s objections:

Although there may be a contradiction in rejecting a predicate while retaining a subject, there is no contradiction in rejecting both the subject and the predicate. One can reject the idea of God altogether, which would involve rejecting the predicate of existence. However, this criticism rests on a distinction between the positive existential statement that God is non-existent and the negative existential statement that there is no God; Kant would then have to show that no negative existential statement could be contradictory to show that the ontological argument is impossible.

It is a contradiction to ascribe the quality of existence to something which you are uncertain about the existence of. You can’t enquire open-mindedly into the existence of God while inputting the notion of existence, disguised as ‘infinite perfection’, into your conception of God. But Descartes is not open-minded: he asserts that the existence of God is undeniable, and this prevents open-mindedness.

Existential propositions are all synthetic, so to claim that the predicate of existence can’t be rejected without contradiction is an encroachment of the synthetic on the analytic. Only analytic propositions can be true by virtue of their meaning. However, Mackie points out that it can be argued that certain existential propositions are analytic, e.g. arithmetical propositions. Though Kant would claim that such truths are a priori synthetic, they still illustrate that this claim is disputable.

Existence/being is not a predicate. To say that God ‘is’ or ‘there is a God’ does not posit a new predicate but merely affirms the existence of God along with God’s predicates. Mackie claims this initial linguistic formulation of his fourth criticism is not satisfactory, though the underlying point is important. Although ‘existent’ can be a first-level predicate, it does not operate in the same way that predicates such as ‘omnipotent’ or ‘perfect’ do; it merely instantiates the concepts and predicates in question.

Mackie claims that the fourth criticism (sufficiently developed by Ludwig Frege) would be fatal to Descartes’ ontological argument. It refutes the notion that existence can be a property such as a perfection, although Frege’s development has criticisms of its own.

Mackie concludes by saying that although to say that something exists is not to describe it, it is not inconceivable that a necessary thing might exist. However, Descartes does not prove that a necessary thing exists; he has only asserted that the other perfections require existence. He then returns to Kant’s first criticism: that even if God could possess necessary existence as an essential property, one could still assert that there is no God. For Descartes ontological argument to work, it would have to follow from ‘God has necessary existence as a predicate’ that ‘there necessarily is a God’, and this doesn’t follow.