  The purpose of this defense of Descartes is not to render a verdict as whether he has the correct account of existence, but to show that he has a rather sophisticated and systematic treatment of what has been one of the great bugbears in the history of philosophy. He does not make the ad hoc assumption that existence is an attribute in order to serve the needs of the ontological argument. Indeed, on Descartes’ view, existence is not a property in the traditional sense, nor can one conceive of something without regarding it as existing. Descartes’ critics might not be convinced by his account of existence, but then they have the burden of providing a better account. The focus of the debate will then be shifted to the question of who has the correct ontology, rather than whether the ontological argument is sound.