  Having said that, Descartes’ best strategy for answering the ontological version of the objection is to concede it, or at least certain aspects of it. Descartes explicitly affirms Kant’s point that existence does not add anything to the idea of something (provided that the terms “idea” and “concept” are regarded as psychological items).  Once again we should recall passage [4] from the Second Replies: “Existence is contained in the idea or concept of every single thing, since we cannot conceive of anything except as existing” (Axiom 10, AT 7:166; CSM 2:117). So, Descartes agrees with Kant that there is no conceptual difference between conceiving of a given substance as actually existing and conceiving it as merely possible. In the first instance one is attending to the existence that is contained in every clear and distinct idea, and in the other instance one is ignoring the thing’s existence without actively excluding it. He would, however, stress another conceptual difference that Kant and other critics do not address, namely that between the two grades of existence — contingent and necessary. The clear and distinct ideas of all finite things contain merely contingent or dependent existence, whereas the clear and distinct idea of God uniquely contains necessary or wholly independent existence (ibid.). As discussed previously, the ontological argument hinges on this distinction.