  While this set of sentences has the surface structure of a formal argument, its persuasive force lies at a different level. A meditator who is having trouble perceiving that necessary existence is contained in the idea of a supreme perfect being can attain this perception indirectly by first recognizing that this idea includes every perfection. Indeed, the idea of a supremely perfect being just is the idea of a being having all perfections. To attempt to exclude any or all perfections from the idea of a supremely being, Descartes observes, involves one in a contradiction and is akin to conceiving a mountain without a valley (or, better, an up-slope without a down-slope). Having formed this perception, one need only intuit that necessary existence is itself a perfection. It will then be clear that necessary existence is one of the attributes included in the idea of a supremely perfect being.