The ontological argument has a long history of defenders and detractors by both Christians and non-Christians alike. First developed by Anselm of Canterbury, it postulates that a being than which none greater can be conceived is a concept that even the fool, in Anselm’s words, can understand. However, a being that only exists in the mind is not as conceivably great as a being that exists in the real world. Therefore, there must exist a being than which none greater can be conceived in the real world. This argument has been debated and developed for close to a thousand years. In particular, Alvin Plantinga and William Lane Craig have developed modal versions of the argument using the language of possible worlds. However, while these versions have several points in common with Anselm, unlike Anselm, they reject the doctrine of divine simplicity upon which Anselm builds his case. Can such an argument succeed? This paper will argue that these models fail to the extent that they reject divine simplicity. Further, as a case study, this paper will engage the Muslim conception of God to argue that both Islam and models like Plantinga’s and Craig’s fall prey to the same snare by denying the identification of God with His attributes and by separating God’s attributes of essence from His attributes of action, thus positing a God that may be the greatest living being, but not a being than which none greater can be conceived.