  There are at least two problems with this argument, though. First, the doctrine of divine simplicity is highly controversial—not all theists accept it. Second, even if the doctrine is accepted, the most that may be required is that God’s essential (real) properties are either identical with each other or equivalent to each other. God also appears to have (real) contingent properties, however, and, if he does, these properties can’t be identical with or equivalent to his essential properties. For consider the property of being the ultimate cause of my existence or the property of knowing that I am the author of this entry. Since acting and knowing are paradigmatic cases of real properties, being the ultimate cause of my existence or knowing that I am the author of this entry would seem to be real properties of God. (Pace Thomas Aquinas and others who implausibly insist that they aren’t even though God really has them, that is, even though God really does stand in these relations to me.) But they are also contingent properties of God, since there are possible worlds in which God exists and doesn’t create me, and possible worlds in which God exists but doesn’t know that I am the author of this entry (because, for example, I never write it). Since God has his essential properties in every possible world in which he exists and does not have his contingent properties in every possible world in which he exists, his contingent properties can’t be identical with, or equivalent to, his essential properties. It follows that if H and non-H are real but contingent properties of two divine beings, they are neither identical with nor equivalent to D. The argument from simplicity thus fails because it leaves open the possibility that two gods could be distinguished by a difference in their real contingent properties.