  Arguments like this make two assumptions. The first is that properties can be exhaustively divided into three classes. The first class is the class of imperfections, that is, limitations (my inability to run a two minute mile, for instance) or privations (for example, blindness or sin—properties that imply defects, some deviation from the standards appropriate for evaluating beings of the kind in question). The second is the class of mixed perfections, that is, good-making properties that entail some limitation (for example, being human or being corporeal) or privation (repentance, for instance). The third class is that of pure perfections—perfections that entail no limitation or privation (for example, being, goodness, love, knowledge, power, unity, or independence). The second assumption is that God possesses all and only pure perfections. With these assumptions in place, the argument works. Two gods couldn’t be distinguished by a difference in their pure perfections since both gods have all of them. And they couldn’t be distinguished by a difference in their other properties because they haven’t any.