  Could two gods be distinguished by a difference in their essential properties, however? (The doctrine of simplicity may entail that they can’t but—as noted above—the doctrine of simplicity is controversial.) Each god would obviously have to have all the properties essential to divinity (omniscience, omnipotence, perfect goodness, and the like). But could they be differentiated by essential properties peculiar to each? Could, in other words, the first god have an essential property which the second god lacks, or vice versa? Zagzebski (1989) thinks that it can’t. Human beings are distinguished in virtue of their having different individual essences, and human rational beings and angelic rational beings are distinguished in virtue of their possessing the properties essential to humanity and to angelhood, respectively. But no individual human (way of being human) exhausts the fullness of humanity (the many ways of being human), and neither humanity nor angelhood exhaust the fullness of rationality (the many different ways of being rational). Being divine, on the other hand, entails being “wholly” or “perfectly” divine, that is, being everything a divine being could possibly be. So “two divine beings” could not differ “in an essential property” in the way in which individual human beings, or human beings and angelic beings, can. (Zagzebski 1989, 10–11)