 God contains all compossible realities in the absolutely highest degree. But He is possible. Wherefore, since the possible can exist, existence can belong to it. Consequently, since existence is a reality, and since realities are compossible which can belong to a being, existence is in the class of compossible realities. Moreover, necessary existence is the absolutely highest degree. Therefore, necessary existence belongs to God or, what is the same, God necessarily exists (NT: II, §21, see Corr 1973).