As an attribute of God, his knowledge of all things which can be, were, are, or will be.  In scholastic terminology, such omniscience is distinguished as: “science of simple intelligence or understanding,” referring to knowledge of all possible realities that have not, do not, and will not exist; “science of vision,” referring to knowledge of realities that have been, are, or will be (considered from the perspective of their existence); “science of approbation,” referring to knowledge of realities that have been, are, or will be (considered as presupposing God’s positive willing, in contrast to his mere permission).