For many the idea of God's simplicity has been a confused subject. For the Arminian to say that God is simple and that God knows by necessity all things is to mean that God is dependent upon something else outside of his nature. However, this is by far outside the truth of things. To say that God is one is to mean that God's love, holiness, Justice, Grace, Mercy, Knowledge, Aseity is one. Love does not contradict God's holiness nor the other way around because it is a Holy Love. God does not love at the expense of his holiness. The fact that God is eternal means that all of His divine attributes are so. God does not grow in anyone of his attributes. His knowledge does not change ever. God never changes as the verses say. But this is far from saying that God's knowledge depends upon something outside of Himself. When the assertion is made that by this knowledge God depends upon His creatures - we respond by asserting first and foremost no. You Arminian synergist are actually the one who makes the love of God depend upon creation. To say that God's knowledge is eternal and that it does not change is to say that God's knowledge is not dependent upon anything outside of Himself. What God knows, God knows fully well and does not change. His knowledge is based upon His own free and elective choice. This sadly has been the issue in Time. The Molinist have also tried to combat this issue by saying that there in God a Middle knowledge. By this assertion God in reality is dependent upon something outside of Himself to Decree. God looks at all the options and decides to create something that really brings Himself greater glory, from which God decrees such. This view of God makes God dependent upon something outside of Himself. No longer is his knowledge said to be original to God Himself or based upon His own pleasure.
For the Reformed, God's knowledge is actually based upon God's eternal being. God's knowledge does not change at all. As it is said, "God is, and always was so perfectly wise, that nothing ever did, or does, or can elude His knowledge. He knew, from all eternity, not only what He Himself intended to do, but also what He would incline and permit others to do. 'Known unto God are all His works from eternity' (Acts 15:18). Consequently, God knows nothing now, nor will know anything hereafter, which He did not know and foresee from everlasting, His foreknowledge being co-eternal with Himself, and extending to everything that is or shall be done (Heb. 4:13). All things, which comprises past, present and future, are naked and open to the eyes of Him with whom we have to do." - Jerome Zanchius
