In short, our pastor noted that Calvin, with Augustine, would think of God as one thinks of the sun. All other lights in this world are derived from the sun. One does not first think of other lights as though they shone in their own power, in order after that to investigate open-mindedly whether the sun exists. So one cannot first think of the facts of the universe, and especially of the mind of man, as though they were possibly not God-dependent but self-sufficient as so many self-powered light bulbs, in order then to inquire whether God exists. One just does not look at light bulbs to find the sun. Knowledge of the sun must precede, and be the foundation of, light bulbs. So one does not look at creation to find a Creator, but rather the latter is the foundation of the former. Therefore true knowledge of creation demands a true knowledge of the Creator.
All the facts of the universe are of necessity God-created, God-dependent facts. Therefore men ought to see that God is man’s Creator and his Judge. “For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse” (Rom 1:20).
– Cornelius Van Til, The Reformed Pastor and Modern Thought.