“You can know almost anything about G-d, provided you put the right questions to Him. You have to learn how to put the questions, and they have to be accurate and airtight. […] [M]y father, for instance, doesn't know that two atoms of hydrogen bind with one atom of oxygen to form a water molecule. Yet it's G-d's truth, and an important one. You don't know it […] you believe it because you read it somewhere, or a teacher told you. I know it. I've put the question, and He answered, straight out. G-d will answer a high school boy. He asks only that you use common sense, pay very close attention to Him, not be sloppy, and count and measure correctly. G-d ignores sloppy questions. Sloppiness is the opposite of G-dliness. G-d is exact. He is marvelously, purely exact. Theology is all slop. Moses gave the best answers you could get, three thousand years ago, and he was no theologian.”

"Inside, Outside", p. 567 of the hardcover edition. The quote is fictional physicist Mark Herz answering the protagonist's question "What can you know about G-d? You either believe or you don't."