C.S. Lewis’ excellent book The Screwtape Letters is a story in which a senior demon (Screwtape) gives advice to a junior demon (Wormwood) about how to stop someone (the ‘patient’) becoming a Christian or living a faithful Christian life. One of the first pieces of advice that Screwtape gives is not to even argue that Christianity is false unless he absolutely has to:
By the very act of arguing, you awake the patient’s reason; and once it is awake, who can foresee the result? Even if a particular train of thought can be twisted so as to end in our favour, you will find that you have been strengthening in your patient the fatal habit of attending to universal issues and withdrawing his attention from the stream of immediate sense experiences. Your business is to fix his attention on the stream. Teach him to call it “real life” and don’t let him ask what he means by “real”.