In "The Screwtape Letters" by C.S. Lewis, what does Lewis say about "real" and "real life"? Do rational arguments convince?

C.S. Lewis is teaching the person in the art of apologetics. He wants "Wormwood" to consider refraining from arguing over the merits of Christianity with a secular opponent. Instead he wants him to use real life context in a discussion rather than using academic and hypothetical arguments.