In addition to demonstrating a Socratic teaching method, the discussion among the Professor, Peter and Susan, shows another mode of teaching used by Lewis--a trichotomy. A trichotomy is a three-part version of the philosophical "dichotomy," which dramatizes that there are only two real choices or options in assessing the truth of a proposition; a trichotomy attempts to force a choice among threethings. The Professor explains that Lucy's story of Narnia shows that she is (a) lying, (b) mad, or (c) telling the truth. Put this way, they all agree that the "logical" conclusion is that Lucy is telling the truth about her adventures beyond the wardrobe. Lewis also uses the trichotomy in Mere Christianity to defend the divinity of Christ, who men variously refer to as "liar, lunatic, or Lord." Lewis adeptly champions the last option.from The Socratic Teaching Method
Seth apparently was making his own connections as he listened before heading outside to play in the snow. He said, "Narnia sounds like the land of Canaan, you know, with honey." Not sure what he heard that made him think of that, but the point is, he is listening and that's important.