This is an illustration of C.S Lewis’ first talk in the series called ‘What Christians Believe’. This became Chapter 11 in the book called ‘Mere Christianity’. You can find the book here: http://www.amazon.com/Mere-Christiani...
The original radio broadcast included another powerful metaphysical argument for Theism (see quote below), however, this was a brand new argument at this stage, with none of the counter arguments addressed due to the broadcast time limit, so it was removed from the book ‘Mere Christianity’ for simplicity’s sake.
However, you can find this argument fully worked through in chapters 3 in Lewis’ book called “Miracles" and in various essays. “There are all sorts of different reasons for believing in God, and here I’ll mention only one. It is this. Supposing there was no intelligence behind the universe, no creative mind. In that case nobody designed my brain for the purpose of thinking. It is merely that when the atoms inside my skull happen for physical or chemical reasons to arrange themselves in a certain way, this gives me, as a by-product, the sensation I call thought. But if so, now can I trust my own thinking to be true? It’s like upsetting the milk-jug and hoping that the way the splash arranges itself will give you a map of London. But if I can’t trust my own thinking, of course I can’t trust the arguments leading to atheism, and therefore have no reason to be an atheist, or anything else. Unless I believe in God, I can‘t believe in thought; so I can never use thought to disbelieve in God.”
Lewis mentioned that Nazism is a form of Pantheism: “Even the German worship of a racial spirit is only Pantheism truncated or whittled down to suit barbarians”. Democracy is founded upon Moral Law/Natural Law and the desire for fair play. I therefore started this production with a Spitfire (representing Christianity) and a Messerschmitt 109 (representing Pantheism) after a dogfight over the Cliffs of Dover on the southern coast of England. 5:28 I depicted eatable vegetables here, but Lewis was, of course, referring all vegetation - the thousands of seed plants, mosses, algae, and ferns.