Contradiction

Miracles 3.6 "... no account of the universe can be true unless that account leaves it possible for our thinking to be a real insight." Lewis here points out the conceptual difficulty with any denial of our ability to really think because it leads to contradictions: ex. "It would have destroyed its own credentials. It would be an argument which proved that no argument was sound -- a proof that there are no such things as proofs -- which is nonsense."