Philip Pullman said this quote

When you look at what C.S. Lewis is saying, his message is so anti-life, so cruel, so unjust. The view that the Narnia books have for the material world is one of almost undisguised contempt. At one point, the old professor says, ‘It’s all in Plato’ — meaning that the physical world we see around us is the crude, shabby, imperfect, second-rate copy of something much better. I want to emphasize the simple physical truth of things, the absolute primacy of the material life, rather than the spiritual or the afterlife.]