Can magic be performed on Earth?
A bit of a strange question as Uncle Andrew is the Magician in The Magician's Nephew and the rings are magical. But for some reason, the White Which cannot perform her magic in our world. Is that special to Earth or is it that the magic of one world cannot be performed on the magic of another?
Now, you might say that of course magic is transferrable, after all the Witch does plenty of magic in Narnia. Actually, not quite. You see, the Witch doesn't do any magic in Narnia in The Magician's Nephew. She understands the magic being put into Narnia, she understands the song of Aslan and she learns from it. She knows the magic put into Narnia at the very beginning. And any magic she performs comes from Narnia - it is Narnian magic used for evil. But the magic of Charn is restricted to Charn.
If this is correct, we learn two things: (1) the magic of one world does not work on another. Every world is fundamentally different, and its magic is unique to that world. (2) The magic of Narnia, and presumably any other world, can be used for good or for evil.
Which brings me to my final question. Who in Narnia uses magic for good? Dr. Cornelius calls himself a minor magician and does some magic, Susan's horn and the liquid of Lucy's vial are said to be magical, Bacchus and Sienus do a dance of magic... Coriander does magic as does Lucy when she reads from his book - but he's star. The music at the Snow Dance is said to be full of good magic. We talk about the Emperor's magic - but I have a hard time calling what God does magic...
I think we need a better definition of magic...