Cats are very independent animals. They're very sexy, if you want. Dogs are different. They're familiar. They're obedient. You call a cat, you go, 'Cat, come here.' He doesn't come to you unless you have something in your hand that he thinks might be food. They're very free animals, and I like that.
During the many centuries that magic, here on this planet, was presumed to have worked, there were at least as many theories as to how magic worked as there were cultures and religions.

