You are taking the metaphysics too seriously. If Dresden makes one to contain magic it should work because it’s part of his abilities. Forget all but the most obvious and crudest ideas physics, metaphysics, and especially magical laws. They all don’t make sense in this context anyway.
Also whether something works as a function of its own properties or as merely a function of universal law is a deep philosophical question that can be asked of anything. While I’m sure the answer is extremely interesting, I think it’s probably bad policy to set up Death Battles to turn on the resolution of thorny philosophy.