Technically speaking, we cannot conclusively prove that a Devil or his demons don’t exist, or that witches cannot work their magic. There just isn’t any evidence that they do. Furthermore, with the advancement of science, supernatural explanations for any given event in our lives become unnecessary and superfluous. A Devil empowered witch may have caused a particular illness by her spell. But what best explains why we can usually trace the illness to some undercooked food that was eaten, as an example? And what best explains why the right medicine always cures the illness? If an illness was caused by the spell of a witch there is no reason to think we could find a natural cause for it. Nor is there a reason to think the right medicine could always overcome the power of the spell by curing it either.