The Power the sorcerers can command is commonly called magic. In the opinion of a certain sorceress I'm acquainted with, magic is chaos, an art and a science, a curse, a blessing and progress. However poetic it may sound, it is hard to find a better simile. Everything depends on the person that uses that Power, of course. Still, it is a fact that it can be used to achieve things not possible to normal humans. The witchers' Signs are also a form of magic, but sorcerers look at them with disdain, since they cannot be compared to the forces the sorcerers themselves command. Without magic our world would certainly be less interesting, and many beautiful things would be forgotten.