Well, your explanation assumes that the magician you would get permission from is still alive. Most material used in modern magic was invented decades if not c

Well, your explanation assumes that the magician you would get permission from is still alive. Most material used in modern magic was invented decades if not centuries ago. In today's world, these age-old effects or gimmicks are popularized by various working magicians, some of whom make a name based on them. And once in a while a completely novel approach is invented. Most new effects are the result of borrowing. A card trick may use a lift invented 100 years ago and a bit of verbal patter similar to something invented last year. The respectful magician will give credit where it's due and will still be respected if he has truly innovated. If there is true innovation no magician will begrudge him the use of the borrowed elements, unless of course they make up the bulk of the trick. The magician's creed is closely correlated with the steps needed to gain the respect of other magicians.