@digitalimpression I agree that knowing how to do karate at a black belt level would not translate into being able to do it at that level. It would mean knowing how to train yourself to be able to do it, though, which means you could have the ability in addition to all that other knowledge with just a few years of work. If we chose the ability, however, a few years of work could not get us all that additional knowledge.
P.S. Having a black belt does not make one an expert. First dan represents competence in the basics of karate, not mastery. I mention this just in case you run across a genie who takes wishes too literally.