Ideas are like seeds: they are abundant, and most of them never grow into anything. Also, ideas are seldom original. Ask several independent groups to brainstorm on the same topic at the same time, and you will likely get many of the same ideas. This is not a limitation of brainstorming; it is true of all creation. Because everything arises from steps, not leaps, most things are invented in several places simultaneously when different people walk the same path, each unaware of the others.