In Zen Buddhism, koan is a story, dialog, question, or statement in the history and lore of Buddhism. You are supposed to meditate on whatever the question or riddle is and by doing so you expand your thought into new mental pathways. If you are a beginner it seems reasonable to solve the stories of the lore of Chan/Zen Buddhism. However is this the only thing you can do with Koan? After learning and mastering it, wouldn't it be just as helpful to meditate on a new idea or problem in your career. For example, say you are a theoretical physicist. You’re trying to expand M-theory more and more into what it could become: the theory of everything. Wouldn't it be helpful to apply your koan reasoning to such a problem as uniting Quantum Mechanics, General Relativity, and the Standard Model? Or perhaps using your koan meditative abilities to solve one of the biggest mysteries of life: how organic molecules formed into the first DNA. Or maybe I have a misunderstanding on how koan works. As far as I have read though, it seems quite valuable to apply to life's problems, especially major problems in science.