Here on Soundcheck, we spend a lot of time picking apart creativity. Where does it come from? How do you harness it? How important is inspiration, how important is perspiration? We're not the only ones. Writer Maria Popova spends her days contemplating the why and how of creativity, and shares what she finds via her website Brain Pickings. Today, she tells us about the creative philosophy that links Russian composer Pyotr Ilyich Tchaikovsky and Jack White.