"So, there's this man, he has a time machine. Up and down history he goes — zip, zip, zip, zip, zip — getting into scrapes. Another thing he has is a passion for the works of Ludwig van Beethoven. Then, one day, he thinks, "What's the point in having a time machine if you don't get to meet your heroes?" So, off he goes to 18th Century Germany, but he can't find Beethoven anywhere. No one's heard of him. Not even his family have any idea who the time traveler is talking about. Beethoven literally doesn't exist. This didn't happen, by the way. I've met Beethoven. Nice chap. Very intense. Loved an arm wrestle. No, this is called the bootstrap paradox. Google it. The time traveler panics. He can't bear the thought of a world without the music of Beethoven. Luckily, he'd brought all of his Beethoven sheet music for Ludwig to sign. So, he copies out all the concertos and the symphonies, and he gets them published. He becomes Beethoven. And history continues with barely a feather ruffled. (the Doctor turns on an amplifier and plugs in his electric guitar) My question is this: who put those notes and phrases together? Who really composed Beethoven's Fifth? (the Doctor plays the opening notes to Beethoven's Fifth on his guitar)"