By: Geoff Colvin | CNN Money
FORTUNE — Rupert Murdoch’s decision to demote his own son is a perfect example of why he’s endlessly interesting. Sometimes he makes business decisions purely with his head, canny and shrewd, occasionally ruthless. That’s what he did this time. But sometimes he makes giant decisions with his heart, appearing misguided or just nuts; for example, he runs the New York Post and the Times of London at deep losses that will apparently continue forever, and he just doesn’t care.