Pick up any newspaper and you’ll find stories – survivors of terrible plane or automobile crashes, or patients with dread diseases who live past their predicted expiration date. Invariably they are described as hugely lucky. That’s puzzling on the face of it; you’d think that somebody really lucky wouldn’t have got cancer or been in a terrible wreck to start with. Such cases raise interesting questions about the nature of luck. Is it something real or is it purely subjective, just a matter of how we happen to feel about the things that happen?