He didn’t have Sam’s interest in How to Think About Bob. If Bob was Zane’s good friend, and Zane had no evidence that Bob had committed the unsolved murder, Zane would have insisted on thinking about Bob the way he had always thought about Bob. He would have gone out of his way to stand by Bob, and to make Bob feel better about what had happened. But if he’d stumbled upon Bob burying a bloody knife in his backyard he’d have shot him on the spot, without even pausing to update his probabilities.
