> But when we assess a machine, we do know everything about it based on its actions. This is obviously false. Every developer has had hour-long debugging sessi

> But when we assess a machine, we do know everything about it based on its actions. This is obviously false. Every developer has had hour-long debugging sessions to track down a mysterious behavior. Sometimes entire teams are stumped by a technical glitch. Until the bug is found, nobody knows everything about the machine.