— So Alice, there’s this cabinet right? It's housing an old mainframe. And there’s a switch on it, but with only one wire. And that wire is pretty clearly a ground. The switch is labeled “magic” and the rumor is that it will crash the server even though switches on principle have to have at least two ungrounded wires — — Bob, I know what a switch is. A switch is a thing that breaks another thing but only if those two things are linearly or otherwise correlated — — Alice, a switch is not ...