An addict promises everyone, with all his heart: “I’ll never use again.” Eventually his words become meaningless. But the need to be believed doesn’t go away. Every time he makes his promise, he means it. He is sincere. If no one will believe him, why make the promise at all? “Not that you lied to me, but that I can no longer believe you, has shaken me,” Nietzsche remarked. Fair enough. But that you can no longer trust me makes us both pretty shaky.

For a recovering alcoholic like me, the biggest obstacle to the successful co-parenting of your children with your ex—after successfully staying sober—is winning back the trust eroded by your addiction. So when my ex-wife finally stopped trusting that I wouldn’t drink around my children, I turned to infallible, impersonal technology.