Mental illness often expresses itself in terms of the era in which it’s experienced, whether it’s the time of Napoleon’s belated funeral procession or one of a parade of cameras. We live in the latter, and it’s not only the deeply ill who feel paranoid, and for good reason. We are being monitored and measured, corporations wanting what’s in our heads, and with the Internet of Things, the ubiquity of surveillance will reach full saturation, seeming coincidences that are anything but will multiply.

Walter Kirn has written an excellent Atlantic piece about this sense of Digital Age disquiet. His opening:

I knew we’d bought walnuts at the store that week, and I wanted to add some to my oatmeal. I called to my wife and asked her where she’d put them. She was washing her face in the bathroom, running the faucet, and must not have heard me—she didn’t answer. I found the bag of nuts without her help and stirred a handful into my bowl. My phone was charging on the counter. Bored, I picked it up to check the app that wirelessly grabs data from the fitness band I’d started wearing a month earlier. I saw that I’d slept for almost eight hours the night before but had gotten a mere two hours of “deep sleep.” I saw that I’d reached exactly 30 percent of my day’s goal of 13,000 steps. And then I noticed a message in a small window reserved for miscellaneous health tips. “Walnuts,” it read. It told me to eat more walnuts.

It was probably a coincidence, a fluke. Still, it caused me to glance down at my wristband and then at my phone, a brand-new model with many unknown, untested capabilities. Had my phone picked up my words through its mic and somehow relayed them to my wristband, which then signaled the app?

The devices spoke to each other behind my back—I’d known they would when I “paired” them—but suddenly I was wary of their relationship. Who else did they talk to, and about what? And what happened to their conversations? Were they temporarily archived, promptly scrubbed, or forever incorporated into the “cloud,” that ghostly entity with the too-disarming name?

It was the winter of 2013, and these “walnut moments” had been multiplying…•