Not long ago, as happens almost every day, I got a Skype call on my smartphone from my dad, who lives in Kolkata, India. My dad is 79 and doesn’t get out very much, having become increasingly housebound. On this day, I was traveling by train from Denmark to Sweden. Speaking to him, I held my phone up against the window, its camera lens facing out. We both took in the view of the Swedish countryside as the train pulled out from Malmo and sped toward Lund. For a brief while, it felt like we were traveling together.

For that moment of connection, and many others like it, my phone deserves my gratitude. But the same device has become a source