Soon after the release of the first iPhone five years ago, an astonishing new ritual began to be performed in cafes and restaurants across the country. It centered on an app called Shazam. When the phone was held up to a radio, Shazam would almost instantly identify whatever song happened to be on, causing any iPhone skeptics in the vicinity to gulp in bewilderment and awe.

There was something unspeakably impressive about a machine that could listen to a snippet of a random hit from 1981, pick out its melody and beat, and somehow cross-reference them against a database that seemed to contain the totality of all recorded music. Seeing it happen for the first time was revelatory. By translating a song into a string of numbers, and identifying what made it different from every other song ever written, Shazam forced us to confront the fact that a computer could hear and process music in a way that we humans simply can’t.