Editors' note: Last year the Foundational Questions Institute's third essay contest posed the following question to physicists and philosophers: “Is Reality Digital or Analog?” The organizers expected entrants to come down on the side of digital. After all, the word “quantum” in quantum physics connotes “discrete” —hence, “digital”. Many of the best essays held, however, that the world is analog. Among them was the entry by David Tong, who shared the second-place prize. The article here is a version of his essay.