I was in the woods when my phone fell out of my pocket. Scooping it back up from the bluebells, I noticed that the time was 20:58 and the remaining battery was one per cent. At that moment, a blackcap began to sing. As the little bird filled the grove with its flute-like song, I watched the numbers dissolve from the screen. The battery had died. A mild panic gripped me. But why? I didn’t need to know the time. I could see for myself that the sun would soon be setting. What more did I need to know?