I recently described the contradictions inherent in my fitness-tracking watch. On the one hand, it had unlocked the joy of running for me, encouraging me to run further and faster and set goals I’d never dreamt of achieving. On the other, the watch could also push me into counter-productive behaviour, such as running through injury — and had a tendency to turn a pleasant run into a quantified grind.

What an eye-opening delight, then, to pick up C Thi Nguyen’s book The Score. Nguyen is a philosopher and, more importantly, an enthusiast for all sorts of playful activity from rock-climbing to yo-yo tricks to role-playing games. He argues that the contradiction I found in my fitness watch is part of a much bigger story about the way we have allowed quantified metrics to seep into so many parts of life.

The tyranny of targets is familiar stuff to social scientists, even if it seems to be a source of endless unpleasant surprises for policymakers and corporate executives. Charles Goodhart, an economist, and Donald Campbell, a psychologist, each famously explained that perfectly decent quantitative metrics become corrupted once they’re pressed into service as targets.