Measuring the Unobservable – Prof Hasok Chang | HAPP Conference 2025

This talk was recorded at the HAPP Centre’s one-day conference, “The History of Measurement,” held the Mathematical Institute, University of Oxford, on Saturday 7 June 2025. The conference explored the evolution of measurement from ancient methods and early instruments to modern standardisation, scientific accuracy, and philosophical reflection. Hosted by St Cross College, the event brought together historians, scientists, and philosophers to reflect on how we measure the world—and why it matters. Professor Hasok Chang (University of Cambridge) investigates how science has made the invisible visible—through ingenious approaches to measuring what we cannot directly observe. From atoms to temperatures, he highlights the conceptual power of indirect measurement. 🔗 Learn more about the HAPP Centre: https://www.stx.ox.ac.uk/happ-centre 🔗 Explore St Cross College: https://www.stx.ox.ac.uk