Insights from big data can cure diseases, control epidemics, end congestion in our cities and aid the just distribution of natural resources. If withholding access to personal data undermines these social goods, does that make privacy selfish? Zeynep Tufekci and Seth Stephens-Davidowitz hash it out at the Festival of Dangerous Ideas 2018 on Cockatoo Island. The panel is chaired by Marc Fennell.