In my book Data and Goliath, I write about the value of privacy. I talk about how it is essential for political liberty and justice, and for commercial fairness and equality. I talk about how it increases personal freedom and individual autonomy, and how the lack of it makes us all less secure. But this is probably the most important argument as to why society as a whole must protect privacy: it allows society to progress. We know that surveillance has a chilling effect on freedom.