It took centuries for the public sphere to develop—and the technology companies have eviscerated it in a flash. By radically remaking the advertising business and commandeering news distribution, Google and Facebook have damaged the economics of journalism. Amazon has thrashed the bookselling business in the U.S. They have shredded old ideas about intellectual property—which had provided the economic and philosophical basis for authorship. The old, enfeebled institutions of the public sphere have grown dependent on the big technology companies for financial survival. And with this dependence, the values of big tech have become the values of the public sphere.