“Even at his ripe age — he is now 87 — Habermas’s passion remains undiminished. As a public intellectual, however, he may seem an unlikely hero. We live in an age when what some of us still fondly call ‘the public sphere’ has grown thick with personalities who prefer the TED Talk to the printed word and the tweet to the rigors of rational argument. For Habermas, it’s clear that without the constant exercise of public deliberation, democracy will collapse, and this means that citizens must be ready to submit their arguments to the acid bath of rational criticism.”