None of this is easy. For too many of us, it’s become safer to retreat into our own bubbles, whether in our neighborhoods or college campuses or places of worship or our social media feeds, surrounded by people who look like us and share the same political outlook and never challenge our assumptions. The rise of naked partisanship, increasing economic and regional stratification, the splintering of our media into a channel for every taste – all this makes this great sorting seem natural, even inevitable. And increasingly, we become so secure in our bubbles that we accept only information, whether true or not, that fits our opinions, instead of basing our opinions on the evidence that’s out there.

­　　This trend represents a third threat to our democracy. Politics is a battle of ideas; in the course of a healthy debate, we’ll prioritize different goals, and the different means of reaching them. But without some common baseline of facts; without a willingness to admit new information, and concede that your opponent is making a fair point, and that science and reason matter, we’ll keep talking past each other, making common ground and compromise impossible.

­　　Isn’t that part of what makes politics so dispiriting? How can elected officials rage about deficits when we propose to spend money on preschool for kids, but not when we’re cutting taxes for corporations? How do we excuse ethical lapses in our own party, but pounce when the other party does the same thing? It’s not just dishonest, this selective sorting of the facts; it’s self-defeating. Because as my mother used to tell me, reality has a way of catching up with you.

­　　Take the challenge of climate change. In just eight years, we’ve halved our dependence on foreign oil, doubled our renewable energy, and led the world to an agreement that has the promise to save this planet. But without bolder action, our children won’t have time to debate the existence of climate change; they’ll be busy dealing with its effects: environmental disasters, economic disruptions, and waves of climate refugees seeking sanctuary.