And that's not easy to do. For too many of us, it's become safer to retreat into our own bubbles, whether in our neighborhoods or on college campuses or places of worship or especially our social media feeds, surrounded by people who look like us and share the same political outlook and never challenge our assumptions. And the rise of naked partisanship and 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 start accepting only information, whether it's true or not, that fits our opinions, instead of basing our opinions on the evidence that is out there.