As we now know, Americans have profoundly different ideas about what is real, ideas that sometimes verge on the irreconcilable. These notions depend on walls of the mind: stubborn boundaries that work to enforce particular points of view, as if each of us was stranded on some other island of idiosyncratic thought. Such divides may seem fleeting and intangible, but they are just as hard as any wall made of brick or concrete. Drawing on lessons from a recently published book—Something Between Us: The Everyday Walls of American Life, and How to Take Them Down—this talk will explore barriers that run through the experience of collective life in the United States, and what it takes instead to open our minds to the lives of others.