And so we polish our own lives, creating landscapes and canyons and peaks with the very silt we try to avoid, the dirt we disavow or hide or deny. It is the dirt of our lives—the depressions, the losses, the inequities, the failing grades in trigonometry, the e-mails sent in fear or hate or haste, the ways in which we encounter people different from us—that shape us, polish us to a heady sheen, make us in fact more beautiful, more elemental, more artful and lasting.