My sister-in-law, who lives in Manhattan’s East Village, recently e-mailed me about the moment the power, out for nearly a week, suddenly returned. With the neighborhood in darkness, the computer and TV screens all black, life had seemed to stop. “And then without warning or fanfare, the screen jolted back on like nothing had happened, and it all was a giant black dream.”

It’s a perfect image of a binary world, on what happens to be our most binary day. Today, we step behind a curtain and choose: him or her, him or him, yes or no. That privilege has obvious limits. When my daughter’s third-grade Brownie troop met last weekend, we talked about the importance of voting, and a few girls asked, “What if you don’t like anybody on the ballot?”