"Our neighbors love him because he'll come up to them and just start talking to them," Beverly says. Even though he thinks he's meeting them for the first time, he's learned through habit that these are people he should feel comfortable around, and he interprets those unconscious feelings of comfort as a good reason to stop and say hello.

We cross the street and I'm alone with EP for the first time. He doesn't know who I am or what I'm doing at his side, although he seems to sense that I'm there for some good reason. He is trapped in the ultimate existential nightmare, blind to the reality in which he lives. The impulse strikes me to help him escape, at least for a second. I want to take him by the arm and shake him. "You have a rare and debilitating memory disorder," I want to tell him. "The last 50 years have been lost to you. In less than a minute, you're going to forget that this conversation ever even happened." I imagine the sheer horror that would befall him, the momentary clarity, the gaping emptiness that would open up in front of him, and close just as quickly. And then the passing car or the singing bird that would snap him back into his oblivious bubble.

We turn around and walk back down the street whose name he's forgotten, past the waving neighbors he doesn't recognize, to a home he doesn't know. In front of the house, there is a car parked with tinted windows. We turn to look at our reflections. I ask EP what he sees.

"An old man," he says. "That's all."