“stubborn as our identity is, the concept of a single person extending from birth to death was always just a useful approximation. The person you are right now is not exactly the same as the person you were a year ago, or even a second ago. Your atoms are in slightly different locations, and some of your atoms might have been exchanged for new ones. (If you’re eating while reading, you might have more atoms now than you had a moment ago.) If we wanted to be more precise than usual, rather than talking about “you,” we should talk about “you at 5:00 p.m.,” “you at 5:01 p.m.,” and so on.”