“Using such a mind-to-mind metric, I would be very “close” to the person I was yesterday, slightly less close to the person I was two days ago, and so forth. In other words, although there is a great degree of overlap between the individuals Douglas Hofstadter today and Douglas Hofstadter yesterday, they are not identical. We nonetheless standardly (and reflexively) choose to consider them identical because it is so convenient, so natural, and so easy. It makes life much simpler. This convention allows us to give things (both animate and inanimate) fixed names and to talk about them from one day to the next without constantly having to update our lexicon. Moreover, this convention is ingrained in us when we are infants — at about the same Piagetian developmental stage as that in which we learn that when a ball rolls behind a box, it still exists even though it’s not visible, and may even reappear on the other side of the box in a second or two!”