Are you the same person you were a year ago? Five? Ten? You may say “No, I am not the same person I was back then but I am still me.”
That still leaves us nowhere. What does it mean to be you? If you’ve changed (both bodily and psychologically), then you are not really you. “You” changed. That would mean that I am not John Rodriguez. It would mean I’d be someone else. But that’s stupid, you’re saying. Of course you’re still John Rodriguez, don’t be ridiculous. But if I acknowledge that, then it would mean that I don’t (or haven’t) change(d); that John is the same person over a lifetime despite changing. That’s not possible.
What then makes us the same person while also being a different person over time? Is it the memories we have? I remember high school, moving to Massachuetts, and getting married. I was a different person each of those times, yet I am still the same person. I don’t remember some of childhood. Does that mean that I wasn’t a person then? That because I have no memory that the person I was then never existed? I’ve grown older. I am not the same physically as I was in high school, yet I am still me. Who was I back then if not who I am today? If I say I am the same person then that would mean that there are two of me: one that exists as John and one that exists as John is today.
What constitutes personhood? What makes you you? Why are you still (insert name here) and not someone else if you’ve changed over time?