I endorse dthomas’ answer in the grandparent; we were talking about uploads.
I have no idea what to do with word “provably” here. It’s not clear to me that I’m provably me right now, or that I’ll be provably me when I wake up tomorrow morning. I don’t know how I would go about proving that I was me, as opposed to being someone else who used my body and acted just like me. I’m not sure the question even makes any sense.
To say that other people’s judgments on the matter define the issue is clearly insufficient. If you put X in a dark cave with no observers for a year, then if X is me then I’ve experienced a year of isolation and if X isn’t me then I haven’t experienced it and if X isn’t anyone then no one has experienced it. The difference between those scenarios does not depend on external observers; if you put me in a dark cave for a year with no observers, I have spent a year in a dark cave.
Mostly, I think that identity is a conceptual node that we attach to certain kinds of complex systems, because our brains are wired that way, but we can in principle decompose identity to component parts—shared memory, continuity of experience, various sorts of physical similarity, etc. -- without anything left over. If a system has all those component parts—it remembers what I remember, it remembers being me, it looks and acts like me, etc. -- then our brains will attach that conceptual node to that system, and we’ll agree that that system is me, and that’s all there is to say about that.
And if a system shares some but not all of those component parts, we may not agree whether that system is me, or we may not be sure if that system is me, or we may decide that it’s mostly me.
Personal identity is similar in this sense to national identity. We all agree that a child born to Spaniards and raised in Spain is Spanish, but is the child of a Spaniard and an Italian who was born in Barcelona and raised in Venice Spanish, or Italian, or neither, or both? There’s no way to study the child to answer that question, because the child’s national identity was never an attribute of the child in the first place.
I endorse dthomas’ answer in the grandparent; we were talking about uploads.
I have no idea what to do with word “provably” here. It’s not clear to me that I’m provably me right now, or that I’ll be provably me when I wake up tomorrow morning. I don’t know how I would go about proving that I was me, as opposed to being someone else who used my body and acted just like me. I’m not sure the question even makes any sense.
To say that other people’s judgments on the matter define the issue is clearly insufficient. If you put X in a dark cave with no observers for a year, then if X is me then I’ve experienced a year of isolation and if X isn’t me then I haven’t experienced it and if X isn’t anyone then no one has experienced it. The difference between those scenarios does not depend on external observers; if you put me in a dark cave for a year with no observers, I have spent a year in a dark cave.
Mostly, I think that identity is a conceptual node that we attach to certain kinds of complex systems, because our brains are wired that way, but we can in principle decompose identity to component parts—shared memory, continuity of experience, various sorts of physical similarity, etc. -- without anything left over. If a system has all those component parts—it remembers what I remember, it remembers being me, it looks and acts like me, etc. -- then our brains will attach that conceptual node to that system, and we’ll agree that that system is me, and that’s all there is to say about that.
And if a system shares some but not all of those component parts, we may not agree whether that system is me, or we may not be sure if that system is me, or we may decide that it’s mostly me.
Personal identity is similar in this sense to national identity. We all agree that a child born to Spaniards and raised in Spain is Spanish, but is the child of a Spaniard and an Italian who was born in Barcelona and raised in Venice Spanish, or Italian, or neither, or both? There’s no way to study the child to answer that question, because the child’s national identity was never an attribute of the child in the first place.