One issue is how you decide whether a given person exists in a given history or not. For example, if I had been born with a different hair color, would I be the same person? Maybe. How about a different personality? At what point do “I” stop existing and someone else starts existing? I guess similar issues bedevil the question of whether a person stays the same person over time, though there we can also use spatiotemporal continuity to help maintain personal identity.
Here are some interesting examples I thought of. If I rearranged someone’s brain cells (and maybe atoms) to basically make a (possibly) completely different brain structure with (possibly) completely different memories and personality, should we consider these different individuals? Consider the following cases:
1. What if all brain function stops, I rearrange their brain, and then brain function starts again?
2. What if all brain function stops, I rearrange their brain to have the same structure (and memories and personality), but with each atom/cell in a completely different area from where it started, and then brain function starts again?
3. What if all brain function stops, the cells and atoms move or change as they naturally would without my intervention, and then brain function starts again?
To me, 1 clearly brings about a completely different individual, and unless we’re willing to say that two physically separate people with the same brain structure, memories and personality are actually one individual, I think 2 should also bring about a completely different individual. 3 only really differs from 1 and 2 only by degree of change, so I think it should also bring about a completely different individual, too.
What this tells me is that if we’re going to use some kind of continuity to track identity at all, it should also include continuity of conscious experiences. Then we have to ask:
Are there frequent (e.g. daily) discontinuities or breaks in a person’s conscious experiences?
Whether there are or not, should our theory of identity even depend on this fact? If it happened to be the case that sleep involved such discontinuities/breaks and people woke up as completely different individuals, would our theory of identity be satisfactory?
Maybe a way around this is to claim that there are continuous degrees of identification between a person at different moments in their life, e.g. me now and me in a week are only 99% the same individual. I’m not sure how we could do ethical calculus with this, though.
Thought experiments like these are why I regard personal identity, and any moral theories that depend on it, as non-starters (including versions of prioritarianism that consider lifetime wellbeing collectively). I think it’s best to think either in terms of empty individualism or open individualism. Empty individualism tends to favor suffering-focused views because any given moment of unbearable suffering can’t be compensated by other moments of pleasure even within what we normally call the same individual, because the pleasure is actually experienced by a different individual. Open individualism tends to undercut suffering-focused intuitions by saying that torturing one person for the happiness of a billion others is no different than one person experiencing pain for later pleasure.
As others have pointed out before, it is legitimate to try to salvage some ethical concern for personal identity despite the paradoxes. By analogy, the idea of consciousness has many paradoxes, but I still try to salvage it for my ethical reasoning. Neither personal identity nor consciousness “actually exists” in any deep ontological sense, but we can still care about them. It’s just that I happen not to care ethically about personal identity.
Here are some interesting examples I thought of. If I rearranged someone’s brain cells (and maybe atoms) to basically make a (possibly) completely different brain structure with (possibly) completely different memories and personality, should we consider these different individuals? Consider the following cases:
1. What if all brain function stops, I rearrange their brain, and then brain function starts again?
2. What if all brain function stops, I rearrange their brain to have the same structure (and memories and personality), but with each atom/cell in a completely different area from where it started, and then brain function starts again?
3. What if all brain function stops, the cells and atoms move or change as they naturally would without my intervention, and then brain function starts again?
To me, 1 clearly brings about a completely different individual, and unless we’re willing to say that two physically separate people with the same brain structure, memories and personality are actually one individual, I think 2 should also bring about a completely different individual. 3 only really differs from 1 and 2 only by degree of change, so I think it should also bring about a completely different individual, too.
What this tells me is that if we’re going to use some kind of continuity to track identity at all, it should also include continuity of conscious experiences. Then we have to ask:
Are there frequent (e.g. daily) discontinuities or breaks in a person’s conscious experiences?
Whether there are or not, should our theory of identity even depend on this fact? If it happened to be the case that sleep involved such discontinuities/breaks and people woke up as completely different individuals, would our theory of identity be satisfactory?
Maybe a way around this is to claim that there are continuous degrees of identification between a person at different moments in their life, e.g. me now and me in a week are only 99% the same individual. I’m not sure how we could do ethical calculus with this, though.
Thought experiments like these are why I regard personal identity, and any moral theories that depend on it, as non-starters (including versions of prioritarianism that consider lifetime wellbeing collectively). I think it’s best to think either in terms of empty individualism or open individualism. Empty individualism tends to favor suffering-focused views because any given moment of unbearable suffering can’t be compensated by other moments of pleasure even within what we normally call the same individual, because the pleasure is actually experienced by a different individual. Open individualism tends to undercut suffering-focused intuitions by saying that torturing one person for the happiness of a billion others is no different than one person experiencing pain for later pleasure.
As others have pointed out before, it is legitimate to try to salvage some ethical concern for personal identity despite the paradoxes. By analogy, the idea of consciousness has many paradoxes, but I still try to salvage it for my ethical reasoning. Neither personal identity nor consciousness “actually exists” in any deep ontological sense, but we can still care about them. It’s just that I happen not to care ethically about personal identity.