ok, i’ve just got through reading a number of philosophy type books to do with the concept of personal identity. As such I’ve been reading a lot about John Lockes theories on the subject. It has been raised that the flaw to John Lockes ideas is the problm of duplication, the idea that if you could transfer the brain patterns of one to another then you could surely crete multiple copies of that identity.
My question is hopefully simple, I havent been able to find a source that bothers to explain why this is supposed to be a problem, why is it that duplication is supposed to discredit John Lockes ideas?
But I’m not sure how we missed this thread the first time around; this is a clear case of Great Debates. Let me move this over there, and maybe it’ll get more interest.
I linked to the first post which broached the subtopic in question (which yes qualified as topic drift), and said discussion went on for more than 100 posts.
Wouldn’t it be nice if someone were to identify exactly what in the hell the OP was talking about, for those of us who have not recently been reading a lot about John Locke’s theories?
I think Locke essentially held personal identity to be founded upon the continuity of consciousness, as shaped by experience and memory—we all start with an ‘empty’ mind (the ‘tabula rasa’-view), which is then given a particular shape through, e.g., sensations, thoughts, and the like. This is in reaction to the Cartesian view that situates identity within an immaterial soul.
It seems that duplication is a problem for such a theory in that it then fails to give a specific answer to the question ‘who am I?’: both the original and the duplicate could lay claim to the same continuity of consciousness, if say one person goes to sleep, is copied, and then both are woken up.
If fails when someone has been duplicated. That is an obvious problem with duplication. I don’t know much about Locke, but I assume if duplicators were available when he formed his idea then he would have expressed the exception to the rule. And it is easy to point out that each duplicate begins a new divergent continuity of consciousness that uniquely identifies them from that point forward.
But then, identity is usually assumed to be transitive: if A is identical to B, and B is identical to C, then A is identical to C. But with duplication, you’d have a point of split that’s common to both psychological continuities, with which each would be identical, but a point to the past of the splitting, with which neither would be. Say A is a person at their twelfth birthday, and B is the immediate point of split: those would be the same person, linked by an unbroken thread of psychological continuity. Then, C1 is one duplicate, at some further point down the line, and C2 the other. Both would be identical with B, and hence, one should think, with A; but then, how could each begin a new, divergent continuity of consciousness? It seems odd to say, just because I’ve been copied (which I might not even have noticed), I’m no longer identical to some past me. But if I still am, then I also ought to be identical to the copy, which seems nonsensical.
Because it would be odd to say that I am identical to my copy, when we’re clearly two distinct things. If C1 is identical to B, and B is identical to C2, then C1 would be identical to C2—but I’m clearly not my copy. Hence, the theory doesn’t handle such a case.
Sorry, still not seeing it. Are you saying that you’re still identical at a point in time after the copy? Haven’t you had different experiences since the copy? I’m no philosopher but to me, you’re only identical at the moment the copy occurs.
If more than one copy is made simultaneously then the copies are identical in that moment. I get that you find it “odd” but is it logically inconsistent or something like that?
Is handling a case in a way you consider “odd” the same thing as not handling the case?
There was just one person up to the point of duplication. After duplication they are two distinct people with new life experiences and shouldn’t expect to be the same as their duplicate. Both are still the same person that they were in their perceived past. It is odd that two people share an identity for part of their life, but that’s exactly what’s expected when duplication occurs, but each of them still has a unique continuity of consciousness throughout their lives.
The duplication method could make a difference in how the duplicates feel about it. If it the process produces an original and a copy, the copy could know they didn’t materially exist prior to duplication, unlike the original. If the process destroys the original and produces two copies then neither materially existed before duplication, but their perceived prior existence is the same.
I’m not John Locke, so I can’t really answer for him, but if he’s starting with a tabula rasa and everything past that is an accumulation of experiences then the answer would seem to be that the two people are:
The accumulation prior to now + the continued accumulation from the point of waking up in body A
The accumulation prior to now + the continued accumulation from the point of waking up in body B
The two identities will be, effectively, the same identity at the moment of waking up in separate bodies but they would start to diverge from there and, potentially, could continue to accumulate experiences, ideas, and beliefs that are wildly independent as time goes on.
Likewise, if you had two universes that were identical up until moment X, then our person in universe Alpha and our person in universe Beta would both be (effectively) the same individual up until moment X for they have no idea nor experience that differentiates them. But after X, when the universes start to produce different experiences, the two persons will start to have a different lives, with different encounters, different thoughts, etc. They become two different individuals.
Identical in the sense of personal identity—in the same way I’m still the same person I was when I was a child.
Well, it depends on what you want ‘identity’ to mean. There’s two traditional senses in philosophy—numerical and qualitative identity. If two things have the same qualities, they’re qualitatively identical; if they’re numerically identical, they’re one and the same thing. But in the copy example, you have two things that are qualitatively distinct (having had different experiences from the point of copying), but which the theory of psychological continuity would still hold to be identical, as in, the same person. That might not be something we want a theory of personal identity to permit.
Sure, but on Locke’s account, it’s hard to see how that would work. Both the copy and the original are identical (the same person as) the person before the copying, so one would expect them to be identical, by transitivity. But they’re numerically distinct—there’s that one and this one. Should a theory of personal identity permit such a situation?
Otherwise, the copying process ‘breaks’ continuity in some sense, such that neither the copy nor the original is the same person as the pre-copy person. But such a copy could be made without either original or copy ever learning about it. So how could it be that, despite the psychological continuity with the pre-copy person, neither actually is identical with it? If that’s possible, then what is it that ensures that I’m the same person as I was yesterday? Clearly, in this case, psychological continuity would be necessary, but not sufficient—but then, what is sufficient? Psychological continuity plus nobody ever made a copy of you? That seems a strange criterion.
That still runs into the transitivity problem. If each is the same person as the person before the split, then if A = B and B = C implies A = C, they’re still the same person. If both copies are different from the person before the split, then psychological continuity is not sufficient for personal identity.
Yeah, the problem is that’s not what John Locke said, though. He said that consciousness alone, not the substance of your body, is what makes self. If you have a consciousness stretching back over time to the beginning of an individual being, that is what defines your identity.
If there are two people who fit that description, they’re both the same person.
Raise the same baby in two different countries. The person will end up speaking different languages, meet a different partner, learn a different trade, etc. Same body, different countries, different personalities/ideas/beliefs.
I’m not saying that the country makes the person any more than I said that the body makes the person.