That isn’t really a good analogy. The road is just one thing, with one identity, that happens to split; but in the case of persons, there’s suddenly two people that seem to be the same person. But, for instance, if I’m one of them, there’s only one of them that’s me, and the other isn’t: thus, they’re different. Locke’s theory has no resources to say, I am that person rather than this one, because it has no way to pick one of the two; but there’s clearly a fact of the matter: I am, in fact, that person rather than this one. Hence, there’s a material fact that Locke’s theory fails to capture.
I don’t see a contradiction.
At the exact, precise, infinitesimal of a moment that the two minds wake up they are the same person. They will then, almost guaranteed, start to diverge.
While it seemed to us that we made a copy, the functional difference is that we’ve generated a fork.
A self is a thing. Multiple things are multiple things.
Ok. I’m pretty sure we’re not arguing about the same thing and probably because I don’t know what Locke said. If Locke said, “74westy at 61 years old is identical with 74westy at 21”, then I disagree. If that’s not what he said then I don’t understand what transitivity has to do with it when there are only 2 people involved.
Identical as in ‘the same person’—in the same sense that your 21 year old self is still you, not identical in all of your attributes. If you point at an old photograph and say, ‘that’s me’, then this is the sense of identity you employ—you’re saying that both the person pointing at the photograph and the person being depicted are the same person.
And this is exactly what Locke’s theory fails to account for. On it, after waking up, both are either still the same, both sharing the same psychological continuity with the person before copying, or they’re not—but then, psychological continuity is insufficient.
But that’s not possible when there is duplication? Is that only for consciousness or is it impossible to duplicate any object?
Zeno’s paradox is a paradox of looking at things wrong. It’s a false paradox.
In one way of looking at things, a ball can never arrive at its destination because it must be traveling halves of distances towards the target and there’s an infinite number of halves.
In the other way of looking at things, the ball passed from the source to the destination. Zooming in on subsections of that passage doesn’t influence what actually happened and you’re just overthinking it by conflating zoom levels with movement over time. How you choose to cast your gaze on it is a problem with you, not with reality.
Likewise, if I’m looking at the cartesian graph of a horizontal line that forks and goes in two different directions NE and SE then, if I take an infinitely thin vertical slice I’ll see two distinct dots to the right of the fork and only one dot to the left. Deciding that these must be slices of two separate charts doesn’t make it so. There really is two on the right and there really is one on the left, and those really were part of the same thing.
In Locke’s method, after the divergence, they can both look back and say, “I was that person.” And now they can say, “He’s another person and I’m this other person.”
No, they can’t, that’s the thing—they can both say ‘I am that person’, being psychologically continuous with them, and then saying ‘but I am not that person’ about each other is a contradiction. So, on Locke’s theory, I could say the following about my copy:
- I, sitting over here, am not him, standing over there: we are not psychologically continuous.
- I am the person who went to bed last night and was copied: I am psychologically continuous with that person.
- He is the person who went to bed last night and was copied: he is psychologically continuous with that person.
- He is the person that I am, which is the person that went to bed last night and was copied.
Which is simply a contradiction: the theory affirms that the two copies both are and aren’t the same person.
Consciousness doesn’t really have anything to do with it; claiming that two things are both distinct and one and the same thing simply is contradictory, and that’s what Locke’s theory leads to.
Sounds Like we’re just nitpicking a definition then and not arguing about anything real. For example, philosophers can agree to use any definition of “self” they want but that doesn’t have any bearing on who is entitled to my property or family: me or the guy I’m a copy of.
Well… yes. Locke said, here’s a way to unambiguously tell if two persons are the same person, so then somebody else said, but well, it doesn’t work if there’s duplicates. So the theory just doesn’t work in every case. Of course, that doesn’t have any bearings on whatever doesn’t require a perfectly general theory of personal identity. Which, fortunately, is almost everything.
Thanks. At least I’m beginning to understand what we’ve been talking about. 
You’re ignoring time.
A_{T}=B_{T} does not mean that A_{T+1}=B_{T+1}
Your contention is that Locke’s idea of identity is universal, regardless of time, even though his whole premise is that identity is a moving accretion that starts from a set point (tabula rasa) and migrates around willy-nilly through the space of experiences over time. Time is an inherent component and that means that eternal consistency is not necessary.
No, we’re talking about identity across time, i.e. what makes it so that when you’re saying ‘that’s me’ while pointing at an old photograph of yourself, you’re saying something true (diachronic identity). So Locke’s theory aims at elucidating the sense in which A_{T+1}=A_T and B_{T+1}=B_T, from which with A_T=B_T it indeed follows that A_{T+1}=B_{T+1}.
Consider how a theory of substantial continuity handels the issue. Say you have a wooden cube: when you get it, it’s all shiny and new, but over the years, it has accumulated some wear, scuff marks, maybe the paint has flaked etc. Yet, the material continuity of the cube gives you plausible reason that this is the same cube as the one you got years ago.
Now suppose I construct an extract replica, scuff marks and all, of your cube. I start with a block of wood, cut it to the right size, apply paint and varnish, age it artificially, until the two can’t be told apart to whatever degree of exactness seems satisfactory. Then, still, there is no trouble with the identity question: the original is the one that is materially continuous with the one you got years ago, the copy is the one materially continuous with a slab of wood the other day. No trouble there.
But such a notion of identity is difficult to apply to persons. First of all, most of our material gets replaced overtime, which leads to ‘Ship of Theseus’-type issues. But moreover, there are things materially continuous with a person we wouldn’t call identical to a person, i.e. that person’s corpse, which isn’t a person at all. So we’ll need something else in that case.
A substance dualist, like Descartes, has an easy way out: they can still appeal to substantial continuity in whatever immaterial substance they believe in, souls or mind-stuff or whatever. But this just seems as hoc, and incurs a host of other issues.
So we might want a theory of personal identity across time that doesn’t depend on substantial continuity. Hence, Locke’s view of psychological continuity: this solves the problem of material continuity without personal identity being preserved, and does not need to postulate immaterial souls. But instead, it runs into problems of duplication, and other issues with the transitivity of identity.
I disagree. I’d say it’s something akin to religion; it’s not a practical question that affects your every action, but the actual truth of it is fundamental to your existence.
Consider: if we go with an understanding of personal identity that the only thing that matters is the identical nature of a conscious state, and it turns out that the universe is both eternal and forever active (i.e. after the heat death it cycles back somehow to matter and useful energy) then it entails that I will live forever, because it is just a matter of time before this conscious state is reached again.
Conversely, if we go for the simplest (but also most depressing) view, that there is never continuity of the self, only a human who feels as if there has been continuity. (i.e. the person reading this sentence is a whole new, separate entity from the person who read the first sentence of this post, and just feels like they are one and the same because of having memories of being the other), then that entails not only no afterlife, but that you actually die at every instance.
Finally, while star trek style transporters might forever be impossible, we could, in the far future, attempt to upload consciousness – qualitatively, not perfectly – to some other form like computer memory. Your views on personal identity will dictate whether such a proposition is possible, impossible or practically impossible to actually move your consciousness.
I disagree back atcha. I gave up religion and things akin to it many years ago and I don’t believe the nature of the universe depends on how I define any particular word.
I came into this thread hoping to learn how things actually are but most posters seem to be claiming that, “X is true because it’s what I want to be true” or “Y is true because not-Y seems weird to me”.
By all means carry on but those kinds of arguments don’t interest me.
You can’t avoid holding philosophical positions though, you can merely choose whether to examine them or not.
And unexamined positions tend to be the worst
None of which applies to me.
For example, in terms of the transporter problem, I think there are 3 main positions, all of which are weird, and I think the most unpleasant one (that there is no continuity of existence from moment to moment) is the one best supported by evidence at this time.
Oh, and in terms of “how things actually are”, the simple answer is: “we don’t know”. All we can do, is engage in reasoned speculation based on what we do know. But if you came here looking for clear answers, I don’t have them, and nor does anyone else.
You’re not obliged to post in this thread.
As I say, I’m happy to discuss more everyday issues, but for me, more abstract and philosophical questions are valid too.
Also, as a final point, bear in mind that pretty much all branches of science were once considered philosophy. Philosophy of mind is clearly on that trajectory, it is not an “angels on the head of a pin” topic, it’s something real and important.
What makes each consciousness unique is their unique experiences. If they split, they will almost certainly start to have different experiences at that point, making them into different people. While this might be a problem for legal system (who owns what property, is entitled to be the one to go to the job they hold, etc.) I don’t think it presents any special problems in terms of self identity. For a famous fictional example, there’s Thomas Riker from Star Trek TNG.
There’s obvious problems with how the system will treat them, but none as far as seeing themselves as the literal same person.
There are two things we can mean by “sameness”.
If I have two coins, that appear identical to the atom, then we could say that they are the same, in the sense of having the same properties. In philosophy this is known as being qualitatively identical.
OTOH, if I have a coin in my pocket, and then a magician pulls a coin out from behind my ear, and reveals that it’s the same coin somehow stolen from my pocket, then it is one and the same coin. In philosophy this is known as being numerically identical.
Now, in your example, as soon as two entities’ experiences diverge then of course they are qualitatively different. That’s trivial. The difficulty with personal identity comes with answering questions of numerical identity.
With physical objects, like the coin, it’s all relatively simple (though you still have the Ship of Theseus problem, for example).
With abstract things it becomes more difficult. If copy a binary file and then delete the original, is it one and the same file? Well, we could answer “who cares?” and indeed we don’t. In software, we typically consider “copy, and delete original” to be exactly the same thing as “move”. We don’t need to make any distinction between these things.
In terms of human consciousness though, it matters. My entire viewpoint on the universe is confined to this consciousness. I can’t see through any other eyes than my own. My consciousness feels like it flowed up to this moment, and I presume when my heart beats for the last time, I won’t see anything at all. For my consciousness there is a massive difference between “copy, and delete original” versus “move”; in the former, my entire view of the universe is gone, *I* am gone.
And, right now, we don’t have the philosophical or scientific tools to know whether consciousness can be moved, or split, or duplicated. We don’t have a model of consciousness.