I try to view problems as opportunities. If it's raining outside, that's training in the rain. Snowing? Awesome, snow running! Too hot? High-temperature training. Too cold? Low-temperature training. I'm too tired? Fatigue training. I also try to look at things from what I call a "mediative" point of view. So let's say I'm out running my regular route but it's cold, windy, raining, etc, and I feel miserable. I try to remember how I felt running the same route on a beautiful day and bring my mind back to that state. Or if I'm fatigued, I try to remember a day when what I was doing felt easy and set myself the challenge of trying to regain that mindset. Again, it's about turning problems into opportunities: fatigue is an opportunity for fatigue-mastery. It helps to take an interest in the mental element of training, sports, etc, so you can think of mastering mental adversity as part of your training.

All true, but it just strengthens the case for what you call "stipulating a new meaning for the words 'survival', 'death', etc". Or perhaps, making up new words to replace those. Contemplating cases like these makes me realize that I have stopped caring about 'death' in its old exact meaning. In some scenarios "this will kill you" becomes a mere technicality.

I agree that uploading is copying-then-death. I think you're basically correct with your thought experiment, but your worries about vagueness are unfounded. The appropriate question is what counts as death? Consider the following two scenarios: 1. A copy of you is stored on a supercomputer and you're then obliterated in a furnace. 2. A procedure is being performed on your brain, you're awake the entire time, and you remain coherent throughout. In scenario 1 we have a paradigmatic example of death: obliteration in a furnace. In scenario 2 we have a paradigmatic example of surviving an operation without harm. I would say that, if the procedure in 2 involves replacing all or part of your brain, whether it is performed swiftly or slowly is unimportant. Moreover, even if you lost consciousness, it would not be death; people can lose consciousness without any harm coming to them.

Note that you can adjust the first scenario - say, by insisting that the copy is made at the instant of death or that the copying process is destructive as it transpires, or whatever - but the scenario still could go as described. That is, we are supposed to believe that the copy is a continuation of the person despite the possibility of inserting paradigmatic examples of death into the process. This is a clear case of simply stipulating that 'death' (and 'survival') should mean something entirely different. You can't hold that you're still speaking about survival, when you insist on surviving any number of paradigmatic cases of death (such as being obliterated in a furnace). There are no forms of death - as we ordinarily conceive of death - that cannot be inserted into the uploading scenario. So we have here as clear a case of something that cannot count as survival as is possible to have. Anybody who argues otherwise is not arguing for survival, but stipulating a new meaning for the words 'survival', 'death', etc. That's fine, but they're still dead, they're just not 'dead'.

I think this realisation makes understanding something like the brain transplant you describe a little easier. For we can say that we are living so long as we don't undergo anything that would count as dying (which is just to say that we don't die). There's nothing mysterious about this. We don't need to go looking for the one part of the body that maintains our identity under transformation, or start reifying information into a pseudo-soul, or whatever. We just need to ensure whatever we do doesn't count as death (as ordinarily conceived). Now, in the case of undergoing an operation, there are clear guidelines. We need to maintain viability. I cannot do certain things to you and keep you alive, unless I perform certain interventions. So I think the answer is quite simple: I can do anything to you - make any change - as long as I can keep you alive throughout the process. I can replace your whole brain, as long as you remain viable throughout the process, and you'll still be alive at the end of it. You will, of course, be 'brain dead' unless I maintain certain features of your nervous system too. But this isn't mysterious either; it's just that I need to maintain certain structural features of your nervous system to avoid permanent loss of faculties (such as motor control, memory, etc). Replacement with an artificial nervous system is likewise unproblematic, as long as it maintains these important faculties.

A lot of the confusion here comes from unnecessary reification. For example, that the nervous system must be kept structurally intact to maintain certain faculties, does not mean that it somehow 'contains' those faculties. You can replace it at will, so long as you can keep the patient alive. The person is not 'in' the structure (or the material), but the structure is a prerequisite for maintaining certain faculties. The common mistake here is thinking that we must be the structure (or pattern) if we're not the material, but neither claim makes sense. Alternatively, say you have a major part of your brain replaced, and the match is not exact. Somebody might, for example, point out that your personality has changed. Horrified, you might wonder, "Am I still me?" But this question is clearly absurd. There is no sense in which you could ask if you are still you. Nor can you coherently ask, "Did I die on the operating table?" Now, you might ask whether you merely came into existence on the operating table, after the original died, etc. But this, too, is nonsense. It assumes a reified concept of "self" or "identity." There is nothing you can "lose" that would count as a prior version of you 'dying' and your being born anew (whether slightly different or not). Of course, there are such things as irreversible mental degradation, dementia, etc. These are tragic and we rightfully speak of a loss of identity, but there'd be no such tragedy in a bout of dementia. A temporary loss of identity is not a loss of identity followed by gaining a new identity; it's a behavioural aberration. A temporary loss of identity with a change in temperament when one recovers is, likewise, unproblematic in this sense; we undergo changes in temperament regardless. Of course, extreme change can bring with it questions of loss of identity, but this is no more problematic for our scenario than an operation gone wrong. "He never fully recovered from his operation," we might say. Sad, yes, but this type of thing happens even outside of thought experiments.

Move something eye-catching into an odd place where you'll see it shortly after waking up in the morning. Whenever you see it say to yourself, "I put that there."

If you'd deferred to the leading authorities over the past 100 years, you would have been an introspectionist, then a behaviourist, then a cognitive scientist and now you'd probably be a cognitive neuroscientist.

I think you are right, but is it so bad? If I were living at the time of the introspectionists, was there a better alternative for me? I suspect that unless I personally worked out some other theory (unlikely), I'd have to either take that one or something equally bad. Maybe it's slightly different around boundaries of these paradigm shifts where I could possibly adopt the new ideas before the mainstream did, but most of the time it wouldn't happen. I am far from being confident that I'd do a better job personally then the general consensus, even if that tends to be very conservative.

Look at something like psychology. If you'd deferred to the leading authorities over the past 100 years, you would have been an introspectionist, then a behaviourist, then a cognitive scientist and now you'd probably be a cognitive neuroscientist. Note that these paradigms primarily differ on what they think counts as evidence, rather than quality or quantity of evidence. They all performed experiments. They share many of the same experimental methods. They all had numerous results they could point to and a neat story about how the same method could be carried on to explain everything else.

Unfortunately, the authorities get divided up into schools of thought before even they have examined all the alternatives. Typically the mainstream school has a way of dismissing alternatives without examining them. A school can become mainstream for all sorts of reasons (it provides ideological support, it's sexier, there's a lack of alternatives, mere persistence, it has charismatic advocates, etc). So I think you have to be very careful who you take to be an authority on a given subject. Assessing authorities probably isn't much easier than assessing the subject directly.

If the duplicate says "I did X on my nth birthday" it's not true since it didn't even exist.

Correct.

So what does the duplicate say when I point out that it didn't exist at that time?

When talking to you, or someone who shares your attitude, my duplicate probably says something like "You're right, of course. I'm in the habit of talking about my original's experiences as though they're mine, because I experience them as though they were, and both I and my original are perfectly happy talking that way and will probably keep doing so. But technically speaking you're quite correct... I didn't actually do X on my 9th birthday, nor did I have a 9th birthday to do anything on in the first place. Thanks for pointing that out."

Which is closest to your last option, I suppose.

Incidentally, my duplicate likely does this in roughly the same tone of voice that an adoptive child might say analogous things when someone corrects their reference to "my parents" by claiming that no, their parents didn't do any of that, their adoptive parents did. If you were to infer a certain hostility from that tone, you would not be incorrect.

It gets very difficult to call this "memory."

It's not difficult for me to call this a memory at all... it's the original's memory, which has been copied to and is being experienced by the duplicate. But if you'd rather come up with some special word for that to avoid confusion with a memory experienced by the same body that formed it in the first place, that's OK with me too. (I choose not to refer to it as "knowledge of what the original did", both because that's unwieldy and because it ignores the experiential nature of memory,, which I value.)

but then in what sense is it a duplicate?

Sufficient similarity to the original. Which is what we typically mean when we say that X is a duplicate of Y.

There's no delusion or deception involved in any of the examples I gave.

In each example the duplicate knows it's the duplicate, the original knows it's the original; at no time does the duplicate believe it's the original. The original knows it's going to die. The duplicate does not believe that its memories reflect events that occurred to its body; it knows perfectly well that those events occurred to a different body.

Everyone in each of those examples knows everything relevant.

From your point of view, you don't care about your survival, as long as somebody is deluded into thinking they're you.

No, this isn't true. There are lots of scenarios in which I would greatly prefer my survival to someone being deluded into thinking that they're me after my death. And, as I said above, the scenarios I describe don't involve anyone being deluded about anything; the duplicate knows perfectly well that it's the duplicate and not the original.

I don't think the question of whether you're the same person when you wake up as when you went to sleep [..] is meaningful.

I'm content to say that, though I'd also be content to say that sufficient loss of faculties (e.g., due to a stroke while I slept) can destroy my identity, making me no longer the same person. Ultimately I consider this a question about words, not about things.

Do [your faculties] change without there being any physical change?

Well, physical change is constant in living systems, so the whole notion of "without physical change" is somewhat bewildering. But I'm not assuming the absence of any particular physical change.

I can make them as similar as I like and they will never become the same! And so it goes with people.

Sure, that's fine. I don't insist otherwise.

I just don't think the condition you refer to as "being the same person" is a condition that matters. I simply don't care whether they're the same person or not, as long as various other conditions obtain. Same-person-ness provides no differential value on its own, over and above the sum of the value of the various attributes that it implies. I don't see any reason to concern myself with it, and I think the degree to which you concern yourself with it here is unjustified, and the idea that there's some objective sense in which its valuable is just goofy.

So while your doppelgänger might have the same faculties as you, it doesn't make him the same human being as you, and, unlike you, he wasn't the person who did X on your nth birthday, etc, and no amount of tinkering will ever make it so.

Again: so what? Why should I care? I don't claim that your understanding of sameness is false, nor do I claim it's meaningless, I just claim it's valueless. OK, he's not the same person. So what? What makes sameness important?

To turn it around: suppose I am informed right now that I'm not the same person who did X on Dave's 9th birthday, that person died in 2012 and I'm a duplicate with all the same memories, personality, etc. I didn't actually marry my husband, I didn't actuallybuy my house, I'm not actually my dog's owner, I wasn't actually hired to do my job.

This is certainly startling, and I'd greet such a claim with skepticism, but ultimately: why in the world should I care? What difference does it make?

Perhaps that is the scenario you prefer, but, you're quite right, I find it very odd.

Prefer to what?

So, as above, I'm informed that I'm actually a duplicate of Dave.

Do I prefer this state of affairs to the one where Dave didn't die in 2012 and I was never created? No, not especially... I'm rather indifferent between them.

Do I prefer this state of affairs to the one where Dave died in 2012 and I was never created? Absolutely!

Do I prefer this state of affairs to the one where Dave continued to live and I was created anyway? Probably not, although the existence of two people in 2013 who map in such detailed functional ways to one person in 2012 will take some getting used to.

Similarly: I am told I'm dying, and given the option of creating such a duplicate. My preferences here seem symmetrical. That is:
* Do I prefer that option to not dying and not having a duplicate? No, not especially, though the more confident I am of the duplicate's similarity to me the more indifferent I become.
* Do I prefer it to dying and not having a duplicate? Absolutely!
* Do I prefer it to having a duplicate and not-dying? Probably not, though I will take some getting used to.

Which of those preferences seem odd to you? What is odd about them?

Ah, gotcha. Yeah, here again, I just can't imagine why I ought to care.

I mean, I agree that the attributes can't be "stored" if I understand what you mean by that. When I remove the air from a ball, there is no more bounciness; when I add air to a ball, there is bounciness again; in between, there is no bounciness. If I do that carefully enough, the bounciness now is in-principle indistinguishable from the bounciness then, but that's really all I can say. Sure.

That said, while I can imagine caring whether my ball bounces or not, and I can imagine caring whether my ball bounces in particular ways, if my ball bounces exactly the way it did five minutes ago I can't imagine caring whether what it has now is the same bounciness, or merely in-principle indistinguishable bounciness.

To me, this seems like an obvious case of having distinctions between words that simply don't map to distinctions between states of the world, and getting too caught up in the words.

By contrast, I can imagine caring whether I have the same faculties that constitute my identity as the guy who went to bed in my room last night, or merely in-principle indistinguishable faculties, in much the same way that I can imagine caring about whether my immortal soul goes to Heaven or Hell after I die. But it pretty much requires that I not think about the question carefully, because otherwise I conclude pretty quickly that I have no grounds whatsoever for caring, any more than I do about the ball.

So, yeah... I'd still much rather be survived by something that has memories, personality, and other identity-constituting faculties which are in-principle indistinguishable from my own, but doesn't share any of my cells (all of which are now tied up in my rapidly-cooling corpse), than by something that shares all of my cells but loses a significant chunk of those faculties.

Which I suppose gets us back to the same question of incompatible values we had the other day. That is, you think the above is clear, but that it's a strange preference for me to have, and you'd prefer the latter case, which I find equally strange. Yes?