Luckily, Quantum Mechanics has that covered: the notion of swapping 2 identical particles doesn't make physical sense (that statement has testable consequences). This notion of "no swap" can of course be extended to larger things, like a whole human body.
Therefore, a sufficiently perfect copy of you _is_ you. For instance, if I freeze your body, copy it, then unfreeze the copy, it will not even end your conciousness and replace it by a new "identical" one. It simply does not make physical sense.
Now, uploading may be a bit different, (you wouldn't run on biological neurons any more), but it still looks like it should work. First, if the upload is of sufficient quality to permit a later download (I expect it to be), then when you're back to your physical body, QM says that your conciousness didn't end, but merely lived something while in a computer. I therefore expect my conciousness not to end, even if I'm never downloaded back. Further, I strongly suspect that conciousness is nothing more than a not yet understood mathematical property of running software.
For further reading, I strongly recommend the sequence on quantum physics by Eliezer Yudkowsky, on lesswrong. The introduction about philosophical zombies is also quite interesting. It's long, but you can absorb it in chunks.
Sir Roger Penrose has written at length on the topic of consciousness, and his views are very far from yours or Eliezer Yudkowsky's, and you can't deny that he probably also knows a thing or two about Quantum Mechanics.
Which is not to say Penrose is right, but clearly, the matter can't be as clear cut as you make it sound. Personally I'd say it's not a good sign if you find yourself invoking Quantum Mechanics to support your opinions on subjects like the nature of consciousness, the existence of God, etc.
I use QM in my argument because it is a direct cause of my believing that cut & paste transportation is in principle possible. Before I knew about that, I was in fact quite worried: philosophical arguments (like the Generalized Anti Zombie Principle) make sense, but I trust physics better.
I don't know of the views of Penrose. Do you recommend a link?
Penrose believes that the nature of consciousness is connected to a physical phenomenon which happens in our brains but not in computers, therefore he does not believe a computer can posses consciousness no matter what software you put on it. He's written several books on the subject as well as given a number of talks which are available on YouTube, but I don't have one link which I'd recommend above others. Sorry.
I don't think the properties of identical particles in Quantum Mechanics bring much if anything to the discussion at hand. Even if we lived in a classical universe, in which every atom would be unique and numbered, we could come up with thought experiments, in which, say, (a) a mad scientist makes an exact copy of your body including brain, (b) then kills you and feeds your ground body to your unsuspecting copy as hamburgers, and (c) all the atoms from your digested body make it to the same spots in your copy's body that they used to occupy in your own. (That last part might seem like a stretch, but really, is it more of a stretch than postulating that you and your copy would be identical in a sense you invoke in QM?) The end result from the world's point of view is exactly the same as if nothing happened to you.
And all that has not even that much to do with the question of what happens when you upload your brain to the computer, let it run for a while, and then recreate a physical brain with the updated state from the computer, since then the final state is emphatically not identical.
§2: Your argument actually doesn't feel like such a stretch. QM is just the final nail in the coffin, that made me actually comfortable with cut & paste transportation.
§3: We could actually get the same effect as the mad scientist, actually. Freeze my body, upload, lock me in a virtual cell for a few subjective hours, download by rearranging my neurons (or even my whole body) according to my virtual trip, reboot. There, you get the same final state: same atoms, and same memories compared to what they would be if you locked me in a physical cell instead.
Those 'testable consequences' have only been verified to within experimental accuracy. However small the deviation: when scaling up, consequences of small deviations soon start overshadowing the original guiding principles. The unsolvable three body problem, the flow of sandpiles, turbulence in water. Chaos has been far from solved. Your argument will hold when you provide an actual, experimentally verifiable reduction of macroscopic laws to microscopic principles. Until then, it is all handwaving and make-belief.
In short, your argument hinges on reductionist assertions that are easily debatable. They may even turn out to be impossible to prove correct. The hard problem of consciousness has not been solved and you should not pretend that it does not exist.
> Those 'testable consequences' have only been verified to within experimental accuracy.
No, they have been verified up to perfect accuracy. That's because when 2 configurations are actually the same, the experimental measures are the squared modulus of complex numbers. If they are a tiny bit different (not the same), then the measures are the sum of the squared modulus of complex numbers. The two cases lead to very different results.
> In short, your argument hinges on reductionist assertions that are easily debatable.
It does hinges on reductionistic assumptions (there's only one territory out there, only maps are multi-level, and ontologically basic mental things don't exist). I doubt those are easily debatable, however. Up until now those assumptions worked, and I see no reason why they should break down some day. I am fully aware that the problem of conciousness has not been solved, but since we discovered that the mind is made of neurons, I think it is reasonable to believe it is solvable (though intractable at the moment).
No, they have been verified up to perfect accuracy.
There is no such thing in experimental physics. You are glossing over a number of experimental details surrounding these 'experimental measures'. This experiment does not succeed all the time. The measures are taken a million times and the results averaged. You don't know the results of the switch of two individual particles. Hell, you can't even know for sure you actually switched them. That's a nice conundrum.
And your claim that this notion can 'of course' be extended to larger things is begging the question.
I'm afraid you just don't understand the QM experiments in question. For there to be a secret difference between the two particles requires observed reality to be a lie.
I think I understand these experiments pretty well, having executed experiments of their kind myself. The mathematics tells us the particles are indistinguishable. The physics tells us that the mathematics describes the observations pretty accurately. But they remain observations with an experimental error and they leave room for the especially interesting options of
1) small deviations that are amplified when you increase the scale of the problem and
2) small deviations that simply occur only 1 in a billion times, for whatever reason (the assumptions of homogeneity, isotropy, time-invariance, and so forth are dangerous assumptions).
No observation allows you to conclude anything about what gives rise to those observations. You certainly cannot conclude it obeys the same mathematical relations used to predict the observations.
We can't solve a trivial 3-body problem and the deviations in numerical approximations are problematic for some purposes. As we get more ambitious, those deviations will become smaller, but may remain too large for the goal. We don't know whether the law of gravity contains an exact exponent of 2. The Voyager spacecraft seem to suggest there may be more involved and nobody has offered a decent suggestion in the past decades. We can't predict the flow of sand rolling of a dune and we may never be able to do that, because the complexity of the problem may turn out to exceed the theoretically possible computational power of the universe.
As for the second sentence: it's not observed reality that lies: it is our overinterpretation of the observations that are lies. We extrapolate beyond what is reasonable. There are too many trivial puzzles unsolved or even proven unsolvable. How can you possibly trust or accept a description with those defects to be the say-all, end-all description of our universe? I have every reason to believe that my universe defies complete description, modelling, simulation. How about yours?
> No observation allows you to conclude anything about what gives rise to those observations.
No, but they sure should have a damn powerful influence over your estimated probabilities for your previous hypothesises. Many of those observations are tests, after all.
Now, though I don't yield QM with my own strength, I can tell that the basics have little to do with chaotic systems, and that most of our intuitions are better thrown out the widow. Really, go read that sequence, at least until you can parse "complex amplitude distribution over a configuration space". It's accessible, it's established science, and I trust Eliezer reported it accurately.
From glancing through the materials, I gather there is much in that sequence I already know. The problem is that I disagree with the conclusions that are drawn, which is entirely possible, because there are many opportunities for disagreement in these sketches of reality.
For instance, the whole sequence about MWI doesn't succeed in making a point with me. I understand it perfectly well: it's an interpretation that speaks to the imagination and I fully agree it's the interpretation that makes the most sense, but there actually is no experimental evidence whatsoever that distinguishes MWI as a better interpretation than many others out there. MWI is just another narrative that attempts to make a mathematical framework yield to our understanding. What makes sense is the actual criterion being used here and, as you said earlier, we should leave our intuitions behind.
No, the actual criterion being used here is what is simplest according to Kolmogorov complexity. In other words, Occam's razor. Nothing to do with human intuitions. If you have Occam's priors, then MWI is far more probable than OWI, and the fact that physicists thought about it later simply doesn't count. (Well, it counts in the social process that is Science, but Science is different from Occam's priors + probability theory).
Anyway, MWI is irrelevant with respect to cut & paste transportation. Just remember that perfect equality in QM is different in kind from almost perfect equality. Meaning that even with imperfect instruments, the result you obtain with perfect equality are wildly different from the results you obtain otherwise. Way past the margin for error of the instruments we have.
Yes, the theory says that there is a way for testing something perfectly, with imperfect instruments. By some miracle, the theory is the Kolmogorov-simplest one we currently know that match the experimental results. By another miracle, the theory is (as far as I know) uncontroversial up to MWI vs OWI.
Another thing the theory says is that the notion of identity should be thrown out the window. That applies to small factors in configuration space (particles) as well as large ones (paintings, human bodies). It doesn't say we should treat small factors differently than large ones. So basically, if you manage to make a copy accurate up to thermal noise, you got yourself a second original. And if the "original" original were destroyed, well, what's left is the "copy" original, which actually is the original, period (because identity doesn't count).
I'd be surprised to learn that this argument is controversial among physicists.
I'm not sure what the best place to continue such subdiscussions is, but I think we should put an end to it here. Let me just conclude with this:
I'd be surprised to learn that this argument is controversial among physicists.
The fact that an argument in philosophy is uncontroversial among physicists means exactly nothing, because they are generally too philosophically unsophisticated to respect the post-Popperian criticisms of what their jobs entail and what it is that 'science' produces.
Therefore, a sufficiently perfect copy of you _is_ you. For instance, if I freeze your body, copy it, then unfreeze the copy, it will not even end your conciousness and replace it by a new "identical" one. It simply does not make physical sense.
Now, uploading may be a bit different, (you wouldn't run on biological neurons any more), but it still looks like it should work. First, if the upload is of sufficient quality to permit a later download (I expect it to be), then when you're back to your physical body, QM says that your conciousness didn't end, but merely lived something while in a computer. I therefore expect my conciousness not to end, even if I'm never downloaded back. Further, I strongly suspect that conciousness is nothing more than a not yet understood mathematical property of running software.
For further reading, I strongly recommend the sequence on quantum physics by Eliezer Yudkowsky, on lesswrong. The introduction about philosophical zombies is also quite interesting. It's long, but you can absorb it in chunks.
http://lesswrong.com/lw/r5/the_quantum_physics_sequence/