On 10 January 2014 09:20, Edgar L. Owen <[email protected]> wrote: > Terren, > > I understand very well that's what the 'yes dr.' scenario is but it's an > impossibility to be exactly 'me' for the reasons I pointed out. You can't > come up with a hypothetical scenario which isn't actually physically > possible and make a correct deduction about reality on that basis. > > The no-cloning theorem means that if the correct substitution level is the quantum level (or below), then it is physically impossible for us to create a digital copy of a brain that creates the same state of consciousness, in which case the above objection is valid.
However, it isn't clear that this *is *the substitution level. Max Tegmark has suggested that the brain is essentially a classical computer (rather than quantum) which may in principle put the level above the quantum. If he's right, then making a copy of a brain at the right level becomes possible, albeit beyond present technology, and thought experiments may legitimately use that idea (because it's possible in principle). Personally I don't agree, I think that any copy made above the quantum level isn't *guaranteed* to be the same, while a quantum recreation is *guaranteed by the laws of physics to be identical*. So assuming the substitution level is the quantum level cuts out a host of possible objections. However, assuming that is true, and bearing in mind the no-cloning theorem, there is still at least one caveat -- namely that if the MWI is correct, this sort of duplication is happening all the time, and one can proceed with the analysis on that basis (in fact I believe the comp derivation of the FPI becomes the same as Everett's for this "limiting case"). Bruno's thought experiments with matter duplicators can be rephrased to involve MWI style duplication instead, and I believe the same conclusions can be reached via this route. Another caveat is the question of the continuation of consciousness through time. If the brain is at some level performing computations (as it must be in Edgar's theory, because in that theory everything is, at the fundamental level) then one has to ask what (in principle) links the computational state of a brain at time T1 with the state of the same brain at time T2? The state is constantly changing, so what makes it generate the same being, the same consciousness? This question is actually a version of "Yes doctor", and any reasonable answer appears to involve the fact that the brain has stepped from one state to another state that is the "closest possible continuation" according to some measure - i.e. it's the most similar thing available in the universe (or multiverse), and that similarity is what creates the feeling of continuity. This seems to be the case, rather than simple physical continuity (assuming there is such a thing in reality) because we know about cases where the brain's "next step" has been drastically different - amnesia, brain damage, the "Memento syndrome" and so on - and the person often *doesn't* feel that they have continuity - or much continuity - with who they were before. (Over a longer timescale, none of us feel that we are the same person that we were years ago...) So suppose that, for example, as in Frank Tipler's "Physics of immortality", our remote descendants create computers so powerful that they can simulate every possible brain state of everyone who has lived. Or if that seems a bit unlikely given the accelerated expansion of the univese, suppose that the universe is infinite and the initial conditions are random. In either of these cases, it's inevitable that any given brain state will be recreated (possible an infinite number of times). It's also the case in the MWI, and as we know, if AR is correct it's also happening in Platonia ... there are so many infinities of ur around the place, it's a wonder we know who we are! Oh. Anyhoo.... Duplication, therefore, certainly isn't ruled out by our present knowledge. There are various scenarios in which an infinite number of copies of any given brain state will occur. Can they all be considered a continuation of the brain's previous state? If not, why not? (This might be called the "Heraclitean" argument.) Any of the above scenarios may be invoked to make deductions about the nature of reality based on the possibility that consciousness is (at some level) digital, which leads us to Bruno's conclusion *unless* he can be shown to have made a mistake. (PS This gives a whole new meaning to the phrase "thought experiment" ...! ) -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
