On Jan 18, 2:11 pm, Stathis Papaioannou <stath...@gmail.com> wrote: > 2010/1/18 Nick Prince <m...@dtech.fsnet.co.uk>: > > > > > > >> If you had to guess you would say that your present OM is a common > >> rather than a rare one, because you are more likely to be right. > >> However, knowledge trumps probability. If you know that your present > >> OM is common and your successor OM a minute from now rare - because > >> there are many copies of you now running in lockstep and most of those > >> copies are soon going to be terminated - then you can be certain that > >> a minute from now you will be one of the rare copies. This is what > >> happens in a quantum suicide experiment under the MWI. To put some > >> numbers on it, if there are 100 copies of you now, and in a minute 90 > >> of those copies will be terminated, and of the remaining 10 copies 3 > >> will be given a cup of coffee and 7 a cup of tea, then as one of the > >> 100 original copies according to the RSSA you have a 30% chance of > >> surviving and getting coffee and a 70% chance of surviving and getting > >> tea; i.e. you have a 100% chance of surviving. Proponents of the ASSA > >> would say you have a 3% chance of surviving and getting coffee and a > >> 7% chance of surviving and getting tea, or a 10% chance of surviving > >> overall. I think they would say something like this - the > >> probabilities may be off since the total contribution of pre/post > >> termination OM's has to be tallied up, but in any case they would not > >> say you are guaranteed of surviving. The only way I can understand > >> this latter view is in the context of an essentialist theory of > >> personal identity, according to which once a body is dead it's dead, > >> and it's impossible to live on as even a perfect copy. > > > Thank you Stathis, that was a really helpful reply and has confirmed > > my own thinking on this in many respects. I'm never quite sure why > > list members work in copies though. I am hoping you (or anyone) can > > clarify the following queries. > > Copies are concrete and finite, and therefore easier to grasp than > abstract OM's. Copies could in theory be made in whatever universe we > live in, if necessary biological copies if not computer uploads (in > case it turns out the brain is uncomputable). A prerequisite to most > of the discussions on this list is a clarification of your view on > personal identity, and even in the philosophical literature this is > often discussed by reference to thought experiments involving copies, > as created by Star Trek type teleportation. Derek Parfit's "Reasons > and Persons" is a good book to read on the subject. > > > 1. Can we not say that (under RSSA) my measure of existence has > > initially say 100 units and if there is a 90% chance of being blown up > > before being offered the tea or coffee then if I end up drinking tea > > my relative measure has reduced to 70 units in this branch (note the > > word relative here - I hope I'm getting this right). If I find myself > > drinking coffee then my relative measure has reduced to 30 (my global > > measure over all universes still remains at 100 though?) > > Your "relative measure" before the termination event is not relevant > and maybe not coherent: relative to what? The importance of your > relative measure is in trying to predict what you can expect for the > future. Looking forward, you can expect that you will certainly > survive since there will be at least one copy surviving. Of the 10 > copies that do survive, each has equal claim to being you. Since the > ratio of coffee drinkers to tea drinkers is 3:7, you have a 3/10 > expectation of ending up a coffee drinker and a 7/10 expectation of > ending up a tea drinker. So the "relative" part is in the 3:7 ratio, > whether the absolute numbers are 3:7 or 30:70 or 3000:7000. When I > consider what I will experience the next moment, I take into > consideration all the possible successor OM's (those that have my > present moment in their immediate subjective past), and my > expectations about the future depend on their relative frequency. This > is simple in the present example but becomes difficult when we deal > with infinite sets of OM's where there is a gradation between the > definitely-next-moment-me's and definitely-next-moment-not-me's. > > > 2. In this way (under RSSA) my relative measure continually decreases > > within each branch(hence use of word relative) but my global measure > > across the multiverse is conserved. According to ASSA though my > > measure deceases both across universes and in each branch - in all > > branches I eventually die as well as differentiate. > > According to RSSA and the RSSA your absolute measure in the multiverse > decreases with each branching as versions of you die. According to the > RSSA this doesn't matter as at least one of you is left standing; > according to the ASSA, this does matter and you eventually die. The > only way I can make sense of the latter is if you have an essentialist > view of personal identity. Under this view if a copy is made of you > and the original dies, you die. Under what Parfit calls the > reductionist view of personal identity, you live. > > > 3. Is this copy concept used because of the idea of "differentiation" > > as mentioned in Russells book on p144. I guess in a huge universe > > there will be a very large (infinite?) number of identical me's, > > currently all in lockstep. A single consciousness supervenes over > > these copies until such time as they differentiate due to some bundles > > going through different OM's. The bundle's "thickness" is the measure > > of my existence. In RSSA terms my measure of existence is always > > constant globally ( I am using a definition of measure based on Lev > > Vaidman’s measure of existence as in the link below). > > >http://plato.stanford.edu/entries/qm-manyworlds/ > > Russell makes the point that there are two possible views of your > passage through the multiverse: (a) there are multiple versions of you > whose worldlines differentiate as time goes on and you (the subject) > are one, and only one of these versions, so that when that version > dies, it's the end for you even though your other versions might go > on; or (b) your consciousness supervenes over all identical versions > of you, and when the worldlines differentiate your consciousness is > indeterminate and differentiates according to the weighting as in the > above coffee/tea example. I actually don't think there is a difference > between the versions, even if you do choose to believe that > consciousness must supervene on one and only one particular concrete > physical process. For although my current OM may be attached to a > particular physical process, I can't know which physical process if > more than one produce the same OM, and I can't know which physical > process out of all the possible candidates will produce my next OM. > This reasoning converts (a) into (b). > > -- > Stathis Papaioannou- Hide quoted text - > > - Show quoted text -
Once again many thanks for these helpful comments. I would really like to come back to you on some of these issues when I have had time to properly think about your responses. Hope you do not mind if we revisit them because I feel that before I can properly think creatively in this field I must understand to some extent the definitions and concepts which are used as thinking tools or "pitons in the rock" e.g. like OM's, measure, A/RSSA etc. I hope you will bear with me. Perhaps you misunderstood my reference to the use of copies. What I meant was why they are considered as an indication of measure at the beginning of thought experiments such as the one you discussed (tea/ coffe). Jaques Mallah uses them too (I’d like to discuss one of these on the list at a later time). I am not sure why we cannot consider the experiment as just happening to a single copy. That way there would be no confusion regarding whether “differentiation” is playing an important role. Otherwise I have no difficulty in realising the value of using the copy idea. In particular, my views on personal identity have been shaped by these, and I especially can relate to Bruno's ideas the (eight steps of his SANE paper) at least up to the stage just before he discusses platonic realism as a source of a UD which actually "exists"platonically rather than concretely. I do need to think more about this part though. In short the idea that a copy of me can/could be made, to such a level of detail so that it is essentially me, I feel intuitively is correct in principle. However I am concerned that the no clone theorem might be a problem for the continuity of personhood. From what I can gather Bruno seems to think not - or at least not important for what he wants to convey - but I would want to explore this at some stage. Otherwise I can feel that there should be no reason why copies should not have continuity of personhood over spatio-temporal intervals and feel themselves to be "identical" (I think of identity as continuity of personhood) - or at least consistent extensions of the original person. Moreover I also believe that if a suitable computer simulation can be built to the right level of detail, which contained the copy as a software construct, then this copy could be a virtual implementation within a rendered environment that would indeed similarly believe himself/ herself to be a consistent extension of the original. I suppose I am essentially a computationalist, although I am not clear as to the difference between it and functionalism yet apart from Turing emulability. I am also comfortable with the idea of differentiation so that if copies can be placed in lock step, as they presumably are across worlds, then 10, 20 or 2000 copies will be felt to be the same conscious entity. You will see that I accept the many worlds theory too. These beliefs are based on either my own prejudice or my intuition but are really more like working hypotheses rather than fixed beliefs and are certainly open to revision or modification. I find the QTI difficult to swallow which is why I want to understand the definitions and concepts associated with it. I want to be able to understand the heated debate about it and QS between Jack and Russell. Kind regards Nick
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