RE: A calculus of personal identity

From: Stathis Papaioannou <stathispapaioannou.domain.name.hidden>
Date: Sun, 2 Jul 2006 01:58:55 +1000

Hal Finney writes:
 
> > OK, this is the old ASSA versus RSSA distinction. But leaving this> > argument aside, I don't see how teleportation could be analogous to a> > risky, measure reducing activity if it seemed to be a reliable process> > from a third person perspective. If someone plays Russian Roulette, we> > both agree that from a third person perspective, we are likely to observe> > a dead body eventually. But with teleportation (destructive, to one place)> > there is a 1:1 ratio between pre-experiment subjects and post-experiment> > subjects from a third person perspective. Are you suggesting that the> > predicted drop in measure will have no third person observable effect?> > First, I tend to think that the phrase "third person observable" is> something of a contradiction. Observation is a first-person activity.> I would prefer to think of third person effects as simply the physical> record of events.> > In this case, there will definitely be a third person effect. Having> someone teleport is a third-person difference from not having them> teleport. We are talking about two cases here that are third-person> distinguishable, with very different physical histories, hence it is> plausible that there be different subjective first-person effects.> > As far as the comparison with Russian Roulette, if someone only plays it> once, there might not be a third person difference. Yet I would argue> his measure was reduced (in the multiverse).> > Really, when we are talking about third person records, all we have> is the actual sequence of events that occurs. Suppose someone plays> Russian Roulette multiple times. In this universe, perhaps we see them> pull the trigger five times and survive, and on the sixth pull they die.> That subjective history, of playing RR six times, is instantiated in> this universe. This universe contributes measure to that history.> > Other universes, not observable to us, may have him die after different> trials. Each of those contributes measure to subjective histories that> end at different points. The result is that the measure of his lifespan> is reduced at each trigger pull, but that in any single third-person> universe that reduction in measure is unobservable. Instead we see no> change until the final trigger pull.> > Consider this example: someone commits to killing himself if you die, and> now you play Russian Roulette yourself. Each time you pull the trigger> you reduce his measure, that of the other person who will kill himself> if you die. But you will never observe him dying (in the first-person> sense). This is a case of an unobservable measure decrease which you> might nevertheless believe in.
OK, I used "third person observable" too loosely. What I meant was this: if a person's measure in the multiverse falls as a result of teleportation compared to, say, taking the train, then there will be fewer copies of that person in the multiverse after teleportation compared to what would have been the case had he taken the train. "Fewer copies in the multiverse" assumes a God's eye view, but a probabilistic analysis will give an indication of the right answer if the experiment can be repeated enough times and if the experimenter can avoid becoming a victim of the effect he is studying. In this case, given that teleportation does not obviously result in a dead subject any more often than the train journey does, the only way I can see that would allow you to say it caused a greater drop in measure would be if the subject entering the teleporter, at least some of the time, were not really the same person as the one exiting the teleporter at the destination. I assumed this is in fact what you were saying, but...
 
> > > As far as Lee's suggestion that people could be dying thousands of> > > times a second, my framework does not allow for arbitrary statements> > > like that. Given a physical circumstance, we can calculate what happens.> > > It's not just arbitrary what we choose to say about life and death.> > > We can calculate the measure of different subjective life experiences,> > > based on the physical record.> > > > > > If we wanted to create a physical record where this framework would> > > be compatible with saying that people die often, it would be necessary> > > to physically teleport people thousands of times a second. Or perhaps> > > the same thing could be done by freezing people for a substantial time,> > > reviving them for a thousandth of a second, then re-freezing them again> > > for a while, etc.> > > > > > If we consider the practical implications of such experiments I don't> > > think it is so implausible to view them as being worse than living a> > > single, connected, subjective life. It would be quite difficult to> > > interact in a meaningful way with the world under such circumstances.> >> > Assuming it could be done seamlessly, how would it make any difference? If> > you believe the important aspect of our consciousness resides in the> > activity at neural synapses, this is exactly what is happening. They> > are constantly falling apart and being repaired in an energy-requiring> > process, such that the matter comprising our synapses completely turns> > over in a matter of minutes. It's just the basic brain template that> > is maintained over time, and even that changes as we change. If you> > could somehow gold plate your neurones so that the normal turnover of> > matter due to wear and tear stops, and only the turnover due to thinking> > different thoughts occurs, do you think it would make any subjective> > difference? What if the turnover increased, or it happened all at once> > in bursts rather than gradually, all the while maintaining the same> > basic structure as occurs normally?> > Yes, I think these physiological differences might make a difference in> measure, although it would probably be small. Why would you believe> otherwise? Would you suggest that no physiological change could make> a difference? The basic functionalist/computationalist paradigm?> > I have argued before some problems with functionalism, and of course there> is a vast philosophical literature pro and con. The most basic problem> is that functionalism assumes that there is meaning to the question of> whether a given physical system implements a given abstract computation,> and IMO no one has ever given a satisfactory method to answer this.
Teleportation need not rely on functionalism to work. At one extreme, you could have quantum teleportation, producing a perfect replica. I did not read your original argument as a prediction that technical glitches would result in a dead or brain-damaged subject, but rather that despite apparent success, the subject would in some sense still not survive. Is this what you meant?
 
> In practice, as long as you stick fairly close to conventional> implementations, you're probably OK. Your gold-plated neurons are> not a big deal. People are still interacting with the real world. But> computationalism commits you to far more exotic kinds of implementations.> Uploaded brains running millions of times faster than regular ones,> for example. Or brains scattered across the universe exchanging data> at incredibly slow paces. Brains which have been suspended - are they> still alive, still "conscious", or not? The guy who gets teleported every> millisecond - what is his life like, exposed to a kaleidoscopic of images> and realities that would be impossible to meaningfully interact with?
A competent experimenter would control for these side-effects. Of course teleportation would produce a discontinuity in conscious experience. To allow for this, you could render the subject unconscious and do the same for the control who travels by train, and ideally do this in a double-blind manner to see what effect can be attributed to the teleportation alone. An alternative, slightly more difficult, strategy would be to design the experiment so there are no side-effects. Or we could leave it in the realm of the thought experiment and just assume that it is all done seamlessly.
 
> To roughly translate my mathematical principles into words, our subjective> lives gain reality from being embedded and instantiated in real worlds.> As our connection to reality becomes fuzzier and less direct, the> degree to which we can be said to gain measure from those realities> is diminished. And likewise, as the instantiation is made simpler and> more solidly grounded to reality, measure increases. This is based> on the mathematical principle of conditional Kolmogorov complexity,> where we ask how short a program could be to output the trace of a given> subjective experience, starting from the third-person physical record.> > When we come up with these exotic thought experiments that make the> concept of implementation fuzzy, it makes sense that measure would> be reduced. The more we break the connection between physical reality> and a straightforward implementation of a logical calculation, the less> measure that reality will contribute to the calculation. This is what> I see going on in some of these experiments.
You may be right, but I'm still not clear that it would make any difference. As discussed previously, our bodies are falling apart and being rebuilt constantly by the cellular nanomachinery, but we don't notice anything strange happening and it's difficult to even get people to see how amazing this fact is.
 
Stathis Papaioannou
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Received on Sat Jul 01 2006 - 11:59:57 PDT

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