On Mon, Jul 9, 2018 at 12:23 PM, John Clark <[email protected]> wrote:
> On Mon, Jul 9, 2018 at 7:03 AM, Bruno Marchal <[email protected]> wrote: > > That would be true if the man were like you and didn't understand what the > words "YOU WILL BE DUPLICATED" mean. > > >>> >> >>> Bruno, you're always talking about definitions but this is one of those >>> rare occasions where one is desperately needed, so if you want me to answer >>> that question you must first give me a PRECISE definition of exactly what >>> you mean by "the Helsinki man". >> >> >> >** >> *It is guy who will survive in both Moscow and Washington,* >> > > If that's what "the guy" means then obviously "the guy" will see 2 > cities. And before you start with the from the peepee not the poopoo stuff > remember it was you who said "the guy" means "the guy who will survive in > both Moscow and Washington", if that definition is too simple then give me > a better one. I don't have a fetish about definitions as you do but in this > case I have a precise unambiguous logically self consistent definition of > "The Helsinki Man". Do you? > > > >>> and before I can say we agree about the H-guy I need to know exactly >>> precisely what you mean by "the H-guy”. >>> >>> >> >> *>The guy before the duplication.* >> > > > OK, now with this new definition of yours about what "the H-guy" means > "the H-guy" will never see any city **after** the duplication or see > anything else for that matter because the defining characteristic of "the > H-guy" that you just mentioned is existing **before** the duplication. > Try again, maybe the third time is the charm. As for me I think a more > useful definition is "the H-guy is anybody who remembers being in Helsinki > before the duplication". > > Perhaps this will be precise enough for you: Referring to Informal definition 3.2, it is clear that every guinea pig state X has many (possible) successor states Y , arguably infinitely many. As a colorful example, think about Abby the guinea pig’s state when she is sitting in a caf´e, drinking water and thinking about the weather. One possible successor state describes her experience while still sitting in the caf´e a moment later, still drinking water, and asking herself whether she has enough winter coat for the predicted cold snap next week. Another possible successor state describes Abby, terribly frightened because another guinea pig with a face mask storms the caf´e, shouting and performing a robbery. So far, Informal definition 3.2 seems completely unproblematic — it does not seem to lead to any conclusions that differ significantly from any layman’s perspective in everyday life. It can even be very practical for the advanced civilization of guinea pigs. Suppose that the guinea pigs have decided to take the hypothesis seriously that it is the information content of successor states that determines the firstperson perspective, not the material body itself. Then the guinea pigs may decide to build teleporters. Here, a teleporter is understood as a hypothetical device that is currently beyond our technological abilities, but that does not contradict known physical laws. We can imagine a teleporter as consisting of two devices, a “scanner”, and a “replicator”. Suppose Abby the guinea pig wants to travel long distance, say from Earth to Mars. On Earth she enters the scanner which scans her body and brain cells in great detail at an instant of time, down to all molecular details that are functionally relevant. At the same time, her body is instantly destroyed, and the scanned data is sent to the replicator station located at the journey’s target. There, the replicator instantly builds a perfect copy of Abby’s body and brain, based on the transmitted data. Clearly the material body is destroyed (and rebuilt) in this process, which leads to instant feelings of unease to most guinea pigs or humans who think about this scenario. However, if the guinea pigs accept the conclusion from the previous section (and so will we for the rest of this paper), then there is no need to worry: Abby’s information content is replicated perfectly. The state of the replicated brain on Mars will be a successor state of Abby’s state on Earth in the sense of Informal definition 3.2. Hence Abby’s first-person perspective of temporal experience will persist. The previous argumentation has already brought us a long way into unintuitive and discomforting territory; we have to go one step further to make real progress and draw surprising conclusions. This will be done via a particular thought experiment, inspired by the Star Trek episode “The Enemy Within”. It has been described before in similar form by Parfit [65]. Thought experiment 4.1 (Teleporter malfunction). Like every morning, Abby the guinea pig uses a teleporter to travel to her workplace at a hay farm on Mars. The teleporter scans her body and brain cells in great detail at an instant of time, down to all molecular details that are functionally relevant. Instantly her body is destroyed, and the scanned data is sent to Mars. The receiving part of the teleporter instantly builds a perfect copy of her body and brain. However, this one morning, a malfunction disturbs the daily routine: a malicious admirer of Abby hacks into the transmitter’s computer system and causes the teleporter to create two perfectly identical copies of Abby at exactly the same local time on Mars, next to each other. How does Abby experience this situation? Directly after the replication, there will be two identical twins — let us call them Abby-1 and Abby-2. An instant later, due to differing experiences, Abby-1 and Abby-2 will become different in the information content of their brain. So how will Abby subjectively experience this situation? This seems like a tricky question, even in terms of our terminology of successor states. According to the previous section, we must conclude that Abby will (after the malfunction) experience a successor state. But now, there are two successor states in the world: that of Abby-1 and that of Abby-2. Thus Abby will end up as Abby-1 or Abby-2, but which one of them? And what about the other twin? If we disregard all speculative esoteric resolutions of the dilemma, Abby-1 and Abby-2 will both behave as if they were legitimate successors of pre-teleportation Abby. For other guinea pigs, both will be indistinguishable from the old Abby, at least initially (until the twins start making difference experiences), and both will probably vehemently claim to be the “correct” Abby. It seems to be the only possibility to attribute a valid first-person perspective to both. In other words, Abby-1 and Abby-2 will both believe they are Abby However, they will both only experience themselves, and not the other one. That is, Abby-1 will experience herself as a person that is different from Abby-2, and vice versa. The only possible conclusion seems to be that, after the teleportation, Abby will subjectively perceive to be one of the two, and of course not both at the same time in any strange way. So before the teleportation, should Abby prepare to become Abby-1 or Abby-2? Without further assumptions, there is no way for Abby to predict which one of the two options will be realized in her subjective experience. Vice versa, due to the symmetry between Abby-1 and Abby-2, there will be no way for any of the two copies to retrospectively understand “why” they ended up as one Abby and not the other. Furthermore, none of the two Abbys can be distinguished as the “real” Abby. In summary, before entering the teleporter, Abby should expect to randomly experience to become either Abby-1 or Abby-2. This randomness is not arising from an epistemic restriction, but is irreducible. Is there anything in the above that you disagree with John? Jason -- 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]. 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