flink@umcp-cs.UUCP (06/04/84)
Last time I discussed the identity of persons over time I promised to bring up some of the weird cases that philosophers dream up. My point in describing such cases is to demonstrate that it is not always obvious whether a person B whom we see at time t2 is identical with A whom we saw at t1. Moreover, this is a question that we ordinarily think matters; we ordinarily care which of two people that result from some weird brain-transplant operation (for example) will be us. This is in contrast to the Greek ship problem, where most of us might ask, "Who cares which ship is the original?" (Whether we are justified in thinking these things is a different question.) Suppose our civilization develops a Star Trek type transporter, with one difference. Instead of disassembling your matter and beaming it to the destination for reassembly, only the *information* about the atomic arrangement is "beamed" over; different matter is then reassembled at the destination. (It's uneconomical to "beam" the matter over.) Suppose you have been using this device for years without event. One day as you plan to go to St. Louis from Washington DC, you enter the transport booth and push the button as usual, but nothing happens. You can tell that you are still in the (distinctive) transporter booth in Washington. You try to leave but find the door locked. A voice breaks in over the intercom: "This is your Transport Authority technician speaking. We are sorry for the delay; there has been a slight malfunction in the transporter. However, we are happy to report that you have already been received safely at your destination. Please press the red button on the panel to complete the process at the point of departure." You hesitate, then refuse, suddenly realizing what has happened. Never before had you thought of the three procedures, disassembly, "beaming" of information, and reassembly, as separate. Obviously the latter two have worked fine but the first process remains unperformed. There is an ominous pause, and then: "Obviously you are having trouble deciding. We can offer you a choice. If you wish to abort the transport operation and go home, you can press the green button. If you wish to complete the process, press the red button." "Better him than me!" you think desperately, pushing the green button. The door opens and you go home, shaken. You call the people you were going to meet in St. Louis; they haven't seen you today. You worry that you are not the person you seem to remember being, and can't help feeling like a stranger in someone else's home, living with someone else's spouse. Questions: are you still the same person you used to be? Are any of these worries justified? Is pushing the green button justified? Is there any reason not to use such a transporter, and if so, does the same apply to the type of transporter actually depicted in Star Trek? Suggested answers to the last three questions: no. --Paul Torek, umcp-cs!flink