Patrick Leahy wrote > To answer [the] initial question: interference effects are not branches. > Actually they imply the absence of effective branching. > > You don't get branching in time because time is a parameter, not an > observable: this means that there is no quantum uncertainty about what the > time is. (At least in the non-relativistic theory. Frankly, I don't know > how to handle the relativistic case). > > You might say: we don't know what time the particle will be detected. Yes, > but the theory doesn't consider the detection event as *one thing* with an > uncertain time. In the MWI there are many (a continuum) of detection > events, each of which happens at a well defined time and each of which > starts off its own branch. And the act of detection changes the detector > physically, which is to say that its particles are re-arranged. Hence the > slogan "every measurement is a position measurement". Of course they are > all momentum measurements as well, etc.
It looks as though you advocate a role for each of these: observables measurements detectors and for all I know observers It seemed to me that MWI allowed me to get away with a considerable simplification. Gone were observers and even observations. Even measurements, I discard. (After all, who can say that a measurement occurs in the middle of a star? And yet things do go on there, all the time.) Now *some* of that language perhaps returns when decoherence is discussed. I mean, I'll grant that *something* significant starts off a new branch, and so it's okay for it to have a name. :-) But here is what I'd like to be able to say: A new branch starts, or decoherence obtains, or an irreversible transformation occurs, or a record is made. They all seem the same to me. Why not? My main motivation is to get as far away from Copenhagen as possible, and so thereby get free of observers and observations, and anything else that seems to afford some pieces of matter a privileged status. Do you think that such simplified language leaves out anything important? Thanks, Lee
