So, if one looks at the current configuration space for a point of ‘now’, and works the equations backwards, does one get only one possible past, or an large number of possible pasts? If its the former, how can one claim that the equations are time symmetric? If its the latter, why don’t we remember all of those quantum possibilities?
Both. Many possible pasts, because the many worlds are never entirely causally isolated, so we are to some minuscule degree always affected by parallel worlds (though not enough to notice). But one possible past, because only one of these has any great influence on us (or so it seems for the most part—exceptions aside, e.g. mangled worlds aside). If you want to know how it is possible to have symmetric equations but at the same time the asymmetry of division of worlds in one direction in time, the standard explanation is thermodynamic. It’s fundamentally the same reason that if you drop a glass it breaks but if you drop the shards of glass they don’t spontaneously mend themselves.
So, if one looks at the current configuration space for a point of ‘now’, and works the equations backwards, does one get only one possible past, or an large number of possible pasts? If its the former, how can one claim that the equations are time symmetric? If its the latter, why don’t we remember all of those quantum possibilities?
Both. Many possible pasts, because the many worlds are never entirely causally isolated, so we are to some minuscule degree always affected by parallel worlds (though not enough to notice). But one possible past, because only one of these has any great influence on us (or so it seems for the most part—exceptions aside, e.g. mangled worlds aside). If you want to know how it is possible to have symmetric equations but at the same time the asymmetry of division of worlds in one direction in time, the standard explanation is thermodynamic. It’s fundamentally the same reason that if you drop a glass it breaks but if you drop the shards of glass they don’t spontaneously mend themselves.