There is a spookier possibility. Suppose it is easy to send messages to the past, but that forward causality also holds (i.e. past events determine the future). In one way of reasoning about it, a message sent to the past will “alter” the entire history following its receipt, including the event that sent it, and thus the message itself. Thus altered, the message will change the past in a different way, and so on, until some “equilibrium” is reached—the simplest being the situation where no message at all is sent. Time travel may thus act to erase itself (an idea Larry Niven fans will recognize as “Niven’s Law”).
Fair point—I actually wasn’t 100% convinced myself it fits here… Reason for posting it anyway was that (a) it somehow reminded me of the omega/2-boxes problem (i.e., the paradoxal way how present and past seem to influence each other), (b) Hans Moravec work touches on so many of the AI/transhumanist themes common in LW and (c) I found it such a clever observation that I thought people here would appreciate.
Not sure if that’s enough reason, but that’s how it went.
There might be other equilibria in which the past and future adjust to form a new symmetry. So you kill your grandfather, say, but you’re no longer related to him.
Oh yeah… rationality. Haven’t a clue:/. Its a nice quote.
-- Hans Moravec Time Travel and Computing
Extremely cool in an armchair-physicist sort of way, but what’s the rationality?
Fair point—I actually wasn’t 100% convinced myself it fits here… Reason for posting it anyway was that (a) it somehow reminded me of the omega/2-boxes problem (i.e., the paradoxal way how present and past seem to influence each other), (b) Hans Moravec work touches on so many of the AI/transhumanist themes common in LW and (c) I found it such a clever observation that I thought people here would appreciate.
Not sure if that’s enough reason, but that’s how it went.
I guess ‘it all adds up to normality’, but that’s a stretch.
There might be other equilibria in which the past and future adjust to form a new symmetry. So you kill your grandfather, say, but you’re no longer related to him. Oh yeah… rationality. Haven’t a clue:/. Its a nice quote.
Not quiet, since you need time travel to establish the final timeline.