I just discovered Primer: it is nothing short of amazing IMHO. I've read various sites and graphics explaining how their machine work and I've got a question which, I think, would help me better understand how it works.
What if I'm the original and I plan to use the machine to go six hours back but with a twist...
First to simplify things nobody is ever going to enter the machine besides one time at 2013-oct-15 at 6pm.
I turn the machine on at 11:45am 2013-15-10 with a 15 minutes delay and then leave the area to not have an encounter with my double when it pops up at 12:01pm or so.
I then stay in the area (but somewhere where he can't see me : for example because I have binoculars) and wait for my future-self to come back in the past
My future-self comes back and from my point of view it is just that: my future-self that knows what the lottery number are going to be that day etc.
Because I have my binoculars, I can see my future-self coming out of the facility where the time-travel machine is.
I'm glad that I saw my future-self with my binoculars, I dodge him, I go check the lottery numbers (say the lottery happens at 5pm) and then at 6pm I enter the machine.
And that's it.
How many timelines are now created? An infinity because there's a loop? As I understand it I go in the machine at 2013-oct-15 6pm and come back at 2013-oct-15 12:01pm with "lottery numbers knowledge", I'm seen by past-self, my past-self learns the lottery and enters the machine, he comes out in the past to be seen by his past-self and rinse and repeat? Is this correct?
(basically I'm trying to understand what's going on if I try to use my binoculars to see the one that already has the "lottery knowledge" instead being the one that has the "lottery knowledge" that tries to see the one that hasn't)
Now what if there's an additional twist: what if in addition to "nobody is ever going to enter the machine besides one time at 2013-oct-15 at 6pm" I decided that "I'll enter the machine at 2013-oct-15 at 6pm no matter what, except if I did see my future-self (the one with lottery knowledge) come out at 2013-oct-15 a little bit after 12:01pm, in which case and in which case only I won't enter the machine" ?
Then say I'd be before the first ever use of the machine and I'd check with with my binoculars and not see my future-self popping back in my timeline, so I'd enter the time machine at 6pm. But that means I'd have been back in the past so I should have seen my future self and hence decided not to go into the machine.
I don't know if I've been clear enough but how would that work in the way time travel works in Primer?
Is this later scenario "always enter the timemachine but not if I see my future-self" a paradox? (I don't care about there being two me in one timeline... I just don't see how things would work out with this simple rule : "Always enter on 2013-oct-15 at 6pm unless I've seen my future-self come out".
My question is similar to something posted by someone nicknamed 'Indigo' on http://qntm.org/primer who wrote:
I kept asking myself, how could symmetry really be broken? Wouldn't I always see the end result? In other words, if I wanted to go back a few hours to make a change.. to say hello to myself for instance; wouldn't I have seen myself greet me a few hours ago in the first place? And so, you can get trapped in this circular logic if you don't accept certain rules like the possibility of multiple timelines.
But I do accept the Primer rules and I do accept the possibility of multiple timelines. What I'd like to know is how things would work out if before ever inventing my first time-travel machine I'd fix to myself the very simple rule above: "Always enter on 2013-oct-15 at 6pm and on 2013-oct-15 at 6pm only, unless I've seen my future-self come out".