are we talking about that you only go back in time if you do not find a paper??
that depends what time-model you are in.....
lets think for a moment that you create an alternate universe in going to the past then you will not find a paper and so decide to go back in time (to the other universe) and put one there......now it could have happend that you live in the alternate universe created by yourself going back in time and put the piece of paper there...in which case you do not go back........
on the other linear time-model you run into a f....ing paradox but they may be prevented if the time is not so linear......
omg this is tricky indeed
maybe you would not be able to put the paper there at all because you may be delayed by something.......
that would be the best possibility to prevent those paradoxes in linear time....
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