Comment by shraiyance on Harry Potter and the Methods of Rationality discussion thread, part 20, chapter 90 · 2013-07-15T19:27:43.813Z · LW · GW

The method above might not work if we maintain a fixed past.

You see it can be compared to another similar situation.

Harry an hour (6 to 5 pm) in past and finds there 4 time tuners with 4, 3, 2, 1 hours left.

Now harry has used all the five time tuners (but not all of their remaining hours) , done his work in the past and the time move to 5 again. here harry will have to leave 4 time tuners for another future harry to pick up. If we are preserving the past then the four time tuners should have the time left that the original time tuners had i.e.. 4, 3, 2, 1.

So you see even when harry uses these 4 extra time tuner he still will be unable to use it them to get back more than 6 hours in past.

Now this can be scaled to 1000 time tuners or 1000 harries with time tuners it would make no difference in the amount of time that can be transversed in past by using time tuner.

Summary :- Even if you find "n" more time turners once you go in the past, you would not be able to use them to go more then 6 hours in past because to preserve past you will have to leave "n" time tuners (after their use), thus have to leave as much time in them as you potentially gained earlier.

Sorry for grammar, spelling mistake, complicated language etc. I am bad at languages.