Yeah. You can actually make arbitrarily long chains. You have each person go back in time and stop the next person if they're not stopped. You "start" the chain at the end, and depending on when you do it, you can send back one bit. For example, you give Alice, Bob, Carol, and Daniel time turners. At midnight, Alice goes back to stop Daniel if Bob doesn't stop her, at 6:00 AM, Bob goes back to stop Alice unless Carol stops him, etc. If the enemy attacks on the night of the 28th, Daniel stops Carol. If they don't, he doesn't. This means that if they attack, Daniel and Bob go back every day. If he does, Carol and Alice go back. You'd actually need a fifth person to make up for the fact that none of this is instantaneous, but if you have enough time-turners, you can send arbitrarily long messages arbitrarily far into the past.
You don't actually know that Bob didn't see the enemy at the pass, you only know that for some reason, Bob didn't come back and tell you. Perhaps the reason he didn't is because you would have sent that information back in time, and so he couldn't.
Another possibility is that information loses "coherence" the further back it travels. (or forward, depending on which side your standing on) Think of it as a signal to noise problem - six hours isn't the limit, it's the limit of what we can correct for with the magic of the time turners. Prophecy s...
The next discussion thread is here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 85. The previous thread has long passed 500 comments. Comment in the 15th thread until you read chapter 85.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.
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