Sorry, I wasn’t clear enough. My claim was that p(message[*]|attempt to send info back more than six hours)=1. This is at least reasonable- it’s almost exactly analogous to what happened to Harry in his experimenting.
[*]: More precisely, that the only result is that a message, with no identifying marks, appears in a location nobody is watching, and so forth. Wizards might still try to draw conclusions from this, but they would be wrong.
[**]: Since this is a fictional universe, we can directly specify its fundamental laws with 100% confidence. If this isn’t a fundamental law, then whenever this can be violated so can the 6-hour rule. (eg if this is something Merlin put in place to prevent dangerous experimenting, or whatever.)
If someone plans to go back in time, and doesn’t plan to be interrupted, they won’t normally get the message because they weren’t trying to find a loophole. If someone else decides to send a message further back by standing in front of where they were and going back in time, then how will that message change anything? I suppose it could send you the message before you even think about that, but what if it’s spur of the moment? Will it send you a message just because you were going to do something? Then again, it’s not as if those messages can’t be used to get information. Dumbledore totally did that when he found that message saying “no”.
Sorry, I wasn’t clear enough. My claim was that p(message[*]|attempt to send info back more than six hours)=1. This is at least reasonable- it’s almost exactly analogous to what happened to Harry in his experimenting.
[*]: More precisely, that the only result is that a message, with no identifying marks, appears in a location nobody is watching, and so forth. Wizards might still try to draw conclusions from this, but they would be wrong.
[**]: Since this is a fictional universe, we can directly specify its fundamental laws with 100% confidence. If this isn’t a fundamental law, then whenever this can be violated so can the 6-hour rule. (eg if this is something Merlin put in place to prevent dangerous experimenting, or whatever.)
If someone plans to go back in time, and doesn’t plan to be interrupted, they won’t normally get the message because they weren’t trying to find a loophole. If someone else decides to send a message further back by standing in front of where they were and going back in time, then how will that message change anything? I suppose it could send you the message before you even think about that, but what if it’s spur of the moment? Will it send you a message just because you were going to do something? Then again, it’s not as if those messages can’t be used to get information. Dumbledore totally did that when he found that message saying “no”.