Comment on Beauty quips, "I'd shut up and multiply!"

Sat, 08 May 2010 01:27:58 GMT

OK, I think I have a definite reductio ad absurdum of your point. Suppose you wake up in a room, and the last thing you remember is Omega telling you: "I'm going to toss a coin now. Whatever comes up, I'll put you in the room. However, if it's tails, I'll also put a million other people each in an identical room and manipulate their neural tissue so as to implant them a false memory of having been told all this before the toss. So, when you find yourself in the room, you won't know if we've actually had this conversation, or you've been implanted the memory of it after the toss."

After you find yourself in the room under this scenario, you have the memory of these exact words spoken to you by Omega a few seconds ago. Then he shows up and asks you about the expected value of the coin toss. I'm curious if your 1/2 intuition still holds in this situation? (I'm definitely unable to summon any such intuition at all -- your brain states representing this memory are obviously more likely to have originated from their mass production in case of tails, just like finding a rare widget on the floor would be evidence for tails if Omega pledged to mass-manufacture them if tails come up.)

But if you wouldn't say 1/2, then you've just reached an awful paradox. Instead of just implanting the memories, Omega can also choose to change these other million people in some other small way to make them slightly more similar to you. Or a bit more, or even more -- and in the limit, he'd just use these people as the raw material for manufacturing the copies of you, getting us back to your copying scenario. At which step does the 1/2 intuition emerge?

(Of course, as I wrote in my other comment, all of this is just philosophizing that goes past the domain of validity of human intuitions, and these questions make sense only if tackled using rigorous math with more precisely defined assumptions and questions. But I do find it an interesting exploration of where our intuitions (mis)lead us.)

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