What does an entity that only cares about the kids in its Everett branches even look like? I am confused. Usually things have preferences about lotteries over outcomes, and an outcome is an entire multiverse, and these things are physically realized and their preferences change when the coinflip happens? How does that even work? I guess if you want you can implement an entity that works like that, but I'm not certain why we'd even call it the same entity at any two times. This sort of entity would do very well to cut out its eyes and ears so it never learns it's a decider and begin chanting "nay, nay, nay!" wouldn't it?
What does an entity that only cares about the kids in its Everett branches even look like?
Example 1: Someone that doesn't know about or believe in many worlds. The don't care about kids in alternate Everett branches, because to their mind they don't exist, so have zero value. In his mind, all value is in this single universe, with a coin that he is 90% sure landed Tails. By his beliefs, "yea" wins. Most people just don't think about entire multiverses.
Example 2: Someone who gets many worlds, but tends inclined to be overwhelmingly more charita...
The source is here. I'll restate the problem in simpler terms:
You are one of a group of 10 people who care about saving African kids. You will all be put in separate rooms, then I will flip a coin. If the coin comes up heads, a random one of you will be designated as the "decider". If it comes up tails, nine of you will be designated as "deciders". Next, I will tell everyone their status, without telling the status of others. Each decider will be asked to say "yea" or "nay". If the coin came up tails and all nine deciders say "yea", I donate $1000 to VillageReach. If the coin came up heads and the sole decider says "yea", I donate only $100. If all deciders say "nay", I donate $700 regardless of the result of the coin toss. If the deciders disagree, I don't donate anything.
First let's work out what joint strategy you should coordinate on beforehand. If everyone pledges to answer "yea" in case they end up as deciders, you get 0.5*1000 + 0.5*100 = 550 expected donation. Pledging to say "nay" gives 700 for sure, so it's the better strategy.
But consider what happens when you're already in your room, and I tell you that you're a decider, and you don't know how many other deciders there are. This gives you new information you didn't know before - no anthropic funny business, just your regular kind of information - so you should do a Bayesian update: the coin is 90% likely to have come up tails. So saying "yea" gives 0.9*1000 + 0.1*100 = 910 expected donation. This looks more attractive than the 700 for "nay", so you decide to go with "yea" after all.
Only one answer can be correct. Which is it and why?
(No points for saying that UDT or reflective consistency forces the first solution. If that's your answer, you must also find the error in the second one.)