>From: Wei Dai <[EMAIL PROTECTED]>
>The selection of the proper reference class is a serious problem for
>anthropic reasoning.

    Yes, though there have been suggestions about it.

>But perhaps anthropic reasoning is not necessary to
>take advantage of a theory of everything.
>Consider how an non-sentient being (excluded by most proposals for the
>reference class) can use a TOE. Imagine a non-sentient oracle that was
>built to accomplish some goal (for example to maximize some definition of 
>social welfare) by answering questions people send it.

    Any reasonable goal will, like social welfare, involve a function of the 
(unnormalized) measure distribution of conscious thoughts.  What else would 
social welfare mean?  For example, it could be to maximize the number of 
thoughts with a "happiness" property greater than "life sucks".

>The oracle could work by first locating all instances of itself with 
>significant measure which are about the answer the question it's 
>considering (by simulating all possible worlds and looking for itself in 
>the simulations).

    So you also bring in measure that way.  By the way, this is a bad idea: 
if the simulations are too perfect, they will give rise to conscious 
thoughts of their own!  So, you should be careful with it.  The very act of 
using the oracle could create a peculiar multiverse, when you just want to 
know if you should buy one can of veggies or two.

>Then for every potential answer, it computes the approximate consequences 
>for the meta-universe if all of its instances were to give that answer.  
>Finally it gives the answer that would maximize the value function.

    I'm glad you said approximate.  Of course Godel's theorem implies that 
it will never be able to exactly model a system containing itself.

>Sentient beings can follow the same decision procedure used by the oracle.  
>Suppose you are faced with a bet involving a tossed coin. There is no need 
>to consider probabilistic questions like "what is the probability that the 
>coin landed heads?" which would involve anthropic reasoning.
>You know that there are worlds where it landed heads and worlds where it 
>landed tails, and that there are instances of you in all of these worlds 
>which are indistinguishable from each other from the first-person 
>perspective.  You can make the decision by considering the consequences of 
>each choice if all instances of you were to make that choice.

    You need to know which type of thought has greater measure, "I saw 
heads, and ..." or "I saw tails, and ...".  I call the measure of one, 
divided by the total measure, the *effective* probability, since it 
(roughly) plays the role of the probability for decision theory.  But you 
have a point in a way ...
    Decision theory is not exactly the same as anthropic reasoning.  In 
decision theory, you want to do something to maximize some utility function. 
  By contrast, anthropic reasoning is used when you want to find out some 
information.
    This difference could be important in terms of the concern over the 
reference class: while the reference class for anthropic reasoning may leave 
out all thoughts that don't employ anthropic reasoning, there is no reason 
that the utility function shouldn't depend on *all* thoughts.  (It could 
also depend on other things, but any sane person will mainly care about 
thoughts.)
    For example, suppose if I choose A I will be more likely to later think 
about anthropic reasoning than if I choose B.  This will affect my guess as 
to how likely I am to choose A, but it will not affect my decision unless I 
place a special utility on (or have a special dislike of) thinking about it.
    But the reference class issue has another component that does still come 
into play.  How am I to evaluate my utility function, unless I know how to 
identify and measure conscious thoughts in the math model?
    By the way, I don't think you should say "first-person perspective".  
Some people on this list think it means something other than just saying you 
look at all instances of a particular class of thoughts, but it doesn't.  
But that's for another post and another day.  (I guess I'll have to 
partially back up James Higgo.)
    If you really want to see a "first-person perspective", see
http://hammer.prohosting.com/~mathmind/1psqb-a6.exe

                         - - - - - - -
               Jacques Mallah ([EMAIL PROTECTED])
         Physicist  /  Many Worlder  /  Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
         My URL: http://hammer.prohosting.com/~mathmind/
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