# Re: differences with MWI

From: Russell Standish <R.Standish.domain.name.hidden>
Date: Wed, 28 Jul 1999 10:26:00 +1000 (EST)

>
> I think we would live our lives differently if we believed MWI. Firstly, our
> philosopy would be more 'Buddhist' as described in
> http://www.higgo.com/quantum/buddhism.htm.
>
> But also, our decision-making might be different. I would welcome comments
> (and ridicule, of course, Jacques) on the following:
>
> Say you have two possible outcomes (exogenously determined) and three
> options (endogenous) to choose from.
> Outcome 1 has 80% probability and outcome 2 has 20% probability.
> Option A gives 80% utility under outcome 1 and 0% utility under outcome 2.
> Option B gives 80% utility under outcome 2 and 0% utility under outcome 1.
> Option C gives 70% utility under outcome 1 and 20% utility under outcome 2.
>
> In a classical world you would calculate the expected value of each option
> as:
> Utility(Option A)= .8*.8 + .2*0 = 64%
> Utility(Option B)= .8*.2 + 0*.8 = 20%
> Utility(Option C)= .7*.8 + .2*.2 = 60%
>
> So you would choose option A.
>
> However in MWI, if you care about 'yourself', you will also care about those
> of you who end up in the less fortunate branches. You may well decide that
> it is worth reducing your expected utility in order to alleviate the
> suffering of the 'yous' in the less-fortunate-outcome branches. You may opt
> for C.
>

I disagree with this. The distribution of options A,B and C is fixed,
and is unchanged by any decision you make. Therefore it makes no sense
to consider the outcome of the less-fortunate-branches. The only
reasonable decision basis is on what option you select, not on the
other 'yous'. You should therefore select the option that maximises
your utility, not the overall utility of all branches. I believe that
this corresponds to the classical decision process ignoring MWI
altogether. The only situation it may differ is with quantum suicide
type scenarios, but I have yet to be convinced one can use QS to
select favourable outcomes for oneself.

Cheers

> In other words, you will make some preparations for all outcomes, not just
> maximise expected benefit by preparing thoroughly for the most likely
> option. You will 'hedge your bets', even though the total utility in
> subsequent branches declines.
>
> James
>
>

----------------------------------------------------------------------------
Dr. Russell Standish Director
High Performance Computing Support Unit,
University of NSW Phone 9385 6967
Sydney 2052 Fax 9385 6965
Australia R.Standish.domain.name.hidden
Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks
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Received on Tue Jul 27 1999 - 17:24:44 PDT

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