[ExI] Probability is "subjectively objective".

[Damien Broderick]

At 08:13 PM 7/14/2008 -0700, Lee wrote:

>MWI has *no* problem reconciling these things.
>(One copy of you ends up in a universe with a distant friend who reports
>the same result you got, and the other copy of you ends up in the 
>same universe with a copy of your friend, and once again *they* 
>agree upon the result.

And why this curious and convenient restriction? Well, see, because

>The basic mathematical operation of QM exhibits just these two universes,
>not four.)

As a physicist pal once put it to me:

"ALL the action in QM systems comes in the cross terms.  From algebra 
you know (x + y)^2 = x^2 + y^2 + 2*x*y.  The squared terms are called 
intensities and the cross terms are the amplitudes times each 
other.  When you have a term for each atom in a bowling ball or 
brain, it turns out that the coefficient for each of the cross terms 
are random relative to each other due to environmental decoherence 
and they cancel out leaving the sum of intensities, which is, by 
definition, classical."

Which is peachy, but still looks like numerology to me (in my 
ignorance). The "unreasonable effectiveness of mathematics" yet 
again--and thank you, Professor Wigner.

Damien Broderick