# Re: Interested in thoughts on this excerpt from Martin Rees

From: Russell Standish <r.standish.domain.name.hidden>
Date: Fri, 4 Aug 2006 02:10:53 +1000

Someone called me to task for this posting (I forget who, and I've
lost the posting now). I tried to formulate the notion I expressed
here more precisely, and failed! So I never responded.

What I had in mind was that future observer moment of my current one
will at some point have a total measure diminishing at least as fast
as an exponental function of OM age. This is simply a statement that
it becomes increasingly improbable for humans to live longer than a
certain age.

Whilst individual OMs will have exponentially decreasing measure due
to the linear increase in complexity as a function of universe age,
total OM measure requires summing over all OMs of a given age (which
can compensate). This total OM measure is a 3rd person type of
quantity - equivalent to asking what is the probability of a conscious
organism existing at universe age t. It seems plausible that this
might diminish in some exponential or faster fashion after a few
standard deviation beyond the mean time it takes to evolve
consciousness, but I do not have any basis for making this claim. If
we assume a normal distribution of times required for evolving
consciousness, then the statement is true for example, but I'm wise
enough to know that this assumption needs further justification. The
distribution may be a meanless thing like a power law for example.

So sorry if I piqued someones interest too much - but then we can leave
this notion as a conjecture :)

Cheers

On Fri, Jul 28, 2006 at 12:07:37AM +1000, Russell Standish wrote:
> Thanks for giving a digested explanation of the argument. This paper
> was discussed briefly on A-Void a few weeks ago, but I must admit to
> not following the argument too well, nor RTFA.
>
> My comment on the observer moment issue, is that in a Multiverse, the
> measure of older observer moments is less that younger ones. After a
> certain point in time, the measure probably decreases exponentially or
> faster, so there will be a mean observer moment age.
>
> So contra all these old OMs dominating the calculation, and giving
> rise to an expected value of Lambda close to zero, we should expect
> only a finite contribution, leading to an expected finite value of
> Lambda.
>
> We don't know what the mean age for an observer moment should be, but
> presumably one could argue anthropically that is around 10^{10}
> years. What does this give for an expected value of Lambda?
>
> Of course their argument does sound plausible for a single universe -
> is this observational evidence in favour of a Multiverse?
>
> Cheers

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Received on Sat Aug 05 2006 - 06:38:03 PDT

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