Re: Macroscopic Emergence in MWI worlds

On Sat, Aug 24, 2013 at 11:40 AM, hibbsa <hibbsa-/[email protected]> wrote:

> But at what stage does the macroscopic world look different between
> universes, and why?


Any time anything macroscopic is lightly balanced, a single quantum event
can tip the balance.  Take a 3-body system for instance (3 stars or 3
planets or even 3 dust motes in space), which has built-in elements of
orbital instability.  Over a long time (many orbits), a tiny impact from a
photon can create a very different orbital pattern, even leading to one
body being ejected or impacted.

There are thousands of other examples.  A rock falling off a cliff face,
the shape of a cloud, wind patterns, global climate, any sensitively
balanced chemical reaction; all can be affected by a small number (even one
in the limit) of quantum events, like photon emission or absorption, or
anything similar, especially after a long time; certain physical systems
amplify small events.

Look for phenomena that have a fractal pattern of metastability (on the
edge of chaos) -- those are the kind to look for if you're interested in
how microscopic events can have macroscopic impact.  Google for "period
doubling" or "metastability" or "fractal chaos" or "chaotic attractors" or
the like for plenty of examples.

I don't know how to describe this in Deutsch's language of emergence,
sorry.  So perhaps this is helpful, perhaps not.

-- 
Gary


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