Johnathan Corgan wrote:
> Brent Meeker wrote:
>>>These questions may reduce to something like, "Is there a lower limit to
>>>the amplitude of the SWE?"
>>>If measure is infinitely divisible, then is there any natural scale to
>>>its absolute value?
>>I think it is not and there is a lower limit below which cross terms in the 
>>matrix must be strictly (not just FAPP) zero.  The Planck scale provides a 
>>bound on fundamental physical values.  So it makes sense to me that treating 
>>probability measures as a continuum is no more than a convenient 
>>approximation.  But 
>>I have no idea how to make that precise and testable.
> Having measure ultimately having a fixed lower limit would I think be
> fatal to QTI.  But, consider the following:
> At every successive moment our measure is decreasing, possibly by a very
> large fraction, depending on how you count it. Every moment we branch
> into only one of a huge number of possibilities.  A "moment" here is on
> the order a Planck time unit.

First, it may not be such a large factor.  All nearby trajectories in 
space constructively interfere to produce quasi-classical evolution in certain 
So if we are essentially classical and I think we are (c.f. Tegmark's paper on 
brain) then "we" are not decreasing in measure by MWI splitting on a Planckian 
even millisecond time scale.  The evolution of our world is mostly 

Second, if there is a lower limit on the interference terms in the SE of the 
universe, then the density matrix gets diagonalized.  Then the MWI goes away.  
QM is, 
as Omnes' says, a probabilistic theory and it predicts probabilities.  
mean something happens and other things don't.  So we don't risk vanishing.  
The fact 
that our probability seems to become vanishingly small is only a artifact of 
what we 
take as the domain of possibilities and it is no different than our 
improbability pre-QM.

But undoubtedly there are mathematical difficulties with assuming a lower bound 
probabilities.  All our mathematics and theory has been built around continuous 
variables for the very good reason that it seems overwhelmingly difficult to do 
physics in discrete variables - just look at how messy numerical solution of 
differential equations is compared to the equations themselves.

Brent Meeker

You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To post to this group, send email to
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at

Reply via email to