My question to the everything list is: which explaination do you
prefer and why? Are these two accounts compatible, incompatible, or
complimentary? Additionally, if you subscribe to or know of other
justifications I would be interesting in hearing it.
Thanks,
Jason
--
Torgny Tholerus
I take the view that mathematics is all about data
compression. Certain mathematical structures are chosen as the laws of
physics because they have a utility in accurately reprsenting reality
in as minimal a fashion as possible. Note that the most accurate
description of the real worl is just the raw data, and the most
minimal mathematical model has poor predictive ability. As in
everything, useful physical models are a tradeoff.
So if all possible "descriptions" exist (ie all possible forms of raw
data), with overall zero information complexity, then all forms of
mathematical compression will be useful in one context or another,
subject to any anthropic constraints (how can something be useful, if
nobody finds it useful?)
Cheers
--
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A/Prof Russell Standish Phone 0425 253119 (mobile)
Mathematics
UNSW SYDNEY 2052 hpc...@hpcoders.com.au
Australia http://www.hpcoders.com.au
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These two justifications are about equally attractive to me. I also have a
couple of other justifications.
Aesthetic: If anything doesn't exist, it's non-existence would constitute an
element of arbitrariness, given that anything exists at all. We shouldn't
accept arbitrariness unless there's a good reason for it, and there doesn't
seem to be one.
Pragmatic: We have to accept that there is at least a non-zero probability
that all possible universes exist. Unless there is reason to believe that
the probability is so small as to be negligible (and I don't see such a
reason), we will need to consider the everything ensemble when making
predictions and decisions. Given that, why not believe that the probability
is one? The probabilities for all other possible collections of universes
can be "folded" into the measure over the everything ensemble in such a way
that all of the predictions and decisions come out the same way as before.
It would be a peculiar kind of arbitrariness that had a good reason for it. :-)
But what constitutes a "good reason"? Does a good reason have to show that the result is inevitable? or merely probable?
>
> Pragmatic: We have to accept that there is at least a non-zero probability
> that all possible universes exist.
This seems to be a tautology: P>0 <=> "possible". The question is what is possible and in what sense of "possible". Certainly many things are logically possible: flying pigs, Santa Claus, and victory in Iraq. But if we assign a non-zero probability to one of theses we are just quantifying the uncertainty of our knowledge.
Brent Meeker
Another justification is rather indirect. Following the arguments in
Theory of Nothing (also mostly available in "Why Occams Razor" and "On
the Importance of the Observer in Science"), a number of really curly
philosophical problems melt away in a blaze of understanding. I refer
here to
1) Occams Razor
2) The problem of Induction
3) Why anything bothers to exist
4) The Hilbert space structure of QM
Of course its not all plain sailing - the problem of the Occam
catastrophe means that the Anthropic Principle is rather mysterious,
rather than trivially obvious as it is in naive realist theories.
However solving 4 unsolvable mysteries in exchange for having another
one is not a bad deal, and is a pretty good justification for taking
these theories seriously.