RE: Decision theory

From: Higgo James <james.higgo.domain.name.hidden>
Date: Fri, 8 Jan 1999 09:58:47 -0000

        Jacques Bailhache wrote:
        The problem is : can we chose the proportion of universes in which
we
        decide to act in a certain way (for example to ride with care) ? Or
is this
        proportion determinated by the laws of physics which rule the
molecules
        of our neurons ?

James Higgo replies:
All that exists, exists in the block universe; you can choose to see the
universe as containing choices, or you may prefer to view the question as
meaningless (as I do). My view of the universe is put forward, clumsily, in
the following exchange with Vic Stenger:

Vic Stenger:
Suppose humanity never evolved. There still will be supernovas
that spew out
particles in all directions and we need to explain why, greatly
separated in
space and not in contact, at least for ten billion years or so, this
always
happens in the same time direction. That is, we do not have
some spewing out
and some where the same particles converge to make a nice
stable star, carbon
turning back to hydrogen and deuterium, and so on. Or, why
there are
(apparently) black holes and no white holes (maybe the gamma
bursters are
white holes, now that I think of it). As Huw Price makes it clear
(I'm reading
his whole book a second time, and working on my chapter on
time's arrow), this
is an unexplained puzzle--why the universe has this highly
improbable state at
one extreme of the time axis and not the other, thus setting a
universal arrow
of time for macroscopic (but not microscopic) systems.

Bayes that, my old man.

Vic



James Higgo:
 Like so many other paradoxes, the question Vic asks about
supernovas having an arrow of time is shown to be meaningless
when you adopt Deutsch's view that time is an aspect of the
relationship between 'snapshots' (individual 3-d universes) in the
'multiverse'.

Time's arrow points forwards, backwards, everywhichwayyou like
in the multiverse - it just depends on how you want to look at it.
Supernovas would 'exist' without us, but only if someone chose to
string snapshots together so they saw supernovas. It's an infinite
multiverse, but unless someone is looking along some axis, it is
meaningless to say this or that exist. Everything possible exists.

We ourselves only exist in some of the tiny fibres of inter-
universe connections along which time's arrow happens to point
forwards, along which 'cause' precedes 'effect'. Because,
although the multiverse is infinite, we could only exist in this sort
of stable environment, where lots of things don't 'decay' at once.

Decay is not the phenomenon; that any two particles appear to
be related is the rarity. But in an infinite multiverse...

It is pointless to talk about 'supernovas' *per se* - they are merely
a function of the way we string universes together. But there are
very few such strings that would result in 'environments' in which
llife would evolve; of those, most if not all involve supernovas.

Vic Stenger : This explanation borders on solipsim. It explains everything
by explaining
nothing. We see no white holes or imploding supernovae in our universe. Sure
this could be because this is just a statisical fluctuation. The average
universe has half of each and we are way out on the tail of the
distribution.
This is very unsatisfying. Just giving up. "Everything is possible." You are
welcome to do that. I would prefer to keep trying to see if there is some
non-random reason for what we see in our universe. I do not think the WAP,
as
you use it with your fibers above, is enough.

James Higgo: Vic, you may say that recourse to the WAP (weak anthropic
principle) is 'giving up'. But in the context of MWI it explains
everything, such as the absence of vacuum collapses and all
sorts of nasties. It is also the basis for the wacky quantum theory
of immortality, which is another reason for you to be prejudiced
against it. You seem to be denying the validity of WAP, which
makes intuitive sense, as piously as most people deny time's
arrow can point both ways. It isn't as 'satisfactory' as a nice
experimental 'proof' but what if this is as good as it gets? Perhaps
the universe was not designed for satisfaction.
Received on Fri Jan 08 1999 - 02:13:21 PST