Re: Peculiarities of our universe

2004-01-19 Thread Saibal Mitra

- Original Message -
From: Fred Chen [EMAIL PROTECTED]
To: Everything [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 10:17 PM
Subject: Re: Peculiarities of our universe


 One other scenario is that a civilization  has indeed reached this
pervasive
 state, but not in a form we'd readily  recognize. They may be
nano-lifeforms
 or microorganisms, for example. This is probably harder to believe because
 only so much complexity can be stored in such an organism, but you never
 know.

Maybe you could have trillions of these nonolifeforms that are no more than
the eyes and ears of one superintelligent being.



Re: Peculiarities of our universe

2004-01-19 Thread CMR

  One other scenario is that a civilization  has indeed reached this
 pervasive
  state, but not in a form we'd readily  recognize. They may be
 nano-lifeforms
  or microorganisms, for example. This is probably harder to believe
because
  only so much complexity can be stored in such an organism, but you never
  know.

 Maybe you could have trillions of these nonolifeforms that are no more
than
 the eyes and ears of one superintelligent being.


AKA: some distributed intelligence's smart dust?; geez there really isn't
anything new under the sun!



Re: Peculiarities of our universe

2004-01-12 Thread John M
Hal,
thanks for this comprehensive view about universes. This state of the Art
essay is worth reading whether one concurs or discords. I concur with some
tiny remarks (could it be otherwise???)

The position that we don't 'see' other universes is correct, missing,
however,
the possibility of OTHER universes seeing US. Even interfere(?).

Non essential style-wise - (you wrote):
 This observation points to the fact that with our laws of physics,
 the evolution of intelligent life is extremely unlikely.  ...
I would name our universe-system rather than the laws we
abstracted from our (limited?) observations in our system-studies.
Further:
  Presumably, there are universes whose laws make life essentially
 impossible.  
Characteristics (unobserved, in lifeless or intelligence-less universes:
Yes. Laws? in different systems from any what we cannot even
contemplate? No.

I consider your measures in the widest (most general) sense as
circumstances including features unknown to us as well.
Since we cannot see other universes, I do not speculate
about their particulars. Even possibilities of potentials are
restricted to our experience and mindset. Our sci-fi is limited.

Sorry for the hair-splitting and thank you for a good post

John Mikes
- Original Message -
From: Hal Finney [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Sunday, January 11, 2004 12:57 PM
Subject: Re: Peculiarities of our universe


 There has been a huge amount written about the Fermi Paradox (why are
 there no aliens).
SNIP
 Hal Finney





Re: Peculiarities of our universe

2004-01-12 Thread Wei Dai
On Sun, Jan 11, 2004 at 09:57:18AM -0800, Hal Finney wrote:
 [...] That is
 (turning to the Schmidhuber interpretation) it must be much simpler
 to write a program that just barely allows for the possibility of life
 than to write one which makes it easy.  This is a prediction of the AUH,
 and evidence against it would be evidence against the AUH.

evidence against it would be evidence against the AUH is similar to the
Doomsday Argument. Let's assume that in fact universes with lots of
intelligent life don't all have much lower measure than our own. Then AUH
implies the typical observer should see many nearby intelligent life. Your
argument is that since we don't see many nearby intelligent life, AUH is
probably false. In the Doomsday Argument, the non-doomsday hypothesis
implies the typical observer should have a high birth rank, and the
argument is that since we have a low birth rank, the non-doomsday
hypothesis is probably false.

I want to point this out because many people do not think the DA is valid
and some have produced counterarguments. Some of those counterarugments
may work against Hal's argument as well.



RE: Peculiarities of our universe

2004-01-12 Thread David Barrett-Lennard
Let X be some predicate condition on the universes in the multiverse.  I
think Hal is assuming that if all the following are true

1.  X can be described in a compact form (ie it doesn't fill up a
book with detailed data)
2.  X is true for our universe
3.  AUH   =   P(X)=0

then we deduce that AUH is (probably) false.

Are you saying Wei, that there is a flaw in this logic?

- David


 -Original Message-
 From: Wei Dai [mailto:[EMAIL PROTECTED]
 Sent: Tuesday, 13 January 2004 9:22 AM
 To: Hal Finney
 Cc: [EMAIL PROTECTED]
 Subject: Re: Peculiarities of our universe
 
 On Sun, Jan 11, 2004 at 09:57:18AM -0800, Hal Finney wrote:
  [...] That is
  (turning to the Schmidhuber interpretation) it must be much simpler
  to write a program that just barely allows for the possibility of
life
  than to write one which makes it easy.  This is a prediction of the
AUH,
  and evidence against it would be evidence against the AUH.
 
 evidence against it would be evidence against the AUH is similar to
the
 Doomsday Argument. Let's assume that in fact universes with lots of
 intelligent life don't all have much lower measure than our own. Then
AUH
 implies the typical observer should see many nearby intelligent life.
Your
 argument is that since we don't see many nearby intelligent life, AUH
is
 probably false. In the Doomsday Argument, the non-doomsday hypothesis
 implies the typical observer should have a high birth rank, and the
 argument is that since we have a low birth rank, the non-doomsday
 hypothesis is probably false.
 
 I want to point this out because many people do not think the DA is
valid
 and some have produced counterarguments. Some of those
counterarugments
 may work against Hal's argument as well.



Re: Peculiarities of our universe

2004-01-11 Thread John Collins
Why aren't we our own much smarter descendents?
If you see quantum measurement events as 'uncovering' or 'choosing' from
a larger set of, in some sense, pre-existing earlier possibilities, then
this problem solves itself: the future looks 'bigger' than the present, but
in terms of the real microstates, whatever they may be, it would be smaller.
So your earliest observer moments would create a history of thermal,
galactic, stellar, and biological evolution that traces back the shortest
possible route to some sort of generic early universe condition with a very
large measure. It is only the first of these evolutionary stages, explaining
the origin of matter, that we do not yet understand. But I don't think we're
to far off

--Chris Collins

- Original Message -
From: Jesse Mazer [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 9:41 PM
Subject: Re: Peculiarities of our universe


 One possibility for why we do not find ourself in an old, galaxy-spanning
 civilization has already been mentioned--perhaps after a certain point all
 the individual minds in a civilization unite into a single Borg-like
 hivemind, and this reduction in the number of minds might imply that the
 self-sampling assumption would predict we'll find ourselves in a time
before
 this happens (although if the hivemind lasts for billions of years, the
 argument might not work because this individual mind would probably have
 more separate observer-moments than the total number of observer-moments
of
 the hundred billion or so individuals who lived before the mind-merging).

 Another possibility is suggested by a theory about how the measure on
 observer-moments could be influenced by the likelihood of future
 duplications, which I discussed a bit in this post (in response to a post
by
 Bruno Marchal discussing the same idea):

 http://www.escribe.com/science/theory/m4841.html

 If observer-moments which are more likely to have more copies of
themselves
 existing in the future have higher measure, then this might also suggest
why
 I find myself living before civilization has spread throughout the
 galaxy--perhaps observers who are alive right at the time when the
 technological singularity occurs are the ones who are most likely to
 become the earliest uploads and to have the most copies of themselves
living
 in the future galaxy-spanning civilization, thus giving the
pre-singularity
 versions of themselves a much higher measure than any post-singularity
 observer-moments.

 Jesse

 _
 Learn how to choose, serve, and enjoy wine at Wine @ MSN.
 http://wine.msn.com/




Re: Peculiarities of our universe

2004-01-11 Thread Eugen Leitl

Why don't we see Others?

I think the anthropic principle neatly explains both scenarios: why we're
here, yet nobody else seems to be.

If life nucleation density is arbitrarily low (e.g. 1/visible univers) we
still wouldn't fail to observe our existance.

It is also worthwhile to mention that the deep universe is young, and hasn't
yet bred sufficient amount of metals (in the astronomic, not the chemical
sense), so due to delayed hatching we're not yet in the lightcone of an
advanced culture. I.e., don't look at the visible universe without a
probability bias, proportional but thresholded (no H/He life for sure).

It is relatively straightforward to show that an advanced culture is
expansive, in fact relativistically so, and everything past pioneer wave will
be transformed to become unsuitable for an ursoup. Arguably, we're about to
enter that expansive stage (notice that computational physics seem to allow
cognition at a 10^6 speedup, so the time from zero to hero is less than
a year), and we've only become observable within less than a century, the
high-power emitters less than three decades.

What's the probability to observe a 0.9 c pioneer expansion wavefront, which
will kill subexpansive observers (observation window: about a century?), will
prevent emergence of new observers, and will only start in systems with
sufficient metallicity, with a yet unknown (yet probably very low) nucleation
density?

Arbitrarily close to zero, obviously. So I would be very, very surprised if
SETI people actually found the sky hanging full of ~lighthour 300 K
blackbodies, or even if we found independant life nucleation events within
our solar system (which have to compete with impact ejecta
crosscontamination, a very frequent event).


pgp0.pgp
Description: PGP signature


Re: Peculiarities of our universe

2004-01-11 Thread Hal Finney
There has been a huge amount written about the Fermi Paradox (why are
there no aliens) over the years, and I don't want to reiterate that here.
You can come up with scenarios in which intelligent life is common but
where they just aren't visible, but IMO such explanations are not very
natural.  Instead I propose that for the purpose of our discussion here,
we accept the apparent fact that there are no other intelligent life
forms within the visible universe.  Then let us consider the implications
with regard to the All Universe Hypothesis (AUH), which says that all
universes exist.

This observation points to the fact that with our laws of physics,
the evolution of intelligent life is extremely unlikely.  The question
is, why?  Not, why do our laws of physics make it hard for life to form,
but why do we live in a universe whose laws of physics have this property?

Presumably, there are universes whose laws make life essentially
impossible.  For example, they may be completely static, or equally bad,
utterly chaotic.  But on the other extreme, there must exist universes
where intelligent life is common.  At a minimum, we could create a such
a universe in an ad hoc way by letting it be born full of intelligent
life via forced initial conditions.  And probably there are other laws
of physics which would be much more congenial for the formation and
sustenance of intelligent life than our own.

So we have some universes which are full of life, others which are devoid
of life, and others where there is a chance for life to form but it is
relatively small.  We appear to live in the third class.

We talk about measure with regard to universes, and however it is defined,
it seems that some such principle is needed to allow some universes
to be more probable than others.  Otherwise we have our flying rabbit
paradox where the universe could suddenly stop being lawful, or could
have arbitrary exceptions to lawfulness.  Since there are more ways for
things to go wrong than to go right, these exception-full universes would
superficially be more numerous than those where the laws are universal.
So there must be some property of the universal-law universes which makes
it more probable for us to experience them than the others, and this is
basically what we mean by measure.  Universes with more measure somehow
play a larger role in the multiverse and we are more likely to live in
one of them.  If universes with more consistent and uniform laws have
greater measure, then this explains why we don't see exceptions like
flying rabbits.

However, it seems that the measure of a universe is not the only factor
which should determine how likely it is to be observed; but in addition
there should be a factor related to how many observers there are.
The obvious case is for high-measure universes where observers are
impossible.  No one will observe such universes.  This is the basic
anthropic principle.  But I would extend this principle to say that the
probability of observing a universe is proportional to the product of
its intrinsic measure and some factor relating to the number of observers
in that universe.

There are a few different ways this factor might work.  The simplest would
be to count the number of observers.  A universe with similar measure
but twice as many observers would be twice as likely to be experienced.
Another possibility would be to use observer-moments.  If two universes
had the same number of observers, but in one they lived for twice as
long as the other, then perhaps the second one would be twice as likely
to be observed.  Yet another alternative would be to base the factor
on the fraction of the universe's total resources incorporated into
observers, rather than just the number of observers.  This would give a
bonus to universes which were relatively efficient at creating observers,
compared to universes which gained large numbers of observers merely be
being inordinately large.

The question of why we live in a sparsely populated universe, then,
comes down to a comparison between the measure of a typical universe
with many observers versus the measure of a typical universe with few.
The former universes would get a large bonus factor for their many
observers, while universes like ours don't have that.  So for our
observations to be consistent with the AUH, it must be that universes
like ours have much larger intrinsic measure than universes with many
observers.  And since, as far as we can tell, our universe is not
just sparsely populated, but extremely so, the measure differential
in these two classes of universes must be extremely large.  That is
(turning to the Schmidhuber interpretation) it must be much simpler
to write a program that just barely allows for the possibility of life
than to write one which makes it easy.  This is a prediction of the AUH,
and evidence against it would be evidence against the AUH.

On the face of it, this prediction doesn't seem too plausible to me.
Of course, no one 

Re: Peculiarities of our universe

2004-01-10 Thread Saibal Mitra
- Original Message -
From: Hal Finney [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 12:24 AM
Subject: Peculiarities of our universe


 There are a couple of peculiarities of our universe which it would be
 nice if the All-Universe Hypothesis (AUH) could explain, or at least
 shed light on them.

 One is the apparent paucity of life and intelligence in our universe.
 This was first expressed as the Fermi Paradox, i.e., where are the aliens?
 As our understanding of technological possibility has grown the problem
 has become even more acute.  It seems likely that our descendants
 will engage in tremendous cosmic engineering projects in order to take
 control of the very wasteful natural processes occuring throughout space.
 We don't see any evidence of that.  Similarly, proposals for von Neumann
 self reproducing machines that could spread throughout the cosmos at a
 large fraction of the speed of light appear to be almost within reach
 via nanotechnology.  Again, we don't see anything like that.

 So why is it that we live in a universe that has almost no observers?
 Wouldn't it be more likely on anthropic grounds to live in a universe
 that had a vast number of observers?

Assuming the validity of the AP, we should expect to find ourselves in the
most typical of circumstances. We should thus expect that most observers are
similar to us. So, most observers are not part of a very advanced
civilization. Maybe, as I wrote in the other posting, this is because those
civilizations consist of only one individual. This should follow from the
AUH, but it is not very clear how. If most observers are like us, then we
shouldn't expect to find much evidence of intelligent life, even if there
are hundreds of civilizations in our galaxy now.

Maybe the fact that we are in a situation in which we don't have controll
over our own bodies very much is a clue. This should again be a typical
situation observers find themselves in. They are on the verge of
understanding how the universe works, but they don't have a cure for deadly
diseases or old age. They don't have the capacity to design and build
observers like themselves. It should thus be the case that the moment they
do develop such capabilities, their numbers should decline dramatically.
This should be a universal property of civilizations evolving in a universe
with large measure.


 The second peculiarity is the seemingly narrow range of physical laws
 which could allow for our form of life to exist.  Tegmark writes about
 this at http://www.hep.upenn.edu/~max/toe.html.  He shows a chart of
 two physical constants and how if they had departed from their observed
 values by even a tiny percentage, life would be impossible.  In the
 full paper linked from there he offers many more examples of physical
 paramters which are fine-tuned for life.

 So why is this?  Why does it turn out that our form of life (or perhaps,
 any form of life) can exist for only a tiny range of variation?
 Why didn't it turn out that you could change many parameters a great
 deal and still have life form?

 I don't see anything a priori in the AUH that would have led to this
 prediction.  Now, it may just be one of those things that happens to
 happen, a fundamental mathematical property like the distribution of
 primes or the absence of odd perfect numbers.  Self-aware subsystems
 just mathematically turn out to only be possible in a very tiny region
 of parameter space.


 Now, you might be able to make the argument that tiny is not well
 defined, that there is no natural length scale for judging parameter
 ranges.  Tegmark could as easily have zoomed in on the appropriate region
 of his graph and shown a huge, enormous area where parameters could be
 moved around and life would still work.

 However I think there is a more natural way to put the question, which is,
 what fraction of computer programs would lead to simulated universes that
 include observers?  And here, if we follow Tegmark's ideas, the answer
 appears to be that it is a very small fraction.  (Of course, you still
 need to use your own judgement to decide whether that is tiny or not.)

I am not sure this is correct,  I do agree that there is a problem here.
Tegmark looks at what would happen if you change on or more parameters in
the standard model and then concludes that the parameter space for life is
very tiny. Most physicists believe that a fundamental theory with only a few
parameter, e.g. superstring theory, could be behind the standard model. The
standard model is what you get if you ''integrate out'' the as of yet
unknown physics at the smallest length scales. Given that the fundamental
theory is supposed to have only a few parameters, it should have a much
larger measure than generic versions of the standard model. So, the problem
is actually worse: Why does life only emerge in a tiny fraction of programs
describing versions of the standard model? And of those programs that do
give

Re: Peculiarities of our universe

2004-01-10 Thread Eric Hawthorne


Hal Finney wrote:

One is the apparent paucity of life and intelligence in our universe.
This was first expressed as the Fermi Paradox, i.e., where are the aliens?
As our understanding of technological possibility has grown the problem
has become even more acute.  It seems likely that our descendants
will engage in tremendous cosmic engineering projects in order to take
control of the very wasteful natural processes occuring throughout space.
We don't see any evidence of that.  Similarly, proposals for von Neumann
self reproducing machines that could spread throughout the cosmos at a
large fraction of the speed of light appear to be almost within reach
via nanotechnology.  Again, we don't see anything like that.
 

So why is it that we live in a universe that has almost no observers?
Wouldn't it be more likely on anthropic grounds to live in a universe
that had a vast number of observers?
Could be that
1. It's extremely rare to have a window for biological evolution to our 
level. (I highly recommend
the  well written  basic-level but accurate and comprehensive new book 
called Origins of Existence
by Fred Adams ISBN 0-7432-1262-2 which gives a complete summary of what 
had to  happen
for our emergence, and all the many ways how things could have gone 
differently, very few of which
would lead to life anything like we know it.)

2. We're a distinguished member of the successful evolvers in the first 
available window-of-opportunity
club.

3. If you believe 1 and 2, then note that we ourselves have not yet made 
galactically observable construction
projects or self-replicating space-probes. Sure, we talk, but we haven't 
put our money where our mouth
is yet. The (few, lucky to have emerged unscathed) other intelligent 
lifeforms in our observable universe may
also not have done this within out lightcone (space-time horizon) of 
observability yet.





Peculiarities of our universe

2004-01-09 Thread Hal Finney
There are a couple of peculiarities of our universe which it would be
nice if the All-Universe Hypothesis (AUH) could explain, or at least
shed light on them.

One is the apparent paucity of life and intelligence in our universe.
This was first expressed as the Fermi Paradox, i.e., where are the aliens?
As our understanding of technological possibility has grown the problem
has become even more acute.  It seems likely that our descendants
will engage in tremendous cosmic engineering projects in order to take
control of the very wasteful natural processes occuring throughout space.
We don't see any evidence of that.  Similarly, proposals for von Neumann
self reproducing machines that could spread throughout the cosmos at a
large fraction of the speed of light appear to be almost within reach
via nanotechnology.  Again, we don't see anything like that.

So why is it that we live in a universe that has almost no observers?
Wouldn't it be more likely on anthropic grounds to live in a universe
that had a vast number of observers?

The second peculiarity is the seemingly narrow range of physical laws
which could allow for our form of life to exist.  Tegmark writes about
this at http://www.hep.upenn.edu/~max/toe.html.  He shows a chart of
two physical constants and how if they had departed from their observed
values by even a tiny percentage, life would be impossible.  In the
full paper linked from there he offers many more examples of physical
paramters which are fine-tuned for life.

So why is this?  Why does it turn out that our form of life (or perhaps,
any form of life) can exist for only a tiny range of variation?
Why didn't it turn out that you could change many parameters a great
deal and still have life form?

I don't see anything a priori in the AUH that would have led to this
prediction.  Now, it may just be one of those things that happens to
happen, a fundamental mathematical property like the distribution of
primes or the absence of odd perfect numbers.  Self-aware subsystems
just mathematically turn out to only be possible in a very tiny region
of parameter space.

Now, you might be able to make the argument that tiny is not well
defined, that there is no natural length scale for judging parameter
ranges.  Tegmark could as easily have zoomed in on the appropriate region
of his graph and shown a huge, enormous area where parameters could be
moved around and life would still work.

However I think there is a more natural way to put the question, which is,
what fraction of computer programs would lead to simulated universes that
include observers?  And here, if we follow Tegmark's ideas, the answer
appears to be that it is a very small fraction.  (Of course, you still
need to use your own judgement to decide whether that is tiny or not.)

In a way, then, these two questions are both related, and perhaps the
same.  They both ask, why so few observers?  One question looks around the
interior of our universe, and the other looks at the set of all universes.
In each case, it seems that intelligent life is terribly uncommon.

Hal Finney



Re: Peculiarities of our universe

2004-01-09 Thread Frank
- Original Message - 
From: Hal Finney [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Friday, January 09, 2004 3:24 PM
Subject: Peculiarities of our universe

 There are a couple of peculiarities of our universe which it would be
 nice if the All-Universe Hypothesis (AUH) could explain, or at least
 shed light on them.

 One is the apparent paucity of life and intelligence in our universe.
 This was first expressed as the Fermi Paradox, i.e., where are the aliens?


According to the anthropic principle, all conditions are such that our
existence is possible.
Also, all events up until now have been such that they favored our
existence. This doesn't necessarily mean that those events were probable. In
fact, they could have been wildly improbable. (that asteroid killing the
dinosaurs at just the right moment might have helped us)

Let us say you're repeatedly throwing a thousand dice on the floor, and that
you are waiting for a pattern of fifty sixes to group close together on the
floor. When they finally show up, it's doubtful that another distinct group
of fifty sixes will show up in the same throw.
In this analogy, the floor and dice represents (roughly) *this* universe and
its galaxies and stars, and the groups of fifty sixes represent planets
harboring intelligent life.

After all, we seem to be very, very complex creatures. Most of the matter in
the universe looks quite disorganized in comparison.
Wouldn't this intuitive analogy explain why life is so rare ?