Re: Variations in measure
[EMAIL PROTECTED] wrote:
>
> Wei writes:
> > If by flying-rabbit you mean any deviation from simplicity, then I agree
> > with you. Notice that our own universe is full of quantum randomness, but
> > we don't see any pattern to the randomness. Similarly, an observer in a
> > Conway's life universe may observe these anomolies that you described, but
> > most observers would perceive them as random fluctuations rather than
> > flying rabbits.
> >
> > The universes where the deviations form patterns meaningful to their
> > observers would collectively have a very small measure compared to the
> > universes where the deviations are perceived as random, because in the
> > former case the programs to generate the meaningful deviations would have
> > to contain information about what kinds of deviations would be meaningful
> > to the observers, and that would make them much longer than programs that
> > simply generate random deviations.
>
> Russell Standish sent me private mail referring to his article at
> http://parallel.hpc.unsw.edu.au/rks/docs/occam/, where he made a similar
> argument. However I am not completely convinced.
>
> Parenthetically, I don't see that the presence of quantum randomness
> in our universe is relevant. If we assume that many-worlds is the true
> physics of our universe, then in fact our universe is deterministic and is
> not full of quantum randomness. Even if we do have quantum randomness,
> that would not be like the situation I am describing, where you have a
> universe which is almost entirely lawful and has some kind of extremely
> rare exception.
>From the viewpoint of my paper "Occam's Razor" paper, QM is not the
"true physics" of the universe. It is just that any observer is
unlikely to be able to distinguish the behaviour of er world from one
described by QM. That is the result of the last section of that paper.
>
> I agree however that you (and Russell) are right that one would not
> literally expect to see a flying rabbit or a materializing dragon.
> The information content of such a manifestation would be large, and most
> "miracles" which used a similar quantity of information would be random
> in their effects, and probably unnoticeable.
I hadn't noticed until now that Wei Dai agrees with my argument in
Occam's razor...
>
> Nevertheless I think there could be exceptions to the laws of nature which
> have major, observable effects while being relatively concise to specify.
> Going back to my CA example, in some CA worlds if you had a cell fixed
> in the "1" state, that could have dramatic macroscopic effects. It might
> appear to be continually radiating the equivalent of energy, for example.
> In such a situation, you might have conservation of energy throughout
> the entire universe, except at this one location it would be violated.
>
A rather poor choice of example - our universe appears to have a
violation of exactly this sort at its origin. But then, that is
required of the Anthropic Principle, otherwise we would be here to
argue about it :)
More seriously, any undergraduate will be able to demonstrate the
failure of conservation of energy. I did it several times - even at
high school. However, the reason this is not worthy of a Nobel prize
is that experimental error is a more likely explanation for the
experimental results, than that the conservation law broke down. It
would require a really massive violation of the magnitude of the
afore-mentioned dragon to convince the Nobel Prize committee...
Now of course, with more sophisticated experimental and statistical
techniques one can increase the sensitivity of the test by many
orders of magnitude (ie reduce the amount of extra information
required for a "magical" universe). Of course this can be done so far,
that the violating universe is no longer considered "magical". For
example, if some experimenter should show that mass/energy was violated on
the scale of 10^{-20} (lets say), then it is unlikely that people
would say the universe was not regular, and that science failed. The
researcher might get the Nobel prize, but that would probably be the
limit of the discovery's impact on the methodology of science.
Incidently, experiments were conducted in the 1980s to detect
violations of the baryon conservation no, which were expected to be of
the order of 10^{-32}/year. In the event, the violations were not
detected, ruling a particular class of GUT.
> The collection of all universes which have this kind of violation of the
> laws of nature could, by my argument, have measure not much less than
> that of a universe which had the simpler laws of physics which allowed
> for no such violation. Inhabitants of such a universe who have not yet
> stumbled upon the magic location might think that their observations
> give them reason to believe that the laws of physics hold everywhere.
> But they are wrong. There is a significant probability that violations
> of this sort exist. Occam's razor is not as
Re: Variations in measure
Wei writes: > If by flying-rabbit you mean any deviation from simplicity, then I agree > with you. Notice that our own universe is full of quantum randomness, but > we don't see any pattern to the randomness. Similarly, an observer in a > Conway's life universe may observe these anomolies that you described, but > most observers would perceive them as random fluctuations rather than > flying rabbits. > > The universes where the deviations form patterns meaningful to their > observers would collectively have a very small measure compared to the > universes where the deviations are perceived as random, because in the > former case the programs to generate the meaningful deviations would have > to contain information about what kinds of deviations would be meaningful > to the observers, and that would make them much longer than programs that > simply generate random deviations. Russell Standish sent me private mail referring to his article at http://parallel.hpc.unsw.edu.au/rks/docs/occam/, where he made a similar argument. However I am not completely convinced. Parenthetically, I don't see that the presence of quantum randomness in our universe is relevant. If we assume that many-worlds is the true physics of our universe, then in fact our universe is deterministic and is not full of quantum randomness. Even if we do have quantum randomness, that would not be like the situation I am describing, where you have a universe which is almost entirely lawful and has some kind of extremely rare exception. I agree however that you (and Russell) are right that one would not literally expect to see a flying rabbit or a materializing dragon. The information content of such a manifestation would be large, and most "miracles" which used a similar quantity of information would be random in their effects, and probably unnoticeable. Nevertheless I think there could be exceptions to the laws of nature which have major, observable effects while being relatively concise to specify. Going back to my CA example, in some CA worlds if you had a cell fixed in the "1" state, that could have dramatic macroscopic effects. It might appear to be continually radiating the equivalent of energy, for example. In such a situation, you might have conservation of energy throughout the entire universe, except at this one location it would be violated. The collection of all universes which have this kind of violation of the laws of nature could, by my argument, have measure not much less than that of a universe which had the simpler laws of physics which allowed for no such violation. Inhabitants of such a universe who have not yet stumbled upon the magic location might think that their observations give them reason to believe that the laws of physics hold everywhere. But they are wrong. There is a significant probability that violations of this sort exist. Occam's razor is not as sharp as they believe. Hal
Re: Variations in measure
On Wed, Dec 19, 2001 at 09:39:09AM -0800, [EMAIL PROTECTED] wrote: > This suggests that the simplicity explanation against flying-rabbit > universes is not strong, because the total collection of flying-rabbit > universes is close in measure to the simple universe to which they > rerpesent exceptions. That's the problem as I see it. If by flying-rabbit you mean any deviation from simplicity, then I agree with you. Notice that our own universe is full of quantum randomness, but we don't see any pattern to the randomness. Similarly, an observer in a Conway's life universe may observe these anomolies that you described, but most observers would perceive them as random fluctuations rather than flying rabbits. The universes where the deviations form patterns meaningful to their observers would collectively have a very small measure compared to the universes where the deviations are perceived as random, because in the former case the programs to generate the meaningful deviations would have to contain information about what kinds of deviations would be meaningful to the observers, and that would make them much longer than programs that simply generate random deviations.
Re: Variations in measure
Wei writes: > If you think about it more, I think you'll realize that the greater number > of observer-moments observing flying rabbits or similar happenings can't > make up for the much smaller measure of each such observer-moment. > Unfortunately right now I can't find a way to easily articulate the > reasoning behind that conclusion. Here is an example. Suppose we had a universe which was a CA system like Conway's Life game, but more complex. It still has a fairly simple program to represent its functions and so will have generally high measure. Now suppose we modify that program to be, "follow the normal rules except at position X, always set the cell to 0". This represents a "flying rabbit" universe, one which has relatively simple laws of physics but where there is an exception. If the universe is very large, then to specify X will take a large number of bits. Hence the flying rabbit universe program is much larger than the simple universe program, and its measure is much less. This is the explanation I accepted for why we are not in a flying rabbit universe. (I am assuming the universal distribution as a measure, where the measure of an n-bit minimal program is 2^(-n).) However if you consider all possible universes of this type, that is, all possible values of X, then there are 2^n of these if X is n bits long, exactly countering the loss in measure due to the size of X. The collection of this kind of flying rabbit universes has only modestly less measure than the simple universe. The only decrease is due to the size of the "except at position" and "set to 0" clauses, which might be only a few bits long. And this is only one possible kind of exceptional universe. If we consider the various other special-case exceptions to the normal rule then the collective measure of all of these will come even closer to the simple case. This suggests that the simplicity explanation against flying-rabbit universes is not strong, because the total collection of flying-rabbit universes is close in measure to the simple universe to which they rerpesent exceptions. That's the problem as I see it. Hal
Re: Variations in measure
On Sun, Dec 16, 2001 at 02:24:07PM -0800, [EMAIL PROTECTED] wrote: > Hence the all universe principle does not easily explain the absence of > flying rabbits, because while flying-rabbit universes are more complex > and of lower measure, there are so many more ways to come up with complex > universes. It seems that the explanatory power of the principle is less > than I had realized. If you think about it more, I think you'll realize that the greater number of observer-moments observing flying rabbits or similar happenings can't make up for the much smaller measure of each such observer-moment. Unfortunately right now I can't find a way to easily articulate the reasoning behind that conclusion.
Re: Variations in measure
Wei Dai Wrote >On Sat, Dec 08, 2001 at 12:57:16PM -0800, [EMAIL PROTECTED] wrote: >> For example, suppose he took a drug which made his mental processes >> become confused. He was no longer sure of basic facts about himself >> and the universe. This mental state would no longer be bound to one >> specific universe. Instead, a large collection of distinct universes >> could be consistent with this mental state. These observer-moments >> might therefore have larger measure, since they would correspond to a >> larger part of the multiverse. > >I think this is a common occurance. Every time you forget something, >a post-forgetting observer-moment would have larger measure than a >pre-forgetting observer-moment. And similarly, every time you observe >something new, a post-observation observer-moment would have smaller >measure than a pre-observation observer-moment. Not necessarily so because the set of accessible observer moments can be infinite. I agree in principle that a post-forgetting observer-moment should have larger measure than a pre-forgetting observer-moment (note this entails, in some sense QTI and/or COMPI). But post observations lead to continua of extensions (most undistinguishable), so that acquiring informations does not make the measure smaller, even if it diminish the set of consistent extensions. In an older post Wei Dai wrote >> Nick Bostrom wrote: >> ... >> Hmm. Would you say the analogous thing about temporally distinct but >> qualitatively identical observations of the same person? Say, you wake up >> first at 7 am for one minute and again at 8 am for another minute. Suppose >> you know all along that you will awake on these two occasions and that both >> times you will be in the same conscious state of thinking "It is 7 am now." >> It would seem natural to say that the first time you awoke, you were right >> and the second time you were wrong. Suppose a little later you look at the >> clock and it says "8:01". Mightn't you then say to yourself "Gee! When just >> a second ago I just thought it was 7 I was badly mistaken!" > >I would say that I was wrong both times, in the sense that both instances >of the belief "It is 7 am now" are unjustified. The correct belief is "It >may be 7 am or 8 am now", or "There are two brain instances implementing >my thoughts, one at 7 am and another one at 8 am." I don't understand. Only some relative correctness should be genuine imo, especially for decision. Bruno
Re: Variations in measure
[EMAIL PROTECTED] wrote:
>
> Wei writes, quoting Hal
> > > In general, one might expect those minds with less observational power
> > > and less specific knowledge and understanding of the universe to have
> > > larger measure.
> >
> > Yes, but that doesn't mean you should be surprised if you find yourself
> > having more observational power and more knowledge, because the set of
> > sharp minds can have greater measure than the set of dull minds even if
> > individual sharp minds has less measure than individual dull minds.
> >
> > > Does this have any implications for the use of the all-universe hypothesis
> > > to explain and predict our observations?
> >
> > What kinds of implications did you have in mind?
>
> What is the right question to ask in terms of relating measure of an
> observer-moment to our likelihood of experiencing it? Equivalently,
> what can we hope to explain via the concept of observer-moments that
> vary in measure?
>
> It seems that the general statement that we would expect to be in a
> high-measure observer-moment is not true, if the number of low-measure
> observer moments is high. We are not more likely to live in a simple
> universe than in a complex one, if the number of possible complex
> universes is correspondingly larger. And the larger number seems
> plausible when there is greater complexity, as in the example above of
> more complex minds existing in higher numbers.
>
> Hence the all universe principle does not easily explain the absence of
> flying rabbits, because while flying-rabbit universes are more complex
> and of lower measure, there are so many more ways to come up with complex
> universes. It seems that the explanatory power of the principle is less
> than I had realized.
>
> Hal
>
What it does explain is the outcomes of events chosen at random - eg
our birth moment, or the beginning of the universe. These are
relatively simple. It does predict that complex moments (eg our
present minds or the present state of the universe), are unlikely to
appear out of nowhere. They are far more likely to appear as a result
of some evolutionary process that delivers the complex moment from
some simple moment.
This, I believe, succinctly sums up the debate on the ASSA vs the
RSSA we had earlier.
Cheers
Dr. Russell Standish Director
High Performance Computing Support Unit, Phone 9385 6967, 8308 3119 (mobile)
UNSW SYDNEY 2052 Fax 9385 6965, 0425 253119 (")
Australia[EMAIL PROTECTED]
Room 2075, Red Centrehttp://parallel.hpc.unsw.edu.au/rks
International prefix +612, Interstate prefix 02
Re: Variations in measure
Wei writes, quoting Hal > > In general, one might expect those minds with less observational power > > and less specific knowledge and understanding of the universe to have > > larger measure. > > Yes, but that doesn't mean you should be surprised if you find yourself > having more observational power and more knowledge, because the set of > sharp minds can have greater measure than the set of dull minds even if > individual sharp minds has less measure than individual dull minds. > > > Does this have any implications for the use of the all-universe hypothesis > > to explain and predict our observations? > > What kinds of implications did you have in mind? What is the right question to ask in terms of relating measure of an observer-moment to our likelihood of experiencing it? Equivalently, what can we hope to explain via the concept of observer-moments that vary in measure? It seems that the general statement that we would expect to be in a high-measure observer-moment is not true, if the number of low-measure observer moments is high. We are not more likely to live in a simple universe than in a complex one, if the number of possible complex universes is correspondingly larger. And the larger number seems plausible when there is greater complexity, as in the example above of more complex minds existing in higher numbers. Hence the all universe principle does not easily explain the absence of flying rabbits, because while flying-rabbit universes are more complex and of lower measure, there are so many more ways to come up with complex universes. It seems that the explanatory power of the principle is less than I had realized. Hal
Re: Variations in measure
On Sat, Dec 08, 2001 at 12:57:16PM -0800, [EMAIL PROTECTED] wrote: > For example, suppose he took a drug which made his mental processes > become confused. He was no longer sure of basic facts about himself > and the universe. This mental state would no longer be bound to one > specific universe. Instead, a large collection of distinct universes > could be consistent with this mental state. These observer-moments > might therefore have larger measure, since they would correspond to a > larger part of the multiverse. I think this is a common occurance. Every time you forget something, a post-forgetting observer-moment would have larger measure than a pre-forgetting observer-moment. And similarly, every time you observe something new, a post-observation observer-moment would have smaller measure than a pre-observation observer-moment. > In general, one might expect those minds with less observational power > and less specific knowledge and understanding of the universe to have > larger measure. Yes, but that doesn't mean you should be surprised if you find yourself having more observational power and more knowledge, because the set of sharp minds can have greater measure than the set of dull minds even if individual sharp minds has less measure than individual dull minds. > Does this have any implications for the use of the all-universe hypothesis > to explain and predict our observations? What kinds of implications did you have in mind?
Re: Variations in measure
Russel wrote: > Saibal Mitra wrote: > > > > > > Hal wrote: > > > > > > > One of the concepts we have explored is that all universes and hence > > > all minds exist, but that some observer-moments have greater "measure" > > > than others. This may help to explain why we observe the kind of universe > > > that we do, because we must be observer-moments that have relatively > > > large measure. > > > > > > I wonder if it would be possible for the measure of an individual > > > to vary over the course of his lifetime. We do expect the measure > > > to fall as he ages, as he comes to occupy fewer and fewer universes. > > > However there may be other ways that his measure could change. > > > > > > For example, suppose he took a drug which made his mental processes > > > become confused. He was no longer sure of basic facts about himself > > > and the universe. This mental state would no longer be bound to one > > > specific universe. Instead, a large collection of distinct universes > > > could be consistent with this mental state. These observer-moments > > > might therefore have larger measure, since they would correspond to a > > > larger part of the multiverse. > > > > > > In general, one might expect those minds with less observational power > > > and less specific knowledge and understanding of the universe to have > > > larger measure. > > > > > > Does this have any implications for the use of the all-universe hypothesis > > > to explain and predict our observations? > > > > Yes it does. In particular it explains why we are of finite age, contrary to > > what one would naively expect from qti. As I have written some time ago qti > > needs to be modified precisely because of the effect you describe above. > > > > The analogy with the universal prior favoring simpler universes is > > interesting. > > > > Saibal > > > > > > Are you implying that we will not see some "arbitrary large" age > because our minds will become confused (senile perhaps), and so our > self-perceived age might slip back? Or are you saying that the effect > of measure decreasing as a function of psychological time implies that > we must start from a simple nascent state of age 0, then experience > all intermediate states before reaching some enormous age? This later > statement is entirely consistent with the conventional form of QTI. > The former is an interesting point, but I'm not entirely sure how to > formalise it properly (perhaps as a corollory of the second law of > thermodynamics?). > I mean it in the former sense. We could become senile and become identical to a younger person (probably a baby at sleep) and that way evade death, or it could happen as a result of massive head injuries. I think that the probability of ``surviving´´ in this discontinuous way (on the long run) is far larger than in a continuous way, as the conventional QTI seems to imply. Saibal
Re: Variations in measure
Saibal Mitra wrote:
>
>
> Hal wrote:
>
>
> > One of the concepts we have explored is that all universes and hence
> > all minds exist, but that some observer-moments have greater "measure"
> > than others. This may help to explain why we observe the kind of universe
> > that we do, because we must be observer-moments that have relatively
> > large measure.
> >
> > I wonder if it would be possible for the measure of an individual
> > to vary over the course of his lifetime. We do expect the measure
> > to fall as he ages, as he comes to occupy fewer and fewer universes.
> > However there may be other ways that his measure could change.
> >
> > For example, suppose he took a drug which made his mental processes
> > become confused. He was no longer sure of basic facts about himself
> > and the universe. This mental state would no longer be bound to one
> > specific universe. Instead, a large collection of distinct universes
> > could be consistent with this mental state. These observer-moments
> > might therefore have larger measure, since they would correspond to a
> > larger part of the multiverse.
> >
> > In general, one might expect those minds with less observational power
> > and less specific knowledge and understanding of the universe to have
> > larger measure.
> >
> > Does this have any implications for the use of the all-universe hypothesis
> > to explain and predict our observations?
>
> Yes it does. In particular it explains why we are of finite age, contrary to
> what one would naively expect from qti. As I have written some time ago qti
> needs to be modified precisely because of the effect you describe above.
>
> The analogy with the universal prior favoring simpler universes is
> interesting.
>
> Saibal
>
>
Are you implying that we will not see some "arbitrary large" age
because our minds will become confused (senile perhaps), and so our
self-perceived age might slip back? Or are you saying that the effect
of measure decreasing as a function of psychological time implies that
we must start from a simple nascent state of age 0, then experience
all intermediate states before reaching some enormous age? This later
statement is entirely consistent with the conventional form of QTI.
The former is an interesting point, but I'm not entirely sure how to
formalise it properly (perhaps as a corollory of the second law of
thermodynamics?).
Cheers
Dr. Russell Standish Director
High Performance Computing Support Unit, Phone 9385 6967, 8308 3119 (mobile)
UNSW SYDNEY 2052 Fax 9385 6965, 0425 253119 (")
Australia[EMAIL PROTECTED]
Room 2075, Red Centrehttp://parallel.hpc.unsw.edu.au/rks
International prefix +612, Interstate prefix 02
Re: Variations in measure
Hal wrote: > One of the concepts we have explored is that all universes and hence > all minds exist, but that some observer-moments have greater "measure" > than others. This may help to explain why we observe the kind of universe > that we do, because we must be observer-moments that have relatively > large measure. > > I wonder if it would be possible for the measure of an individual > to vary over the course of his lifetime. We do expect the measure > to fall as he ages, as he comes to occupy fewer and fewer universes. > However there may be other ways that his measure could change. > > For example, suppose he took a drug which made his mental processes > become confused. He was no longer sure of basic facts about himself > and the universe. This mental state would no longer be bound to one > specific universe. Instead, a large collection of distinct universes > could be consistent with this mental state. These observer-moments > might therefore have larger measure, since they would correspond to a > larger part of the multiverse. > > In general, one might expect those minds with less observational power > and less specific knowledge and understanding of the universe to have > larger measure. > > Does this have any implications for the use of the all-universe hypothesis > to explain and predict our observations? Yes it does. In particular it explains why we are of finite age, contrary to what one would naively expect from qti. As I have written some time ago qti needs to be modified precisely because of the effect you describe above. The analogy with the universal prior favoring simpler universes is interesting. Saibal
Variations in measure
One of the concepts we have explored is that all universes and hence all minds exist, but that some observer-moments have greater "measure" than others. This may help to explain why we observe the kind of universe that we do, because we must be observer-moments that have relatively large measure. I wonder if it would be possible for the measure of an individual to vary over the course of his lifetime. We do expect the measure to fall as he ages, as he comes to occupy fewer and fewer universes. However there may be other ways that his measure could change. For example, suppose he took a drug which made his mental processes become confused. He was no longer sure of basic facts about himself and the universe. This mental state would no longer be bound to one specific universe. Instead, a large collection of distinct universes could be consistent with this mental state. These observer-moments might therefore have larger measure, since they would correspond to a larger part of the multiverse. In general, one might expect those minds with less observational power and less specific knowledge and understanding of the universe to have larger measure. Does this have any implications for the use of the all-universe hypothesis to explain and predict our observations? Hal
