Discussion:
MWI
hibbsa
2013-05-27 12:32:31 UTC
Permalink
Does this question an answer?

Is it logically possible for the multiverse to produce macroscopic universes exhibiting any statistically significant differences than our own universe?

I mean "statistically significant" in the most rounded possible sense.

- Any difference that our universe couldn't have gone the way of, consistent with its initial conditions all laws of physics assumed constant

- Any difference in terms of any phenomena existing at any level of abstraction in greater or lesser or with any difference in any attribute including (a) abundance (b) probability of occurrence (c) relation with other phenomena (d) internal constituents.

- Any difference on any level at all where to be different at the bottom level requires contradicting the probabilistic rules of QM and/or causing unique consequences of those rules as a result of interaction with macroscopic phenomena and at the top level requires any significant difference in the timing, macroscopic and microscopic structure, and ultimate fate of the universe.

The reason I think this question deserves a proper full answer. And by that I mean...not just a criticism of the way the question is formed is because there could be important consequences...which may not be worked through. And the philosophy is all about intrepidly working through the consequences?

I've got some consequences waiting for your criticism. But I think it's important to establish your criticism or acceptance of the above first.
hibbsa
2013-05-27 12:33:43 UTC
Permalink
"Does this question an answer?" = "does this question deserve an answer?"
Bruno Marchal
2013-05-27 13:52:50 UTC
Permalink
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "

If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.

Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.

The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.

OK?

Bruno
http://iridia.ulb.ac.be/~marchal/





[Non-text portions of this message have been removed]
hibbsa
2013-05-27 14:33:12 UTC
Permalink
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different macroscopic universes. So you need to name your macroscopic object...preferably with clear, known emergent properties. And show how those emergent properties are altered in any of its associated quantum histories, from say,....the differences that would be exhibited by enough copies of the object in this universe to represent all the possible quantum histories.

And if there aren't any differences...and if our macroscopic world is emergent phenomena from the quantum state, then it's hard to see how the multiverse can exhibit statistically significant differences between its macroscopic universes.
Bruno Marchal
2013-05-27 15:19:07 UTC
Permalink
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.

Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.

Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.

I hope this help, feel free to make your question more precise, if I
miss your point,

Bruno
http://iridia.ulb.ac.be/~marchal/





[Non-text portions of this message have been removed]
hibbsa
2013-05-29 20:43:53 UTC
Permalink
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.

One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.

I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?

The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.

I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Brett Hall
2013-05-30 02:04:52 UTC
Permalink
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.
I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?
He states, on page one of that chapter, that emergent phenomena are a "tiny minority" of phenomena. He also talks on page 5 of my kindle edition, about the arrow of time and the second law of thermodynamics. Disorder tends to increase. Energy is reduced in "quality" as time goes on. So although it is possible for water placed in a kettle to freeze...this is crazy unlikely. David explains on that page that it is unknown if the second law can be derived from lower level physics. The second law seems fundamental though.

Will there be universes where the second law *does not hold*? No.

There will be universes where it might seem not to hold...but they are Harry Potter universes again.

A universe where the second law did not hold would not be very interesting for long. What would happen would be that time would *appear* to go backwards. But that would just be appearances. It would just be that things would get more ordered as time went on. So stars and galaxies would become warm nebulae which would then collect together and, I guess either form some great solid mass or just spread out uniformly throughout space in some huge crystalline structure. It would be a boring universe. And at any instant, this order would be shattered, in complete accord with the laws.
Post by hibbsa
The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.
Yes, if what *you* mean by "properties" means "physical objects". If you mean "emergent laws" then no, even these would be the same. Consider that if there was a universe where the internal combustion engine did not exist, the laws governing that engine still would. Likewise, a universe with no life would still have laws governing predator-prey relationships...they just would never be "instantiated" (so to speak).
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Yes. That's exactly how we do understand such universes...as places where it is highly unlikely anything like that might (or might have) ever happened.

Brett
[Non-text portions of this message have been removed]
hibbsa
2013-06-01 13:53:48 UTC
Permalink
Post by Brett Hall
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.
I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?
He states, on page one of that chapter, that emergent phenomena are a "tiny minority" of phenomena.
What significance are you attaching to his point? Emergent properties arise out of huge complexity hence they are a tiny minority of phenoma.

He also talks on page 5 of my kindle edition, about the arrow of time and the second law of thermodynamics. Disorder tends to increase. Energy is reduced in "quality" as time goes on. So although it is possible for water placed in a kettle to freeze...this is crazy unlikely. David explains on that page that it is unknown if the second law can be derived from lower level physics. The second law seems fundamental though.
Post by Brett Hall
Will there be universes where the second law *does not hold*? No.
There will be universes where it might seem not to hold...but they are Harry Potter universes again.
I think your view is debatable, but I don't currently see the importance.
Post by Brett Hall
A universe where the second law did not hold would not be very interesting for long. What would happen would be that time would *appear* to go backwards. But that would just be appearances. It would just be that things would get more ordered as time went on. So stars and galaxies would become warm nebulae which would then collect together and, I guess either form some great solid mass or just spread out uniformly throughout space in some huge crystalline structure. It would be a boring universe. And at any instant, this order would be shattered, in complete accord with the laws.
Or this universe could be the anomaly, and all that we regard as laws could actually be anti-laws - bizarelly unlikely reversals of acutal laws in a harry potter universe, which could be shattered at any moment.

I mean, you don't know do you?
Post by Brett Hall
Post by hibbsa
The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.
Yes, if what *you* mean by "properties" means "physical objects". If you mean "emergent laws" then no, even these would be the same.
If by emergent laws you mean the statistical laws, like in thermodynamics. Then....I can't make sense of the distinction you are making. To the extent they arise from QM, the multiverse cannot create universes that are different. To the extent they arise from something other than QM, the multiverse cannot create universes that are different. So it's the same issue either way.

Consider that if there was a universe where the internal combustion engine did not exist, the laws governing that engine still would. Likewise, a universe with no life would still have laws governing predator-prey relationships...they just would never be "instantiated" (so to speak).

This all seems to be reinforcing the point I'm making. The multiverse doesn't create universes that are different. The point I'm making is...I thought...uncontroversial so far as that goes. Deutsch already says it. But what I'm pointing out is the *extremity* of that sameness.
Post by Brett Hall
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Yes. That's exactly how we do understand such universes...as places where it is highly unlikely anything like that might (or might have) ever happened.
And about that, my point so far is just that, the multiverse of a particular object, looks exactly the same as statistic model of what might happen in this universe. Shouldn't be a controversial point. As I say...where I'm going with this I haven't got to yet. I just want to nail that we all agree on these points.
Brett Hall
2013-06-02 03:48:22 UTC
Permalink
Post by hibbsa
Post by Brett Hall
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.
I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?
He states, on page one of that chapter, that emergent phenomena are a "tiny minority" of phenomena.
What significance are you attaching to his point? Emergent properties arise out of huge complexity hence they are a tiny minority of phenoma.
He also talks on page 5 of my kindle edition, about the arrow of time and the second law of thermodynamics. Disorder tends to increase. Energy is reduced in "quality" as time goes on. So although it is possible for water placed in a kettle to freeze...this is crazy unlikely. David explains on that page that it is unknown if the second law can be derived from lower level physics. The second law seems fundamental though.
Post by Brett Hall
Will there be universes where the second law *does not hold*? No.
There will be universes where it might seem not to hold...but they are Harry Potter universes again.
I think your view is debatable, but I don't currently see the importance.
Post by Brett Hall
A universe where the second law did not hold would not be very interesting for long. What would happen would be that time would *appear* to go backwards. But that would just be appearances. It would just be that things would get more ordered as time went on. So stars and galaxies would become warm nebulae which would then collect together and, I guess either form some great solid mass or just spread out uniformly throughout space in some huge crystalline structure. It would be a boring universe. And at any instant, this order would be shattered, in complete accord with the laws.
Or this universe could be the anomaly, and all that we regard as laws could actually be anti-laws - bizarelly unlikely reversals of acutal laws in a harry potter universe, which could be shattered at any moment.
I mean, you don't know do you?
I do *know* because to *know* means I have a good explanation, not that I am certain. And the explanation I have is quantum theory which explains Harry Potter universes are the minority. Our 'stable' universes with predictable events is more typical.

So yes, I know.

To assert otherwise - that Harry Potter universes are typical, while ours is not, is to presume that we have completely misunderstood the Schrodinger Wave equation and what expectation values are.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.
Yes, if what *you* mean by "properties" means "physical objects". If you mean "emergent laws" then no, even these would be the same.
If by emergent laws you mean the statistical laws, like in thermodynamics. Then....I can't make sense of the distinction you are making. To the extent they arise from QM, the multiverse cannot create universes that are different. To the extent they arise from something other than QM, the multiverse cannot create universes that are different. So it's the same issue either way.
What do you mean "different"? There are many different universes in the multiverse...so I don't know what you mean. They all have the same laws but it's those same laws that ensure that there is differentiation.
Post by hibbsa
Post by Brett Hall
Consider that if there was a universe where the internal combustion engine did not exist, the laws governing that engine still would. Likewise, a universe with no life would still have laws governing predator-prey relationships...they just would never be "instantiated" (so to speak).
This all seems to be reinforcing the point I'm making. The multiverse doesn't create universes that are different. The point I'm making is...I thought...uncontroversial so far as that goes. Deutsch already says it. But what I'm pointing out is the *extremity* of that sameness.
Still not sure what you mean by different. You say the multiverse doesn't create universes that are different - but that *is* precisely what it does do, unless I have some really fundamental misconception. Right now a different universes exists where a copy of me is not typing this post. It's different to the one I am in here now where I am typing away. And the multiverse "created" those different universes.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Yes. That's exactly how we do understand such universes...as places where it is highly unlikely anything like that might (or might have) ever happened.
And about that, my point so far is just that, the multiverse of a particular object, looks exactly the same as statistic model of what might happen in this universe. Shouldn't be a controversial point.
Well I don't understand it clearly enough to appreciate whether it would be controversial or not.
Post by hibbsa
As I say...where I'm going with this I haven't got to yet. I just want to nail that we all agree on these points.
I don't know, in places, even what we are talking about to know if we agree. For example: what you are referring to by the word "different" as applied to universes above and saying the multiverse doesn't create (have? Generate?) different universes. But it does. So you must have something else in mind.

I don't know what.

Brett.
[Non-text portions of this message have been removed]
hibbsa
2013-06-04 23:01:42 UTC
Permalink
Post by Brett Hall
Post by hibbsa
Post by Brett Hall
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.
I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?
He states, on page one of that chapter, that emergent phenomena are a "tiny minority" of phenomena.
What significance are you attaching to his point? Emergent properties arise out of huge complexity hence they are a tiny minority of phenoma.
He also talks on page 5 of my kindle edition, about the arrow of time and the second law of thermodynamics. Disorder tends to increase. Energy is reduced in "quality" as time goes on. So although it is possible for water placed in a kettle to freeze...this is crazy unlikely. David explains on that page that it is unknown if the second law can be derived from lower level physics. The second law seems fundamental though.
Post by Brett Hall
Will there be universes where the second law *does not hold*? No.
There will be universes where it might seem not to hold...but they are Harry Potter universes again.
I think your view is debatable, but I don't currently see the importance.
Post by Brett Hall
A universe where the second law did not hold would not be very interesting for long. What would happen would be that time would *appear* to go backwards. But that would just be appearances. It would just be that things would get more ordered as time went on. So stars and galaxies would become warm nebulae which would then collect together and, I guess either form some great solid mass or just spread out uniformly throughout space in some huge crystalline structure. It would be a boring universe. And at any instant, this order would be shattered, in complete accord with the laws.
Or this universe could be the anomaly, and all that we regard as laws could actually be anti-laws - bizarelly unlikely reversals of acutal laws in a harry potter universe, which could be shattered at any moment.
I mean, you don't know do you?
I do *know* because to *know* means I have a good explanation, not that I am certain. And the explanation I have is quantum theory which explains Harry Potter universes are the minority. Our 'stable' universes with predictable events is more typical.
So yes, I know.
To assert otherwise - that Harry Potter universes are typical, while ours is not, is to presume that we have completely misunderstood the Schrodinger Wave equation and what expectation values are.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.
Yes, if what *you* mean by "properties" means "physical objects". If you mean "emergent laws" then no, even these would be the same.
If by emergent laws you mean the statistical laws, like in thermodynamics. Then....I can't make sense of the distinction you are making. To the extent they arise from QM, the multiverse cannot create universes that are different. To the extent they arise from something other than QM, the multiverse cannot create universes that are different. So it's the same issue either way.
What do you mean "different"? There are many different universes in the multiverse...so I don't know what you mean. They all have the same laws but it's those same laws that ensure that there is differentiation.
Post by hibbsa
Post by Brett Hall
Consider that if there was a universe where the internal combustion engine did not exist, the laws governing that engine still would. Likewise, a universe with no life would still have laws governing predator-prey relationships...they just would never be "instantiated" (so to speak).
This all seems to be reinforcing the point I'm making. The multiverse doesn't create universes that are different. The point I'm making is...I thought...uncontroversial so far as that goes. Deutsch already says it. But what I'm pointing out is the *extremity* of that sameness.
Still not sure what you mean by different. You say the multiverse doesn't create universes that are different - but that *is* precisely what it does do, unless I have some really fundamental misconception. Right now a different universes exists where a copy of me is not typing this post. It's different to the one I am in here now where I am typing away. And the multiverse "created" those different universes.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Yes. That's exactly how we do understand such universes...as places where it is highly unlikely anything like that might (or might have) ever happened.
And about that, my point so far is just that, the multiverse of a particular object, looks exactly the same as statistic model of what might happen in this universe. Shouldn't be a controversial point.
Well I don't understand it clearly enough to appreciate whether it would be controversial or not.
Post by hibbsa
As I say...where I'm going with this I haven't got to yet. I just want to nail that we all agree on these points.
I don't know, in places, even what we are talking about to know if we agree. For example: what you are referring to by the word "different" as applied to universes above and saying the multiverse doesn't create (have? Generate?) different universes. But it does. So you must have something else in mind.
I don't know what.
Brett.
Brett - on my side I'm at risk of becoming confused as to what the issues are between us. Would you mind if I just restated my original question (not necessarily verbatim)?

My question is whether MWI adherents agree that for a given multiverse divergence of a given 'object' from a given common ancestor world, the maximum divergence for the vast majority of histories will be governed by the first emergence of the first macroscopic 'emergent' properties?

About the above...I would like to know...does this question make sense? If it kind-sorta makes sense, then that's a start...what do you (or anyone else) think it might most sensibly mean? Do you have an answer for that meaning?

To reiterate. I don't think what I am suggesting (I.e an affirmative answer) is, or should be, controversial. I think Deutsch pretty much already says it is the case. I think it is a straight consequence of some hard aspects of MWI that it is the case.

So from my perspective I think it should be possible for people to say something like "of course that is the case!"
Brett Hall
2013-06-05 04:45:56 UTC
Permalink
Post by hibbsa
Post by Brett Hall
Post by hibbsa
Post by Brett Hall
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic
universes exhibiting any statistically significant differences than
our own universe?
I mean "statistically significant" in the most rounded possible sense.
- Any difference that our universe couldn't have gone the way of,
consistent with its initial conditions all laws of physics assumed
constant
- Any difference in terms of any phenomena existing at any level of
abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of occurrence (c)
relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different at the
bottom level requires contradicting the probabilistic rules of QM
and/or causing unique consequences of those rules as a result of
interaction with macroscopic phenomena and at the top level requires
any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And
by that I mean...not just a criticism of the way the question is
formed is because there could be important consequences...which may
not be worked through. And the philosophy is all about intrepidly
working through the consequences?
I've got some consequences waiting for your criticism. But I think
it's important to establish your criticism or acceptance of the
above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you measure
its up/down state, QM predicts that you will end up yourself in the
"seeing-up + seeing-down" state. If you had decided to go in the North
or in the south, according to the result of that measurement, you end
up in the visiting-North + visiting-South. from your points of view
that is statistically different, imo. You get two macroscopically
quite different lives. This with a probability 1/2, when evaluated
before the measurement, about your future first person points of view.
Now if your question is just "is there a macroscopic world in which
elephant can fly?", the answer is also "yes", but the probability,
here-and-now, that you will see such an elephant is equivalent to
winning the big lottery every second for a time much bigger than the
age of the universe, so don't count on it. Near death, that question
is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to everything,
macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And show
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to see
how the multiverse can exhibit statistically significant differences
between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
One of the issues is that what I'm saying here about emergence and emergent properties is very much based on David Deutsch's BoI book and also his version of MWI.
I'm not saying your points aren't valid or important....but would it be possible for you to reference his Reality of Abstractions chapter and then answer the question ,more generally in terms of emergent properties as he defines them?
He states, on page one of that chapter, that emergent phenomena are a "tiny minority" of phenomena.
What significance are you attaching to his point? Emergent properties arise out of huge complexity hence they are a tiny minority of phenoma.
He also talks on page 5 of my kindle edition, about the arrow of time and the second law of thermodynamics. Disorder tends to increase. Energy is reduced in "quality" as time goes on. So although it is possible for water placed in a kettle to freeze...this is crazy unlikely. David explains on that page that it is unknown if the second law can be derived from lower level physics. The second law seems fundamental though.
Post by Brett Hall
Will there be universes where the second law *does not hold*? No.
There will be universes where it might seem not to hold...but they are Harry Potter universes again.
I think your view is debatable, but I don't currently see the importance.
Post by Brett Hall
A universe where the second law did not hold would not be very interesting for long. What would happen would be that time would *appear* to go backwards. But that would just be appearances. It would just be that things would get more ordered as time went on. So stars and galaxies would become warm nebulae which would then collect together and, I guess either form some great solid mass or just spread out uniformly throughout space in some huge crystalline structure. It would be a boring universe. And at any instant, this order would be shattered, in complete accord with the laws.
Or this universe could be the anomaly, and all that we regard as laws could actually be anti-laws - bizarelly unlikely reversals of acutal laws in a harry potter universe, which could be shattered at any moment.
I mean, you don't know do you?
I do *know* because to *know* means I have a good explanation, not that I am certain. And the explanation I have is quantum theory which explains Harry Potter universes are the minority. Our 'stable' universes with predictable events is more typical.
So yes, I know.
To assert otherwise - that Harry Potter universes are typical, while ours is not, is to presume that we have completely misunderstood the Schrodinger Wave equation and what expectation values are.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
The basic argument from me is that, since macroscopic reality is in terms of emergence, for the multiverse to produce a significantly different macroscopic world, it would have to change the emergent properties.
Yes, if what *you* mean by "properties" means "physical objects". If you mean "emergent laws" then no, even these would be the same.
If by emergent laws you mean the statistical laws, like in thermodynamics. Then....I can't make sense of the distinction you are making. To the extent they arise from QM, the multiverse cannot create universes that are different. To the extent they arise from something other than QM, the multiverse cannot create universes that are different. So it's the same issue either way.
What do you mean "different"? There are many different universes in the multiverse...so I don't know what you mean. They all have the same laws but it's those same laws that ensure that there is differentiation.
Post by hibbsa
Post by Brett Hall
Consider that if there was a universe where the internal combustion engine did not exist, the laws governing that engine still would. Likewise, a universe with no life would still have laws governing predator-prey relationships...they just would never be "instantiated" (so to speak).
This all seems to be reinforcing the point I'm making. The multiverse doesn't create universes that are different. The point I'm making is...I thought...uncontroversial so far as that goes. Deutsch already says it. But what I'm pointing out is the *extremity* of that sameness.
Still not sure what you mean by different. You say the multiverse doesn't create universes that are different - but that *is* precisely what it does do, unless I have some really fundamental misconception. Right now a different universes exists where a copy of me is not typing this post. It's different to the one I am in here now where I am typing away. And the multiverse "created" those different universes.
Post by hibbsa
Post by Brett Hall
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but surely...that world can also be understood in terms of something that * might*, or *might have* happened in this world?
Yes. That's exactly how we do understand such universes...as places where it is highly unlikely anything like that might (or might have) ever happened.
And about that, my point so far is just that, the multiverse of a particular object, looks exactly the same as statistic model of what might happen in this universe. Shouldn't be a controversial point.
Well I don't understand it clearly enough to appreciate whether it would be controversial or not.
Post by hibbsa
As I say...where I'm going with this I haven't got to yet. I just want to nail that we all agree on these points.
I don't know, in places, even what we are talking about to know if we agree. For example: what you are referring to by the word "different" as applied to universes above and saying the multiverse doesn't create (have? Generate?) different universes. But it does. So you must have something else in mind.
I don't know what.
Brett.
Brett - on my side I'm at risk of becoming confused as to what the issues are between us. Would you mind if I just restated my original question (not necessarily verbatim)?
My question is whether MWI adherents agree that for a given multiverse divergence of a given 'object' from a given common ancestor world, the maximum divergence for the vast majority of histories will be governed by the first emergence of the first macroscopic 'emergent' properties?
About the above...I would like to know...does this question make sense? If it kind-sorta makes sense, then that's a start...what do you (or anyone else) think it might most sensibly mean? Do you have an answer for that meaning?
To reiterate. I don't think what I am suggesting (I.e an affirmative answer) is, or should be, controversial. I think Deutsch pretty much already says it is the case. I think it is a straight consequence of some hard aspects of MWI that it is the case.
So from my perspective I think it should be possible for people to say something like "of course that is the case!"
We are in complete agreement on that point. It is entirely possible for someone to say "of course that is the case!" with respect to everything you have written above.

Brett.

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Bruno Marchal
2013-05-30 09:59:11 UTC
Permalink
Post by hibbsa
Post by Bruno Marchal
Post by hibbsa
Post by Bruno Marchal
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Does this question an answer?
Is it logically possible for the multiverse to produce
macroscopic
Post by Bruno Marchal
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universes exhibiting any statistically significant
differences than
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our own universe?
I mean "statistically significant" in the most rounded
possible sense.
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- Any difference that our universe couldn't have gone the
way of,
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consistent with its initial conditions all laws of physics
assumed
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constant
- Any difference in terms of any phenomena existing at any
level of
Post by Bruno Marchal
Post by hibbsa
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abstraction in greater or lesser or with any difference in any
attribute including (a) abundance (b) probability of
occurrence (c)
Post by Bruno Marchal
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relation with other phenomena (d) internal constituents.
- Any difference on any level at all where to be different
at the
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bottom level requires contradicting the probabilistic rules
of QM
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and/or causing unique consequences of those rules as a
result of
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interaction with macroscopic phenomena and at the top level
requires
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any significant difference in the timing, macroscopic and
microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full
answer. And
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by that I mean...not just a criticism of the way the
question is
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formed is because there could be important
consequences...which may
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not be worked through. And the philosophy is all about
intrepidly
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working through the consequences?
I've got some consequences waiting for your criticism. But I
think
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it's important to establish your criticism or acceptance of
the
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above first.
What do you mean by "exhibiting any statistically significant
differences than our own universe? "
If you prepare an electron in the up + down state, and if you
measure
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its up/down state, QM predicts that you will end up yourself
in the
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"seeing-up + seeing-down" state. If you had decided to go in
the North
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or in the south, according to the result of that measurement,
you end
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up in the visiting-North + visiting-South. from your points of
view
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that is statistically different, imo. You get two
macroscopically
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quite different lives. This with a probability 1/2, when
evaluated
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before the measurement, about your future first person points
of view.
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Now if your question is just "is there a macroscopic world in
which
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elephant can fly?", the answer is also "yes", but the
probability,
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here-and-now, that you will see such an elephant is equivalent
to
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winning the big lottery every second for a time much bigger
than the
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age of the universe, so don't count on it. Near death, that
question
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is just much more complex to get an answer today.
The MWI is just the statement that the SWE applies to
everything,
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macrosocopic, mesoscopic, microscopic, etc.
OK?
Bruno
Hi Bruno - no not OK but my fault. I meant statistically different
macroscopic universes. So you need to name your macroscopic
object...preferably with clear, known emergent properties. And
show
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Post by hibbsa
how those emergent properties are altered in any of its associated
quantum histories, from say,....the differences that would be
exhibited by enough copies of the object in this universe to
represent all the possible quantum histories.
And if there aren't any differences...and if our macroscopic world
is emergent phenomena from the quantum state, then it's hard to
see
Post by Bruno Marchal
Post by hibbsa
how the multiverse can exhibit statistically significant
differences
Post by Bruno Marchal
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between its macroscopic universes.
I am still not sure I really grasp your question. Planck constant is
very little. So if you decide to boil some water, QM predicts that
it
Post by Bruno Marchal
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
Our macroscopic world is not emergent from the multiverse, except
for
Post by Bruno Marchal
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by
an
Post by Bruno Marchal
asteroid a long time ago), but such branches will still obeys the
same
Post by Bruno Marchal
macroscopic laws, like classical mechanics, for example.
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that
level, we
Post by Bruno Marchal
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
Bruno
Sorry for the delay...I just wanted to think about your response for a couple of days.
No problem. Take your time.
Post by hibbsa
One of the issues is that what I'm saying here about emergence and
emergent properties is very much based on David Deutsch's BoI book
and also his version of MWI.
I'm not saying your points aren't valid or important....but would it
be possible for you to reference his Reality of Abstractions chapter
and then answer the question ,more generally in terms of emergent
properties as he defines them?
The basic argument from me is that, since macroscopic reality is in
terms of emergence, for the multiverse to produce a significantly
different macroscopic world, it would have to change the emergent
properties.
I don't know for David. With computationalism made explicit, the whole
of the physical reality emerges from the first person experience that
you can associate to some infinities of arithmetical relations. The
whole of physics is emergent, I think, from arithmetic or Turing
equivalent. But that view from inside arithmetic is not Turing
equivalent.
Post by hibbsa
I appreciate you've pointed to a Harry Potter world...but
surely...that world can also be understood in terms of something
that * might*, or *might have* happened in this world?
Yes, but with a very small relative probability, which is eventually
determined by the axioms for the basic ontology (arithmetic or Turing
equivalent). The view from inside is much more rich, and indeed
arguably beyond the whole of mathematics.

Bruno
http://iridia.ulb.ac.be/~marchal/





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Brett Hall
2013-05-27 23:53:25 UTC
Permalink
Post by hibbsa
Does this question an answer?
Is it logically possible for the multiverse to produce macroscopic universes exhibiting any statistically significant differences than our own universe?
Some universes will be "Harry Potter" universes where, for example, the entire Pacific Ocean suddenly evapourates away into outer space. These are of vanishingly small measure. But that strange occurrence, although rare is pretty "significant". You need to explain what you mean by "statistically significant" because...
Post by hibbsa
I mean "statistically significant" in the most rounded possible sense.
There is no "most rounded possible sense". The term is most typically associated with how confident one is with probability values in terms of the *standard deviation*. You can learn more here: http://en.wikipedia.org/wiki/Statistical_significance and then ask some questions or perhaps decide if using this term while chatting to Bruno (who is a mathematician and, while I do not wish to speak for him, presumably likes precision) is the best choice. Bruno, or me, or David - who have all now engaged with you on this might be thinking one thing about "statistically significant" while you are thinking something else entirely.
Post by hibbsa
- Any difference that our universe couldn't have gone the way of, consistent with its initial conditions all laws of physics assumed constant
The multiverse prescribes exactly that. We answered that before. Different universes will evolve differently as a consequence of the very laws explaining their existence. Those laws holding in exactly the same way in all universes.
Post by hibbsa
- Any difference in terms of any phenomena existing at any level of abstraction in greater or lesser or with any difference in any attribute including (a) abundance (b) probability of occurrence (c) relation with other phenomena (d) internal constituents.
I do not understand all that. It's too much all at once for me. So...my fault then, perhaps.
Post by hibbsa
- Any difference on any level at all where to be different at the bottom level requires contradicting the probabilistic rules of QM
That won't happen. Why should it? Unless you have a better theory, then why should we guess that some times in some places the laws of QM are "contradicted". To assume that *is* a contradiction if we are talking science.
Post by hibbsa
and/or causing unique consequences of those rules as a result of interaction with macroscopic phenomena and at the top level requires any significant difference in the timing, macroscopic and microscopic structure, and ultimate fate of the universe.
The reason I think this question deserves a proper full answer. And by that I mean...not just a criticism of the way the question is formed is because there could be important consequences...which may not be worked through.
That is a bizarre condition actually bordering on the dogmatic/insulting. As if to say answers provided *so far* have not been "proper full". But we have tried! There's no reason to imply, with that line, that you are not being taken seriously or being given something less than "proper full" answers.

So far you'e had myself, David Deutsch and now Bruno Marchal each independently ask you what you mean in various places. This is the best, most courteous, truth seeking way of proceeding. As I have conceded in another post on this exact topic - you may indeed have something here. I just don't know. No need for you to imply that so far I (for one) haven't given a full proper answer. I'm doing my best.
Post by hibbsa
Is it logically possible for the multiverse to produce macroscopic universes exhibiting any statistically significant differences than our own universe?
You have to understand that...we don't understand. We are not criticising *you* the person. We just want to understand the question. I thought I had a really good go at this. I thought David also responded to this in a very clear way. And now so too has Bruno. But it seems you are not happy with our responses and instead of asking further questions, or trying to rephrase, we get instructions to not provide
Post by hibbsa
a criticism of the way the question is formed is because there could be important consequences
But that "criticism" of the way the question is formed is the only way we can get to what you are actually talking about. Clearly you do need to change the *form* because all present attempts have failed. There can never be perfect transmission of a message so that receipt is error-free. All is fallible. In this case both you (the sender) and us (the receiver) are prone to errors. We just are not communicating well at all now so I'm asking for some error correction in the form of a re-transmission but in a different form because the current form seems to be error prone (whether it's with sender or receiver or both, I don't know - so this asking for rephrasing is one tactic I'm employing).
Post by hibbsa
I am still not sure I really grasp your question.
I think that's fair. But it's *not* fair to say he should not be able to say this sort of thing (it *is* a criticism of form until we can get at the substance).
Post by hibbsa
Planck constant is
very little. So if you decide to boil some water, QM predicts that it
will boil normally in most of the branches you can access in the
multiverse, with some non negligible probability. Then you will have
the many universes fluctuating from that behavior, but,
proportionally, they will be rarer. At the extremal point of the
spectrum of the possibilities, you will have the "Harry Potter"
universe, but those are quasi-impossible to access (a good thing),
except perhaps near death, as the probabilities on the first person
expectancies get harder to compute.
I agree with all this. And it is what I was saying using the example of the cans of your water - some small measure of which boil instantly and some not at all (they are your Harry Potter universes).
Post by hibbsa
Our macroscopic world is not emergent from the multiverse, except for
most quantum properties, so our universe is quantum normal, with
solid, liquid and gaz well described by the quantum statistics. but
each branches differ on orthogonal or quasi orthogonal state, and so
can differ in macroscopic properties (like if earth was not hit by an
asteroid a long time ago), but such branches will still obeys the same
macroscopic laws, like classical mechanics, for example.
Yes, the same laws exist in all places in the multiverse.
Post by hibbsa
Our local realities are Gaussian, and that's why we can discern all
sort of laws. In fact that appears with just computationalism too.
Below our level of substitution, we emerge from infinities of
computations, which interfere statiostically, but above that level, we
have much simpler classical laws. In QM this is explained by MWI +
decoherence. With digital mechanism it is far more complex, but then
we can explain where the quantum comes from.
I hope this help, feel free to make your question more precise, if I
miss your point,
I am an optimist that hibbsa will!
Post by hibbsa
And the philosophy is all about intrepidly working through the consequences?
But, hibbsa, how can we work through the consequences when we do not even understand the antecedents (the conditions, the thought experiment, the *question*?).
Post by hibbsa
I've got some consequences waiting for your criticism. But I think it's important to establish your criticism or acceptance of the above first.
I am still asking "criticism or acceptance *of what*?". Again, we *can* reach consensus. We just have to keep trying. But asking the same question, without rephrasing, is not trying (not trying something new anyways) and that's no way to make progress...or come to some meeting of minds.



Brett.





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