Bad Science and the Anthropic Cosmological Principle

[moving finger]

"Bad Science" and the Anthropic Cosmological Principle

Many observers have noted that the physical laws, parameters and constants of our cosmos appear to be remarkably "fine tuned" in accordance with our existence. There are a number of suggestions that if certain parameters were to be significantly different to what they are then the cosmos would be completely different and possibly unable to support life (see for example Barrow & Tipler's book The Anthropic Cosmological Principle).

If (and I grant that is currently a big "IF") one accepts that the cosmos does appear to be fine-tuned in accordance with our existence, then I believe there are three basic possible approaches to understanding this particular observation :

Argument from Design
One possible answer is that the universe comprises one cosmos, and our universe was simply designed this way (ie to support life). This would then be strong evidence for a "Designer". This would explain why the physical laws, parameters and constants are what they are, and also why they are consistent with intelligent life. Of course it does mean that "humans are special" (but that is exactly what we would expect if the universe had been designed for us!).

Argument from Good Luck
Another possible answer is that the universe again comprises only one cosmos, and the physical laws, parameters and constants all arise from (ie are predicted by) some grand Theory of Everything (ToE), which ToE also (fortuitously for us!) happens to be compatible with the emergence of intelligent life. However, this approach has the unsatisfactory consequence that although it would explain "why" the physical laws, parameters and constants are what they are, it would NOT explain why they also happen to coincide with the requirements for intelligent life. Like the Design argument, this hypothesis would also seem to put humans in the position of "we must be special", since there is only one cosmos, and fortuitously the ToE which constrains the parameters of that cosmos is also just right for our existence!

Argument from Anthropic Considerations
A third possible answer is that the universe comprises a multiple (possibly infinite) number of possibly parallel "worlds", of which we happen to inhabit just one. Each "world" has slightly different physical laws, parameters and constants (perhaps selected at random in each one), and (as we would expect) only some of these are compatible with the emergence of intelligent life. We, of course, happen to inhabit one of the compatible ones. This argument has the advantage that it posits no Designer, does not require any fortuitous fine-tuning of parameters, and consequently also implies that "we are not special" (we just happen to have emerged where conditions were right). Such a principle could also be consistent with the many "eternal inflation" theories going the rounds.

In summary :

Argument from Design : There is one cosmos, we are special, and there is a Designer.
Argument from Good Luck : There is one cosmos, we are special, and there is a ToE which fixes the parameters.
Argument from Anthropic Considerations : There are multiple worlds, we are not special, and there is no ToE which fixes parameters.

The Anthropic argument is often criticised on the basis that it makes no testable predictions, and for this reason is usually rejected by many mainstream scientists as being "Bad Science". Presumably most of these scientists would favour instead the "Good Luck" argument, and prefer to spend their time in pursuit of the ToE.

I want to say some words in defence of the Anthropic argument.

Firstly, if it turns out that the universe IS very finely tuned to support our existence, then it seems to me that the Anthropic argument is the ONLY one of the three explanations which does not assume a "special status" for human beings. this is appealing to me, and I think should be appealing to others.

Secondly, if the Anthropic principle IS correct, then we may end up wasting an enormous amount of time and energy trying to chase the Holy Grail of a ToE which does not exist.

Thirdly, it may indeed be the case that the Anthropic argument does not make any testable predictions at the moment, but this does NOT mean that it will continue to be devoid of predictions forever. If we do indeed live in a universe comprising "multiple worlds" then it may be the case that one day we can somehow probe the other worlds (which should have different physical parameters to our own). Just because an hypothesis cannot make testable predictions today is NO reason to consign it to the trash heap.

In closing - a small joke :

A drunk was down on his hands and knees under a streetlight at night, obviously looking for something. A policeman came along and asked him what he was looking for.
“My keys,” replied the drunk.
The officer, in much better shape than the other, could plainly see there were no keys there. Curious, he asked “Where did you lose them ?”
To the officer’s surprise the drunk pointed down the dark street and said, “Back there.”
“But if you lost them down the street,” asked the policeman, “why are you looking for them here ?”
“Because,” came the drunk’s reply, “the light is much better here."

In searching for the ToE and ignoring the Anthropic principle, are we, like the drunk in the story, perhaps searching for solutions only where the light makes it easy to see?

MF

 

[tdunc]

A grand theory of everything doesn't necessarily involve what your saying it would. For example physicists are trying to merge gravity with QED, if done then that would be their holy grail, ToE. But I know what your saying, a ToE for exsistence. What is the point of your post? Are you asking a question? I have already figured out everything you said on my own. Everything is clearly designed for the development and support of life. Besides what would be the point of the exsistence of a vast Universe, full of rocks?

parallel worlds? No. Why? What is the point of parallel worlds? Anyone who even mentions them is a nut. Besides they don't work.

"humans are special", you better believe it. Are you kidding me? Damn right we are. Can you even imagine a species uh, more special? I can't. I mean I could, but who knows where we will go, evolve into. On the question of how advanced are we, Id say pretty damn advanced, and we arent going backwards only forwards so who knows where we will go. Eventually, we will know how it all goes together, and when we reach that point, what is the difference between us and the original creators?

Basically it goes like this, in order to create the Universe we live in, you need to figure out the laws of physics. In other words you cannot create the Universe without establishing laws of physics first, then implement them- by experiment. You cannot create the laws of physics without knowing them, you cannot know the laws of physics without learning the laws of physics - by experiment, by test worlds to get everything to work together. The Universe and the laws of physics didnt just create themselves, didnt just bang into exsistence, there is just NO way.

My 2 cents.

 

[Chronos]

I'm not convinced we will ever find the ToE to end all ToE's. It would be a huge disappointment if we did, for it would signal we have reached the limits of our imagination. Every answer raises new questions. We know less about the universe now than ever. And the questions are profoundly difficult. A few centuries ago our ancestor looked at the night sky and wondered "What is that fuzzy blob in the constellation Andromeda?". A door that opens into a room with no other exits is called a dead end.

 

[SpaceTiger]

A link to a similar thread in the philosophy section. Most of what I have to say on the issue was covered there.

 

[moving finger]

A grand theory of everything doesn't necessarily involve what your saying it would. For example physicists are trying to merge gravity with QED, if done then that would be their holy grail, ToE. But I know what your saying, a ToE for exsistence.

Yes, sorry, I should have said that to my mind a ToE would be what it claims to be - a Theory of Everything (not just a theory linking gravity & QED).

What is the point of your post? Are you asking a question?

I am trying to stimulate discussion and an exchange of views - isn't that what a forum is supposed to be for?

I have already figured out everything you said on my own.

Well done!

Everything is clearly designed for the development and support of life. Besides what would be the point of the exsistence of a vast Universe, full of rocks?

No, this is not "clear". Does this mean that you support the "Design" argument?

parallel worlds? No. Why? What is the point of parallel worlds?

Why does there have to be a "point"? Is there purpose in everything?

Anyone who even mentions them is a nut.

I could say that anyone who believes in a Designer is a nut, but I have more respect for my weak-minded brethren.

Besides they don't work.

Oh yes they do.

"humans are special", you better believe it. Are you kidding me? Damn right we are. Can you even imagine a species uh, more special? I can't. I mean I could, but who knows where we will go, evolve into. On the question of how advanced are we, Id say pretty damn advanced, and we arent going backwards only forwards so who knows where we will go. Eventually, we will know how it all goes together, and when we reach that point, what is the difference between us and the original creators?

I think you totally misunderstand the meaning of special in this context. Have you heard of the Copernican Principle?

Basically it goes like this, in order to create the Universe we live in, you need to figure out the laws of physics. In other words you cannot create the Universe without establishing laws of physics first, then implement them- by experiment. You cannot create the laws of physics without knowing them, you cannot know the laws of physics without learning the laws of physics - by experiment, by test worlds to get everything to work together. The Universe and the laws of physics didnt just create themselves, didnt just bang into exsistence, there is just NO way.

This does not logically follow, but I respect your faith. Thus you believe the universe was designed and created by something even greater than the universe?

MF

 

[moving finger]

I'm not convinced we will ever find the ToE to end all ToE's. It would be a huge disappointment if we did, for it would signal we have reached the limits of our imagination. Every answer raises new questions. We know less about the universe now than ever. And the questions are profoundly difficult. A few centuries ago our ancestor looked at the night sky and wondered "What is that fuzzy blob in the constellation Andromeda?". A door that opens into a room with no other exits is called a dead end.

I tend to agree with you. I suspect it may be "turtles all the way down".

But if it turns out that the universe is "finrly tuned" to allow our existence, then I would put my money on the Anthropic principle rather than one of the other explanations (because the other explanations simply replace one question with a deeper one).

MF

 

[marcus]

But if it turns out that the universe is "finrly tuned" to allow our existence, then I would put my money on the Anthropic principle rather than one of the other explanations (because the other explanations simply replace one question with a deeper one).

I am sympathetic to the general spirit, but I wonder if you would accept as a FRIENDLY addition to your trichotomy a fourth possibility.

this is the possibility that the parameters of the standard models of particle physics and cosmology are "fine-tuned" to promote the abundant formation of black holes.

not "fine-tuned" a conscious agency, of course, (the almighty Turkey of the Cosmos, who happens to like black holes ) but that the parameters HAPPEN TO BE FAVORABLE to black hole formation, which may be explainable or may not be.

One possible explanation for why the physical constants seem favorable to black holes has been offered (you may be familiar with the paper) in the 2004 paper "Scientific Alternatives to the Anthropic Principle" due to be published this year by Cambridge Press.

the conjecture appears to be empirically testable----i.e. possible to refute if one could find some parameters which are grossly suboptimal from the BH production standpoint.

to make a lot of black holes you need a long-lived tract of spacetime that doesn't die in a crunch soon after inception, and which does not expand too fast for galaxies and stars to condense, and which has enough heavy elements like carbon etc to help gravitating clouds radiate away heat so they can condense. and one may guess that there should be not too high a limit on the mass of neutron stars above which they collapse-----so it seems possible that a lot of the constants of physics could be included in the picture and constrained by this requirement (this is what the author of "Scientific Alternatives" tries to accomplish)

 

[Locrian]

I disagree with the way the second argument is presented. There is no need for the existence of a TOE for the good luck argument to be applied.

In fact, I disagree with the third as well. There is no need for the lack of existence of a TOE in that case; there could be a TOE that allows many universes of which we are one. The landscape of string physics is one such example.

 

[moving finger]

I am sympathetic to the general spirit, but I wonder if you would accept as a FRIENDLY addition to your trichotomy a fourth possibility.

certainly open to suggestions...

this is the possibility that the parameters of the standard models of particle physics and cosmology are "fine-tuned" to promote the abundant formation of black holes.

not "fine-tuned" a conscious agency, of course, (the almighty Turkey of the Cosmos, who happens to like black holes ) but that the parameters HAPPEN TO BE FAVORABLE to black hole formation, which may be explainable or may not be.

ok... but so far this seems to be very similar to the third option - the anthropic principle - if black holes are necessary for the existence of intelligent beings. However I see no reason why black holes should be necessary for the existence of intelligent beings - so why does it matter whether the universe contains black holes or not? (I think I know the answer, but am asking the question because you have not stated it explicitly...)

One possible explanation for why the physical constants seem favorable to black holes has been offered (you may be familiar with the paper) in the 2004 paper "Scientific Alternatives to the Anthropic Principle" due to be published this year by Cambridge Press.

Nope, can't say I am familiar with the paper. What is the explanation you refer to please?

the conjecture appears to be empirically testable----i.e. possible to refute if one could find some parameters which are grossly suboptimal from the BH production standpoint.

OK.

to make a lot of black holes you need a long-lived tract of spacetime that doesn't die in a crunch soon after inception, and which does not expand too fast for galaxies and stars to condense, and which has enough heavy elements like carbon etc to help gravitating clouds radiate away heat so they can condense. and one may guess that there should be not too high a limit on the mass of neutron stars above which they collapse-----so it seems possible that a lot of the constants of physics could be included in the picture and constrained by this requirement (this is what the author of "Scientific Alternatives" tries to accomplish)

OK, but you have not explained why it should matter whether the universe contains black holes or not?

MF

 

[moving finger]

I disagree with the way the second argument is presented. There is no need for the existence of a TOE for the good luck argument to be applied.

Can you elaborate please?
(1) assumes Design - good luck is hardly relevant here (the universe is the way it is because it was deliberately designed that way)

and

(3) as I have stated it assumes an unlimited (infinite?) number of different worlds, each with different parameters, thus all possible combinations of laws exist and we happen (necessarily) to inhabit a world where the laws allow our existence. There is therefore also no "good luck" involved here.

In case (2) the ToE would seem to result in precisely the right kind of universe for our existence - which seems like good luck to me.

Can you please elaborate on your statement that "There is no need for the existence of a TOE for the good luck argument to be applied."?

In fact, I disagree with the third as well. There is no need for the lack of existence of a TOE in that case; there could be a TOE that allows many universes of which we are one. The landscape of string physics is one such example.

I agree (3) does not imply the total "lack" of a ToE, but it does imply that the ToE does not "need to explain" why the physical laws and parameters are as they are in our world - whereas the ToE in (2) DOES need to explain why the physical laws and parameters are as they are in our world (or, in absence of an explanation, we simply assume that we have been extremely lucky).

MF

 

[Locrian]

Can you please elaborate on your statement that "There is no need for the existence of a TOE for the good luck argument to be applied."?

The universe could be made up of many separate physical systems that require entirely separate theories and therefore can never be described by one TOE; each of these could luckily be tuned correctly.

I'm not saying I believe this, but as long as you are making a good luck argument, there is no reason to include a TOE.

 

[marcus]

certainly open to suggestions...

One possible explanation for why the physical constants seem favorable to black holes has been offered (you may be familiar with the paper) in the 2004 paper "Scientific Alternatives to the Anthropic Principle" due to be published this year by Cambridge Press.

Nope, can't say I am familiar with the paper. What is the explanation you refer to please?

"Scientific Alternatives to the Anthropic Principle"
http://arxiv.org/hep-th/0407213

for more discussion
https://www.physicsforums.com/showthread.php?t=70737

 

[moving finger]

The universe could be made up of many separate physical systems that require entirely separate theories and therefore can never be described by one TOE; each of these could luckily be tuned correctly.

I'm not saying I believe this, but as long as you are making a good luck argument, there is no reason to include a TOE.

OK, I think I see what you are saying.

Please correct me if I am wrong :

The suggestion you are making is that there is one cosmos.
That there may not be one single all-encompassing ToE in this one cosmos, but that we need several unrelated theories to explain why the physical constants are what they are.
This would (I agree) imply that we are indeed lucky.

However, this then seems to be a variant of (2) - ie one cosmos, we are special, and we are very lucky - the only difference with (2) is that there is no single ToE but instead multiple unrelated theories.

Possibilities (1) and (3) still stand (and these possibilities do not imply luck).

MF

 

[marcus]

"Scientific Alternatives to the Anthropic Principle"
http://arxiv.org/hep-th/0407213

for more discussion
https://www.physicsforums.com/showthread.php?t=70737

I'd say that one of the main points of Smolin's paper is that the Anthropic Principle is "Bad Science" because it is not falsifiable. It does not bet its life (and risk refutation) on the outcome of some future experiment. Instead it appears to be able to accommodate any outcome of any future observation because, well, "here we are".

So the title of your thread, "Bad Science" and the AP, is (perhaps unintendedly!) a propos.


the trichotomy you give at the beginning does not exhaust the possibilities

One possibility is that the parameters of the Standard Models (for particle physics and astronomy) are approximately optimized for Black Hole production by an evolutionary mechanism described in Smolin's paper and also discussed in the thread for which I provided the link.

the implications of Smolin's model, and the opportunities to test it, are only partially worked out, and it could be falsified tomorrow for example by observing a neutron star with a mass exceeding what the theory predicts.
But it is a possible theory with some predictive and explanatory power, and one which can be wrong which the premise of conscious life cannot be.

 

[moving finger]

"Scientific Alternatives to the Anthropic Principle"
http://arxiv.org/hep-th/0407213

for more discussion
https://www.physicsforums.com/showthread.php?t=70737

Thanks!

I'd say that one of the main points of Smolin's paper is that the Anthropic Principle is "Bad Science" because it is not falsifiable. It does not bet its life (and risk refutation) on the outcome of some future experiment. Instead it appears to be able to accommodate any outcome of any future observation because, well, "here we are".

I do not agree that this means the anthropic principle will necessarily "always be" not falsifiable, therefore it does not qualify as "bad science" in my book (a point I tried to make in my post). Any hypothesis (inlcuding the anthropic principle) must have some assumptions or axioms, and it is these assumptions or axioms that we need to have access to in order to try and falsify the hypothesis.

One variant of the anthropic principle is that there are an unlimited number of worlds, each with slightly different physical laws/constants. Thus an assumption or axiom in this variant is that such other worlds exist.

So the title of your thread, "Bad Science" and the AP, is (perhaps unintendedly!) a propos.

Nope, it was entirely intended, since I anticipated exactly what you said!

the trichotomy you give at the beginning does not exhaust the possibilities

One possibility is that the parameters of the Standard Models (for particle physics and astronomy) are approximately optimized for Black Hole production by an evolutionary mechanism described in Smolin's paper and also discussed in the thread for which I provided the link.

OK, thanks, I will read up on it and get back to you

the implications of Smolin's model, and the opportunities to test it, are only partially worked out, and it could be falsified tomorrow for example by observing a neutron star with a mass exceeding what the theory predicts.
But it is a possible theory with some predictive and explanatory power, and one which can be wrong which the premise of conscious life cannot be.

OK

MF

 

[Garth]

Whether the Anthropic Principle is 'bad science' or not because it is not falsifiable is an interesting question.

Instead it appears to be able to accommodate any outcome of any future observation

Like the theory of evolution then? Which is ironic because Smolin's own alternative CNS is a cosmological version of the theory of evolution!

It depends how exactly the principle is being defined. As a simple acknowledgment that our existence requires tight constraints on physical and cosmological parameters, ("The universe is as it is because we are" - Stephen Hawking), it is not so much a theory to be falsified but a tautological truth; it is self-evident.

The Anthropic Principle makes plenty of predictions, the problem is, "because here we are" they all have to turn out to be correct! So that's not falsifiability?

Just a thought or two.

Garth

 

[marcus]

...One variant of the anthropic principle is that there are an unlimited number of worlds, each with slightly different physical laws/constants. Thus an assumption or axiom in this variant is that such other worlds exist.

...Nope, it was entirely intended, since I anticipated exactly what you said!


...I will read up on it and get back to you

reason and courtesy shows, I will try to manage not to be outdone in that respect. I hope you do have a look at the article (and perhaps the first halfdozen posts of that thread). Am looking forward to your getting back about it.

 

[moving finger]

As a simple acknowledgment that our existence requires tight constraints on physical and cosmological parameters, ("The universe is as it is because we are" - Stephen Hawking), it is not so much a theory to be falsified but a tautological truth; it is self-evident.

The Anthropic Principle makes plenty of predictions, the problem is, "because here we are" they all have to turn out to be correct! So that's not falsifiability?

I agree, which is why to be acceptable the Anthropic Principle (AP) stated simply as "the universe is as it is because we are here" is not enough. What needs to be developed from that is an Anthropic Hypothesis (AH).

It's a bit like the Cosmological Principle (CP), which simply says that we are not in a special place in the universe. This principle is well accepted because it in turn implies the hypothesis that the universe should then appear isotropic and homogeneous to us - which is falsifiable.

To be credible, perhaps the AP needs to be linked to one or more AH's.

I think the real message of the AP is not "we are here because we are here" (which as you say is tautological) but that it assumes (like the CP) that humans are not in a special place, that we are not specially favoured by good design or good luck. This to me seems a very strong principle.

One AH could be the suggestion that there are multiple worlds each with slightly varying constants. This would be consistent with the AP and thus would not require design or "good luck".

The alternatives to the AP seem to require either good design or good luck - which to me seems far less acceptable than the AP.

MF

 

[Garth]

The alternatives to the AP seem to require either good design or good luck - which to me seems far less acceptable than the AP.

MF

"The alternatives to the AP seem to require either good design or good luck" ... or a multiverse.

The problem is that at the limit of scientific observability the preference of either of these three possibilities requires an act of faith, for until we can observe 'other universes' in which the laws of physics are demonstrably different from our own then the hypothesis of a multiverse is as much an act of faith as the hypothesis of a creator. Neither are scientifically verifiable or falsifiable.

Garth

 

[moving finger]

The problem is that at the limit of scientific observability the preference of either of these three possibilities requires an act of faith

All hypotheses require an "act of faith" as you put it, unless and until such time as they can be tested.

At the moment the multiverse hypothesis does not seem to be verifiable, but as I said in my original post, does this mean it will never be verifiable?

until we can observe 'other universes' in which the laws of physics are demonstrably different from our own then the hypothesis of a multiverse is as much an act of faith as the hypothesis of a creator. Neither are scientifically verifiable or falsifiable.

I am glad you prefaced your comment with the word "until".

Should we always discard a plausible hypothesis just because it cannnot be tested immediately, and focus on only what we can verify today, just like the drunk searching for his keys under the streetlight? Or should we remain open-minded and work with all plausible hypotheses, attempting to move towards a situation where we can find evidence to falsify each of them?

IMHO, unless and until such time as the 3 optional explanations I have suggested can be tested, I am more comfortable believing that we live in a "multiverse" which is not "designed" and does not require incredible "good luck", rather than believing in a Designer or that intelligent life has somehow been incredibly lucky to exist.

MF

 

[moving finger]

"Scientific Alternatives to the Anthropic Principle"
http://arxiv.org/hep-th/0407213

Excellent paper, thank you! I enjoyed it immensely (even though I did not entirely agree with the content).

Some quick points :

The AP and testable predictions : I agree the AP as it stands makes no testable predictions - but this is perhaps a consequence of it being a very general principle (ie a statement) rather than a hypothesis. The AP makes a "statement" about our universe, such that alternative cosmological hypotheses can be either consistent with, or inconsistent with, the AP.

The Cosmological Principle (CP) is somewhat analogous in this respect. The CP states that we do not live in a special part of the universe. Taken at face value, it is hard to see how the CP (as stated) can be tested (apart from traveling to many other parts of the universe and checking them out). However we can hypothesise that, if the CP is true, then the universe should appear pretty much homogeneous and isotropic from our perspective - and this hypothesis IS testable.

IMHO, all that is needed is a hypothesis (or set of hypotheses) which is based on the AP, and which can be tested.

The hypothesis of a single universe with a ToE which determines all physical constants is not consistent with the AP. This hypothesis may be scientifically testable (but we may also find that it is "turtles all the way down, and we never reach the final ToE - thus rendering it untestable).

The hypothesis of a single designer universe is also not consistent with the AP. This theory is generally acknowledged to be not scientifically testable.

The hypothesis of multiple "universes", each with different physical constants, is however an hypothesis consistent with the AP, and this hypothesis is (in principle) testable. Smolin even considers this hypothesis part of "good science" (whilst he rejects the AP itself as part of "bad science").

Thus (above) we have 3 hypotheses, two of which may be testable, one of which is consistent with the AP.

The suggested hypothesis of "selection effects" within a multiverse, also discussed by Smolin, is also consistent with the AP.

I sympathise to some extent with Smolin's views about the AP, but I think he is over-reacting. Where Smolin seems to want to reject the AP completely (because the AP is unverifiable), I believe it is in fact possible to phrase the AP such that, as a statement of principle, it forms the basis of legitimate and testable hypotheses about our universe.

Conclusion : As a principle, the AP may indeed be unverifiable, but hypotheses which build upon and adhere to this principle are not so constrained.

Thus (IMHO) I believe it comes down to the following :

Any hypothesis about the origin of the universe(s) can be put into one of the following three categories :

The hypothesis is based on the Design Principle (DP) (ie the universe is unique, and it is designed for our benefit; which implies that we are somehow special)

The hypothesis is based on the Good Luck Principle (GLP) (ie the universe is unique, and there is a ToE which determines the physical constants, and we are just very fortunate that this ToE happens to be compatible with our existence; which implies that we are somehow special)

The hypothesis is based on the Anthropic Principle (AP) (ie the universe is not designed and there is no ToE which fixes all physical parameters, but instead there is something akin to a multitude of different worlds of which we happen to inhabit one; we are not special)

These three principles (DP, GLP and AP) I believe are normally intended to be mutually exclusive (ie a particular hypothesis can adhere to at most one principle, never to two or all three simultaneously).

Depending on the precise details of a particular multiverse hypothesis, the hypothesis could be made to be consistent with either AP or GLP (or even DP).

Most multiverse hypotheses, including the ones reviewed by Smolin, (I submit) are normally written to be consistent with the AP.

MF

 

[marcus]

These three principles (DP, GLP and AP) I believe are normally intended to be mutually exclusive (ie a particular hypothesis can adhere to at most one principle, never to two or all three simultaneously).

Depending on the precise details of a particular multiverse hypothesis, the hypothesis could be made to be consistent with either AP or GLP (or even DP).

Most multiverse hypotheses, including the ones reviewed by Smolin, (I submit) are normally written to be consistent with the AP.

MF thanks for giving the BH hypothesis your consideration, and reading "Scientific Alternatives"!

I was wondering if you would add BHP to your trichotomy, but at least for now you have not. I suspect this may be because you see a fair amount of similarity or overlap between AP and BHP, and you made the point explicitly that you want these various hypotheses to be mutually exclusive.

 

[moving finger]

MF thanks for giving the BH hypothesis your consideration, and reading "Scientific Alternatives"!

I was wondering if you would add BHP to your trichotomy, but at least for now you have not. I suspect this may be because you see a fair amount of similarity or overlap between AP and BHP, and you made the point explicitly that you want these various hypotheses to be mutually exclusive.

Hi Marcus
I owe a fuller explanation.
The Black Hole Principle (BHP) that you refer to (as far as I can understand it) is that new "universes" can be created via the collapse and "bounce" of black holes. The new region of spacetime created in the "bounce" is a new universe.

Now, one can suggest that the ToE and the laws of physics are carried through rigidly and deterministically from one universe to the next, in which case this becomes a subset of the "Good Luck Principle" - there is one ToE which determines the laws of physics in all universes, and our existence in ANY universe is fortunate.

Or one can suggest that the laws of physics are somehow "scrambled" or "modified" during the bounce, in which case I would suggest this becomes a subset of the Anthropic Principle - we end up with multiple universes with different physical laws and we necessarily happen to inhabit one that is conducive to our health!

Thus, the hypotheses which emerge from the BHP should (I believe) each fall under either the GLP or the AP, depending on whether or not the laws of physics are preserved at the bounce.

Hope this make sense?

MF

 

[marcus]

Hi Marcus
I owe a fuller explanation.
The Black Hole Principle (BHP) that you refer to (as far as I can understand it) is that new "universes" can be created via the collapse and "bounce" of black holes. The new region of spacetime created in the "bounce" is a new universe.

Now, one can suggest that the ToE and the laws of physics are carried through rigidly and deterministically from one universe to the next, in which case this becomes a subset of the "Good Luck Principle" - there is one ToE which determines the laws of physics in all universes, and our existence in ANY universe is fortunate.

Or one can suggest that the laws of physics are somehow "scrambled" or "modified" during the bounce, in which case I would suggest this becomes a subset of the Anthropic Principle - we end up with multiple universes with different physical laws and we necessarily happen to inhabit one that is conducive to our health!

Thus, the hypotheses which emerge from the BHP should (I believe) each fall under either the GLP or the AP, depending on whether or not the laws of physics are preserved at the bounce.

Hope this make sense?

MF

What you say makes sense but does not adequately connect with Smolin's idea (which he calls CNS or cosmological natural selection and which I would call BHP to fit it into your notation)

what Smolin postulates in this theory is that parameters are perfectly transmitted or SLIGHTLY altered by passage thru the former singularity

It seems to me that you picture an extreme dichotomy in which parameters are passed thru either 100 percent, or totally randomized. In neither case would one get evolution.

As a metaphor, the child should not be an exact copy of the parent but should also not be a totally different species with randomly different DNA.

the way evolutionary mechanisms work is by near-perfect reproduction but with (usually at least) SLIGHT mutation

think of the size of the change of a parameter as a bellcurve.

In this case what one gets is neither good luck nor anthropic.

it is not anthropic because it does not depend on or refer to the existence of life (parameters are optimized and gradually stabilize at values favoring plentiful black hole formation-----values which INCIDENTALLY permit carbonbased life)

it is also not good luck, any more than a gazelles genes permit it to run fast by good luck, there was a selection mechanism that determined the genes and (in our case) determined the physical constants.

essentially we are talking about selection for reproductive success leading to something that is reproductively successful (and how that explains the values of the constants)-----it does not fit into your trichotomy, I believe, and needs to appear as a fourth possibility

 

[marcus]

Thus, the hypotheses which emerge from the BHP should (I believe) each fall under either the GLP or the AP, depending on whether or not the laws of physics are preserved at the bounce.

trying to be concise: when you way "whether or not" it is too much a zero or 1 portrayal. How about the laws of physics are 99.9 percent preserved at the bounce?

then its is neither good luck or anthropic-----life is irrelevant and the system naturally evolves towards a set of fundamental constants that give a lot of black holes. (incidentally making life possible as byproduct or side effect)

more explanation and discussion here:
https://www.physicsforums.com/showthread.php?t=70737

 

[moving finger]

What you say makes sense but does not adequately connect with Smolin's idea (which he calls CNS or cosmological natural selection and which I would call BHP to fit it into your notation)

sorry, I disagree, as explained below. I think what we have here is a case of “different shades of grey” which can be sliced up (segmented) in different ways (explained below).

what Smolin postulates in this theory is that parameters are perfectly transmitted or SLIGHTLY altered by passage thru the former singularity

(BTW - the content of Smolin’s paper represents at best an hypothesis, not a theory)
what I said in my last post is :

one can suggest that the ToE and the laws of physics are carried through

(this corresponds to Smolin’s “perfectly transmitted” case, let’s call this A)
or

one can suggest that the laws of physics are somehow "scrambled" or "modified"

(this can incorporate Smolin’s “SLIGHTLY altered” case, let’s call this B)

there is also a third possibility (let’s call it C) which is not included in either (A) “perfectly transmitted” or (B) “SLIGHTLY altered”, which is “GROSSLY altered”. But “GROSSLY altered” IS already incorporated into my “one can suggest that the laws of physics are somehow "scrambled" or "modified"”

Thus (in my scheme) everything becomes a subset of two possibilities – the parameters are either perfectly transmitted (A), or they are transmitted with some modification (either B or C).

It seems to me that you picture an extreme dichotomy in which parameters are passed thru either 100 percent, or totally randomized. In neither case would one get evolution.

No, sorry but you misread my post. I did NOT say that parameters are necessarily either preserved or completely randomised, I said

one can suggest that the laws of physics are somehow "scrambled" or "modified"

now “modified” (at least to me) incorporates the “SLIGHTLY altered” possibility.

As a metaphor, the child should not be an exact copy of the parent but should also not be a totally different species with randomly different DNA.

Again, I did not suggest that each daughter universe must be a totally different species, I said

one can suggest that the laws of physics are somehow "scrambled" or "modified"

now, “modified” (at least to me) incorporates the “should not be an exact copy of the parent but should also not be a totally different” possibility.

(with respect, marcus, it seems that you are maybe reading words or meanings into my post that are not there?)

the way evolutionary mechanisms work is by near-perfect reproduction but with (usually at least) SLIGHT mutation

yes, I am aware of Darwin’s theory

In this case what one gets is neither good luck nor anthropic.

I disagree, in this case (ie the SLIGHTLY modified case, but without unnecessarily constraining the physical parameters in any other way) what one gets is something which can completely accord with the AP (see below).

it is not anthropic because it does not depend on or refer to the existence of life

Sorry, but I think we have different concepts of the AP (yours seems much more limited and restrictive than mine). To me, the AP does NOT say that any particular universe "depends on or refers to the existence of life", it simply says "the fact we exist shows that the particular universe we inhabit must be conducive to life, for which there must be a rational (and not a design or good luck) explanation".

We need to emphasise this, because it is important. To my mind, the AP tells us NOT that “life is a priori necessary, therefore a universe (multiverse) conducive to life is also a priori necessary”. I do not believe that life is a priori necessary, and I can envisage a multiverse in which there is no life at all.
However, in the case where we observe that life exists (ie the present case), we conclude that the universe (multiverse) we inhabit is conducive to life, and what the AP tells us in this case is that there must be some rational explanation WHY the universe (multiverse) is conducive to the life that we observe which is NOT based solely on either Design or Good Luck”

(parameters are optimized and gradually stabilize at values favoring plentiful black hole formation-----values which INCIDENTALLY permit carbonbased life)

Now this is the interesting bit. What you are suggesting seems to be a restrictive “constraint” (even if a Darwinian type of constraint) on the parameters. If we are suggesting that there are in fact only a limited number of universes and all of these universes have physical parameters which are somehow constrained (in the Darwinian sense) within a narrow range such that they must “favour plentiful black hole formation”, and it is then simply INCIDENTAL that at least one of them also happens to be conducive to life, then I would say this is an example which is more in accordance with the Good Luck Principle than the AP. In other words, in such a constrained multiverse we simply are fortunate that the physical parameters which favour black hole formation (for some unexplained reason) also incidentally just happen to be conducive to life.

An analogy – imagine we are actually a particular type of special non-living dust particles which exist and only exist on the backs of gazelles. Our particular type of particle needs the “gazelle” environment (but the gazelle does not need us, and I am not suggesting any kind of co-evolution or symbiosis), we cannot exist on dogs or cats or fish for example. We ask “why are the conditions on the back of this gazelle apparently just perfect for our existence?”

We could say “the gazelle was designed that way, such that we would exist on it’s back” (DP), or “gazelles are the only animals which exist, and it is just simply (incidentally) the case that the conditions on gazelles are just right for us” (GLP), or “there are in fact many different animals, apart from gazelles, but only this particular species (gazelles) has conditions which are right for us” (AP).

Now, I humbly suggest that the case where “natural selection” of the universes within a multiverse is constrained to produce only universes favoring black hole production, and where such universes are also (incidentally) conducive to life, is like saying “only gazelles exist, and we are simply lucky that the conditions on gazelles are just right for us”.

it is also not good luck, any more than a gazelles genes permit it to run fast by good luck, there was a selection mechanism that determined the genes and (in our case) determined the physical constants.

Disagree, for the reasons given above. In the example I gave, the gazelle’s genes are optimised (Darwinian-sense) for the reproduction of gazelles, NOT to enable the special dust particles to exist comfortably on its back (the analogy : your BHP says that the physical constants are optimised for the reproduction of universes with black holes, and not for the emergence of life within anyone universe). The fact that the gazelle’s genes therefore INCIDENTALLY also result in an environment (the gazelle) which is conducive to the special dust existing on its back is therefore (if gazelle’s are the only game in town) very fortunate for the special dust! (ie GLP).

Now if gazelle’s are NOT the only game in town (ie there are many other, possibly unlimited, different species of animals), then this becomes a version of the AP from the special-dust perspective – it matters not whether the gazelle’s back is conducive to special-dust existence or not, because there are plenty of other environments to choose from. This is analogous to the case where universes are NOT constrained to have parameters which are simply conducive to black hole production, ie there are many different kinds (possibly an unlimited number) of universes, with many different kinds of parameters, and this is in accord with the AP.

Thus it really boils down to :

If the physical parameters are constrained to lie within a narrow range, for whatever reason (an example would be an “evolutionary constraint” of universes to produce only black-hole favoured conditions), then this indicates GLP.

But if the physical parameters are NOT constrained to lie within a narrow range, then this indicates AP.

As I said earlier, it becomes “different shades of grey”, and what matters is only where you draw the line between “constrained” and “unconstrained”.

essentially we are talking about selection for reproductive success leading to something that is reproductively successful (and how that explains the values of the constants)

Sorry, but you’ve changed the paradigm here - you have not shown how a “series of universes which is reproductively successful” (in the sense of reproducing universes) has necessarily anything to do with conditions within one of the universes being conducive to life WITHIN that universe. We could conceivably have a fantastically “successful” reproducing multiverse (in the sense of it spawning vast numbers of SLIGHTLY different universes) which is completely devoid of life.

-----it does not fit into your trichotomy, I believe, and needs to appear as a fourth possibility

Sorry, but as explained it does fit into the trichotomy, either under AP or GLP (depending on whether you are postulating that the BHP constrains physical parameters or not, and where you draw the line).

MF

 

[moving finger]

life is irrelevant and the system naturally evolves towards a set of fundamental constants that give a lot of black holes. (incidentally making life possible as byproduct or side effect)

as explained in much more detail in my previous post, if by this you mean that physical parameters are constrained (in the Darwinian sense) to lie within a certain range which is conducive to black hole production, and "life is incidentally made as a byproduct", then I would say that this is a good example of the GLP (ie we are very fortunate that the conditions for black hole production also, for some unexplained reason, seem to be conducive to life).
MF

 

[Garth]

In the CNS does Smolin give any explanation why?:

the laws of physics are 99.9 percent preserved at the bounce

Now, in Natural Selection DNA both preserves the information necessary to order the progeny organism and also varies it slightly through natural mutations to allow the necessary variation of the species over and above that produced by sexual reproduction. Is there a mechanism in Smolin's CNS that carries the information from a previous universe into a new one with "99.9%" accuracy?

Garth

 

[marcus]

as explained in much more detail in my previous post, if by this you mean that physical parameters are constrained (in the Darwinian sense) to lie within a certain range which is conducive to black hole production, and "life is incidentally made as a byproduct", then I would say that this is a good example of the GLP (ie we are very fortunate that the conditions for black hole production also, for some unexplained reason, seem to be conducive to life).
MF

You have partially got it. All right except for the word "unexplained".
I thought you had read Smolin's article (hep-th/0407213), which explains why several aspects of nature favoring BH formation also incidentally (as a side effect) also favor carbon-based life. I certainly wouldn't call it "luck" :-)

I can paraphrase the discussion in Smolin's article for you, MF, but you might find it enlightening to read it yourself.

I like your image of the special dust on the back of the gazelle. but in this case if one really understands the gazelle one can foresee the dust.
Or maybe I don't understand your image of the dusty gazelle.

Maybe metaphors allow too much chance for confusion, so I will focus on carbonbase life as a side effect of optimizing for black holes.
If you really understand how the world needs to be in order to have abundant black holes then even if you (were a computer who had never seen our universe, only been told about it, and ) didnt know about carbonbased life, then you could predict certain things favoring long slow expansion (no immediate big crunch), galaxy formation, formation of long-lived stars, extensive periodic table including non-radioactive elements, and a correspondingly rich chemistry just from knowing that our tract of nature was conducive to black holes (you must judge for yourself how you like Smolin's arguments about this)

 

[marcus]

In the CNS does Smolin give any explanation why?:

Now, in Natural Selection DNA both preserves the information necessary to order the progeny organism and also varies it slightly through natural mutations to allow the encessary variation of the species over and above that produced by sexual reproduction. Is there a mechanism in Smolin's CNS that carries the information from a previous universe into a new one with "99.9%" accuracy?

Garth

No, Garth, he doesn't offer a mechanism for that. He explicitly makes it as an assumption. You might draw an analogy with the logical status of Darwinian theory before the understanding of how chromosomes work, or how DNA works.

One postulates that there is SOME mechanism that makes the child like the parent, but allows slight differences. One constructs a theory of biological evolution based on assuming that mechanism and tests it. Then some 100 years later the mechanism comes to light.

CNS has been offered rather tentatively, as if to say: "Here is one way the fundamental constants of nature might have evolved. Here are some things it predicts, about astronomical observations that are being made, or experiments that could be made (this is less worked out). See if you can shoot it down."

what is being worked on in the context of LQG now is simply the connection between BH and BB.
the first real progress on that occurred this spring.
A paper of Bojowald, Goswami, Maartens, and Singh that appeared in March 2005 is a good example. they made a LQG model of BH collapse and found that after collapse it began to imitate the LQG model of BB.
they included matter in a simplified form.

including the "DNA", namely physical constants, and having it be slightly modified while passing thru the regime where the classical singularities used to be, is only going to be accomplished in LQG much later, if at all.
it could even take some other theory of QG, if it can be done.

but even tho the necessary mutation mechanism has not been identified, the CNS hypothesis offers explanation and makes predictions allowing it to be tested. So I think it is worth testing and trying to falsify it.