can only string theory --> black holes ? [Archive]

Charlie Stromeyer Jr.

May14-04, 05:21 PM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>GTR by itself does not dynamically and physically require the\nexistence of black holes (BHs). Even Einstein himself wrote two papers\narguing against the existence of black holes (BHs), and his conclusion\nmight turn out to be correct even if his particular arguments in his\ntwo papers are not.\n\nBHs are one proposed or chosen mathematical solution to the possibilty\nof gravitational collapse within GTR. However, there may be other\npotential solutions which are mathematically valid if not yet\nphysically validated.\n\nOne such solution is the idea of thick-shelled gravastars [1].\nRecently, some physicists experimentally discovered "fermionic\ncondensates" in addition to the already well establised Bose- Einstein\ncondensates (BECs). Now consider that there might also be a\ngravitational analogue of BECs, and this is roughly what gravastars\nare.\n\nInstead of a collapse to a singularity there is a phase transition to\na spherical object which has de Sitter space as its interior, a "thick\nshell" to enable stability against further gravitational collapse, and\nan asymptotically Schwarzschild exterior.\n\nIt might seem for now at least that according to Occam\'s razor,\ngravastars should be the preferred solution vs. BHs because gravastars\nare a more mathematically simple and elegant solution, and because\ngravastars avoid some of the very difficult challenges of trying to\nunderstand the physics of BHs such as with BH thermodynamics or\ninformation.\n\nIt does not yet seem that it would be possible to distinguish\nastrophysically between these gravastars vs. BHs. Thus, we might never\nhope to know if BHs actually exist unless some theory such as string\ntheory is confirmed by experimental evidence, and such a theory\nsomehow compels the existence of BHs.\n\n\n[1] http://arxiv.org/abs/gr-qc/0310107\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>GTR by itself does not dynamically and physically require the
existence of black holes (BHs). Even Einstein himself wrote two papers
arguing against the existence of black holes (BHs), and his conclusion
might turn out to be correct even if his particular arguments in his
two papers are not.

BHs are one proposed or chosen mathematical solution to the possibilty
of gravitational collapse within GTR. However, there may be other
potential solutions which are mathematically valid if not yet
physically validated.

One such solution is the idea of thick-shelled gravastars [1].
Recently, some physicists experimentally discovered "fermionic
condensates" in addition to the already well establised Bose- Einstein
condensates (BECs). Now consider that there might also be a
gravitational analogue of BECs, and this is roughly what gravastars
are.

Instead of a collapse to a singularity there is a phase transition to
a spherical object which has de Sitter space as its interior, a "thick
shell" to enable stability against further gravitational collapse, and
an asymptotically Schwarzschild exterior.

It might seem for now at least that according to Occam's razor,
gravastars should be the preferred solution vs. BHs because gravastars
are a more mathematically simple and elegant solution, and because
gravastars avoid some of the very difficult challenges of trying to
understand the physics of BHs such as with BH thermodynamics or
information.

It does not yet seem that it would be possible to distinguish
astrophysically between these gravastars vs. BHs. Thus, we might never
hope to know if BHs actually exist unless some theory such as string
theory is confirmed by experimental evidence, and such a theory
somehow compels the existence of BHs.

[1] http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/0310107

Jake Mannix

May15-04, 05:30 PM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Charlie Stromeyer Jr." <cstromey@hotmail.com> wrote\n<snip>\n> One such solution is the idea of thick-shelled gravastars [1].\n> Recently, some physicists experimentally discovered "fermionic\n> condensates" in addition to the already well establised Bose- Einstein\n> condensates (BECs). Now consider that there might also be a\n> gravitational analogue of BECs, and this is roughly what gravastars\n> are.\n>\n> Instead of a collapse to a singularity there is a phase transition to\n> a spherical object which has de Sitter space as its interior, a "thick\n> shell" to enable stability against further gravitational collapse, and\n> an asymptotically Schwarzschild exterior.\n\nWhile I\'m willing to give the benefit of the doubt to this possibility,\neven without a specific microscopic theory handy which would predict\nthis phase transition, my first wonder would be whether this would\nreally rule out black holes after all, or just small ones.\n\nWhat I mean is that if when densities and curvatures get high, it\'s\npossible that GR breaks down, and there is a phase transition, sure, ok,\nthe density of a solar mass black hole is about 10^14 g/cm^3, and the\nsurface gravity is pretty high too, so maybe weird stuff happens, and\nsolar mass black holes are actually gravitational condensates of some\nkind, with no singularity at all.\n\nBut supermassive black holes, like at the center of galaxies, can have\ntens or hundreds of millions of times that mass, and hence densities\nwhich lie around that of liquid water.\n\nAt these densities and surface gravities, why would we expect that\nthis transition would occur then? On a local level, it would seem that\nnothing would tell the system to start behaving strangely, and by the\ntime that pressures due to gravity were such that it would, we\'d\nalready have an event horizon, and then equations of state on the\ninside would be irrelevant, due to singularity theorems.\n\nAt least, this is my thinking based on the assumption that these\ngravastars are based on local (but emergent) physics as in Bob\nLaughlin\'s "Emergent Relativity" line of thought (gr-qc/0302028).\nIf there\'s something nonlocal in these proposals which allow for\ndetection of the forming event horizon even when there\'s nothing\nstrange happening in the local equation of state, then my thinking\ndoesn\'t help.\n\n> It might seem for now at least that according to Occam\'s razor,\n> gravastars should be the preferred solution vs. BHs because gravastars\n> are a more mathematically simple and elegant solution, and because\n> gravastars avoid some of the very difficult challenges of trying to\n> understand the physics of BHs such as with BH thermodynamics or\n> information.\n\nI object to this paragraph a little, because gravastars are still not\n*solutions* - they rely on unknown equations of state which have the\nproposed properties, and give no mechanism to support them (at least\nin the papers I\'ve read on the topic). And I wouldn\'t say they\'re more\nsimple and elegant, as they require unknown physics in the region of\nthe event horizon, while black holes only require new physics in the\nregion of the singularity.\n\nI\'ll hand it to you though, that without black holes we\'d have no\nworries about information paradoxes of quantum mechanics, or the\nnon-extensivity of entropy.\n\nBut before I\'d really consider a universe without black holes, I\'d\nneed to see that *all* black holes were really ruled out, because all\nit takes is one black hole to bring back these classical "paradoxes"\nof black hole physics.\n\n> It does not yet seem that it would be possible to distinguish\n> astrophysically between these gravastars vs. BHs. Thus, we might never\n> hope to know if BHs actually exist unless some theory such as string\n> theory is confirmed by experimental evidence, and such a theory\n> somehow compels the existence of BHs.\n\nOf course, playing devil\'s advocate against myself here, in Laughlin\'s\nline of thinking, even knowing the "Fundamental Laws" doesn\'t always\nhelp when some properties end up being emergent anyways, and then\njust knowing the microphysics of quantum gravity might not really tell\nus that we\'d understand if and when it would undergo phase transitions.\n:)\n\n-Jake Mannix\n\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Charlie Stromeyer Jr." <cstromey@hotmail.com> wrote
<snip>
> One such solution is the idea of thick-shelled gravastars [1].
> Recently, some physicists experimentally discovered "fermionic
> condensates" in addition to the already well establised Bose- Einstein
> condensates (BECs). Now consider that there might also be a
> gravitational analogue of BECs, and this is roughly what gravastars
> are.
>
> Instead of a collapse to a singularity there is a phase transition to
> a spherical object which has de Sitter space as its interior, a "thick
> shell" to enable stability against further gravitational collapse, and
> an asymptotically Schwarzschild exterior.

While I'm willing to give the benefit of the doubt to this possibility,
even without a specific microscopic theory handy which would predict
this phase transition, my first wonder would be whether this would
really rule out black holes after all, or just small ones.

What I mean is that if when densities and curvatures get high, it's
possible that GR breaks down, and there is a phase transition, sure, ok,
the density of a solar mass black hole is about 10^14 g/cm^3, and the
surface gravity is pretty high too, so maybe weird stuff happens, and
solar mass black holes are actually gravitational condensates of some
kind, with no singularity at all.

But supermassive black holes, like at the center of galaxies, can have
tens or hundreds of millions of times that mass, and hence densities
which lie around that of liquid water.

At these densities and surface gravities, why would we expect that
this transition would occur then? On a local level, it would seem that
nothing would tell the system to start behaving strangely, and by the
time that pressures due to gravity were such that it would, we'd
already have an event horizon, and then equations of state on the
inside would be irrelevant, due to singularity theorems.

At least, this is my thinking based on the assumption that these
gravastars are based on local (but emergent) physics as in Bob
Laughlin's "Emergent Relativity" line of thought (http://www.arxiv.org/abs/gr-qc/0302028).
If there's something nonlocal in these proposals which allow for
detection of the forming event horizon even when there's nothing
strange happening in the local equation of state, then my thinking
doesn't help.

> It might seem for now at least that according to Occam's razor,
> gravastars should be the preferred solution vs. BHs because gravastars
> are a more mathematically simple and elegant solution, and because
> gravastars avoid some of the very difficult challenges of trying to
> understand the physics of BHs such as with BH thermodynamics or
> information.

I object to this paragraph a little, because gravastars are still not
*solutions* - they rely on unknown equations of state which have the
proposed properties, and give no mechanism to support them (at least
in the papers I've read on the topic). And I wouldn't say they're more
simple and elegant, as they require unknown physics in the region of
the event horizon, while black holes only require new physics in the
region of the singularity.

I'll hand it to you though, that without black holes we'd have no
worries about information paradoxes of quantum mechanics, or the
non-extensivity of entropy.

But before I'd really consider a universe without black holes, I'd
need to see that *all* black holes were really ruled out, because all
it takes is one black hole to bring back these classical "paradoxes"
of black hole physics.

> It does not yet seem that it would be possible to distinguish
> astrophysically between these gravastars vs. BHs. Thus, we might never
> hope to know if BHs actually exist unless some theory such as string
> theory is confirmed by experimental evidence, and such a theory
> somehow compels the existence of BHs.

Of course, playing devil's advocate against myself here, in Laughlin's
line of thinking, even knowing the "Fundamental Laws" doesn't always
help when some properties end up being emergent anyways, and then
just knowing the microphysics of quantum gravity might not really tell
us that we'd understand if and when it would undergo phase transitions.
:)

-Jake Mannix

Stewart

May16-04, 07:02 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>I\'m not sure if I understand the points correctly. My understanding is that\neven if black holes cannot be physically formed in our universe, the fact\nthat there exist solutions in GR with singularities etc. allows us to do\ngedanken experiments about them. For example, one can always consider an\neternal black hole as a solution to supergravity and demand to know what its\nstringy resolution is. In that sense the problems such as the information\nparadox are there not because we want to explain a possible phenomenon, but\nbecause we want to theory to be consistent.\n\nStewart\n\n\n\n\n\n\n\n\n"Charlie Stromeyer Jr." <cstromey@hotmail.com> wrote in message\nnews:61773ed7.0405141131.6c95e70d-100000@posting.google.com...\n> GTR by itself does not dynamically and physically require the\n> existence of black holes (BHs). Even Einstein himself wrote two papers\n> arguing against the existence of black holes (BHs), and his conclusion\n> might turn out to be correct even if his particular arguments in his\n> two papers are not.\n>\n> BHs are one proposed or chosen mathematical solution to the possibilty\n> of gravitational collapse within GTR. However, there may be other\n> potential solutions which are mathematically valid if not yet\n> physically validated.\n>\n> One such solution is the idea of thick-shelled gravastars [1].\n> Recently, some physicists experimentally discovered "fermionic\n> condensates" in addition to the already well establised Bose- Einstein\n> condensates (BECs). Now consider that there might also be a\n> gravitational analogue of BECs, and this is roughly what gravastars\n> are.\n>\n> Instead of a collapse to a singularity there is a phase transition to\n> a spherical object which has de Sitter space as its interior, a "thick\n> shell" to enable stability against further gravitational collapse, and\n> an asymptotically Schwarzschild exterior.\n>\n> It might seem for now at least that according to Occam\'s razor,\n> gravastars should be the preferred solution vs. BHs because gravastars\n> are a more mathematically simple and elegant solution, and because\n> gravastars avoid some of the very difficult challenges of trying to\n> understand the physics of BHs such as with BH thermodynamics or\n> information.\n>\n> It does not yet seem that it would be possible to distinguish\n> astrophysically between these gravastars vs. BHs. Thus, we might never\n> hope to know if BHs actually exist unless some theory such as string\n> theory is confirmed by experimental evidence, and such a theory\n> somehow compels the existence of BHs.\n>\n>\n> [1] http://arxiv.org/abs/gr-qc/0310107\n>\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>I'm not sure if I understand the points correctly. My understanding is that
even if black holes cannot be physically formed in our universe, the fact
that there exist solutions in GR with singularities etc. allows us to do
gedanken experiments about them. For example, one can always consider an
eternal black hole as a solution to supergravity and demand to know what its
stringy resolution is. In that sense the problems such as the information
paradox are there not because we want to explain a possible phenomenon, but
because we want to theory to be consistent.

Stewart

"Charlie Stromeyer Jr." <cstromey@hotmail.com> wrote in message
news:61773ed7.0405141131.6c95e70d-100000@posting.google.com...
> GTR by itself does not dynamically and physically require the
> existence of black holes (BHs). Even Einstein himself wrote two papers
> arguing against the existence of black holes (BHs), and his conclusion
> might turn out to be correct even if his particular arguments in his
> two papers are not.
>
> BHs are one proposed or chosen mathematical solution to the possibilty
> of gravitational collapse within GTR. However, there may be other
> potential solutions which are mathematically valid if not yet
> physically validated.
>
> One such solution is the idea of thick-shelled gravastars [1].
> Recently, some physicists experimentally discovered "fermionic
> condensates" in addition to the already well establised Bose- Einstein
> condensates (BECs). Now consider that there might also be a
> gravitational analogue of BECs, and this is roughly what gravastars
> are.
>
> Instead of a collapse to a singularity there is a phase transition to
> a spherical object which has de Sitter space as its interior, a "thick
> shell" to enable stability against further gravitational collapse, and
> an asymptotically Schwarzschild exterior.
>
> It might seem for now at least that according to Occam's razor,
> gravastars should be the preferred solution vs. BHs because gravastars
> are a more mathematically simple and elegant solution, and because
> gravastars avoid some of the very difficult challenges of trying to
> understand the physics of BHs such as with BH thermodynamics or
> information.
>
> It does not yet seem that it would be possible to distinguish
> astrophysically between these gravastars vs. BHs. Thus, we might never
> hope to know if BHs actually exist unless some theory such as string
> theory is confirmed by experimental evidence, and such a theory
> somehow compels the existence of BHs.
>
>
> [1] http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/0310107
>

Charlie Stromeyer Jr.

May16-04, 04:06 PM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Jake Mannix <jake@rset.net> wrote in message news:\n\n> While I\'m willing to give the benefit of the doubt to this possibility,\n> even without a specific microscopic theory handy which would predict\n> this phase transition (...)\n\nAlthough I personally favor M-theory as a potential theory of quantum\ngravity, it is not yet physically clear that there is some correct\nmicroscopic theory handy for black holes either.\n\n> At least, this is my thinking based on the assumption that these\n> gravastars are based on local (but emergent) physics as in Bob\n> Laughlin\'s "Emergent Relativity" line of thought (gr-qc/0302028).\n> If there\'s something nonlocal in these proposals which allow for\n> detection of the forming event horizon even when there\'s nothing\n> strange happening in the local equation of state, then my thinking\n> doesn\'t help. [...]\n\n> I object to this paragraph a little, because gravastars are still not\n> *solutions* - they rely on unknown equations of state which have the\n> proposed properties, and give no mechanism to support them (at least\n> in the papers I\'ve read on the topic).\n\nYou are referring to "thin" shell gravastars, and AFAIK it is still\ntrue that there is not a generic and stable solution for these "thin"\nshell gravastars. However, the main point of the more recent paper\nwhich I cited is that the authors have found reasonable equations of\nstate for "thick" shell gravastars.\n\nBtw, this same paper also has something brief to say on page 18 about\nLaughlin\'s ideas and other similar scenarios.\n\n> And I wouldn\'t say they\'re more\n> simple and elegant, as they require unknown physics in the region of\n> the event horizon, while black holes only require new physics in the\n> region of the singularity.\n\nI agree that there may be some truth with what you say here in regards\nto the physics (but not necessarily in regards to the math), and I\nmyself am not a strong advocate for the theory of gravastars.\n\nI meant this thread as merely something to consider with the hope that\nperhaps one day someone might figure out more about how to potentially\ndistinguish between gravastars vs. black holes.\n\nAlso, Occam\'s razor is merely a rough guide - like a handy reminder of\nEinstein\'s similar advice "to try to make things as simple as\npossible, but no simpler".\n\nWe also should not take Occam\'s razor too seriously due to\nconsiderations from thinking about diverse areas of complexity theory,\nand because we now know that there are six different types/degrees of\nconfirmation for assessing the validity of outcomes: either the sense\nof incremental or absolute confirmation and within each of these two\nsenses there are three types of confirmation: qualitative,\nquantitative and comparitive.\n\nNote, that here I am referring to the classical case which should be\ndifferent from the fundamentally new considerations logic,\ncomputability and maybe probability theory necessitated by the\nfindings of the papers on quantum theory which I cited in the thread\n"On acausality in string theory" as well as the findings of other\npapers on quantum theory.\n\n> But before I\'d really consider a universe without black holes, I\'d\n> need to see that *all* black holes were really ruled out, because all\n> it takes is one black hole to bring back these classical "paradoxes"\n> of black hole physics.\n\nThe implicit question you raise here is an extremely challenging and\nongoing field of inquiry because e.g. it includes considering the\nfundamental physics of a potential dS/CFT correspondence, the nature\nof Hilbert space and whatever "quantum observables" might mean in dS,\nthe behavior of the quasinormal modes of a dS black hole etc.\n\n> Of course, playing devil\'s advocate against myself here, in Laughlin\'s\n> line of thinking, even knowing the "Fundamental Laws" doesn\'t always\n> help when some properties end up being emergent anyways, and then\n> just knowing the microphysics of quantum gravity might not really tell\n> us that we\'d understand if and when it would undergo phase transitions.\n> :)\n\nYou seem to realize the distinction I am about to make but I will do\nso anyways in case some novice should ever read this post. Various\nphysicists have thought of ways to explain concepts such as\nBoltzmann\'s equations or the Second Law of Thermodynamics without\nrequiring any reference to what should be their underlying theory in\nterms of statistical mechanics.\n\nHowever, the underlying foundations of quantum gravity cannot be\nsimilar to the underlying foundations of statistical mechanics for a\nvariety of reasons such as the observation that the result of one of\nthe experiments I cited on the fundamental nature of the wavefunction\nin QM is a result that is both Lorentz invariant and correlated in a\nBell- like way.\n\nFinally, it might be that the newer "thick" shell gravastars discussed\nabove are a special case of spherically symmetric solutions of generic\ngravitational models, however, before thinking like this one needs to\nconsider the implications of an important caveat from this two page\ncautionary note:\n\nhttp://arxiv.org/abs/gr-qc/0404120\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>Jake Mannix <jake@rset.net> wrote in message news:

> While I'm willing to give the benefit of the doubt to this possibility,
> even without a specific microscopic theory handy which would predict
> this phase transition (...)

Although I personally favor M-theory as a potential theory of quantum
gravity, it is not yet physically clear that there is some correct
microscopic theory handy for black holes either.

> At least, this is my thinking based on the assumption that these
> gravastars are based on local (but emergent) physics as in Bob
> Laughlin's "Emergent Relativity" line of thought (http://www.arxiv.org/abs/gr-qc/0302028).
> If there's something nonlocal in these proposals which allow for
> detection of the forming event horizon even when there's nothing
> strange happening in the local equation of state, then my thinking
> doesn't help. [...]

> I object to this paragraph a little, because gravastars are still not
> *solutions* - they rely on unknown equations of state which have the
> proposed properties, and give no mechanism to support them (at least
> in the papers I've read on the topic).

You are referring to "thin" shell gravastars, and AFAIK it is still
true that there is not a generic and stable solution for these "thin"
shell gravastars. However, the main point of the more recent paper
which I cited is that the authors have found reasonable equations of
state for "thick" shell gravastars.

Btw, this same paper also has something brief to say on page 18 about
Laughlin's ideas and other similar scenarios.

> And I wouldn't say they're more
> simple and elegant, as they require unknown physics in the region of
> the event horizon, while black holes only require new physics in the
> region of the singularity.

I agree that there may be some truth with what you say here in regards
to the physics (but not necessarily in regards to the math), and I
myself am not a strong advocate for the theory of gravastars.

I meant this thread as merely something to consider with the hope that
perhaps one day someone might figure out more about how to potentially
distinguish between gravastars vs. black holes.

Also, Occam's razor is merely a rough guide - like a handy reminder of
Einstein's similar advice "to try to make things as simple as
possible, but no simpler".

We also should not take Occam's razor too seriously due to
considerations from thinking about diverse areas of complexity theory,
and because we now know that there are six different types/degrees of
confirmation for assessing the validity of outcomes: either the sense
of incremental or absolute confirmation and within each of these two
senses there are three types of confirmation: qualitative,
quantitative and comparitive.

Note, that here I am referring to the classical case which should be
different from the fundamentally new considerations logic,
computability and maybe probability theory necessitated by the
findings of the papers on quantum theory which I cited in the thread
"On acausality in string theory" as well as the findings of other
papers on quantum theory.

> But before I'd really consider a universe without black holes, I'd
> need to see that *all* black holes were really ruled out, because all
> it takes is one black hole to bring back these classical "paradoxes"
> of black hole physics.

The implicit question you raise here is an extremely challenging and
ongoing field of inquiry because e.g. it includes considering the
fundamental physics of a potential dS/CFT correspondence, the nature
of Hilbert space and whatever "quantum observables" might mean in dS,
the behavior of the quasinormal modes of a dS black hole etc.

> Of course, playing devil's advocate against myself here, in Laughlin's
> line of thinking, even knowing the "Fundamental Laws" doesn't always
> help when some properties end up being emergent anyways, and then
> just knowing the microphysics of quantum gravity might not really tell
> us that we'd understand if and when it would undergo phase transitions.
> :)

You seem to realize the distinction I am about to make but I will do
so anyways in case some novice should ever read this post. Various
physicists have thought of ways to explain concepts such as
Boltzmann's equations or the Second Law of Thermodynamics without
requiring any reference to what should be their underlying theory in
terms of statistical mechanics.

However, the underlying foundations of quantum gravity cannot be
similar to the underlying foundations of statistical mechanics for a
variety of reasons such as the observation that the result of one of
the experiments I cited on the fundamental nature of the wavefunction
in QM is a result that is both Lorentz invariant and correlated in a
Bell- like way.

Finally, it might be that the newer "thick" shell gravastars discussed
above are a special case of spherically symmetric solutions of generic
gravitational models, however, before thinking like this one needs to
consider the implications of an important caveat from this two page
cautionary note:

http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/0404120