Daryl Janzen, a Professor of Astrophysics & Philosophy, has an intriguing essay which asks-
'What if black holes never actually form?'How confusing inevitability with reality built decades of paradox'
Black holes are among the most captivating and scientifically intriguing phenomena in modern physics, inspiring both scientists and the public alike.
It is because there is so much evidence that they exist that they captivate us.
But do they really exist?
Yes. At least, that's the best explanation we currently have for what Astronomer's observe.
What if they are only ever forming, never formed?
If, there is a boundary beyond which we can't detect further 'forming', then all we can say, empirically speaking, is that the thing has formed.
Currently, Doctors use various protocols to determine when a person has died. It may be, in the future, these protocols will be changed because 'signs of life' or viability for resurrection currently undetectable become observable.
Just imagine — what if the whole edifice of black hole physics is built on an invalid logical inference that’s gone unnoticed (or unacknowledged?) for the better part of a century?
This wouldn't matter if the existence of the thing is empirically observed. Suppose Sherlock Holmes finds a clue that suggest Moriarty will be at the Charing Cross Hotel to kill the Archduke at 9 pm. This turns out to actually be the case. Mycroft Holmes points out that Holmes's logic was faulty. All that could be validly deduced was that there was a strong likelihood that a member of Moriarty's organization would seek to carry out the assassination at a particular time. Sherlock might reply 'look, my logic was good enough to serve my purpose. My job was to save the Archduke. The fact that I was also able to capture Moriarty was a bonus. I guess, he underestimated me. He should have sent some minion to do the dirty deed.'
Inevitability is not actuality — that’s obvious enough.
But it will be. Moreover, if it applies to a class of objects, then it is likely that some actual cases can be found. There is no proof that everybody currently alive will die but there is a lot of evidence that everybody who lived more than two centuries ago did actually die.
Yet for sixty years physicists have ignored relativity’s most basic rule,
which is that there are no privileged frames of reference. I suppose one could say 'for human beings who can only move forward in time, that which is inevitable will have actual examples. Maybe there are other sorts of beings for whom this would not appear to be the case.' But this doesn't greatly matter because, while alive, we have no means to stop being human and become some other type of being.
and we’ve taken for granted that the latter is implied by the former. Like fools walking around imagining we’re all dead because someday we’ll die, they look at the evidence that nothing can stop black holes from collapsing toward their horizons and imagine that a process which remains forever incomplete has already come to its end.
Death may be a longer process than we realize. A thousand years from now, they may have the technology to revive a corpse which has been dead for twenty years. What is certain is that, as far as we are concerned, death is both actual and inevitable. We think the same is true of existing black holes and things which will become black holes.
Consider the following. We build a spaceship with three items onboard: a hot cup of coffee, a thermometer to measure the coffee’s temperature,
at some point the thermometer won't be able to find any difference between the coffee's temperature and that of the ambient atmosphere. Better and better thermometers may extend that limit from, let us say, 90 minutes to 90 minutes and three seconds or 90 minutes and 3.000001 seconds, etc. etc.
and a clock that measures the arctangent of elapsed time since launch.
The clock will soon show Pi/2 radians. Better and better clocks will only be able to distinguish tiny increments on elapsed time. But they are a convergent series. Thus we can say with certainty that there is an upper bound.
The ship, which has perfect insulating walls, is launched — and through some future technological innovation it is capable of constant proper acceleration away from Earth for all time.A continuous signal is transmitted back to Earth, sending two pieces of information: the coffee’s temperature and the arctangent time.
Quite soon, they both have an upper bound- i.e. improving the clock or the thermometer only makes an infinitesimal increment. Still, this may be important for testing the predictions of some other theory.
According to Newton’s Law of Cooling, the coffee’s temperature will approach the ambient cabin temperature exponentially and asymptotically — meaning it will very quickly approach the cabin temperature, but it actually takes infinite time to reach equilibrium.
For any given clock and thermometer, 90 minutes is that limit.
Therefore, the temperature value sent back to Earth will exponentially approach a finite value, but it will only reach that value exactly in the infinite future.
But that won't be observable. Our equations are artefacts of our mathematic model but that model is not reality.
Since the elapsed time is sent back as its arctangent, that value will also asymptotically approach a finite value of π/2 in the infinite future.
But the elapsed time, for any given receptor, will have quite a small upper bound.
And since the ship will be forever accelerating, the signal that transmits this information will quickly become practically invisible due to redshift. However, in principle the signal will forever be received back on Earth, as the coffee gradually cools and elapsed time increases — all while the ship’s velocity asymptotically approaches the speed of light.
In other words, there is no need to mention a spaceship. My cup of coffee too will only reach ambient temperature after infinite time, though no clock and thermometer, however advanced, will be able to show elapsed time as more than about 90 minutes.
People die. Coffee cools down. Black holes have formed and will form. That is what empirical observation teaches us.
, when the radius of a star collapses to the finite value of its event horizon, only a finite amount of proper time will have passed on a clock carried by a particle at its surface. These two values — the star’s radius and the elapsed time since it started collapsing — are approached in essentially the same manner as the coffee’s temperature approaches its asymptotic limit while the arctangent time approaches π/2.
In other words, black holes form as inevitably and ubiquitously as cups of coffee cool down. True, we may have a theory that says it takes infinite time for the boundary to be reached but that just means that any cut off we observe could be infinitesimally bettered if we had better tech. Thus, instead of saying the patient died at 3.02 AM, we may be able to say time of death was 3.0199999997 A.M.
And from the standpoint of external observation, the light emitted outwards from a collapsing star exponentially fades and quickly becomes invisible
in other words, the thing ceases to be observable- unless you are moving away from it at the speed of light.
— though in principle, no matter how long an external observer waits, they will forever “observe” that when the light they are now receiving was emitted,
there is no such light save in the case mentioned above.
the star still had not collapsed below its event horizon — just as the future civilization above will forever see that the coffee hadn’t yet reached equilibrium when the signal now being observed was sent.
No. Future beings won't be able to detect any difference in the coffee's temperature just like us. They won't see the black hole after we stop seeing it. Obviously, if an astronomer says 'there used to be light coming from this patch of the sky. Today, that light disappeared.' then his peers will understand that if the object is 3000 light years away, a particular object became a black hole 3000 years ago.
But regardless of which past events are observed now, we’d also like to know whether collapsing stars should be thought to have already crossed this observational threshold,
the moment you cease to observe them, you know that they became black holes x number of years ago where x is the number of light-years separating us from the collapsing star.
or if they are more accurately thought of as still approaching their event horizons.
If at 10 AM some light was received but none was at 10.01 AM then we know the thing became a black hole x number of years ago.
In essence, while the image of the star freezes and fades, we’d like to know: Do gravitationally collapsing stars really pass through their event horizons and form massive singularities in our universe?
Currently, that is the best hypothesis. In 2015, a massive star, designated N6946-BH1, that was expected to explode as a supernova was observed to disappear entirely, a phenomenon called a "failed supernova". The star's quiet demise suggests it collapsed directly into a black hole, and instruments like the Hubble and Spitzer space telescopes helped confirm its disappearance, say NASA scientists. It may
Or, do they instead remain forever collapsing towards their event horizons, approaching asymptotic limits in both radius and proper time just as, in reality, the coffee’s temperature approaches equilibrium with the ship’s cabin while the arctangent time approaches π/2?
The 'failed supernova' mentioned above is still detectable on the infrared frequency. Currently we think it is generated from stuff falling into the black hole.
General relativity is agnostic about which distant events are coincident with one another.
Not for inhabitants of this tiny planet. We have a common frame of reference. It's just that we finding 'simultaneous' some species on a planet far far away might not.
This is by design: whether or not any two particular events occur “simultaneously” is not supposed to have any objective meaning in standard general relativistic descriptions.
No. The thing is well defined for a local frame of reference- e.g. the one all mankind currently shares.
In principle, we can hear Lord Jesus deliver the sermon on the Mount. However, it is likely that there is a limit beyond which coherence of sound waves is irretrievably lost.
What happens to an astronaut as he falls into a black hole? To an observer, the astronaut would appear to slow down and freeze at the event horizon, eventually fading from view completely. However the last photon to reach us will be so 'redshifted' as to only reach us much later. But this doesn't mean that we can't say 'in (2015 minus x, where x is distance in light years) such and such failed supernova became a black hole'.
The only thing external reality can ever know for sure is that when the information now being received left the star, it had not yet reached its event horizon.
Sadly we can't know anything for sure. The Universe may be a hologram.
Since no external event is ever causally connected to the horizon formation event,
so far as we know.
this is the only empirically valid claim that can ever be made.
For the moment.
Naming the fallacy
Empirical claims may be false. Logical claims may be fallacious. The question, for the former, is whether the best available information confirms them or, at the very least, does not contradict them. There may be a 'structural causal model' associated with the empirical claim or prediction. It may feature logical fallacies which it may or may not be worthwhile to correct.
The primary problem with the canonical picture of black holes emerging through gravitational collapse is one of metaphysical overreach:
if a problem is metaphysical, physicists need not bother with it. I suppose, since Janzen wears two hats- that of a philosopher as well as that of a physicist- he has a certain scruple which others need not share. I suppose a Theologian who is also a Physicist may have a different scruple. Why is God not being mentioned by the theory?
we infer one of two essentially different potentialities to be true while ignoring the other, even though both must remain forever unobservable.
One might say 'we can't point to the exact moment when Achilles overtook the tortoise, we can only say 'with current 'photo-finish' technology, this is our best guess of when that happened.' But this doesn't mean there is any fallacy in deducing that Achilles swiftly overtook the tortoise.
The inference is therefore scientifically illegitimate, unjustified metaphysics.
It is scientifically legitimate if the physics community overwhelmingly considers it to be so even if they also believe that the inference will be 'sublated' at a later date. Still, it may be some valuable Research Program is motivated by the scruple raised by Janzen.
This does not bear on the Penrose-Hawking singularity theorems themselves. Rather, the issue is with ontological overreach in drawing specific physical implications on the basis of these mathematical theorems.
Life involves 'ontological overreach'. How can we be sure we aren't already dead? Anyway, that's the reason I put off doing the washing up.
The theorems tell us that if certain energy and causality conditions hold, and if space-time is extended in a particular way, then geodesic incompleteness is inevitable. The upshot in the case of black hole singularities is that these must be a global feature of the space-time manifold.
In 1783, John Michell hypothesized 'dark stars' on the basis of Newton's theory. In 1916, Karl Schwarzschild found the first solution to Einstein's equations that described a black hole. But it was only in 1971 that the first strong evidence for a black hole was found in the X-ray source Cygnus X-1- which is now widely regarded as the first black hole identified.
But inevitability and actuality are not the same, and conflating them is a modal fallacy.
No fallacy arises where empirical evidence supports the existence of an object predicted by a theory. However, that empirical evidence might turn out to be wrong.
We might name this the tense-import fallacy
which isn't really a fallacy. It is merely a linguistic misunderstanding. But nothing of the sort arises here.
— or, more specifically, the present-tense import fallacy — the slide from atemporal mathematical features (event horizons, singularities) to present-tense claims about what has “already” occurred in our universe.
There is no such slide. What happened was that mathematical physics theorized a type of object which, many years later, empirical observation confirmed as actually existing. Mathematics is a separate language from that of Astronomy- which is concerned with objects existing in the cosmos. It turns out that black holes exist in the same way that galaxies exist.
The canonical interpretation of black holes as real, already actualised objects within our universe is tied to a deeply problematic view by which space-time manifolds, along with the individual events such as those in the regions “inside” event horizons — including singularities at r = 0 — physically exist.
One would only say so if one also felt that believing you are alive, and thus can do the washing up, is deeply problematic.
But the points in space-time should not be confused with physical reality.
Nor should an infinite series be confused with the passage of time as we humans experience it. Achilles really does overtake the tortoise because the distance between them is a 'converging sequence' till he overtakes it.
Rather, space-time should be understood as
a model or map. It isn't the actual terrain.
a set of events that happen in our existing reality.
No. Stuff that happens may, for some particular purpose, be given a mathematical mapping.
From this perspective, the manifold is a descriptive tool, not the fabric of reality itself.
No one has suggested otherwise. It is not the case that by manipulating a manifold we can turn into rabbits living on a planet in the Andromeda galaxy.
It does not have to be maximally extended in any ontological sense; it only has to describe the physical events that occur in our existing universe in its domain of applicability.
Such descriptions are either useful or useless. It is fair to say, the philosopher's 'domain of applicability' is different from that of the physicist. It may be that the scruple expressed by Janzen is motivating some potentially very useful Scientific Research Programs.
Janzen concludes thus
In a universe that continues to expand and undergo hierarchical structure formation, ultra-compact Kerr-like bodies will continue to merge and grow.
but we don't have to assume they contain actual singularities. Even if this is not the case, it is useful to have people working on theories which account for existing observations without the relevant assumption.
But from any external vantage point, each collision will always be observed in its pre-horizon phase. The observational future of the universe is
dependent on the compossibility of observation. It may be that everything really interesting about the Universe is essentially unobservable. But it may still be very useful. Observation is like verification. A lot can be done- and the most interesting things may be of this sort- without either observation or verification save in the sense that a superior outcome becomes available.
thus not one of mergers between completed black holes, but of ever-larger, ever-more-compact collapsing objects whose horizons are approached only asymptotically from the outside universe’s perspective.
Emerson, grieving for his dead son, wrote in his essay 'Experience'- ' Was it Boscovich who found out that bodies never come in contact? Well, souls never touch their objects. An innavigable sea washes with silent waves between us and the things we aim at and converse with.' Emerson was aware of the new 'field' theories (which the Jesuit Boscovich may have learnt about from a translation of the Vimalakirti sutra). It turned out that the 'sea' which washes between us is composed of forces- e.g. electro-magnetism- which we can very profitably harness to our own ends. But, for now, death remains death and black holes remain black holes.
13 comments:
This is partly a semantic question. Are the dark objects that astronomy has inferred, still black holes if they don't actually have event horizons? If usage is dictated by the technical criteria of general-relativists, the answer is no, but if Janzen turned out to be right, popular usage might dictate a redefinition.
This question of event horizons shows up in Frank Tipler's Christian-transhumanist "Omega Point Theory". For his theo-physical teleology to work, there can only be one true singularity in the history of the universe, into which all information eventually falls. But in classical general relativity, there is also a singularity inside each event horizon that forms. So Tipler concludes that the cosmos-spanning robot civilization of the future must actively prevent all event horizons from forming!
Among the ideas in *quantum* gravity is a "membrane paradigm" due to Leonard Susskind (also called "black hole complementarity"), according to which the space behind the event horizon is actually just a scrambled description of the space immediately about the event horizon. It would mean that there's a description of Hawking radiation in which nothing ever crosses an event horizon, but instead just becomes part of the membrane hovering above it. I should think about how this relates to the purely classical debate that informs Janzen's remarks.
I suppose, for natural language, it isn't a hole if it hasn't a horizon.
Tielhard's noosphere is a bit like Umaswati's kevalya as the inevitable outcome of karmic heat death (so to speak). The notion of bodily resurrection- probably Iranian in origin- arises from the notion that the Earth must observe 'Rta' by giving up a full account of what has been assigned to it. This was probably combined with Hindu type karma-as-reincarnation. In Judaism, the concept of ibbur unifies them. I believe there was a 'discrete math' tradition used for tax assessment/financial forecasting. This, by itself, gives rise to something like Noether's theorem. If there isn't too much 'dissipation', then there will be symmetries corresponding to conservation laws. For Hinduism this is karma, across time, and dharma across space. There is still the problem of concurrency (which is a generalisation of the problem of simultaneity). One solution is Occassionalism though, by Djikstra (or Razbarov-Rudhich) there is no 'naturality'. The thing is arbitrary. The other is purely 'geometric'- i.e. amplituhedrons & Quantum
Oscillatory TQC/NMSI or stuff yet more arcane. This is the Parmenidean universe where Zeno's paradoxes are nothing but the pain that is the comfort of love. For Plato, Parmenides & Zeno have together found the perfection of Platonic Love. It is also what Rumi & Shamsuddin Tabrizi find. But it isn't Indic. Arjuna totes forgets what Krishna was gassing on about. So does Ananda, Buddha's beloved disciple. Interestingly, Gandhi & Kallenbach did have a version of this doctrine, but they got it out of a book by Bulwer Lytton which Gandhi's Sanskrit Prof at Samaldas Coll. translated and Indianized. But that shite did not take off amongst us. It is silly. Pals are pals and great to hang out with till Mummy, or Wifey, or the daughter-in-law (if you are a widower) calls you home and assigns some chore to you. It is no great scandal for the Hindu if life and love and knowledge and beauty and Truth and all the other other good stuff is 'dissipative'. After all, geometry itself may merely be imitative in a Tardean manner of the stupidity I display in writing this now.
I'm sorry, what I have written must seem incomprehensible to non Indians of a certain age and class. I don't get a lot of comments on my blog (which would be seen as 'Hindutva'- i.e. supportive of the current Administration, in India) and virtually none (in recent years) from smart people.
I am currently reading your blogs and getting some basic orientation re. your intellectual formation and passional (prohairesis) trajectory.
I would be happy to rewrite, in an accessible manner, anything I have written which is 'emic' or otherwise crepuscular. Just 'copy and paste' anything which appears vague or ideographic and I can recast the thing in terms of current mathematical paradigms.
As a poet, I am attracted to the philosophy and personality of Marni Dee Sheppeard. Could you point me to original sources w.r.t to her life story and category theoretical ideas? Email me at polypubs@gmail.com'. I maintain complete confidentiality and respect for Intellectual Property in such matters.
I should have said, a hole with a membrane aint a hole- it is a Virgin. As Joyce said 'only in the virgin womb of the Imagination is the Word made flesh'- i.e only if you didn't stick your dick in it ,and get an actual son or daughter who provides you utility like you would never have fucking believed ; only then do we have the choice between Baby Jesus/Krishna for Xmas/Divali and just fucking getting drunk all on our lonesome.
The problem with applying math to anything we know is 'co-evolved' is that 'ontologically dysphoric' solution concepts predominate for coordination/discoordination games.
As and economist who actually knows accountancy- not to mention a poet- I know that 'artha' (meaning but also 'incentive' or 'intentionality) is 'Economia' not 'Akribeia. It is easy enough to steer clear of semantic or what Godel called 'intensional' paradoxes if you restrict 'unitarity' in a manner adverse to your own prohairesis as the one who shits highest above his own arsehole.
Oh dear. I just lost a friend. But, being older than you, it is what happens anyway.
To my mind, 'ontological dysphoria' is a powerful solution concept for focal solutions in coordination games or co-evolved systems. It is the opposite of 'swampland' which, au fond, is 'presentist'. But, utility rules over all. Swampland was useless. Roberto Unger wasn't just useless, he was actively mischievous. Information theoretic approaches must recognise that anything not useful is almost infinitely compressible- as in the slogan 'fuck my life'. Do get in touch with me by Skype or whatever. It would be nice to put a face to a smart guy who, it appears to me, ventured into the labyrinth as a 'hopeful monster' but for whom, to climb out of it, would provoke the fate of a Marni Dee who, like a character in a Noh play, died upon a mountain rather than seek such valley mole-hills ascending which Zen monks hide the more lonely depths of their hearts.
Mitchell Porter is a decent person who writes well. I think he was part of the Penrose-Hameroff 'microtubule' shite from 25 years ago. It wasn't tarted up Popper-Eccles. I'm kidding. It was exactly that stripe of shite.
I don't suppose we will be seeing Mitchell commenting on this site again.
Sad. All my other visitors are bots or kids in Haryana looking for porn.
Fuck! Should have seen it. Mitchell writes 'too well'. He is a second or third generation Commie shithead. Browder's sons were Math mavens.
I'm still here, just busy!
You may have confused me with someone else in that last comment. I do not come from an academic family. Anyway, you're an interesting character and I enjoy trying to figure out unfamiliar ideas, but I have demands on my time and don't know exactly when I will be able to take up your invitation to deeper engagement. I haven't even been keeping up with the blog as I would wish, it's just that the topic here was in an area that I do know something about. I did, however, send you something about Marni.
I'm an elderly shithead and tend to lash out. The truth is I'm incapable of 'deeper engagement' because I'm stupid and ignorant. Accept this as an apology or, save your valuable time, and steer clear of this septic blog.
You say you have sent me something about Marni. Was it to this email address 'polypubs@gmail.com' ? When I was a kid in North London I heard of two 'mad' people (I'm crazy myself) who died under tragic circumstances. One was Price of the Price equation. The other was Farquharson who, along with Dummett, gave an early version of Gibbard-Satterthwaite. My intuition- similar, I believe, to David Deutsch (who went to the same school as me but some ten years earlier)- was that everything is 'co-evolutionary' and only arbitrarily, and for a limited purpose, mathematically tractable. My feeling is this was 'in the air' in North London (which had a lot of Ashkenazi Jewish refugees but also some (admittedly lower IQ) darkies like my folk. Admittedly, Deutsch took a different tack. But information is about 'surprisal' and thus co-evolved. It has no naturality or categoricity or unicity. My guess is that you have this 'Progressive Protestant' thing, found in Brouwer or Husserl, which was seductive for the 'kravatenjuden' which carried over into the North London type stupidity I encountered in 1977.
My interest in the period has to do with a novel I need to complete called 'Minyan Murders' set in London circa '77 or '78. I personally think it hilarious that a Curry & Chips Cockney like myself is pretending to have great insights into Rabbinical Judaism. You, I imagine, have no time for belly laughs.
Good for you. L' Chaim!
Hi - yes, I sent it to that address.
I'm an Australian transhumanist. I am very online in that I have generally been physically remote from the intellectual communities that mattered to me. I did spend a year with Hameroff in Arizona, however, which ended with 9/11.
My knowledge of 1970s London is limited to British TV comedy of that era. My favorite British thinker is Celia Green.
I didn't get it but thanks for making the effort. The Australian educational system was so much better than ours (I speak as a Brit) that the Sydney 'Push' took a dominating position in English literature in the late Sixties.UK Civil Service reform followed (or failed to follow) the Australian model.
Since Indic religion is 'transhumanist', as is theosophical Socialism, or 'Spiritist' Marxism, I was- as a kid- exposed to a version of the doctrine. Arthur Koestler was my favourite writer when I was 15. Later I learnt of Soviet research in parapsychology (vide https://socioproctology.blogspot.com/2015/04/a-green-ghost-chief-justice-vr-krishna.html).
For lowly Accountants or Economists, however, the key takeaway must be the importance of 'ontological dysphoria' under conditions of Knightian Uncertainty because this is the Hannan Consistent, 'regret minimizing', strategy.
But this also means that the ancient 'transhumanist' (Shraman) strategy of 'vivikthades sevitvam' (seeking out isolated places so as to, in some sense, come closer to what most essentially binds all sentience together) is merely what happens to oddballs anyway. Nothing wrong in that at all. We are hopeful monsters. So is the Cosmos.
I thought you might be Jewish but perhaps you are of relatively working/professional class British descent? This was and remains a highly productive class- more particularly if they emigrated to Australia, New Zealand etc. Bill Phillips was a legendary LSE economist who had learnt Chinese as a Japanese POW. I believe that he was involved in some very interesting work at the time of his death- something like 'Tao of Econ' with its own 'bootstrap' and 'fundamental equality of all (posited) elementary particles.
When I was a teenager in the London of the late Seventies, the world of ideas was an exciting place. Sadly, it soon turned into shrill, pseudo-intellectual, cries for Social Justice and the destruction of every and all engine of prosperity. Smart people fucked off to Silicon Valley. Stupid people, like myself, turned to crepuscular poetry. My own coroner's report on myself is that I died of exposure on the hills, which were never high, of the lonely deepness of my heart. My fear is that, because I cavilled at illness, God won't grant me death. That's a line worthy of Spike Milligan from the cancelled second series of 'Curry & Chips' which, alas, I alone continue to inhabit.
If you are ever in London...
Hark at me for imagining a smart Ozzie wouldn't dismiss me (albeit not as brutally) as did Clive James, Tambimuttu, in his poem 'Old Shantih Town'.
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