• Kym
    86
    DO BLACK HOLES SUCK?

    P1: I mean... the escape velocity of a black hole exceeds the escape velocity of light, so even light can't escape. (Wow)
    P2: Gravity propagates via gravitational waves which have been shown to travel at light speed
    C1: Even gravity can't move fast enough to escape a black hole!
    C2: Black holes do not suck

    I can see how my question can be seen as a flippant bit of sophistry - after all, the observations (like gravitational lensing) show pretty conclusively that all-consuming black holes do exist. So why waste our time?

    Investigating paradoxes can, and have, pointed to flaws in scientific paradigms. Flaws that only played out fully much much later, when further observations finally forced the adoption of new and better paradigms. For many detailed examples I'd recommend Thomas Khun's 1962 book The Structure of Scientific Revolutions.

    Meanwhile here's an example I'm fond of from my youth. Zeno of Elea came up with some pretty curly paradoxes. Perhaps the most vivid was Achilles and the Tortoise. Here's the Stanford Encyclopedia of Philosophy's description:

    In the paradox of Achilles and the tortoise, Achilles is in a footrace with the tortoise. Achilles allows the tortoise a head start of 100 meters, for example. If we suppose that each racer starts running at some constant speed (one very fast and one very slow), then after some finite time, Achilles will have run 100 meters, bringing him to the tortoise's starting point. During this time, the tortoise has run a much shorter distance, say, 10 meters. It will then take Achilles some further time to run that distance, by which time the tortoise will have advanced farther; and then more time still to reach this third point, while the tortoise moves ahead. Thus, whenever Achilles arrives somewhere the tortoise has been, he still has some distance to go before he can even reach the tortoise. — Huggett, Nick (2010).

    Pasting in a graphic right here would be helpful, but sadly that exceeds my Paleolithic skill set. However, Aristotle succeeed in reducing this to fairly dry summary:

    In a race, the quickest runner can never overtake the slowest, since the pursuer must first reach the point whence the pursued started, so that the slower must always hold a lead. — — Aristotle, Physics VI:9, 239b15

    But why waste our time? We've run the experiment, Achilles won. Case closed.

    But it turns out this non-problem arising from assuming the infinitely divisible was not to remain an academic one. By the 1900s the formulae of physics, as we knew then it, was having to predict infinities that just weren't observed (the Black Body Problem). The solution was that radical paradigm shift to Quantum Mechanics which abandoned the previous assumptions and opted to include indivisible quanta (photons in that case). Now we recognise all kinds of quanta, including indivisible Plank length and Plank time - which I'm sure would have been great of interest to old Zeno. In practice QM has become so important that we now must use it to successfully design things like this PC I'm using right here.

    Ok we could at this point say, well that's still all 'Sciencey Stuff'. Personally, I never bought into the 'Two Cultures' view of Science vs Humanities they started pushing on us during the late Enlightenment (but that was during my middle years and I was getting pretty recalcitrant by then). Nor do I did think did the famous paradigm-busting thought experimenters of science ever drew this distinction (e.g. Galileo, Einstein). They were philosophers as much as they were scientists.
  • SophistiCat
    2.2k
    I am not sure what it is that you want to talk about. Is it scientific puzzles and paradoxes in general? The three examples that you gave really don't have much in common, even under that broad topic.

    Your black hole question most likely belongs to the category of layman misunderstandings of complex science. I am not saying this from a position of expertise - my own physics background is insufficient to answer your question - but from the position of common sense. An elementary question like that, if it was a genuine puzzle, surely wouldn't have gone unnoticed. Given your almost total ignorance of this difficult topic, the surest way to find an answer would be to learn more about it. Which is why you ought not assume right away that you have stumbled upon some paradigm-shattering paradox and, if investing years into the study of math and physics doesn't sound promising, at least go ask your question on a friendly science board, where someone might be able to give you a lies-for-children version of the answer.

    Zeno's problems are more of a philosophical topic, and I encourage you to read the rest of the excellent SEP entry.

    The Black Body Problem, aka the Ultraviolet Catastrophe doesn't really have much to do with Zeno. Whereas Zeno's problems, on their most generous reading, come down to the general metaphysical issue of super-tasks (performing an infinite number of actions in a finite interval of time), the black body problem was an indication of an inconsistency of a particular physical model. It did not go unnoticed and was not ignored. Physicists at the time recognized it as a genuine problem, but what no one realized was just how radical the resolution of the problem would be.
  • Kym
    86
    I am not sure what it is that you want to talk about....SophistiCat
    Fisrt up I want to talk about one role philosophy has in the progress of science - with a view to discovering others. My general position is the dichotomy between Philosophy and Science has been exaggerated.

    Your black hole question most likely belongs to the category of layman misunderstandings of complex science.SophistiCat
    Yeah, there's a misunderstanding there all right. But exactly where? Only when false premises have been identified have we been able to the escape gravitiational capture of paradigms.

    my own physics background is insufficient to answer your question ...SophistiCat
    The proper authorities have everything in hand - nothing to see here folks. Hmm ... like 98% of the missing mass in the unvierse it turns out. Now I'm not saying that particular solution lies in the Black Hole Paradox. But I am saying the whole field is ripe for (desperate for) a huge paradigm shift. Let's get on board that train, It's going to be a great ride!

    - but from the position of common sense.SophistiCat
    Common sense is the view seen through the eyes of the locally accepted paradigm. Sometimes it's right, but for a long time it was common sense that the Earth was at the centre of the universe. This is kind of just what I'm trying to have a crack at here.

    ... you ought not assume right away that you have stumbled upon some paradigm-shattering paradoxSophistiCat
    Agreed, that would be hubriistic indeed. Sure, I'm curious enough about the Black Hole Question, but I really lead with it to launch a broader discussion.


    Thanks for the feedback
  • Artemis
    1.9k
    My general position is the dichotomy between Philosophy and Science has been exaggerated.Kym

    Yes. And not only because science originates in philosophy, and is (strictly speaking) a sub-discipline thereof.

    Yeah, there's a misunderstanding there all right. But exactly where?Kym

    Well, for one, that a paradox cannot actually exist. It is, at best, a seeming paradox--paradoxical according to our current theories about the laws of physics, and/or what black holes are/do. We simply need to learn more and then we will figure out how it's not actually a paradox. The apparent paradoxical nature of something like a black hole is useful, though. It serves as a red flag saying "wait guys, we need to do some more research and theorizing here!"

    Same reason I'm skeptical of any talk about quantum physics, btw. Someday scientists will have a reasonable explanation for the double slit experiment, but it won't be that a particle is in two absolutely separate places at the exact same time. IMO.
  • SophistiCat
    2.2k
    Fisrt up I want to talk about one role philosophy has in the progress of science - with a view to discovering others.Kym

    Well, I am still not seeing much of that in what you have posted. Unless you think that "Hey, here is a naive layman question about some complex science" constitutes an example of such a contribution. Those philosophers of science who are serious about their subject usually have a decent grasp on the science. If you are interested, I suggest you look at some actual examples. Perhaps flip through a philosophy of science journal, or look at some papers available online. Here is, for instance, a selection of philosophical papers about General Relativity on Philpapers.
  • apokrisis
    7.3k
    My general position is the dichotomy between Philosophy and Science has been exaggerated.Kym

    That is true. But if that is your main point, the problem would be that your OP didn't advance some particular argument.

    P1: I mean... the escape velocity of a black hole exceeds the escape velocity of light, so even light can't escape. (Wow)
    P2: Gravity propagates via gravitational waves which have been shown to travel at light speed
    C1: Even gravity can't move fast enough to escape a black hole!
    C2: Black holes do not suck
    Kym

    It is easy to google the answer and see that you have set up the science wrong and so not established a paradox.

    The mass doing all the gravitating and spacetime bending takes forever falling into the hole. So yes, the in-falling light or electromagnetic radiation is trapped in the hole, but the historical gravitational effect of that matter - or rather that distortion it all makes in the general spacetime metric surrounding the hole - is not. So if the hole bobs about, it would make gravitational ripples in the surrounding spacetime that propagate outwards at c. And just standing still, the hole would radiate a steady gravitational attraction which propagates at c due to the general warpage it creates in the larger fabric of the surrounding spacetime.

    So you have confused in-falling light (a source of gravitating matter) with the gravitational effect of all the matter being concentrated at a point on the surrounding universe.

    Now philosophically, or metaphysically, we can then start to question the presumptions of this successful scientific account.

    For instance, we might note how there are two actual competing paradigms in play here. Is gravity "actually" general relativity's curvature in spacetime, or is it "actually" itself a radiating force -a quantum flux of gravitons?

    And that could get us back to the issue of whether the divide between science and philosophy is much exaggerated.

    Science would say its all just models, so the paradigms only need to work. One view can only be better than another view in that pragmatic sense. Philosophy might then say it cares about what is actually the case. Which is where the two would be very strongly divided as practices.

    But then a further argument is that philosophy also is just reality modelling. As critical thinking, it is about questioning paradigms so that better paradigms can be imagined. Then science would be a principle way of exploring the rational consequences of alternative paradigms, (although there might be others, perhaps).

    Anyway, that is the direction my own thoughts would go on the "exaggerated divide" issue, starting with what is actually a little bit paradoxical or self-contradictory about our contrasting general relativity and quantum mechanical models of gravity.
  • Kym
    86
    Sorry guys, I've been reclining rather than rebutting.


    I kind of regret using my own 'Black Hole's Don’t Suck' example here. Really, I don't hold it in ANY esteem. It's a curiosity, and it's obviously it's wrong. It was originally meant as a stand-alone conversation starter, from which a general dialectical on philosophy-in-science might unfold. The only reason it's in caps is to have a gentle dig at a moderator who censored two very short posts I made using that title.

    (But if you do know which bit is broken I'd be grateful if you'd satisfy my curiosity. Otherwise I will post it on a science forum down the track).


    .... science originates in philosophy, and is (strictly speaking) a sub-discipline thereof.NKBJ
    The apparent paradoxical nature of something like a black hole is useful, though. It serves as a red flag saying "wait guys, we need to do some more research and theorizing here!"NKBJ

    Give that man a koala stamp!

    Same reason I'm sceptical of any talk about quantum physics, btw. Someday scientists will have a reasonable explanation for the double slit experiment, but it won't be that a particle is in two absolutely separate places at the exact same time. IMO.NKBJ

    An orthodox interpretation is to invoke particle-wave duality. This proposes that the particle's wave nature is at play during the experiment, allowing the interference pattern to be produced, before the particle is observed in it's 'particle form' as it finally hits the screen.

    I find this interesting. Is quantum 'particle-wave duality' just a place-holder paradox being tolerated to make the numbers work? Or is this duality really the quality of the world at the very smallest scale? Personally, I'd much prefer the former.

    But since this freaky duality idea has allowed the QM guys to go on and make stunningly accurate predictions - I have to doff my hat to them. This in turn raises very interesting questions on the relationships between theory and observation.


    Science would say its all just models, so the paradigms only need to work. One view can only be better than another view in that pragmatic sense. Philosophy might then say it cares about what is actually the case. Which is where the two would be very strongly divided as practices.apokrisis
    I agree with this distinction of emphasis. The "paradigms only need to work view" of science is laudable in that it allows them to crack on and get a lot of work done. It would have been tragic if Newton had spent all his time on paradoxes rather than cracking on with Principia Mathematica, especially it's Law of Universal Gravitation. At the very least this kicked off a golden age in astronomy, now the movement of the planets were predictable. In fact the very existence and location of still unobserved planets could be predicted by perturbations on those we observed.

    All good. Then the very innermost planet Vulcan was predicted from perturbations of Mercury's orbit. Being so close to the sun this would be difficult to observe. Funds were funnelled, contraptions were erected. Decades past. More money, more building, more cold nights in the dome. Vulcan was never seen.

    Turns out that Mercury’s orbit was a bit off because it's time line was being stretched out by its close proximity to the Sun's mass. Who would have though it? Well, a couple of guys were way ahead of game and had a new paradigm all ready to go: General Relativity.

    Historically, there have been a few great cases like this. Kudos to these guys. Not just for their ability spot a leaky paradigm ahead of time, and then having the wits to jump out if it - but for their skills in building a new one that floats.

    Me, I'm far too dim to do the maths. But the history of science is a great spectator sport!

    Live long and prosper
  • SophistiCat
    2.2k
    It's interesting to note though just how philosophical Einstein's thinking was throughout his work on relativity and quantum physics It wasn't just "let's find a mathematical model that fits the data better," which would have probably ended up with epicycles rather than with a radically new (and at the same time old as Galileo!) theory.
  • Kym
    86
    He allways said he was bad at math too. I just find reasons to like that guy more and more!
  • Kym
    86
    AFK for a time guys. Sorry for any lack of responses
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