I wondered if any poster would mention the Pythagoreans around 500 BC or so. They were stuck on the the idea that numbers meant reality as anything observable by the senses had numerical values. At least that's might limited understanding of their "values". I'll give 'em a 7.5. Once non-integer numbers were discovered, they became....irrational, which didn't help their already ascetic lifestyle. [Reportedly, they killed the guy that leaked their discover of irrational numbers to others.]

Nice carrot. And, I agree with Ken's response.

He only bat 200? I wonder if he is getting beaned a little here and not allowed to walk to the base. Discovering a vein of gold may prove to be only pyrite, but it is a discovery that may teach us things we never would have considered. Yet, I am not saying Dunbar is wrong.

This seems to go straight to the heart of string theory? Wasn't it the spin 2 value predicted that stirred early interest? [Not that I understand this, of course.]

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Lighten up! This is a stellar board!

Newtonian science is superior to the emperical Tychonian model or Kepler's laws (from Tycho's data but with ellipses).

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Lighten up! This is a stellar board!

... from "the elegant universe", Chapter 5 ("The Need for a New Theory"), the section called "General Relativity vs Quantum Mechanics", which is a four and a bit page section, one page of which is a diagram illustrating 'quantum foam':The rest of this section doesn't add much to this extract, I feel.

What do y'all think of this, as a non-mathematical explanation of the nature of the incompatibility?

Myself, I feel it would seem quite unsatisfying, if you didn't already have some idea of the nature of both QM and GR!

For example, this says nothing at all about how the uncertainty principle destroys smooth spatial geometry (on short scales).

From "Patterns in the Void", ISBN 0-8133-3938-3, Chapter 8 "Between Shadow and Light (Quantum Gravity and the Nature of Space)".

Sten's non-math account of the GR/QM incompatibility is, I feel, good; the best I've read so far.

Unfortunately, it is not easy to find a paragraph or two to quote - the chapter itself is some 26 pages long, and the key part, addressing the incompatibility, is at least 3 pages long.

Has any other reader of this thread read that book (apart from Spaceman Spiff)? If so, do you agree with my assessment?

Yes, it is too limited unless one already knows some of the basic differences already. I read his Fabric of the Cosmos when it came out in hopes I would get a solid feel of what the fabric fells like. I was disappointed with the lack of feel I obtained, but I was impressed with the rest of his content.

It seems logical that there would be limit to the size of substances which build up to make the tangibles we feel and see. Greene points out that strings near, but larger than, the Planck length may offer compatibility. Less than the Planck length the equations produce infinity results. I think, in his book, he likes the word jitters to describe quantum behavior. Once I learned how fast atoms are traveling, it isn't that much of a step to see quantum things jittery, too.

It seems to make some sense to me in that a close look only gets you probabilities of this or that being here or there. Kinda like looking at Swiss cheese but where the holes come and go at fantastic speed. Unfortunately, we can't just switch to cheddar as Swiss is all there is. [I asked my father once which cheese had fewer calories. Can you guess his answer? ]

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Lighten up! This is a stellar board!

Yes, that's exactly what I'd cite here. It sounds like we are talking about what I called "google science", the approach to science that says it doesn't matter how you organize the information, so long as you have access to it when you need it. That is what computers are good at, and some (like Wolfram) feel that increased reliance on computers will cause science to move in that direction inexorably. But I don't agree, because I don't think science is limited to the purpose of accessing predictions, it is also about understanding. We wish to conceptualize our reality, not just build good bridges. This is why Occam's Razor is an essential part of science, and why we must never satisfy ourselves with a "black box" approach to science. Reality is the black box, we already have that-- we want to pull out what's inside it and look at it a little at a time until our minds can get some understanding. The tradeoff is, we no longer know that what we are seeing is really the whole story, or even a tiny part of the whole story, but we accept that price to gain understanding with our puny minds. And we keep pressing on because of the success we've had so far. It might "dry up" at some point, we might reach the limit of what our minds can handle, and then we'll be forced to use black boxes from there on. But we should have "dried up" with the invention of fire and the wheel-- we've come so far past that that I see no reason to keep pressing, as long as we don't get too wrapped up in the process that we forget its limitations.

I was unavailable over the holidays; I'll try to catch up!

I'll agree that there might be a distinction between these two types of errors. And yes, I'd say that a theory that makes no errors of comission should be considered an accurate reflection of reality. That it, it describes certain things, and makes no mistakes about the things it describes. Now, as we discovered on one of the threads on falsification, whether or not a theory is correct, and whether we can know that it's correct, are two different things. In all things scientific, we can never be absolutely certain that a given theory is right.

I absolutely disagree with this assessment of what "fundamentally random" means. If something is random, then there cannot be any mechanism by which the result was chosen. It has to have been equally possible that it could have come out some other way. If instead there were some reason why one result happened instead of a different one (even if it's some hidden variable that we don't or can't observe), that's exactly what is meant by "deterministic". I think you are correct, that this is exactly the sort of thing Einstein disliked.

Absolutely not. A quantum mechanical description of a particle can tell you which results are possible, which are not, and for those that are possible, which ones are likely and which are not. It should be pretty clear that a quantum model that cannot tell you why the electron in a hydrogen atom seems to be at one spot when you measure it as opposed to some different spot still gives you a good deal more information about how a hydrogen atom and its electron behaves than if you had just thrown up your hands at the start.

Nope. Precisely because we understand the mechanism behind tossing a coin, we know that the result is merely very difficult to predict, not truly random. If you don't like the idea of the universe being able to go down one of two paths with no reason whatsoever for chosing one over the other, I think you're beginning to understand why Einstein did not like quantum mechanics.

Actually, I think that Gödel's theorem goes exactly the other way. That is, the reason it works is that it turns out that even relatively simple systems end up being able to describe themselves, even if you specifically try to avoid it.

Even if it's true (and it probably is) that an intelligence can always surprise itself, that does not lead to the conclusion that an intelligence cannot describe itself. Perhaps not perfectly, but I've certainly never claimed that a perfect description of anything is possible.

But neither is there particularly any reason to suspect that, although some aspect of the universe appears to behave as though it were X, that in reality it is definitely not X, and instead only seem to be X because of some odd happenstance.

Perhaops, but I'd say the difference is this. If there were no discrepancy, we would not be sure that such a unified theory could not work at any energy scale. We might be suspicious of it at scales that had not been directly tested, but we couldn't know for sure. As it stands, though, we absolutely know that at least one of these theories has to be revised.

I really think the media is more responsible for this kind of presentation than the scientists themselves.

But here's your assumption again. I would agree that it's likely that our description of the universe will never be perfect, and so will always leave things out. But are those things taht will be left out the "most important things"? I think you have no real support for that.

Well, unless you think that the "most important things" are what the poets write about. That may well be true, and certainly I can't think of any physicist who thinks that poetry will be made obsolete by any amount of physics.

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Conserve energy. Commute with the Hamiltonian.

I think you're seeing an arrogance that is not really there. Although non-scientists often view bodies of scientific knowledge as "absolute facts", I think the majority of scientists (and certainly many of the best and best known), if asked, would quickly acknowledge that one of the hallmarks of science is the understanding that all conclusions are tentative.

Here you seem to be suggesting that nothing can be part of reality unless it is at the very bottom level. I dispute that. You also seem to be saying that since we use concepts and descriptions when talking about reality, that they can't actually be real unless reality is sentient so that it, too, could have concepts. I dispute that, too.

Yes, the term "star" is shorthand for a collection of simpler entities. But the reason that it is a "useful" term is precisely because of the way the universe behaves. That is, simpler elements seem to group together in certain ways that have similar features. To pretend that those groups are not "reality" because it would in principle be possible to instead describe those groups by only referring to their individual elements is to take an extremely narrow view of what "reality" is.

Nope, if stars aren't real because they are composite, then protons look like they aren't real either, because they appear to be composite as well. You really are the ultimate reductionist. Reality doesn't "need" them, but that doesn't mean they don't exist. Our concept of "star" is certainly created by our own intelligence, but the reason it is useful is precisely because it describes the way the universe seems to behave.



That's a pretty good thought, but I'd claim that you'd never have a chance to be able to figure out which was which. Remember, you have to stay on the other side of the wall, so you'd only be told the results of various events. Unless you know more physics than the alien, you'll never be able to come up with an experiment that could clearly reveal which was which.

Now, wait. That's like saying that an apple falling is different from a description of the apple falling. That's trivially true, like saying that a computer can't pass a Turing test, because you'd be able to recognize it if you tried to go out dancing with it. The question is not whether a description can be reality, it's whether a description can describe reality.

See, I entirely disagree here. Just because something is made of something else does not seem any reason to me to say that the composite something does not exist. The quarks aren't "masquerading" as a proton. They are forming a proton. Yes, referring to them as a proton is a simplification, but the reason that it's a useful one is that quarks (as far as we can tell) really do behave that way.

Here we seem to be again talking about the trivial question of whether a representation is what it represents. The answer is of course not. It's a representation thereof. The question is whether it is inevitable that such a representation leaves out "the most important" features of the thing it represents. I still don't think you've really supported that claim.

I think it was mostly that numerous high school literature teachers (including some of mine), suggested that the essence of many of the stories often involved "pride" being the tragic flaw of the protagonist, which inevitably led to the protagonist's downfall, and my professor finding that to be missing a good deal of the actual point of the works, to the point that I think he would have preferred that they not teach it at all. It's interesting that this could parallel our discussion here if we just substitute "real meaning of work" for "reality" and "simplistic literary view" for "simplistic scientific view", except taht I think he would have put their efforts more on par with stone knives and bearskins than with quantum mechanics and general relativity.

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Conserve energy. Commute with the Hamiltonian.

I'd ask you, like Ken G, why do you know that it's purely coincidental? Especially in the case the Nereid describes, where your program can correctly predict the output even when using input that has never been tried before, doesn't it seem more likely that the only way you'd get it right is if your program were a pretty good representation of what's happening in the box?

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Conserve energy. Commute with the Hamiltonian.

I don't think you mean that, I think you mean there is no predictable mechanism. Rolling a die is a mechanism by which a result is chosen, and it isn't predictable if done properly. My point is that reality must have some way to "roll a die". I'm not agreeing with Einstein that this is unconscionable, I'm saying that it is an unknown mechanism for achieving an unpredictable (by human science) result. Whether there is any other way to "predict" that falls outside human science I cannot even guess, but even if it is absolutely unpredictable, there still has to be a mechanism. There is currently not even a hint of what that mechanism is, and I think we should face the possibility that there never will be. One can certainly say, as I think you would, that the mechanism is irrelevant if you know the probability distribution of the result, but I would say only that it is not required to do science.

Again, is a dice roll a 'deterministic" phenomenon? Perhaps in the hands of Randi it is, but not in the predict-the-weather-a-year-from-now sense. We know the physics of weather, so we know the mechanism of sensitive dependence to initial conditions, but we can't predict it, because exponential growth of uncertainty is a real you-know-what. But at a deeper level, we don't really know the mechanism, because at some point the uncertainty connects to the quantum domain, and there it is something different from sensitivity to initial conditions.
I should not have said that science should never content itself with "reality just does it", because in fact it is part of my point that science must do just that at some point. What I meant to say is that when science does make that resignation, what we are seeing is a fundamental limit of human science. The existence of such a limit is what I view as the fundamental disconnect between reality and science, whereas I think you would say that we are merely seeing the limit of reality itself. I think that's the "when all you have is a hammer, everything looks like a nail" approach to metaphysics.


Now I feel we have left the domain of science, if you feel you can offer a scientific definition of the difference between "truly random" and "impossible to predict in practice". How would you find observational evidence that there's a fundamental difference between predicting a quantum event and predicting the weather a year from now? I'm not talking about "hidden variables", we know those don't work, I'm talking about having machine-precision accuracy on the location of every particle and every field on Earth and still not knowing the weather in a month. Noise is not escapable in science, and exponential growth of noise is also unconquerable when present. How do we know there isn't some similar quantum chaos? Maybe such explorations will discover a way to understand the mechanism that makes the wave function work, but over that hill will be another one.Not quite. Einstein didn't like the universe rolling dice. I have no problem with that-- I want to know what dice it's rolling. Maybe science can determine that, via some quantum chaos approach, but if it can't then it's circular to claim that reality must have no such mechanism because science cannot determine it. This is the fundamental issue once again-- when science encounters limits in probing reality, does this have to mean that reality itself ends there, or just science? I would rather define scientific reality as that objective element of what is "out there" that can be probed by science, and leave it at that. Science need not require there be no other reality outside the domain of science, objective or subjective, yet many scientists seem to think that this is a requirement.
I don't follow. If you are including the real numbers as a "relatively simple system", then Godel's theorem says that you can't prove everything that is true about the reals with a system of axioms that is significantly simpler than the reals themselves. That is, you can substitute something simpler for the reality, and make a kind of working model of the reality, but the reality will always have more going on than your substitute can describe. To me, that's science in a nutshell. The difference is that the kinds of things you can't prove about the reals are really bizarre and esoteric things that you probably don't really care about anyway, but I don't see that as the case when applied to the most profound and sublime elements of reality.
If we agree that a complete description of intelligence is not possible by intelligence, then that is basically my point right there. Intelligence is a subset of reality, and science will never be able to offer a complete description of even that subset (no "theory of everything"). All I'm saying is that science always has cracks that reality will slip through, we certainly both agree that science is the best way we've ever found to learn ways to conceptualize the intesection between objective reality and what we can observe, test, and understand.

There's no scientific way to bring evidence to bear on that suspicion, that's true-- it's just a suspicion that is actually outside of science. This is another interesting point-- the human brain is capable of doing things that are not science, like art and philosophy, and metascience: having suspicions about what science is doing that are hard to establish as being correct because they are outside science. The "blind spots" can be identified using science, but what is really happening when science is highly successful requires going outside science to think about. Unfortunately, science is the only way we have to really know much of anything in an objective way.

That is true, we do get certainty, instead of just a very very very good bet for a gambling man. It's not often that we can be certain of anything, so there's definitely something to be said for it. But even here we see the core irony of science: it is always easier to be certain something is not correct, than that it is! I'm just applying the same principle to the relationship between science and reality.
I think it's a shared culpability. The media encourages it, the scientists want the fame and recognition, and voila: the press conference or catchy phrase. I don't say it's terrible, I'd probably be more than willing to do the same thing given the opportunity. I just think it does science a disservice that should be watched out for.
That's probably true-- the "most important things" are probably rather simple: food, shelter, health, and some level of freedom. Science has given us longer and healthier lives, with much less misery and affliction and slavery ending in early death. To most, that would have to qualify as the "most important things"! I was indeed referring to a more poetic approach to that topic, but I wouldn't defend it-- all that is kind of a luxury in comparison. On a cynical day, I might say chuck the poetry, it was all a bunch of self-delusional drivel, and on an optimistic day, I might say that poetry is the only thing humans created that ever really mattered more than any colony of bacteria. Or would that be the cynical day?

[trivial edits]

I'd say it's about 50-50 among the scientists I've had similar discussions with (few at this level of depth!). There's the pragmatic types, who generally seem to feel that science is the only thing humans do that has any reasonable claim to the title of knowledge or understanding, and then there's the renaissance-man (or woman) types, who accept science as simply our most objective mode for accessing the profundity of the universe and our human condition in it. I obviously fall in the latter group-- but most of the posts I see on this forum would be placed in the former category. It's not so much arrogance exactly, just unsophistication I'd say. My intention is not to rag on science, but to increase the sophistication of our appreciation of what it is, and what it might not be (granted, I said what it isn't, but perhaps more correct is might not be.)
Yes, "very bottom level" is just the concept I have in mind. If there is such a level, then that's reality. But we are certainly laboring under the lack of having an operational definition of what is even meant by the term reality. We are caught between a rock and a hard place. The rock is that it's not sufficient to simply accept the scientific definition, which I would call that which is observable, testable, and understandable by human intelligence, because then it is circular to claim that science is the study of reality. I would call that "scientific reality" to clarify the circularity. But the hard place is, who can offer another definition? Science is our best approach to objective reality, and subjective reality is a very difficult concept to enter into a debate about. The underlying issue is-- is there anything other than scientific reality, objective or subjective? Taking the Godelesque approach, I say we already know there is, but even if we don't go the route of pure logic, it is just horse sense that our limited faculties must be missing a lot of what is out there, not to mention our possibly arbitrary five senses and other biological prejudices. We can also take the historical perspective approach to the issue, and note how radically our paradigms have changed. Is that just the inevitable process that would eventually move everything there is from the realm of the mysterious to the realm of the understood? Or is mystery an inherent element of reality? I'm saying I see much evidence for the latter interpretation.

I wouldn't call it a "narrow" view, I would call it a view that gets completely away from the way we use science to organize our thinking about reality. If we see a bunch of circles and squares drawn on a blackboard, our minds instantly organize them as such. But in "reality", none of those objects are really circles or squares, they are what they are, with all their dimples and flaws. It is our minds that says they are circles and squares, not reality. Of course, the reality is that some are closer to circles, and some are closer to squares, but what does reality care about the difference between a circle and a square? Those are human concepts, and part of what a scientist does to organize reality in ways that reality has no need for, because the goal of science is to understand reality-- that's a very human activity. I view scientists as being like duck hunters (minus the violent associations) who make mechanical versions of ducks that just have to work well enough to bring the real thing into their sights. But there still isn't much point in shooting their own ducks!

Yes, it's the mechanical ducks again. It's mostly a semantic distinction, but I think there's value in making it.

You're certainly right, but that's kind of a cheat. It would be enough to say that you could distinguish that there was a difference, given unlimited resources for doing so. You wouldn't need to know which was the "real" reality, because we always have access to that (assuming we are not insane, which unfortunately does require an untestable assumption!).

Actually, I don't think it's enough to ask if our descriptions can describe reality, because they are descriptions of reality simply because we say they are. They don't have to pass any tests to achieve that distinction, other than the ones we ourselves lay out for them. They are our creations, our mechanical ducks, and we decide the precision desired, so we don't get to determine if they are the reality in that way. What I'm asking is, do they just quack and bob like reality, or are they what reality is actually doing in its essence? In short, can they be the reality. The reason I'm asking this semantically tricky question is that the real question I'm asking is, can there be anything that is real that is not accessible to human science even given unlimited eons and galaxies of resources? When we recognize that our science is just creating models of reality that work for us, it makes it much easier to see what I feel is the answer to that much more important question.

I'm seeing the scientist in those remarks. But what if you had no interest in conceptualizing reality, you just wanted to know what it was really doing? Then a description of everything quarks do is all you need, you'd never need the concept of a proton. It's just like someone doing a hydrodynamic simulation of a supernova-- there's no "star" anywhere in the code, there's just an initial condition describing the locations of lots of stuff, and a computational grid. The "star" is just a conceptualization by the programmer that exists nowhere in the actual program.
I don't believe I claimed that a representation of a star, or a proton, leaves out the most important features of stars or protons. If you are already at the level of thinking about stars and protons, you have already left out the part I was talking about-- the underlying reality. I don't mean it's important to know that part in order to understand how stars evolve or how protons fuse-- we already know that stuff without any deeper understanding of reality. That isn't the "most important" stuff, which was a bad way for me to refer to it anyway-- "more sublime truth" would have been closer to the mark.

Then I'm guessing he'd have been no friend to the expression "pride goeth before a fall"! In fact, I never really understood that expression, I always thought we should take pride in ourselves, like hold ourselves to our own high standard. But I guess there's a type of pride that is more like narcissism, and that does tend to lead to comeuppances. Still, "narcissim goeth before a fall" doesn't have the same ring...Perhaps so, I guess both he and I are just saying, don't be satisfied with a kind of zeroth-order kind of analysis of the meaning of some endeavor, dig deeper.

I don't know if my answer to this would be the same as gzhpcu's, but I think the flaw in this analogy is that if the "black box" admits numerical inputs and generates numerical outputs, then you have already taken the projection of what I'm calling reality onto what science does with reality. The scientific approach is to take reality, apply observations that generate numerical outputs, and conceptualize reality as such a black box. Then it tries to write a code that acts in the same way, within a range of inputs and a precision for the outputs. The step where the reality got replaced by something simpler happened right away there, even before you ever started trying to understand or recreate the outputs. Science manipulates reality when it asks the questions, not when it finds the answers to its own questions. The real issue is, what is the relevance of nonscientific questions? And further, what happens to the possibilities for reality when the very linguistics of a question get applied? Above all, I can summarize my question by asking, isn't it likely (but I'll settle for possible) that reality requires a kind of "glue" to make it work, a glue that bridges over the gaps between the kinds of questions that can be linguistically formed, and the subset of those that can be scientifically addressed in principle, and the subset of those that have been scientifically addressed in practice? I see elements of reality that must "slip through the cracks" of our careful web of objective knowledge, or else we're shooting our own mechanical ducks (to borrow from my duck hunting image for anyone who waded through my last post!).

Without wanting to enter a philosophical discussion we perceive in our everyday world what we consider to be reality through our senses. We attempt to zoom out to higher cosmological scales or zoom in to smaller microscopic scales. Our human senses are limited, so we try to extend them (as far as physically possible) using devices, from telescopes to microscopes/to particle colliders. However, we ultimately reach physical boundaries, where a further extension of our senses is not possible. Here, I believe the troubles begin, because we attempt to extrapolate further beyond the boundary using mathematical models to envision a reality which still retains some of the sensorial aspects which we had to leave behind when crossing the boundary, whereas perhaps in this realm, these probably no longer apply.

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“He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever”
Chinese proverb
"All you need in this life is ignorance and confidence - and then success is sure." - Mark Twain.