A researcher puts you into a room. On the table is a blue ball. Somebody put it there. It could have been Alice, Bob, or Charlie. Given only that information—and no more—who put it there? You have to pick one and only one.
If the choice seems arbitrary, it’s because it is. Whoever you pick has equal justification given only the information provided.
Instead of choosing, we can switch to probability. Given only the information provided, what is the probability Alice placed the ball? Same as for the other two: one-third (the proof of that is found in here).
We have learned three things. One, probability is conditional on only the information given or assumed. Two, decision (or choice) is not probability: decision uses probability, but it is a step beyond it. Three, there must have been a cause for the ball.
The probability is straightforward (but see this page if you want to learn more). The choice, decision, or act is less so. Given the probability, and given what you think will happen if you were to guess right or wrong, you make a choice, a decision, or you act. Two people can have the exact same precise duplicate identical information, and thus must necessarily come to the same probability, but they can easily come to different (even wildly different) decisions because they believe their choices will have different consequences—and their choices may very well have different consequences. And no matter what the (conditional) probability is, and no matter what we decide, there will still be a true cause.
Probability (epistemology), act (or will), and cause (metaphysics). All different steps which must be kept distinct when analyzing any problem.
The philosophical concept of inference to the best explanation can confuse and conflate these three steps or categories. Not systematically, so that we can apply a correction, but willy-nilly, depending on who is wielding the tool.
Inference to the best explanation (IBE) asks us to make a choice on a cause without examining—in any thorough sense—probability or the consequences of decision. This is not to say the technique does not and cannot come to correct probabilities, decisions, and understandings of cause. It can and very often does, especially in those areas in which we have expertise or extensive knowledge.
The reason IBE works, when it works, is that people are good at the individual steps without knowing or explicitly acknowledging they are using those steps. That will be obvious in a moment.
What happens when you see a ball and you really want to know the cause of it being there? You run through possibilities. I specified only three, and then said nothing more except that there were these three. There is no information about Alice’s motives, or her placement (where was she?), her personality, nothing. The information allowed was restricted in the extreme. Given only it, we could make a choice, but we recognized that choice’s arbitrariness. That arbitrariness informs the decision we would make, depending on how we view the consequences of making right or wrong decisions (which may well be different for each reader).
We also implicitly recognized one aspect of the cause: the efficient cause. We know a person placed it there, but we don’t know why. We do not know anything of the final cause, the reason the ball was put there. That we don’t know the motivation does not, obviously, mean we do not know the ball isn’t there. It is there. We also do not know the formal and material causes: we do not know the means the person used. Again, our ignorance of these does not mean the ball is not there.
That the IBE does not work here—there is no single best explanation and no identification of all aspects of the cause—is not the fault of the artificial nature of the problem: it is the fault of IBE. Any epistemological technique that claims to be an algorithm to discover the best guess of truth on given information (IBE does not claim to always find truth) has to work everywhere, or we have to look elsewhere for better algorithms. I claim we can’t find one: we’re stuck with probability, decision, and cause. Life and thinking isn’t so easy.
Now in real life you are not as restricted as in this artificial situation. You are free to guess or assume or measure other probative evidence that will modify the probability, change the decision, or lead to fuller understanding of the causes.
Didn’t I see Alice here earlier? I thought Bob said he was driving somewhere. That looks a lot like a ball Charlie plays with. Fastidious Alice might have been here, but I can’t see why she’d leave a ball lying about. Et cetera. You must play detective.
Means, motive, opportunity. That’s what detectives look for, because why? Because these items identify all aspects of the cause of the event. Detectives know they might not always guess right, that the wrong man is sometimes pegged, that some motives are opaque, and on and on. Detectives also know that the defense attorneys are free to form their own list of probative evidence, and so will come to different probabilities, decisions, and understandings of cause.
The possibility of differences in assumptions is the key to understanding the IBE’s general weakness—and it’s sometime usefullness.
It is the freedom to choose the evidence, and that there is no algorithm that leads us to the right set of perfect evidence that results in uncertainty. Uncertainty is often our lot.
Of course, there will always be a right set of perfect evidence that puts the probability at 0 or 1, as the case may be, evidence that results in a flawless decision, and that nails all parts of the cause. Our goal is to get as close as we can to this perfect set. But there is no guarantee we will even come close to it much of the time. (And there is even proof that in some cases, such as in quantum mechanics, it is impossible to come to it.)
A strange blip on the bubble chamber screen. Something caused it. What? The physicist must piece together the evidence. Means, motive, opportunity. In the end, and especially if the blip never repeats, he may just shrug his shoulders and say “Chance”—which is only and ever a euphemism for “I don’t know.”
The nature of evidence is the same at home, in science, in math, and in religion. Why something is is different from that or how it is. (I won’t prove here it works in math, but I do prove it here.)
None of this is controversial, except to die-hard followers of IBE who somehow believe that if only they exerted themselves sufficiently, they can always come to the best explanation of all aspects of a case—which is not synonymous with true. When IBE works, it’s really common sense, carefully explicated.
Next week we’ll see how Shapiro’s use of IBE to dismiss miracles relies on premises he didn’t know he was assuming, on how he did not account for the freedom to assume what evidence is probative, and how he didn’t grasp all aspects of cause.
Update Since it has arisen, there are other interpretations of quantum mechanics which differ from the classical ones. For instance: Quantum Potency & Probability, which restores Heisenberg’s original surmise. About cause. Now everything potential that becomes actual only can do do by something actual—a fancy way of saying QM events are not “uncaused”, as some would have it. On the nature of cause in QM see inter alia Wolfgang Smith’s The Quantum Enigma: Finding the Hidden Key (3rd Edition) Scholastic Metaphysics: A Contemporary Introduction. There is another recent monograph by (I think) a Dominican scientist on the same subject which is escaping my memory. When I recall, I’ll post.
Categories: Book review, Philosophy, Statistics
To help any students to avoid confusion:
The author here makes two statements about physics, both incorrect.
In quantum mechanics, if, just to give one example, if you have two entangled particles that are prepared so that they must have opposite spins, and you measure one particle to have spin up, then the probability that the other particle, when measured, will have spin down = 1. This is not just theory; it’s routinely verified in experiments and is elementary, undergraduate-level knowledge.
A microscopic event, such as a decay observed in a bubble chamber, when “random” (governed by probabilities) is not random in the classical sense of ‘euphemism for “I don’t know.”’ The conventional interpretation of QM is that these events are uncaused, and that their probabilities are primary, and not the result of incomplete knowledge. Perhaps in the future someone will find a deterministic theory of fundamental processes (that actually works, including relativistically), but there are severe obstacles in the way. Therefore to describe “quantum mechanics” in the way the author does simply displays a lack of understanding of what QM actually claims.
If you are interested in these things you might enjoy https://arstechnica.com/science/2017/07/a-brief-history-of-quantum-alternatives/3/
“We do not know”—the impossible words for many people to utter (Lee, thank you for confirming this). Science is TERRIFIED it might be discovered as not omniscient. That’s required for its godhood. I am constantly amazed at skeptics who come apart screaming if you question evolution or theoretical physics or anything sacred to them. The one thing we know is most people will always insist they know what they do not know and cannot know.
Chance is to cause as virus is to medical diagnosis—it’s a virus if the doctor can’t fix it, it’s chance if nothing else explains the cause.
Personally, I use a dart board for those nasty inferential decisions involving equal probability for all known possible causes with equal outcomes. Same dart board I replaced the weather forecaster with. Probability is far less useful than it’s marketed to be…..Or maybe more correctly, it has been seriously oversold through no fault of its own.
Lee Phillips shows that this blog could use more searching, erudite, knowledgeable, and genuinely instructive type comments. Every one of Mr. Phillips’s remarks is better than the next.
IBE implies that one infers based on certain criteria for being the best. Are you saying that, contrapositively, if one uses a probability criteria or the consequences of decisions to make inference or a choice , thoroughly or not, then it is not IBE? If you are, it doesn’t seem correct
IBE is necessary because we are not all knowing, though some people have the all-knowing disease as Confucius put it.
It seems that you have a penchant for seeing and assuming what people don’t say, what people don’t know or understand, and how intelligent other people are. Gee, Shapiro, a well-trained PhD philosopher, surely knows little.
Here are some great examples of excellent and longer-than-usual book reviews.
Some people may claim to know their God in whatever ways based on whatever reasons. I saw that even Uncle Bill, a devout Catholic once went to seminary to become a priest, cast doubt before his passing. To his doubt, his good friend Fr. R. replied, “I believe it is true.” “I believe.” NOT “I know.”
“And there is even proof that in SOME cases, such as in quantum mechanics, it is impossible to come to it [“it” being perfect evidence allowing one to determine a probability is exactly zero or one].” – Briggs [EMPHASIS added]
Generalizations which apply to the majority of circumstances necessarily have some exceptions. Briggs’ article is clearly [or should be clear it is] a topical broad generalization and proving its validity merely requires it to be true most of the time. Lee Phillips makes the all too common mistake of believing that an exception to such a generalization refutes the generalization.
Specifically, Briggs’ quantum statement IS true regarding “some” cases — the quantum uncertainty principle holds that it is impossible to to know certain pairs of things about a particle at once (e.g. the location and speed of an atom or subatomic particle). As the vast majority of particles one might encounter are not quantum entangled Briggs statement remains true. And even if one did encounter only entangled particles, the likelihood that one would know the relative features of a given entangled particle per the kind of scenario Phillips described is effectively zero because one would have to also know which of the myriad other particles out there to which it is particularly entangled.
From this we can conclude that while Lee Phillips can raise some interesting notions of the “food for thought” sort, he’s still human and can err a bit at the same time … and … JohnK’s gushing accolade is a wee tad bit uber way over the top … which, on a quantum scale relative to our human scale could be infinitesimally tiny. And therein lies a paradox or something.
I generalization of the form “all x are y” can be refuted by a single example of an x that is not a y. Brigg’s claim is that there are some cases, for example the case of QM, where it is impossible to have circumstances where the probability of a measurement outcome is 0 or 1. This is incorrect. The example of entangled particles is one example of where it is wrong, and one example is all that is logically required to show that his claim of impossibility is in error.
Your comment about the “myriad other particles out there” suggests that you might not be aware of the routine and relatively simple nature of experimentation with entangled particles. People do these experiments all the time these days, with tabletop optical setups.
Lee Phillips writes: “if you have two entangled particles that are prepared so that they must have opposite spins, and you measure one particle to have spin up, then the probability that the other particle, when measured, will have spin down = 1”
It is a tautology; how can it be otherwise if these particles have been prepared to be as you subsequently measure them? If I paint it blue, will it surprise me that on measurement, it is blue? It would be surprising to be anything else.
JH writes, “Gee, Shapiro, a well-trained PhD philosopher, surely knows little.”.
That is likely so. The whole point of philosophy assumes lack of knowledge at the outset and then tries to deduce or induce what is true and real.
Belief and knowledge are the same thing; merely degrees of difference of personal certainty. One can be certain and still wrong; a person can “know” things that are simply not true; conversely disbelieve things that are true; and to complete the matrix there’s also knowing true things and disbelieving false things.
Everything I “know” I also believe. Why would I disbelieve a thing I know? But everything I believe is not always a thing I know; because “know” is a more certain form of “belief” and thus includes “belief”. I have not stopped believing in gravity just because I know gravity.
JH also writes “I saw that even Uncle Bill, a devout Catholic once went to seminary to become a priest, cast doubt before his passing” Jesus chose Doubting Thomas probably because doubt serves a useful purpose, it helps create humility. Lack of doubt is certainty, and certainty can lead to pride and a closed mind, a “cup that is already full” (Avatar movie).
Your point is well taken. I was trying to be as brief as possible, and my description would probably sound like a tautology to those who don’t already know about entangled particles in QM. My article goes into a bit more detail, and I’ll try to explain better here. The state of each particle is undefined (not just unknown, but not definable) until one of them is measured. If particle A is then measured to have spin up, then particle B will be measured to have spin down, with P = 1. This is true no matter how far apart they are, or how close in time the measurements are made. This is what Einstein called “spooky action at a distance”. But even in your case of “painting it blue”, this already contradicts what Briggs claims is “proven” about QM, that one can never know with P = 1 or 0 about the outcome of a measurement.
Let me use the following to show the difference between “believe” and “know” that I had in mind.
Mathematicians would tell you that they believe the Riemann hypothesis is true, but not that they know the Riemann hypothesis is true.
In this case, they choose to believe. Belief is necessary but not sufficient for knowledge.
Indeed , lack of doubt is certainty, and certainty can lead to pride and a closed mind, a “cup that is already full”
(I just watched Avatar for the second time this weekend. So, what you said reminds me of the Chinese proverb, “A frog who lives in a little well should not talk about ocean as if it knows ocean.” )
Shapiro, a professor at a flagship university, doesn’t need me to defend him.
I’m not sure why people talk about something being “uncaused” when all they mean is that they don’t know when or where it may occur.
That’s not what they mean. It is not a statement about lack of knowledge. Something that is uncaused is just that. Explained in any elementary QM textbook.
So something can be without being caused. Yet it is often said that extraordinary claims require extraordinary proof. Surely something more that a breezy reference to a textbook somewhere. As Feynman famously remarked, “I think I can safely say that nobody understands quantum mechanics.” (The Character of Physical Law). Many people understand other sophisticated physical theories, including Einstein’s relativity. But quantum mechanics resists an equivalent depth of understanding. Some disagree, proclaiming that they understand quantum mechanics perfectly well. But their understanding disagrees with the supposed understanding of others, equally knowledgeable.
I daresay that the uncausedness of it all in whatever textbook you refer will still boil down to “we can’t predict when or where a thing will happen,” such as the decay of a particular particle. (Esp., by folks who haven’t caught on that causation isn’t a metric thingie in the first place.) But then, we can’t predict when and where the next murder will occur in Chicago, either; but that doesn’t mean we need to reify probabilities.
(Also note that if I observe one side of a US penny and find that it is a head, then the “probability” that the unobserved obverse side is tails is P=1. It might could be that probability ain’t in it at that point — any more than in the Monte Hall problem.)
YOS is a genius! Now take a second penny. What can your observation of the first penny allow you to predict for the state of the second penny you haven’t seen yet? Nothing, becuause it isn’t a quantum correlated system.
“extraordinary claims require extraordinary proof”
Yes. The extraordinary proof is provided by decades of careful experimentation, combined with Bell’s inequality. I can lead you to water, through breezy references to undergraduate-level textbooks that would educate you if you took the trouble, but I can’t force you to drink.
‘I daresay that the uncausedness of it all in whatever textbook you refer will still boil down to “we can’t predict when or where a thing will happen” ‘
Again, no. The role of probabilities in QM is not to reflect a lack of knowledge or the practical inability to make predictions.
I wouldn’t expect someone who’s completely befuddled about basic physics, such as elementary thermodynamics, to somehow know this stuff. No shame in that. But to assume that you already know it, somehow, and that a completely standard and uncontroversial description of basic QM must be wrong because it conflicts with your theological requirements, or something, condemns you to remain stagnantly soaking in your present level of ignorance. If you don’t have convenient access to a textbook, the online Encyclopedia Britannica article on QM is pretty decent.
The extraordinary proof is provided by decades of careful experimentation, combined with Bell’s inequality.
Just as the proof of the geostationary model in astronomy was provided by centuries of careful observation, combined with Ptolemy’s Syntaxis.
The Copenhagen model boils down to “Shut up, and calculate!” And don’t worry about the epicycles. They are proven by the numerous observations of retrograde motion and by the increases and decreases in brightness and diameter of the planets. However, the mechanics of the quanta all wok out — even when they act like waves — regardless which of the “interpretations” one lays on them.
The role of probabilities in QM is not to reflect a lack of knowledge or the practical inability to make predictions.
Hear me. Probabilities do not exist. They have no physical reality, and cannot therefore be physically efficacious. No one else hereabouts has ever been able to cite an example of an uncaused thing; only an example of an unpredictable event. If you can do better, I am all ears.
completely befuddled about basic physics, such as elementary thermodynamics
There is nothing in thermodynamics that is uncaused. It is all ordinary collisions and ricochets. The only superficial resemblance, in your view, is the necessary use of statistics in place of mathematics. When there are more than a handful of bodies or factors, mathematical models crash and burn. Newton never was able to successfully calculate the orbit of the Moon, since the three-body problem has no analytical solutions other than in a few special cases. So when there are massive amounts of bodies, all of which behave identically, the values of each body can be replaced with the statistical mean. Even so, there are difficulties, especially when the model approaches boundary values and/or phase boundaries. (We had an entire two-semester course on numerical approximations and boundary values.)
a completely standard and uncontroversial description of basic QM must be wrong because it conflicts with your theological requirements, or something
“Shut up, and calculate” certainly works if all you care about are the practical applications. But then you can’t be caring about philosophical issues like “causeless things.” But if these things were “completely standard” and “uncontroversial,” there would not be multiple interpretations of QM and Feynman would not have said the things he said.
I’m not sure where you think “theological” comes into this, except that seems to be an obsession of yours.
Bell’s inequality seems to me to be a wonderful test case of someone using statistics wrongly, and everyone else just accepting it for decades. Which sort of proves the point of Mr. Briggs’ book.
Bell’s inequality rests on the assumption that a phenomenon defined as non-random must act as if it were random. When tests reveal it to be non-random, voila, the conjecture is proven!
“Just as the proof of the geostationary model in astronomy was provided by centuries of careful observation, combined with Ptolemy’s Syntaxis.”
Correct. And if, at the time, someone were to say “The current astronomical theory is that the Earth revolves around the Sun”, he would be incorrect. Just as Briggs is incorrect about what the current theory of fundamental processes, QM, says about probabilities. You’re confusing statements about what theories claim with statements about how the world really is. Eventually the current theory about QM will be supplanted by something else. That’s irrelevant to this discussion.
“Hear me. Probabilities do not exist. [etc., etc.]”
Maybe not. In the standard interpretation of QM, they do, and are primary. I’m only explaining what the theory claims. Read my already-linked article, which has many references.
“There is nothing in thermodynamics that is uncaused [etc., etc.]”
Everyone knows this. Nothing to do with what I was saying. I was reminding you and anyone who might be inclined to fall for your act about your egregious attempt to explain the atmosphere of Venus by appealing to your faulty notions of thermodynamics – establishing your M.O. which is to argue confidently from a position of almost hilarious ignorance. Here you are confusing thermodynamics with statistical mechanics, or something.
‘But if these things were “completely standard” and “uncontroversial,” there would not be multiple interpretations of QM’
Again, you are confusing levels of explanation. The theory and its interpretations are controversial – my article is about that controversy. What’s not controversial is what the standard interpretation is. That’s what Briggs got wrong. In the past he claimed that Bell’s Theorem says the opposite of what it actually says. That’s the level of ignorance here. Hence my breezy appeal to textbooks. If you want to talk about a theory, at least learn its basic outlines first.
‘I’m not sure where you think “theological” comes into this’
One of the most prominent “proofs” of the existence of God rather falls apart if there are such things as uncaused events. That’s a motivation for finding an alternative to the standard interpretation of QM, I would think. Even among people who don’t care about these futile “proofs”, there is plenty of metaphysical unease that comes with QM. These are understandable motivations for searching for an alternative interpretation or even theory. But they are not equal to a refutation of the theory. Saying “hear me” doesn’t cut it.
I have no idea what you mean. Bell’s inequality is a mathematical theorem. Have you found a mistake in the math?
If you’re going to talk about IBE and probability, you may enjoy a detour though Bayesian networks and graphical /causal models where ibe gets “probabilized” as Maximum A Posteriori estimates and a full posterior overall explanations, conditional on the model and the data involved . It does get a little mathy though.
One of the most prominent “proofs” of the existence of God rather falls apart if there are such things as uncaused events.
Really? Which one? (cf. Summa contra gentiles II.52.5)
That’s a motivation for finding an alternative to the standard interpretation of QM
Of course, your use of the genetic fallacy cuts both ways. It also serves as a motivation to insist that some things do exist without reason.
Which reminds me. You have still not provided an example of a thing that exists without a cause.
“Broadsword calling Danny Body.”
Then there is the notion that a cause can have more than one effect. Apparently controversial. Also not irrelevant.
Arguing about whether randomness is not a thing which can be a cause is so beyond silly that it flatters the individual stating the obvious in the first place.
That is all that randomness is. Stop pretending its difficult!
QM! Now that’s difficult…
For good understanding and increased likelihood of imparting/receiving good information, i.e. teaching not dysfunctionally, better to remain calm. Listen to someone calm talking about this or any other technical complex subject. Someone nursing a personal, intellectual or religious grievance is merely a hindrance to understanding.
“Broad sword calling Danny boy, ” Thanks.
Well, basic QM is really not difficult at all. It’s when you add relativity and develop quantum field theory, and some other topics, like angular momentum in QM, that things start to get hairy. The problem is that YOS and Briggs are just uneducable. Hence asking for “an example” of something when an entire class of such things has already been presented. And they make the conversation tedious, by continually invoking things that they don’t understand, such as the “genetic fallacy”. There can be no progress if at every stage new mistakes are introduced that need to be corrected. As I said in introducing my first comment, I was only interested in helping any wayward visitors avoid confusion.
Here I am trying to help YOS out of his bind with basic thermodynamics and planetary science. This is what I mean about his speaking authoritatively from a position of ignorance.
Well, basic QM is really not difficult at all.
Right. It’s just mathematical calculations.
It’s when you add relativity…
Who managed that trick, and when? IIRC, a main stumbling block was that relativity and QM each required different values of the cosmological constant. I had not heard that this had been resolved.
The problem is that YOS and Briggs are just uneducable.
When all else fails, try ad hominem. Pay no attention to them, for they are “uneducable.” Sez the guy who still does not apparently grasp the cosmological arguments and thinks that a point raised by Aquinas is somehow a defeater for his argument.
Hence asking for “an example” of something when an entire class of such things has already been presented.
Why the Popperian scare quotes for “example”? I may have missed the entire class when they were presented. How about a reminder?
And they make the conversation tedious, by continually invoking things that they don’t understand, such as the “genetic fallacy”.
The genetic fallacy is an irrelevance argument based on the origin of a claim or proposition; i.e., de genesi. The ad hominem is a particular form of the genetic fallacy, as is the material fallacy of appeal to authority. In the present instance, you insinuated that readers should discount reservations about uncaused things read into the Copenhagen interpretation because of the imputed “theological” motives of the questioner; i.e., the questions have a theological genesis (boo). They don’t, of course; but it pleases you to believe so.
As Hawking once put it, the existence of a term in a mathematical equation does not mean that there must be a corresponding physical entity, even if the math works out.
Some useful references, with the links disguised to fool the software of the site, which objects to having too many links in the comm box…
A review by James Gleick of Adam Becker’s new book on the quanta as to what is real and what is mathematical formalism.
A summary of quantum mechanics by physicist Stephen Barr, contrasting Copenhagen, many-worlds, and standing-wave, indicating why the Copenhagen is fatal to materialism and mechanical determinsm.
A description of recent experiments that indicate new life for the standing-wave interpretation that reproduces on the macroscale phenomena previously thought to apply only on subatomic scales, such as the double-slit experiment. Mentions in passing that “John Stewart Bell went on to prove a seminal theorem that many physicists today misinterpret as rendering hidden variables impossible.” But Bell supported pilot-wave theory.
A brief paper, somewhat technical, on the transactional interpretation, in which the Uncertainty Principle and other “brute facts” appear as consequences of the model rather than as epicycles added onto the model.
A simpler account written for a general audience is here
Lee: Bell’s math is correct. As Mr. Briggs so carefully points out in his essays upon statistics, it is in the assumptions behind the statistical proof that he errs.
Bell’s theorem uses a non-statistical stand-in for a statistical relationship, then proves that is is non-statistical by using statistics. That’s not really a difficult thing to do. It is still accepted because, at this point, it is old established research, and thus not subject to correction. As Max Planck said, “Science advances one funeral at a time.”
There is a lot of silliness in advanced physics. Physicists are mathematicians, not scientists. They quite often have no real concept of what is really going on with certain subjects. All they have to be able to do is complete the computations. Understanding is optional, and in some cases, actively discouraged. Reading through texts and watching lectures, it’s not difficult to spot the inconsistencies and dichotomies.
For instance: most physicists insist that nothing can surpass the speed of light, because Einstein said so. But gravity obviously does, as do several other phenomena, especially in quantum mechanics. They ignore these contradictions, or paper over them with complicated (and unnecessary) kludges to equations. When called upon the error, they point to the mathematical kludge as if it were proof.
It’s not restricted to physicists. Most scientists, and a large majority of engineers, really seem to have little idea about what their equations mean in the real world. It’s the triumph and tragedy of the mathematical modeling process, and the system of education. The model is what is learned, not the reality that the model represents, because that is what is evaluated and tested by their instructors. As the great man said, we are the children of children, and we live as we are shown.
It is very sad.
Some may think at this point that McChuck and YOS must be just trolls, but I don’t think so. They may be deceiving me, but I really think that they sincerely believe they have achieved such a deep understanding of reality that the mere Einsteins and Bells of the world are as but children in comparison, playing with toys that they’re not sophisticated enough to understand.
Humor us, McChuck. Explain how “gravity” “obviously” “can surpass the speed of light”.
Enlighten us, YOS. Explain how the cosmological constant enters into QM, and how QM requires it to have a particular value.
Enlighten us, YOS. Explain how the cosmological constant enters into QM, and how QM requires it to have a particular value.
I first became aware of the conflict in the 1970s in graduate school, but this article from Physics Today from 2004 gives an accessible overview:
As I understand it, quantum field theory predicts a very large energy density for the vacuum, and this density should have large gravitational effects. However, these effects are not observed. The discrepancy is between 60 and 120 orders of magnitude, depending on the cosmological constant. This is a conflict between quantum theory and gravitational theory (relativity) at the most fundamental level.
Usually, when two theories are in such conflict as this, one (or both!) are wrong. Something is awry or has not yet been properly accounted for. Meanwhile, we run along blithely using both theories. Nothing wrong with that except the “blithely” part.
That’s why an understanding of the transition from geostationary theories to geomobile theories in cosmology is of more than historical interest. Physicists did not cling to the Tychonic model because they were stoopid, but because it made reliable predictions and accounted for the observations. It was not until later that they realized that they had been systematically misinterpreting certain data. Once they shifted their paradigm — Oh, those are stellar diameters at all, but aberrations! — the scientific objections to geomobility were resolved.
You seem to be mixing together a lot of ideas irrelevant to anything I said, and getting confused. The article you link to talks about attempts to construct theories of quantum gravity, where of course something like the cosmological constant will need to be dealt with. I was just talking about QM and its standard interpretation.
When people talk about a relativistic theory of QM, they mean quantum electrodynamics. No gravity in there. When we want to talk about quantum gravity, we say “quantum gravity”. Yes, that involves the General Theory of Relativity. Sorry if I was misleading – I was just using terms the way they’re customarily used when talking about physics.
Lee – Through very careful tests, it has been observed that the Earth is attracted to where the sun is, not where it was eight minutes ago. The simplest explanation for this is that the speed of gravity is effectively instantaneous. The mathematical equations are obviously kludges to make the theory very nearly match the observations. They reek of epicycles.
The earth moves to the current position of the sun. The moon moves to the current position of the earth. The sun moves about the current position of the galactic center. The galaxies themselves orbit about their cluster’s current center of gravity, not where it was hundreds of thousands of years ago.
If you agree with Bell (as I do, I just find the argument to be weak), then instantaneous action at arbitrary distances must be possible. Both Bell and Einstein cannot be correct. At least one must be wrong, as they directly contradict each other. Choose.
Here is my choice – They are both correct, but require limits. Bell’s theorem, as Bohm points out, only prohibits local hidden variables. Global hidden variables are perfectly acceptable, and enable instantaneous action. Waves are examples of local actions. No wave can travel faster than c. Normal, every day gravity is not a wave function, but a global variable effect. Gravity waves are, of course, waves, and thus localized functions. No contradictions here, and everything accords with observations.
Assume a quantum field. Give it an enormous positive strength. From this field, all other fields draw their strength, instantaneously (field, not wave), dissipated in root-square fashion. This field governs motion, and we may name it “gravitational potential energy” for convenience. Particles exist as localized waves within this field, with their upslopes directly behind them, and downslopes directly before.
The instantaneous slope of field strength determines everything about a particle’s 4-velocity. The sine of the slope is velocity (and gravitational acceleration), as fraction of c The cosine of the slope is the particle’s perceived time (and distance), as a fraction of 1 (no dilation). Enormous energy with very little practical effect at cosmic distances – check. Gravity – check. Time and space dilation – check. Red and blue shift – check. Accordance with quantum field theory – check. Accordance with relativity – check. Conservation of energy – check. Conservation of momentum – check. Lack of epicycles – check. Lack of contradictions – check. Simple explanation for complex behaviors – check. Possible explanation for ‘dark energy’ – check.
“Through very careful tests, it has been observed that the Earth is attracted to where the sun is, not where it was eight minutes ago. The simplest explanation for this is that the speed of gravity is effectively instantaneous.”
McChuck, I don’t know where you got this bizarre idea, but it’s wrong. The theory of gravity (The General Theory of Relativity) has gravitational influences traveling at the speed of light. Didn’t you hear about the recent direct detection of gravitational waves? They traveled from the source to us at light speed.
I find this conversation very interesting, mostly incomprehensible, but interesting. I actually find many of Briggs’s posts incomprehensible. I would love to have the kind of brain that understands Aquinas, physics, mathematics, quantum physics, science in general, etc. However we all must accept the reality of our limitations. So why do I even look at wmbriggs.com? Because sometimes I DO understand and he’s pure genius and makes me laugh and sometimes a commentator or two says something measured, surprising, interesting, even touching. And whether or not I understand the topic, I always enjoy the undercurrents.
This morning, for instance, I learned a new and delightful word. I will probably never use this word “kludge” , being distinctly not of its milieu, but I am glad to know of its existence. I was one of those children who couldn’t get past long division but read the dictionary for entertainment and I haven’t changed. But the addition to my small store of knowledge that is my favourite today is McChuck’s quote, “As the great man said, we are the children of children, and we live as we are shown.” This, yes, is sad, but it is also so poignantly tender and wise. I don’t know who the “great man” was but this simple statement shows his compassionate grasp of man’s fallen condition. It gives me a glimmer of the mightiness of the struggle in which we are engaged and the immensity of God’s mercy and justice. Thank you.
You seem to be mixing together a lot of ideas irrelevant to anything I said, and getting confused.
But at least now you see where quantum theory and relativity theory require vastly different cosmological constants.
This is assuming the CC is a real entity and not an epicycle that makes the math work out. I share Hawking’s skepticism: just because the math has a term in it, the physical universe is not required to go along with the gag.
“But at least now you see where quantum theory and relativity theory require vastly different cosmological constants. ”
No. QM does not “require a cosmological constant”. The PT article was about one particular (and not, I don’t think, currently active nor very important) class of attempts to build a theory of quantum gravity.
Lee – As I wrote above, waves (including gravity waves) are limited to light speed. The effect we call gravity is not. This has been exhaustively tested, and can be observed by noticing that the moon is in a stable orbit around the earth, which would not be possible if gravity operated at the speed of light. (If it did, the moon would orbit a spot 40,000 km behind the earth-moon center of gravity.) If gravity operated in waves limited to the speed of light, it would be red and blue shifted. That would make the universe a much more interesting, and chaotic, place.
The very equations used to compute gravitational effects include a kludge factor to estimate the current position of the attractor from its apparent position. Because the math only works if you assume that gravity is instantaneous.
True Faith – The quote comes from Abe Vigoda’s character (Chief Tobi) in the movie “Joe versus the Volcano”. I highly recommend the movie, if you can find it. It’s quite touching, especially for a romantic comedy.
McChuck, I think you’re confused about gravity. You’re trying to fit together two incompatible word views. Newtonian physics has planets and forces between them acting instantaneously. Einstein’s first, abandoned attempt at a new theory of gravity was to add a finite speed to the influence of gravity, but keeping the objects-and-forces idea. He abandoned this. Eventually, he (and others) created the General Theory of Relativity, in which the effects of gravity emerge as a kind of fictional force, caused by the spacetime metric. To solve for the Earth-Moon system in GR, you need to find a solution of the field equations with the two masses, which will give you the solution for the motion and the “gravitational field” (the metric) that go together. It’s simply wrong to say that there is some kind of force that acts instantaneously. We abandoned this idea a century ago.