What do scientists mean when they
say that something exists? Every time I give
a public lecture, someone will come and inform me that black holes don’t exist, or quarks don’t exist, or time doesn’t exist. Last time someone asked me “Do you
really believe that gravitational waves exist?”
So, do I believe that gravitational waves exist? Let me ask you in return: Why do you care what I believe? What does it matter for anything?
Look, I am a scientist. Scientists don’t deal with beliefs. They deal with data and hypotheses. Science is about knowledge and facts, not about beliefs.
So, do I believe that gravitational waves exist? Let me ask you in return: Why do you care what I believe? What does it matter for anything?
Look, I am a scientist. Scientists don’t deal with beliefs. They deal with data and hypotheses. Science is about knowledge and facts, not about beliefs.
And what I know is that Einstein’s theory of general relativity
is a mathematical framework from which we can derive predictions that are in
excellent agreement with observation. We have given names to the mathematical structures
in this theory. One of them is called gravitational waves, another one is
called black holes. These are the mathematical structures from which we can
calculate the observational consequences that have now been measured by the
LIGO and VIRGO gravitational wave interferometers.
When we say that these experiments measured “gravitational waves emitted in a black hole merger”, we really mean that specific equations led to correct predictions.
It is a similar story for the Higgs-boson and for quarks. The Higgs-boson and quarks are names that we have given to mathematical structures. In this case the structures are part of what is called the standard model of particle physics. We use this mathematics to make predictions. The predictions agree with measurements. That is what we mean when we say “quarks exist”: We mean that the predictions obtained with the hypothesis agrees with observations.
Same story for time. In General Relativity, time is a coordinate, much like space. It is part of the mathematical framework. We use it to make predictions. The predictions agree with observations. And that’s that.
Now, you may complain that this is not what you mean by “existence”. You may insist that you want to know whether it is “real” or “true”. I do not know what it means for something to be “real” or “true.” You will have to consult a philosopher on that. They will offer you a variety of options, that you may or may not find plausible.
A lot of scientists, for example, subscribe knowingly or unknowingly to a philosophy called “realism” which means that they believe a successful theory is not merely a tool to obtain predictions, but that its elements have an additional property that you can call “true” or “real”. I am loosely speaking here, because there several variants of realism. But they have in common that the elements of the theory are more than just tools.
And this is all well and fine, but realism is a philosophy. It’s a belief system, and science does not tell you whether it is correct.
When we say that these experiments measured “gravitational waves emitted in a black hole merger”, we really mean that specific equations led to correct predictions.
It is a similar story for the Higgs-boson and for quarks. The Higgs-boson and quarks are names that we have given to mathematical structures. In this case the structures are part of what is called the standard model of particle physics. We use this mathematics to make predictions. The predictions agree with measurements. That is what we mean when we say “quarks exist”: We mean that the predictions obtained with the hypothesis agrees with observations.
Same story for time. In General Relativity, time is a coordinate, much like space. It is part of the mathematical framework. We use it to make predictions. The predictions agree with observations. And that’s that.
Now, you may complain that this is not what you mean by “existence”. You may insist that you want to know whether it is “real” or “true”. I do not know what it means for something to be “real” or “true.” You will have to consult a philosopher on that. They will offer you a variety of options, that you may or may not find plausible.
A lot of scientists, for example, subscribe knowingly or unknowingly to a philosophy called “realism” which means that they believe a successful theory is not merely a tool to obtain predictions, but that its elements have an additional property that you can call “true” or “real”. I am loosely speaking here, because there several variants of realism. But they have in common that the elements of the theory are more than just tools.
And this is all well and fine, but realism is a philosophy. It’s a belief system, and science does not tell you whether it is correct.
So here is the thing. If you want to claim that the
Higgs-boson does not exist, you have to demonstrate that the theory which
contains the mathematical structure called “Higgs-boson” does not fit the data.
Whether or not Higgs-bosons ever arrive in a detector is totally irrelevant.
Here is a homework assignment: Do you think that I exist? And what do you even mean by that?
Update: Now with Subtitles in German and Italian. To see them, click on CC in the YouTube toolbar, then chose a language in the settings/gear icon.
Here is a homework assignment: Do you think that I exist? And what do you even mean by that?
Update: Now with Subtitles in German and Italian. To see them, click on CC in the YouTube toolbar, then chose a language in the settings/gear icon.
The word "belief," like its German cognate "Glaube" is derived from a Proto Indo-European word (*ga + *laubh) meaning care, desire, love. So we really do desire to know if you love or care about black holes.
ReplyDeleteYou exist in the database my processor uses. You are virtual when I am not observing you in some way.
ReplyDeleteYou can spin it further: If at some point, the theories that govern the current scientific "framework" (General Relativity etc.) will be replaced by something else (like Newton's framework was replaced by Einstein's), and if at that point we find out that the effects the Higgs has on our detectors is actually caused by "something else" (like a String, a Loop, a Butter Scone, or a fluffy hunk of Quantum Foam, whatever), does it then mean that scientists were wrong all along, like "haaa-haa, I told you the Higgs doesn't exist"? No. It just means that by that time, the Higgs was just the most plausible or easiest way to describe the data and the experimental results. It's just a different name and model for the same thing. Like discovering that your pet bunny is not a "bunny" but actually just a conglomerate of cells, liquids and solids. It doesn't mean that your pet bunny is not a bunny anymore. It's just a different (more detailed/better fitting) view on the things that we call "reality".
ReplyDeleteThe old ... and new ... problems of induction and other things still exist.
ReplyDeleteHomework Assignment: I believe a single human exists that appears in videos and photographs and authors these blog posts, tweets, and answers to commentary. I am aware of no other plausible (to me) explanation for those artifacts and their consistency.
ReplyDeleteBy something "existing" I mean it has consequences within its environment. In principle, it can be measured in some way; i.e. it can be detected. A negative definition would be that something that doesn't exist cannot be detected or measured in any way.
Based on the evidence available from this blog, videos, photo etc."Sabine Hossenfelder" may - as pointed out by Martien in his comment below - be a group of individuals not a single entity.
DeleteVisually it appears that the videos and photographs show the same individual. There is however no conclusive evidence that that individual is the author of this blog, posts tweets or answers commentary.
We 'believe' Sabine exists because on the balance of probabilities there is sufficient circumstantial evidence to indicate that she does.
If Sabina is "real" (whatever that means), Her husband and children have of course more to go by to I do.
DeleteAnd why not add some link(s) about your view that Free Will does not exist?
ReplyDeleteThe physics argument for realism...
ReplyDeleteLet's say you have a ball constrained to move on a sphere in a uniform vertical gravitational field. You can solve this problem by setting up Newton's laws in a coordinate system on the sphere. Or, you can use the method of Lagrange multipliers to incorporate the constraint and forget the sphere. Essentially you are postulating a force field that when added to gravity manifests as motion on a sphere. You have a either a constraint, or a free problem with a magic force. Both reproduce all observations. Each is in its own way the simplest description. You trade a new term in the Lagrangian for avoiding the constraint.
So does the constraining sphere exist? I think we would say, yes.
Now the Higgs field is like that. It is a magic field whose only role is to make the W and Z gauge bosons, which should be massless in an authentic gauge theory, take on mass. So - is it real? Or is it a constraint emerging from an unknown aspect of field theory?
Are the Cooper pairs in superconductivity real particles? Or, is the photon suddenly massive inside the superconductor?
You can't decide by observation. There has to be a judgement about what is real based on some other input.
-drl
I hope you are real. "If Sabine did not exist, it would be necessary to invent her"
ReplyDeleteI wish I could upvote this comment!
DeleteGod said that about Trump, too.
DeleteI think that there is a potential for a great deal of additional clarity in fundamental physics if the concept of "existence" could be connected to physics in a more direct manner than outlined in this essay, by which I mean a specific criterion for existence *within physics*, as opposed to what might be called the meta-criterion that if a physics framework using certain mathematical structures makes predictions with which empirical data agree, then these structures ``exist''.
ReplyDeleteIn my view, the separation of physics out of philosophy is not yet complete: Existence still lies largely within the domain of metaphysics, and other than in the way just described, still makes very little contact with physics.
Just because that is currently how things are, that does not mean it has to be this way.
Physics does not deal with existential questions particularly. This is seen with the plethora of quantum interpretations. These interpretations are either meant to confer reality to quantum waves, called ψ-ontic interpretations, or they confer epistemic meaning, called ψ-epistemic interpretations. Quantum mechanics in its stubborn way tends to resist fitting completely in any of these.
ReplyDeleteDo electric fields exist? As I see it we can say they do exist for all practical purposes (FAPP) according to electromagnetic theory. By FAPP it does mean there is a door open for some deeper theory, and of course that is QED. I think the same holds for gravity waves or the Higgs particle.
Do quantum waves exist? Sure, For All Uncertain Purposes (FAUP) they, well ... might, and that is on a Tuesday when you are thinking of many worlds interpretation.
not 100 % sure for me that you exist. What I read could all be AI generated for instance, and I have no further observations to go by.
ReplyDeleteOr, if current AI is not a good alternative, a group of people working under the name of Sabine Hossenfelder.
ReplyDeleteMartien: I don't think current AI is a good alternative; it would be a massive effort for it to write songs and stage videos, especially the complexity of those in which Dr. Hossenfelder is on a panel being asked questions and interacting with other physicists or non-physicist scientists.
DeleteEven if those are all staged for an actress, I also believe a group would have a very difficult time matching the consistency of language, phrasing, personality and point of view of Dr. Hossenfelder.
To me the evidence is conclusive for Dr. Hossenfelder being a singular person, and the one I see appearing in videos.
Agree, if one is forced to take a position, than the position that Sabine exists is by far the best bet. So "it is safe to assume..", or "it may be assume beyond reasonable doubt.." or "for all practical purposes we may assume .." etc. etc. that Sabine exists. Still that doesn't equal to a 100 % proof of her "existence" (whatever that means).
DeleteAvoid arguing with philosophers. Remember the Philosophy Department doesn't have a waste basket. They deal with unseen worlds where nothing can be proved or disproved. It used to be called shamans and mythology
ReplyDeleteExcellently explained. An outstanding cross-disciplinary post. Should be the basis for the first page of every introductory text in any branch of any science---including mathematics and philosophy. As also the first definition in every scientific paper, so it---and its readers---remain focused on its intent.
ReplyDeleteThe core of your position is that "predictions agree with measurements." That raises the question of what you mean by a measurement. Presumably it is the value of an indicator on an instrument.
ReplyDeleteWhat then is the theory about what produces the indicator reading? That is, how does the instrument interact with the rest of the universe so that its indicator takes on a value?
And what do we mean when we say that the instrument is interacting with "the rest of the universe?" (Or would you put it in other terms?) What is this "rest of the universe" thing, and what is it about that thing that has a consequence for the instrument's indicator? How is all that explained?
Lawrence Crowell:
ReplyDelete"Physics does not deal with existential questions particularly."
That is certainly the current situation, but again, it does not have to be that way. If you just look for them, you will find questions involving existence lurking in the background almost everywhere in fundamental physics. Just two examples:
1. Since speed of light objects are characterized by a zero proper time, this means that their duration of existence (in spacetime) between any two spacetime events, including their ``coming into existence" and their ``going out of existence" is always observed to be exactly zero. Is this just a weird feature of special relativity or does it have a deeper physical meaning with respect to their existence? I once asked Jakob Bekenstein this question, and with a dismissive hand motion, he said: "That's just philosophy", a point of view that seems quite similar to yours.
2. Heisenberg, in his book "Physics and Philosophy", argued that the quantum world is a world of potentialities while measurements and the classical world deal in facts. His words and distinction, however, reflect themselves nowhere in the formalism of quantum mechanics: in the formalism, a pre-measurement state and an immediate post-measurement state ``exist" in precisely the same way.
Just a few days ago, I experienced how difficult it is to get someone who is already well-steeped in contemporary physics to "see" that Heisenberg's is a meaningful distinction which is not at all captured by the mathematics of quantum theory (Whether this distinction is found in reality is a different question, my point is only that if it is there, our mathematical models do not capture it). Despite a lengthy discussion spread over two days, I believe I failed to convey that there is a remarkable disconnect between Heisenberg's words and his mathematics.
This situation strikes me as akin to a version of the Sapir-Whorf hypothesis, except that the language that influences our way of looking at the world is not a natural language, but mathematics.
Indeed it is the case that objects moving the speed of light have zero proper time. The photon is the main example. The metric interval or proper time measured on the “frame” of a photon is zero.
DeleteThe issue with quantum mechanics does illustrate how the measurement question is not captured by quantum mechanics. Quantum mechanics does not describe spontaneous localization of a quantum wave that occurs in a measurement. There are a range of quantum interpretations that conflict or contradict each other. What you describe is Bohr's Copenhagen interpretation (CI), where there necessarily exists a classical world that couples to quantum waves in order to make a measurement. There are other interpretations that do not make this claim, such as the many worlds interpretation (MWI). MWI has everything quantum mechanical all the way down, but has this odd splitting off of worlds according to eigenstates measured. These are respectively ψ-epistemic and ψ-ontic interpretations.
I have this idea, which I have not really developed, that a measurement is a process whereby quantum states encode information about quantum states. This is ultimately a sort of Gödel self-referential loop. For this possible reason quantum interpretations are not quantum mechanics, but are similar in a way to the 5th axiom of geometry. If you do as Mermin advises and “shut up and calculate” then this is like hoding onto the axiom. If you abandon the axiom there is a plethora of geometries that are not consistent with each other, and in QM you have interpretations. I wrote more on this; take a look at the entry Sabine did on QM is wrong. I think I wrote something there on this.
Philosophy and physics have a small overlap, maybe really just a boundary they share. I do not think physics should avoid metaphysics entirely, but a strict minimum is required. By metaphysics I mean the ideas advanced in analytic philosophy or in metaphysical discussion on the nature of existence. I ignore popular metaphysics utterly, such as ideas of telekinesis.
Lawrence Crowell: But as the photon moves through space it is changing in frequency due to red-shift; is it not? (Which I suppose means it is shedding energy into ... something). It seems strange a high-frequency photon can gradually become a lower frequency photon in zero proper time.
DeleteTo continue because I sent this after writing my initial thought and not the second. The change in energy of the photon is no different really than an observer moving relative to some ground frame finding the kinetic energy of another moving mass as different.
DeleteEnrico:
ReplyDeletePhilosophy is more than metaphysics.
Some ``philosophical'' activities which would help any scientist be a better scientist include examining and questioning one's assumptions, examining and questioning one's deductive or inductive chains of reasoning from those assumptions, and being more aware of one's philosophical biases before they turn into cognitive biases.
Making wholesale generalizations of an entire field based on the worst examples can be done for physics, too, and if it were done, physicists (of which I am one, despite my philosophical tone in the posts here) would not come out looking good.
I think it is not an accident that an anti-philosophical attitude like yours is prevalent in the same fundamental physics circles in which the kinds of cognitive biases that Sabine criticizes so forcefully are also prevalent.
As the distinguished American philosopher Ted Nugent said, "If I can take a bite out of it, it's real; otherwise, it doesn't exist."
ReplyDelete"We have given names to the mathematical structures in this theory."
ReplyDeleteThis is the whole thing right there. Perfect.
Does B exist? I'm going to guess yes. Either she, or somebody else with the same name seems to be cutting a rather wide swath in the physics blogosphere, literature, and popular science writing.
ReplyDeleteOf course I could be wrong - or just deluded.
PS - Shakespeare's works were written not by him, but by another poet of the same name.
You need to read The Atlantic article on whether Shakespeare was a woman.
Delete"Scientists don’t deal with beliefs. They deal with data and hypotheses. Science is about knowledge and facts, not about beliefs"...I really wish this were true, but as we have seen, scientists are emotional animals that hold on to cherished beliefs long after any evidence has left the building. As exhibit A I present string theory, SUSY, the multiverse and many other "beautiful" mathematical objects which all pinned their hopes to LHC outcomes. With absolutely no evidence for any of these theories after 30+ years of experimental HEP data, their proponents (who claim to be objective scientists) still cling desperately to their theories, hoping to eliminate experimental observation from the scientific method. I wish we could say this was just the latest fad, but history shows this emotional bias in science going back at least 500 years, were proponents of the epicycle approach to the cosmos attempted to discredit Newton and others for ruining their model with solid evidence and theories that matched it better.
ReplyDeleteAbout "time". Yes. Relativity is a good example of where it has a precise and useful meaning.
ReplyDeleteHowever, there is another example, equally good, and much older: thermodynamics. It is not philosophically obvious that these are the same thing. But careful examinations of the math show that they are the same thing. So does, of course, experiment.
This is NOT trivial, it very profound.
Has the theory of "anthropomorphic climate change" met these standards: We use it to make predictions. The predictions agree with observations.
ReplyDeleteI start by assuming the BackReaction entity does not exist. This means what I observe is a virtual BackReaction entity, which Quantum Mechanics tells me must be one half of an entity + anti-entity pair. However, there is no evidence for the anti-BackReaction entity; there is a complete lack of evidence for such an entity promoting string theory and a newer bigger particle collider. Therefore the assumption must be false and a physical BackReaction entity must exist. Not only must it exist but it must be extremely stable, which to me is self-evident.
ReplyDeleteI start with Descartes: It is obvious to me that I think about your blog, therefore something must exist in my mind or elsewhere that created that blog. This something calls itself Sabine. In this sense I believe that you, Sabine, exist.
ReplyDeleteUltra massive black holes, orbits of galaxies around their center, increase in the redshift of light as we look farther out. All data that doesn't fit without ad-hoc explanations. Most logical action take the reams of what was learned in GR, and as Einstein did with Newton, start again using more foundational axioms that agree with observations and increased knowledge.
ReplyDeleteHi Sabine, a new book came out by a very respectable cosmologist:
ReplyDeleteCosmological Koans: A Journey to the Heart of Physical Reality
by Aguirre. I haven't read any reviews yet but will probably end up getting it.
This argument is philosophically silly. I can construct any number of mathematical models that predict observation, including the Standard Model, and also including Ptolemaic crystal spheres and invisible demons pulling on invisible strings made of virtue and unicorn pee.
ReplyDeleteThe test of "truth" has to *at the least* have some argument of uniqueness. When people are asking you "Do you believe in the Higgs mechanism?" they aren't asking "Does the math work out?" They assume nobody's an idiot and failed to check *that*. They're asking "How confident are you that NO OTHER mathematical model can predict the observed data?" If the answer of the physicist community is "We have no idea!" or "Who cares?" then people -- including those who fork out tax money to pay for these things -- very reasonably can dismiss the whole shebang as angels on the head of a pin scholastic debate, sterile.
Occam's razor. There's only so much you can squeeze into 3 minutes.
DeleteI wonder whether one can ever rule out new mathematical structures or models which give an alternative description of some part of reality. When one can not rule out other descriptions /math models (and my hunch is, that this is most often the case), that of course does not imply that existing models which do a good job within certain limits can be considered useless. I think that is utterly nonsense.
DeleteSabina, does your husband and children know for sure that you exist?
ReplyDeleteIf I remember correctly what I've read, Planck took his quanta to be a device to explain the spectrum of black body radiation but he did not take them to be "real", and this precluded him from further advancing quantum theory, something which was left to Einstein and others to do. Perhaps it is more a psychological thing than a philosophical one. Anyway, I think Planck should have kept asking "what if the world is really like this, what other consequences would these quanta have?"
ReplyDeleteSo one can punt on the generally fruitless discussion of what "real" and "exist" mean, but one has to not fall into "this is a convenient device" trap.
Similarly, IMO, if one takes Ptolemy's model of the solar system just to be a device to calculate the positions of the planets at any time, but is agnostic on whether the model represents something real or not, one might not be impelled to search for mechanisms, and it is that search that leads one to the more real model and to a law of gravitation.
If you want to claim that the Higgs-boson does not exist, you have to demonstrate that the theory which contains the mathematical structure called “Higgs-boson” does not fit the data. Whether or not Higgs-bosons ever arrive in a detector is totally irrelevant.
ReplyDeleteThat is an illogical argument. The Ptolemaic example is an unequivocal demonstration of the fact that a mathematical model based on a completely erroneous qualitative model of a physical system can, nonetheless, produce useful predictions of observed phenomena.
Your model may "work" perfectly well and still be a completely inaccurate description of physical reality. So, what is irrelevant is the fact that the model can be massaged to fit the data - in almost all cases it can, especially when the model can be freely parameterized.
And because the two standard models of theoretical physics are both heavily populated with entities and events that have no correlate in physical reality, it is perfectly reasonable to assume they are Ptolemaic in nature. That is to say the models appear, on their merits, to misrepresent the nature of physical reality.
Your argument that the absence of empirical confirmation, for the entities and events required by the standard models to make them "work", is somehow irrelevant simply eviscerates the explanatory power of science. The standard models simply cannot and do not explain the underlying causes of the physical phenomena they describe mathematically. In fact, the standard models obscure the underlying physical causes of observed physical phenomena with their profligate invocation of supernatural (invisible) things.
Physical reality does not contain or require, quarks, gluons, dark matter, dark energy, and etc, to achieve its observed results. We know this because those things are not empirically present in physical reality. They are only required by, and present in, the models that contain them.
What you are espousing here is a variant of the mathematicism belief that has become the default operating paradigm in theoretical physics over the last forty years. This belief - that mathematics underlies and determines the nature of physical reality has no basis in science, mathematics, or logic. It is simply a falsehood without any meaningful justification to sustain it. The sooner mathematicism is banished from the halls of science, the sooner the "crisis in physics will end".
bud rap,
DeleteWhat you say is wrong. But if you didn't understand it after I just explained it, it probably makes no sense to explain it again, so I am just adding this for the other comments: Bud rap has exactly the confusion that my blogpost is addressing. Scientist do not "believe" that mathematics "determines the nature of physical reality", we simply notice that it works, and that's all there is to say about it.
bud rap: Something being invisible does not make it "supernatural". Air is invisible, a magnetic field is invisible. Gravity is invisible. We know they are real via their effects on other things we know are real; which ultimately rests on knowing we are real (which I share).
DeleteSabine,
DeleteI understood perfectly well what you said, that's why I called your argument a variant of the mathematicism belief. Your position simply seeks to avoid the hard question of whether your "working" model accurately describes physical reality. You seem to be saying that the question doesn't matter; the model "works", and that's good enough for scientists.
I disagree with your position precisely because I do understand it. I think it is a fundamentally unscientific argument that precludes the possibility, and even the meaningfulness, of scientific understanding. To calculate is not to understand.
Scientist do not "believe" that mathematics "determines the nature of physical reality"...
That will be news to Max Tegmark and other scientists who share his views. But quite apart from your personal beliefs, mathematicism is the default framework and operating paradigm in modern theoretical physics. It is the framework that permits, and accepts, all the empirically baseless assertions of the two standard models.
...we simply notice that it works, and that's all there is to say about it.
Sorry, but there is much more to say about it. If the model "works" but provides no plausible physical explanation for the matter under consideration, then it is, at best, scientifically inadequate. That inadequacy should be a compelling scientific reason to search for a more plausible model.
That no such compulsion exists in the modern theoretical physics community is as inarguable as it is inexcusable. Theoretical physics is a mess precisely because it ignores the fundamental importance of empiricism to any and all scientific projects.
Empiricism is a sine qua non component of science. "The model works" is just not, scientifically speaking, good enough. If your model's axioms and postulates are not empirically verifiable, then that model does not constitute a scientifically reasonable depiction of physical reality, regardless of its calculational utility.
bud rap said… “...that mathematics underlies and determines the nature of physical reality has no basis in science, mathematics, or logic. It is simply a falsehood without any meaningful justification to sustain it.”
DeleteWhile I would agree with that statement to a point, I also would have to say mathematics is far and away the most precise, and therefore the best form of communication humans have to represent the workings of physical systems. Nothing else comes close to being as accurate and specific in defining the writers meaning.
I would also say physicists get fixated on their existing models and it causes them to perfunctorily dismiss and ignore empirical facts (a current biggie is time/space-time) because it would create a complete upheaval to their existing models. This is a natural human behavior for everyone and thus for now that math trumps facts; unfortunately like everyone else that’s a problem you see in others and not yourself.
bud rap,
Delete"Your position simply seeks to avoid the hard question of whether your "working" model accurately describes physical reality. You seem to be saying that the question doesn't matter; the model "works", and that's good enough for scientists."
Science is all about whether the model accurately describes observations. If you think that "reality" is more than that, you have made a claim that is not based on evidence and you have left the terrain of science.
To state the obvious, Tegmark is not "scientists".
"If your model's axioms and postulates are not empirically verifiable...
You cannot "empirically verify" anything. The best you can do is notice that a model works well to describe observations, as I said.
Frankly I get the impression you haven't thought about this much.
And please stop making proclamations about my supposed "mathematicism belief" which is something that you have invented. I have not made any statement in my video about the use of math or the limits of that use.
Dr. Castaldo, I was using the term "invisible" broadly, in the sense of impervious to direct detection. I apologize for the imprecision of that usage.
DeleteSabine,
DeleteScience is all about whether the model accurately describes observations. If you think that "reality" is more than that, you have made a claim that is not based on evidence and you have left the terrain of science.
So, reality is dependent on your model accurately describing observations? Well, that is an argument from mathematicism alright. But I'm afraid it is an argument that has diverged far from the terrain of logic and reason, let alone science.
You cannot "empirically verify" anything.
Of course I can. There is a prediction in today's newspaper regarding the time of sunrise tomorrow morning. As I live along the western shores of the Atlantic Ocean I can easily go to the beach tomorrow and empirically verify (or refute) that prediction.
To state the obvious, Tegmark was a counter example to your broad general claim that "scientists" do not believe that math underlies reality. Some do, some don't.
I suspect that the real root of our disagreements here, lies in our differing educational backgrounds. I was educated at least a quarter of a century before you. When I learned science it was explicitly stated that science was the study of those things that could be observed (or detected) and measured. That foundational concept does not appear to have been part of your science training.
In that I don't think your experience was unique. Something changed broadly in the way science was taught somewhere in the late 1970s or perhaps early 80s, which is also right about the time that theoretical physics went off the scientific rails and into the deep weeds of metaphysics. When you start believing in things that aren't there science is undone.
You have a good mind and a good heart, Sabine. If anyone of your generation can extract herself from the pseudo-philosophical nonsense that was foisted on you back there in graduate school, it is you. Good luck.
bud rap,
Delete"So, reality is dependent on your model accurately describing observations? "
No, I didn't say anything like that. Please read what I wrote more carefully. You are the one who talks about "reality". I have told you repeatedly that all science does is explain observations.
"There is a prediction in today's newspaper regarding the time of sunrise tomorrow morning. As I live along the western shores of the Atlantic Ocean I can easily go to the beach tomorrow and empirically verify (or refute) that prediction."
You have changed the content of your statement. You were explicitly speaking about verifying "your model's axioms and postulates". Now you are instead talking about predictions being correct or not correct. I have pointed out that you cannot ever verify postulates. Of course you cannot. If you could, you wouldn't have to postulate them.
Look, it's not like I am saying anything new here. That it is not possible to verify models is the reason why Popper was going on about falsification in the first place. Really why don't you do some reading first before you blame me for your lack of knowledge?
Sabine,
DeleteYou have changed the content of your statement.
I didn't change anything - I was simply refuting your sweeping generalization, "You cannot "empirically verify" anything." That statement is false. If you don't want easily refuted statements like that refuted - don't make them.
I have told you repeatedly that all science does is explain observations.
I have repeatedly told you that your mathematical models do not explain anything. Rather, they obfuscate the causal chain underlying observations by invoking empirically undetectable entities and events. Your models do not resemble observed reality, they only resemble themselves; they have no explanatory power.
I have pointed out that you cannot ever verify postulates. Of course you cannot. If you could, you wouldn't have to postulate them.
Yes, in mathematics postulates are true by definition. But science is not mathematics and mathematics is not science. Nothing can be true by definition in science. What you call postulates in math, are only hypotheses when applied to science and, hypotheses are not true by definition.
Dark matter, for instance, is a hypothetical explanation for the inability of mathematical modelers to construct realistic models of galactic dynamics. An extensive search has turned up no empirical evidence of dark matter.
Scientifically speaking, therefore, dark matter is a failed hypothesis. To theoretical physicists however, this failure is inconsequential, dark matter is still invoked - as if it were a postulate.
The beauty of that for theorists is that it allows them to pretend that this complete failure of their hypothesis has no consequent implication regarding the failure of their model of galactic dynamics. The model is thus rendered unfalsifiable, and no effort need be made to develop a better, more realistic model of galactic dynamics.
That it is not possible to verify models is the reason...
So, it is not possible to verify models? That's another overly broad generalization. Does that mean, in your opinion, that the solar-centric model of the solar system has not been verified and the geo-centric model has not consequently been falsified? It is indeed not possible to verify models full of metaphysical content - like LCDM. Realistic models can be verified.
Really why don't you do some reading first before you blame me for your lack of knowledge?
What would you suggest I read, some 1980s deconstructionist drivel, in hopes it would render me also incapable of defining existence, or differentiating between physical reality and a mathematical model? No thanks, once was enough. Unlike you, I was old enough, at the time, to see through that scientifically useless, philosophical nonsense.
I don't blame you for having absorbed such an infertile philosophical stance during your formative school years, but you're a grown woman now. It's time to revisit that received wisdom with a critical eye.
Your philosophical education served you ill. You have the intellectual capacity to find your way out of the morass - but you do have to make the effort.
bud rap,
DeleteYou are correct in pointing out that my statement "you cannot empirically verify anything" was a sloppy response to your false statement that one can verify a "model's axioms and postulates". Alas, this does not change anything about the fact that your statement was (a) wrong and (b) you later changed it to being able to tell whether a prediction is correct or not, an entirely different matter.
I have no patience for people who refuse to acknowledge they made statements that they evidently made, so I will end the conversation here, good bye.
Your description of how the scientific method works is accurate, but the WHY of science is to explain the natural world. If science were truly silent about what does and does not exist it wouldn’t have achieved its very obvious successes
ReplyDeleteWhat do you mean with 'explain'?
DeleteOne definition of 'to explain' might be something like "make people understand".
DeleteThan what is "to understand"? In my view it is something like relating new experiences to previous ones. Maybe with the awareness that goes with it. Understanding than is an incremental process, a gradual evolving model of parts of an assumed external reality in the brain of a person.
In your view then the role of science is to facilitate this process.
Not sure. 'Science' is producing knowledge, but whose role is it to dissiminate. What about peoples own responsibility or not to learn?
Etc etc.
I frequently make similar arguments on Quora (I say "Belief is overrated.")
ReplyDeleteBut at times I also say "reality is the stuff that can still hurt you even if you don't believe in it", loosely paraphrasing the science fiction writer Philip K. Dick. So I will take issue with one of your statements: "But they [variants of realism] have in common that the elements of the theory are more than just tools."
My response is that until the advent of modern physics, pretty much everyone assumed that a "tool" worked on "reality". What is the tool doing, after all, if not modifying reality? And if a tool is not doing anything, why do we use it?
Jeff: The tool is to make a prediction about future behavior. That does not exactly modify reality, other than our neural state of belief about outcomes. (If our belief causes us to take action a more drastic modification of reality ensues).
DeleteIf I can presume for a moment that integers are not "real" physical things in any sense, then a number theorist proving that there are an infinite number of twin primes is working entirely in the mental realm, her ideas are combined to create new ideas that will only affect the beliefs and certainties of others. But she doesn't have to believe integers or primes have any physical existence, mass or energy, or that her mathematical tools modify any kind of reality (other than neural models). Why would she do it? I'm not sure there is any practical application of the proof; so I presume she does it for the reward of satisfying her curiosity (and possibly career goals).
To design an electronic circuit we work with a belief system of how particles work. They are very predictive and let us design massively complex circuits that work quite nearly flawlessly. But we don't have to believe the particles exist, any more than we believe integers exist. What we know is experiments have shown x=f(x) so often we can rely on it to hold with what might as well be certainty. In other words, reality behaves as if these underlying objects with defined properties exist, and it makes no difference if that is how it "really" works.
Thus we can design circuits by adhering to many such rules that model reality; and get predictable observed results.
It doesn't really matter if particles are real things, the predictions held and our device reliably does what we wanted it to do.
Just like if a valid proof of infinite twin primes emerges, perhaps all it will change is our belief system, removing the last tiny shred of doubt about infinite twin primes. But it doesn't make them any more "real".
"If you want to claim that the Higgs-boson does not exist, you have to demonstrate that the theory which contains the mathematical structure called “Higgs-boson” does not fit the data. Whether or not Higgs-bosons ever arrive in a detector is totally irrelevant."
ReplyDeleteBudd Rap pointed out this is just idiotic.
Your "answer" was "...Scientist do not "believe" that mathematics "determines the nature of physical reality", we simply notice that it works,."
Are now pretending that a beautiful series of equations and what looks like a great example of scientific fraud is to be accepted...because the maths says so.?
You can wax lyrically and wave your hands about having no beliefs, but you end up with no data either.
Several of us now know you don't have the integrity to allow Alexander Unzicker, the author of
The Higgs Fake: How Particle Physicists Fooled the Nobel Committee to post his responses here.
My non belief is..this post will never appear :)
mike,
Delete"Are now pretending that a beautiful series of equations and what looks like a great example of scientific fraud is to be accepted...because the maths says so.?"
No, you misunderstood this. The math does not tell you that you have to accept the equations. The statement doesn't even makes sense. The math agrees with observations, and that's what science is all about.
I have no idea what's with Unzicker and he has not posted anything.
Hi again,
DeleteI have had a look at the junk folder and it seems that Unzicker tried to post a comment as "Unknown" which includes a link. How about you do not blame me for other people's mistakes for a change?
This is a possible explanation as to why you might be seeing so many 'Unknown' comments.
DeleteIn the course of posting a comment I noticed that Google had me signed in as 'Unknown' when it knew perfectly well who I was. There was no way to edit the name. I eventually clicked on the little red and yellow button which took me to the profile page where I found I could enter a name.
I can imagine that many don't notice they are 'Unknown' and even if they do see no way to edit the name. Perhaps a note about clicking the red button to access where a Blogger name can be entered would help to reduce the number of 'Unknown' comments.
moonkoon,
DeleteThe vast majority of "Unknown" comments are spam, and here I mean spam of the usual kind, return your lost lover spells, visit our great travel deal website, that kind of thing. That's why I've just directed all of them right to junk.
I am afraid I don't know what red button you refer to. Do you mean the orange-white blogger icon?
Yes, the Blogger icon. And once you get to the Blogger profile page there is a red/orange edit button at top right that enables one to actually edit the profile details.
DeleteAnd by the way, thanks for running a great blog.
moonkoon,
DeleteOk, thanks. I have added a note below the comment window for that. Let us see if this helps.
What is considered real?
ReplyDeleteThat is actually a question related to questions in "semiology" (linguistics and literature).
You get there if you think about how an encyclopaedia works. Every item in an encyclopaedia or dictionary refers to other items and words in the encyclopaedia. The real "meaning" derives ultimately from those words signifying things we can experience directly by our senses or feelings. That is, the whole encyclopaedia is grounded in our senses and feelings.
This links to the famous question of how to describe color to a congenital blind person, or fire to someone who has never seen it. Words, including mathematics, cannot give the realism we expect from real life. Science never can supply that level of realism, as most subjects are beyond direct personal "senses".
In the far future we might possibly be able to experience a black hole the way it is portrayed in the movie Interstellar. Then it would be real. Until then, black holes will be noting more like stories, akin to T Rex, unicorns, or the core of the earth.
So, the question "Does Sabine exist?" comes down to "Can I meet Sabine in real life and is she the person whose thoughts and songs I have seen here?". If I ever meet Sabine, say by visiting a talk, then I know beyond doubt she exists. Until then, I have to take the word of those who did meet her for it.
Let us say I postulate an entity, godzwill, and add it to our current physics. My theory uses godzwill to account for any known discrepancies between predictions and observations. Godzwill predicts dark matter for example. Godzwill predicts that the wave function will collapse after a quantum measurement.
DeleteNote I specified known discrepancies, so the effect of godzwill can be predicted.
Does godzwill exist?
"The Higgs-boson and quarks are names that we have given to mathematical structures. "
ReplyDeleteBut what if these names are misleading?
We don't think in numbers and formula - we think in names.
So bad chosen names may mislead to bad neighbourhood, with yet worse names, and so on and on ...
“Three quarks for Muster Mark!
DeleteSure he hasn’t got much of a bark
And sure any he has it’s all beside the mark.”
If we call a (borderless) field as (limited) thing - eg - how can we consider about correctly?
DeleteThat's what I meant.
Words are not noise nor smoke. You shouldn't mingle it with names. ("Namen sind Schall und Rauch", German proverb)
Ah, but as prophesized: "beside the mark." It's not unbounded in space (only time). Just ask the mouse.
DeleteBetter ask James, in that concern.
DeleteMore Homework: Why do you care what I believe? What does it matter for anything?
ReplyDeleteBecause you are a trained professional in your field and you have a track record of insights I did not have myself. IMO you have reasoned them well and communicate that well.
In my mind your track record greatly increases the probability that what you believe or do not believe (in your area of expertise) is not just whim, or following the group, but has merit. Thus "it matters" to me in the sense that it does influence my perceptions of what is and is not worth my time to pursue, or (like the FCC) worth the public spending time or money to pursue.
We can't know the future, so we have to prioritize based on odds. For me your professional endorsement or dismissal carries weight in those odds.
The only thing I can be confident is "real" is my own consciousness -- a cluster of positive and negative experiences. This makes it a priority to perform actions that (based on my memory and an assumption of consistent behavior in the apparent external experience) will minimize unnecessary pain. Note that it is important to acknowledge *necessary* pain -- short-term sacrifice for long-term benefit.
ReplyDeleteAgain, this is based on an assumption that my external experience will continue to follow the rules my memory implies exist. Having faith in that consistency and discerning what those rules are is the purpose of science.
I have avoided saying "the past" or "the future", because these are ultimately constructs my consciousness creates from memory and anticipation -- the arrow of time. Only "now" can be regarded as "real." Everything else is a mathematical extrusion from the starting condition of the present.
The way some scientists do write though, they do take some mathematical theory and make it "real", ironically to conclude that there is no objective reality. This (in Scientific American, a source of science writing I read in my youth) seems to be the way some physicists write today—the new antimaterialism:
ReplyDelete"One of the weirdest theoretical implications of quantum mechanics is that different observers can give different—though equally valid—accounts of the same sequence of events. As highlighted by physicist Carlo Rovelli in his relational quantum mechanics (RQM), this means that there should be no absolute, observer-independent physical quantities. All physical quantities—the whole physical universe—must be relative to the observer. The notion that we all share the same physical environment must, therefore, be an illusion."
- https://blogs.scientificamerican.com/observations/the-universe-as-cosmic-dashboard/
When we use a term such as "exist" we usually have in mind some observable which will or will not obtain under a given set of conditions.
ReplyDeleteThis an operational approach to a definition of "exist."
Sometimes we talk of the "existence" of a number or of a solution to a problem. Some set of formal operations, some chain of reasoning, might demonstrate that something can be said to "exist" in this sense of the term.
The existence of God might fall under this category. The ancients approached it in this way, I think, although the prophets were said to have encountered Him.
As far as observables in re the existence of a Supreme Being, what is posited is likely to leave at least some of us dissatisfied. In the nature of things, this is unavoidable, I think.
If we say that we "believe" something exists, I think we must be saying something about our confidence as to the outcome of a set of observations or of the likelihood that a given solution can be found.
John Wheeler said something like "what exists is what is experienced". I agree and I'd say the word "exist" simply has no other meaning. And the word "physical" has no meaning at all; it's just a word that's thrown about, with no concept behind it.
ReplyDeleteWhen we use a term such as "exist" we usually have in mind some observable which will or will not obtain under a given set of conditions.
ReplyDeleteThis an operational approach to a definition of "exist."
Sometimes we talk of the "existence" of a number or of a solution to a problem. Some set of formal operations, some chain of reasoning, might demonstrate that something can be said to "exist" in this sense of the term.
The existence of God might fall under this category. The ancients approached it in this way, I think, although the prophets were said to have encountered Him.
As far as observables in re the existence of a Supreme Being, what is posited is likely to leave at least some of us dissatisfied. In the nature of things, this is unavoidable, I think.
If we say that we "believe" something exists, I think we must be saying something about our confidence as to the outcome of a set of observations or of the likelihood that a given solution can be found.
We can be realists about entities without being realists about theories. For example, our theories about electrons have changed greatly over time, but we still call them electrons. We can reasonably believe that all of those theories were mere approximations, but there is something real that those approximate theories were all talking about, and we call those real things electrons. This philosophical position is called Entity Realism (see the Wikipedia entry).
ReplyDeleteOne day, when I did an internship in a Dutch University Hospital, a nurse told me that for many years professors had been weighing people just before and after their deaths. Each time they found a difference of 4 grams. Ergo souls exist, each weighing 4 grams.
ReplyDeleteWhether or not a soul turns up some day is totally irrelevant.
Marten,
DeleteYou seem to be claiming that the LHC measurement is wrong. Do you even know how the measurement and data analysis works?
I do not claim that they are wrong. I am just afraid that the results do not prove that the theory is definitely right.
DeleteOf course the results do not prove that the theory is definitely right. You cannot prove a scientific theory right. You can only demonstrate that it describes observations.
DeleteHello, Friends
ReplyDeleteLet us take a moment
to be bid Farewell to
Murray Gell-Mann.
A thought will do,
- any words
would be lacking.
All the best,
"If I have seen farther than others, it is because I was surrounded by midgets." MGM
ReplyDelete-drl
Sabinne,
ReplyDeleteWhen you say,
"Scientists don’t deal with beliefs. They deal with data and hypotheses. Science is about knowledge and facts, not about beliefs,"
I "believe" you are wrong here. What we call science is contingent on our beliefs about the natural world and our perception of that world. The only thing science can do is help us understand our own experiences; whatever "ultimate reality" is, is inaccessible to us. All of our assumptions about the natural world, that things are made of particles, or fields or strings, that their dynamics are governed by a mathematical formalism, are all "beliefs" that we assign some degree to (we cannot be absolutely certain). Any experiments we conduct are also contingent on our beliefs about how the experiment works, something else we can never be absolutely sure of.
At the end of the day, the proper way to do things is to realize that physics is just an exercise in inductive inference; we are trying to reason with incomplete information. A foundation is probability theory and entropic inference is key for making progress, something which is certainly needed in QFT (which is still a mess).
infoPhysics,
DeleteIt is correct that science is based on some beliefs, too. I will write about this some other time.
But what you call beliefs is simply what I call axioms of the model. You do not actually have to believe them, you merely notice that they work, in the sense that they help you to explain observations.
Mainstream consensus is a belief. The scientific truth is created by a democratic, conventional agreement of what is right and what is wrong, of what is true and what is false, of what must be praised and what must be doomed. Of course, the Higgs boson does not not exist. The Higgs boson will exist when it were routinely detected by other laboratories and experiments. Of course, gravitational waves do not exist. Gravitational waves will exist when Chinese and Russian scientists detect them by means of their own observatories, not only by LIGO (and the abduced, aka collaboration, VIRGO). Dark matter does not exist, because it is a product of mainstream consensus, where General Relativity is preserved as correct versus resolving the anomaly by means of a better gravitational model other than that GR. Realism ends when you passed away. Maybe, the Moon still exists when you stop watching it, but the Moon stops existing when you passed away. Who gives a shit? Thinking is not a belief, but a process of revealing the lies that science could try to endorse as truths. The main property of that general belief, called mainstream consensus, is a gross censorship for alternative hypothesis and theories. That what is out of mainstream consensus is seen as wrong or as if it didn't exist. But sometimes, it happens that what is wrong is the general consensus, not the alternative and "cranky" theory.
ReplyDeleteNo, scientific truth is not created by a democratic agreement. I explained this here.
DeleteAlbert Zotkin: ... but the Moon stops existing when you passed away. Who gives a shit?
DeleteMe. I give a shit. That's why I have a will and pay for life insurance, to help the people I believe will continue to exist after I am dead, with the money and assets I have that I believe will also continue to exist after I am dead.
Empirically speaking, having seen more than average person's share of death, the universe continues to exist after someone dies. Although my particular belief in the Moon' existence will cease, that doesn't mean the Moon will cease to exist.
Dr. AMC:
DeleteYou've hit on the key point. Instrumentalism may or may not work with respect to the physical world, but, when it comes to other people, instrumentalism becomes a rather dangerous form of solipsism.
So, if we accept that people are part of the natural world, then instrumentalism towards the natural world reduces to solipsism.
I can't resist quoting Russell's famous comment on solipsism: "I once received a letter from an eminent logician, Mrs. Christine Ladd-Franklin, saying that she was a solipsist, and was surprised that there were no others. Coming from a logician and a solipsist, her surprise surprised me.”
Dave
P.S If anyone wants my own brilliant solution to the problem of existence, I am afraid I have none. But, I am pretty sure the moon does still exist even when no one is looking at it.
PhysicistDave,
DeleteI am afraid I have to disagree. Solipsism does not follow from instrumentalism. Instrumentalism is the smallest common denominator that we all agree on (or, well, at least we would if we were rational). It says: This is what we can state with (limited) confidence. Realism and solipsism both go beyond that by making additional statements that cannot be backed up by evidence.
In the case of realism that's saying the Higgs-boson is real, in the case of solipsism that's saying it's not real. Instrumentalism is just silent on the matter, which is a way of saying it's really compatible with both, so pick whatever suits you better.
Sabine, Instrumentalism is a cop-out. It only becomes necessary when you abandon empiricism. Empiricism combined with logic is the only way science has ever worked to provide a rational and incrementally increasing understanding of physical reality.
DeleteFor myself I sidestepped the problem of existence (and other complications) a long time ago by adopting the simple phrase "one way of looking at things is ...".
ReplyDeleteSo for this blog-post I have "one way of looking at things is that (..) exists ...", where the term in brackets can be any of: Higgs-boson; quarks; black holes; gravitational waves; God; etc. At the practical/operational level this works for me.
"Scientists don't deal with beliefs. They deal with data and hypotheses. Science is about knowledge and facts, not about beliefs." My guess is that beliefs are particular types of electromagnetic field associated with the brains of mammals and birds. I suggest that data and hypotheses NEVER exist apart from beliefs. I tried to convince Motl that Kroupa is a better scientist than he is but Motl doesn't believe me. I believe that Milfgrom is the Kepler of contemporary cosmology — based upon the data and the facts. Is my belief wrong?
ReplyDeleteDo I think that I myself exist...?
ReplyDeleteWell... - I do so!
Do I think that SuSy, higher dimensions, branes and the notorious stringscape exist?
Not really!
However: what does 'existence' mean in our non-objective, non-real quantum world?
ReplyDeleteHello,
ReplyDeletepeople have contacted me telling suggesting that I should comment here, so I do. ***
I appreciate very much what you say about current so-called fundamental physics.
With respect to concepts such as quarks and the Higgs boson, I think however an even more critical view is necessary.
The question in not merely whether a model makes predictions -geocentric astronomy did quite well on that - but whether it makes sense from a epistomological perspective and leads to new insights.
I have elaborated my arguments - concerning simplicity, unsolved problems, history, method and transparency in particle physics in my book "The Higgs Fake", thus without boasting too much, I can say it has become a wellknown
source at least among the critics.
There is a vivid exchange of arguments on amazon among close to 100 reviewers worldwide. Thus I think it would be great, in case you like to deepen the discussion, if you addressed some of the issues raised there. Needless to say, I am happy to provide a copy in case don't have it.
Alexander Unzicker
The scientific method works because the information about the physical world happens to be extremely compressible. If that were not the case, e.g. if we were Boltzmann brains observing a random World, then science would not work for us.
ReplyDeleteor it would in a different way ...
DeleteIs the Higgs boson real? It depends on your own concept of the Higgs. What has been measured is a real resonance at a typical energy in proton-proton collision. This corresponds to a real symmetry. The important question here is: Are the particles observed a product of the decay of the Higgs or just produced from the collision as an interaction. In any case, the symmetry corresponding to the Higgs is real. In a probabilistic context, it is difficult to interpret. In my opinion, the fact that the Higgs may decay into many different particles indicates that the Higgs is a transitory process with a specific symmetry at the energy of the resonance but it has different possible symmetries corresponding to each decay produced.
ReplyDeleteIn a theory without probabilities and where particles have definite trajectories and where they are extended in space (no point particles), these different symmetries would be explained by the symmetry-asymmetry of the proton-proton collisions...
I forgot to mention that a realistic solution to the vacuum energy would be necessary, indeed.
ReplyDeletePhysicists are the experts in he interactions of matter and energy at all length and time scales in the physical universe. If you lot don't know what's real, nobody does. We have no other way than the natural sciences to produce high quality models about regularities we observe.
ReplyDeleteStuff we call electrons have certain properties. If we have a reliable way to test for these properties seems to me enough to say electrons are real. Though this doesn't prove electrons are real, I cannot think of a better use for the word 'real'.
Scientific realism is probably not a matter of being right, but a matter of being less wrong.
I'd give you 3 out of 5 sigmas that you actually exist.
ReplyDeleteEither way, you're still a 10 in my book.
As I live and breathe, I just discovered that we live in a Higgs field full of Bosons.
ReplyDeleteThat's why it hurts when you bump into things.