I recently commented on an astrophysicist’s blog regarding a claim I consider ahistorical and inaccurate. The comment was deleted. I don’t have a problem with that – a blog is a personal space. However, I was responding to a specific claim about the origin of General Relativity that is both common and false. What follows is the one paragraph remark I was commenting on and my now-deleted response which admittedly ranges a bit further than simply refuting the quote requires:
The equivalence of inertial mass with gravitational charge is a foundational principle of general relativity. There are flavors of GR in which it falls out explicitly, e.g., Yilmaz’s gravity. But it is basically an assumption.
The equivalence of inertial and gravitational mass was an observed and measured fact known to Galileo and Newton. It was not an assumption of GR. The mid-20th century extensions of what is now called the Weak Equivalence Principle were little more than conjectures of mathematical convenience “suggested” by Robert H. Dicke. They had nothing to do with the development of GR.
Along with John A. Wheeler’s aphoristic, empirically baseless, invocation of a causally interacting spacetime, Dicke’s two extensions of the WEP were surreptitiously hung on Einstein’s General Relativity producing a grotesque variant that by rights should be known as Dicke-Wheeler Relativity Theory. It is DWRT that has been the officially taught version for the better part of 50 years although the D-W distortions are almost always attributed to Einstein. He would have puked.
It is DWRT that prompts otherwise rational people to insist that, despite theoretical and empirical evidence to the contrary, the speed of light is some sort of universal constant. It is DWRT that promotes the false claim that Einstein explained gravity as being caused by the curvature of space.
As far as space itself goes, it is a relational concept exactly like distance. That is all the evidence supports. In fact, space is best understood as the aggregate of all distances that separate you from all the other things in the Cosmos that aren’t you. Substantival space is a mathematicist fiction that has no scientific basis.
Throughout the Cosmos, everywhere within our observational range where there is no matter there is only electromagnetic radiation. That is an empirical fact. Everywhere people imagine they see space there is electromagnetic radiation. At any given 3D location that radiation is flowing omnidirectionally from all the omnidirectional emitters (stars and galaxies) within range. That is what we observe and that is how we observe.
As Mach surmised we are connected to the rest of the Cosmos or at least to those objects within range. That non-simultaneous connection is via electromagnetic radiation – that is what’s there. Until recently no one had bothered to do a full survey of what might be called the Ambient Cosmic Electromagnetic Radiation. The authors of this interesting paper seem to think they are the first. Everybody else was too busy looking for some dark stuff apparently.
Modern theoretical physics is all theory and no physics; it consists of nothing but the unrelenting and fruitless effort to prop up two inert century old models whose assumptions of mathematical convenience were lapped by physical reality decades ago. Tinkering with obsolete mathematical models does not constitute a scientific endeavor even if that is all that has been taught for the last 40 years.
This very interesting paper originally caught my attention because it demonstrates that Einstein rejected what the paper calls the “geometrization” of gravity and did so throughout his career not just at the end of his life. On a recent rereading I was struck by something else which is easy to forget – the subtly of Einstein’s thought.
The geometrization of gravity is an awkward term because it elides the central problem which is the reification of spacetime. It is well known that Einstein’s Relativity Theory employs the geometric math of Gauss-Riemann. What is at issue is whether that geometric math refers to a physical spacetime that causally interacts with matter and energy (electromagnetic radiation). Many argued that it did while Einstein rejected that interpretation as unphysical and uninformative.
Beyond the issue of what Einstein did not believe, the paper illuminates a seldom discussed subject – what Einstein did believe Relativity Theory accomplished, the unification of gravity and inertia. This unification is not found in the famous gravitational equation of General Relativity but in the lesser known geodesic equation. From the paper:
“We found that (i) Einstein thought of the geodesic equation in GR as a generalisation of the law of inertia; (ii) in which inertia and gravity were unified so that (iii) the very labeling of terms as ‘inertial’ and ‘gravitational’ respectively, becomes in principle “unnecessary”, even if useful when comparing GR to Newtonian theory.“
While it is well understood that the Equivalence Principle* played a role in Einstein’s thought process while developing GR the importance of the geodesic equation as a formal realization of the EP is certainly not widely acknowledged as far as I am aware. The implications of that unification are profound.
One of the peculiarities of the modern theoretical physics community is their apparent disinterest in determining the physical cause of the gravitational effect. The reason for this disinterest is a philosophical attitude known as instrumentalism – if some math describes an observed outcome adequately then a causal explanation is superfluous. Instrumentalism is a variant of the scientifically baseless philosophical belief called mathematicism.
The purpose of science is to investigate the nature of physical reality, not to sit around fiddling with poorly constructed mathematical models of physical reality that do not remotely make sense when you inquire of the model, What does the math mean with regard to the physical system being modeled? The answer that typically comes back is a peculiar kind of bullshit that can be thought of as Big Science Babble.
Superposition Of States is Exhibit A of BSB on the quantum scale. Almost all quantum scale babble winds up at SOS or at Wave-Particle Duality. SOS tells us that an electron is never at a particular position until it is observed.
When an electron is detected it is always, not surprisingly, at a particular location but according to the mathematicists at all other times when not being observed the electron is in a SOS – it is spread out over all of its possible locations as described by some math (the wavefunction). How do they know this? Because the math doesn’t know where the electron is, so it can’t be anywhere in particular. Sure, of course.
BSB is rife on the cosmological scale. According the standard model of cosmology the Cosmos is 95% made up of some invisible stuff while the stuff we actually observe provides the remaining 5%. How do scientists know this invisible stuff is there? Because it has to be there to make the Big Bang model work and everybody knows the BB model is correct because they said so in graduate school, so the invisible stuff has to be there, like it or not. Sure, of course.
At the root of all BSB, of course, is mathematicism. A mathematical model dictates an absurd story about physical reality which we are then supposed to believe without evidence because math determines the nature of physical reality. If mathematicists with pieces of paper saying they are scientists believe in BSB, shouldn’t you? No, you should not.
Physical reality is an afterthought to mathematicists for whom only math is of interest. That’s why no effort is being expended in the scientific academy to understand the physical cause of gravity; research funding is controlled by mathematicists. And since they already have some math that kind of works (as long as reality contains things it does not appear to contain), well that’s good enough – for mathematicists.
In real science, physical events and behaviors occur as a consequence of physical interactions. Those interactions can be matter/matter (collision), matter/radiation (emission, absorption, reflection), or radiation/radiation (interference) in nature. There is a good argument to be made that all observed gravitational and inertial effects arise as a consequence of matter/radiation interactions:
By observation, everywhere in the Cosmos that there is no matter, there is electromagnetic radiation.
Light traversing a gravitational field behaves as it does in a transparent medium with a density gradient. All approximately spherical gravitating bodies emit electromagnetic radiation omnidirectionally with a density gradient that falls off as 1/r2.
The gravitational effect surrounding a spherical gravitating body falls off as 1/r2.
The gravitational field then is just the Ambient Local Electromagnetic Radiation field surrounding a gravitating body.
In the intergalactic regions, far from any significant gravitating bodies there is only the ubiquitous Ambient Cosmic Electromagnetic Radiation.
The ACER is, to a good approximation, isotropic and this cosmically sourced electromagnetic field does not have a density gradient. It can be thought of as the inertial field.
This unified physical account of gravity and inertia is consistent with Einstein’s mathematical description of a unified gravity and inertia in the geodesic equation.**
*The Equivalence Principle Einstein employed is now known, since the mid 20th century, as the Weak Equivalence Principle to distinguish it from later, dubious extensions, added with little scientific justification after Einstein’s death in 1955.
**The forgoing does not constitute conclusive evidence that gravity is an effect of matter/electromagnetic-energy interactions – but it is evidence based on empirical observations. In contrast, there is no empirical evidence for the concept of gravity as a fundamental force.
Forces are themselves not things, they are effects. Of the four fundamental forces claimed by science to exist, only the electromagnetic force has any empirical basis. In fact though electromagnetic radiation is no more a “force” than a golf club is a “force”.
A golf club exerts a force on a golf ball by striking it, resulting in an acceleration of the ball. That applied force can be quantified using known mechanical laws. The term force describes that interaction but force is just a descriptive term for the interaction between the golf club and golf ball, it is not the golf club nor is it a separate thing in itself. The same analysis applies to EMR; it is not a force but it can exert a force when it strikes a physical object.
Here are some choice tidbits from a recent Tim Anderson article titled Zero-point energy may not exist. I’m always supportive of any effort to drag theoretical physics back into contact with empirical reality so the suggestion that ZPE may not exist is at least promising. It even suggests the possibility that modern theoretical physics might emerge from its self-imposed exile in Plato’s cave, the cave-of-choice in this case being mathematicism.
In reading the article any hope of a scientific restoration is dashed, as one is quickly immersed in sea of mathematicist illogic. Here for instance is the “reasoning” that underlies the ZPE concept:
…it means that nothing has non-zero energy and because there is an infinite amount of nothing there must be an infinite amount of energy.
While it is clear that the author is distancing himself from the ZPE concept, that account of the underlying “reasoning” gives rise to the simple question, how did such flamboyantly illogical nonsense gain any traction in the scientific community? The answer of course is mathematicism which is itself a flagrantly illogical proposition, just not recognized as such by the denizens of the mathematicist cave. Then there is this little gem (emphasis added):
Quantum field theory, which is the best theory of how matter works in the universe that we have, suggests that all matter particles are excitations of fields. The fields permeate the universe and matter interacts with those fields in various ways. That is all well and good of course. We are not questioning that these fields exist. The question is whether a field in a ground state has any measureable effect on matter.
So in their “best theory” the universe is permeated by many fields and matter is an excitation of those fields. Physical reality however only contains one observed field and that is the electromagnetic field which is the aggregate of all the electromagnetic radiation that permeates the Cosmos. That radiation is constantly being emitted by all the luminous matter that also permeate the Cosmos. There are no additional observed fields as described by QFT.
Despite the fact that the QFT fields are not observed the author does not wish to question their existence. Why? Mathematicism, of course. If a math model says something is there and physical reality declines to offer any evidence in support of such a conjecture, the mathematicist position is that the math is correct and reality is perversely withholding the evidence.
Imagine we have a sensitive Hawking radiation detector orbiting a black hole. The detector is in a state of free fall, meaning that it experiences no gravitational forces on it.
This last bit invokes a wholly imaginary thought experiment involving imaginary radiation emitted by an imaginary black hole. Without any empirical basis or logical connection to known physics, it has no scientific significance even if the “experiment” somehow reflects badly on the ZPE concept. In that, it only amounts to an illogical argument refuting an illogical concept.
The second sentence also presents a widely promulgated claim that has no basis in physics. The idea that an observer or detector in free fall experiences no gravitational forces on it is purely unphysical nonsense. An observer or detector can only be in a state of free fall if they are experiencing a gravitational force. The typical basis for this claim is that the observer is prohibited from making observations that would clearly show the presence of a gravitating body and thus demonstrate the presence of a gravitational field.
Einstein is usually credited with this view but in fact his conception of the equivalence principle was highly constrained and did not extend to fundamentally illogical claims like the one made above. The version of the equivalence principle Einstein employed is now called the Weak Equivalence Principle.
The two extensions of the equivalence principle contrived and adopted after Einstein’s death, the disingenuously named Einstein EP (he had nothing to do with it) and the Strong EP have no logical, scientific or theoretical justification. They were merely conjectures of mathematical convenience proposed by the physicist Robert H. Dicke, who along with his colleague John A. Wheeler, concocted a distorted variant of Einstein’s Relativity Theory. That variant is presented today as Einstein’s RT but it is a separate theory and should have it’s own name — Dicke-Wheeler Relativity Theory.
It is in DWRT that you will find the EEP and SEP as well as a reified version of spacetime which is said to causally interact with matter and energy causing the gravitational effect and facilitating the Expansion of the Universe. There is no empirical evidence supporting those ad hoc additions to ERT. They are simply mathematicist conjectures that have no scientific basis or logical connection to physical reality. In modern theoretical physics though, they are treated as axioms — true by definition.
Mathematicism is the principle driver of the Crisis in Physics. The reason for this is simple: math is not physics. The controlling paradigm in modern theoretical physics, however, is that math is the basis of physics and mathematical models determine the nature of physical reality. That paradigm is a philosophical belief that has no scientific basis.
As a consequence of mathematicism theoretical physicists espouse two standard models that describe a physical reality containing a large number of entities and events that are not part of the physical reality we actually observe. Modern theoretical physics does not constitute a science so much as a cult of belief.
You have to believe in the expanding universe, in dark matter and dark energy, in quarks and gluons. You have to believe that the speed of light in a vacuum is a universal constant even though it cannot be measured as such and is not constant in General Relativity — at least according to Einstein.* You have to believe in these things because they are not demonstrably part of physical reality. Scientists don’t traffic in beliefs but mathematicists do and so there is a Crisis in Physics
* The speed of light is a universal constant according to Dicke-Wheeler Relativity Theory.
Robert A. Wilson commented on something I posted over at Triton Station:
Certainly, one can hardly argue with the principle of general relativity as a fundamental physical principle. The various forms of the equivalence principle, on the other hand, presume that we already know what mass is – which we clearly don’t.
I’ve invited Robert to elaborate a bit here. So Robert, I agree with you on the principle of general relativity but could you explain what you mean when you say we don’t know what mass is and how that relates to the equivalence principle?
Well here’s a cute little video that manages to do a good job of conveying just how daft and detached from reality theoretical physics has gotten over the last century:
The first 11 minutes or so are effectively a sales pitch for one of the structural elements of the Big Bang Model – Spacetime. The deal is, you’re supposed to believe that the force of gravity is not really there – nothing is holding you to the surface of the earth, rather the earth is accelerating upward and pushing against you.
And the reason this is happening is that you are not following a curved path in –Spacetime, because according to the video you are being knocked off of that curved path by the earth that is accelerating upwards and you are in the way and that’s gravity, tada! How do we know this? Well that’s obvious, it’s in the math and the math tells reality what’s going on and if reality doesn’t like it, that’s too bad. So don’t go trusting your lying eyes, alright.
In addition to Spacetime, this fairy tale is predicated on a ridiculous over-extension of the Principle of Equivalence that Einstein used in developing Special Relativity. Einstein was very clear that the POE applied only under the severely constrained circumstances of a thought experiment. His main purpose seems to have been to provide a physical interpretation for the observed equivalency between gravitational and inertial masses. Einstein presented the POE as informing his ideas about gravity.
The video ignores Einstein’s constraints and pretends the POE is fundamental to General Relativity, so it winds up insisting that things that are obviously not true in physical reality, are, nonetheless, true simply because the math can be framed that way – your lying eyes be damned.
We are told that a man falling off a roof is in the exact same situation as an observer in a non-accelerating rocket ship far from any gravitating body. This claim is made even though it is obviously not true; the falling man will be injured, if not killed, when he hits the ground, whereas no such fate will befall the observer in the rocket ship.
So the idea is, until the falling man meets his unfortunate fate, the situation is the same and therefore both situations are the same, the different outcomes not withstanding – because the math is the same. Observers free falling in orbit won’t be able to tell they’re not in an inertial frame – unless they look out the window, so that’s just like being in an inertial frame too. Right, of course.
In a similar vein, the video insists that an observer in a rocket accelerating at 9.8 m/s^2 will not be able to tell the difference between that situation and standing on the surface of the earth. The presenter fails to mention however, that only holds true as long as the observer doesn’t observe out the window, which will alert the observer that the rocket and therefore the observer are not at rest on the surface of a large gravitating body and therefore the situation is not comparable to standing at rest on the surface of the earth. Also, if any observer steps off the rocket, they will be left behind as the rocket accelerates away. But nevertheless, it’s all the same – as long as no one looks out the window, and maybe you remember that the earth is actually accelerating upwards under your feet, like the floor of the rocket. Sure, of course.
For the sake of introducing some sanity in this matter, here is Einstein on the POE. Note that the second paragraph completely contradicts the claims made in the video implying the equivalence of all inertial and non-inertial frames.
We must note carefully that the possibility of this mode of interpretation rests on the fundamental property of the gravitational field of giving all bodies the same acceleration, or, what comes to the same thing, on the law of the equality of inertial and gravitational mass…
Now we might easily suppose that the existence of a gravitational field is always only an apparent one. We might also think that, regardless of the kind of gravitational field which may be present, we could always choose another reference-body such that no gravitational field exists with reference to it. This is by no means true for all gravitational fields, but only for those of quite special form. It is, for instance, impossible to choose a body of reference such that, as judged from it, the gravitational field of the earth (in its entirety) vanishes.
RELATIVITY THE SPECIAL AND GENERAL THEORIES, ALBERT EINSTEIN, authorized translation by Robert W. Lawson, original version 1916, translated 1920, appendices 3 and 4 added 1920, appendix 5 added to English translation 1954
It is clear from this statement that the POE of Einstein’s thought experiment is the Galilean version, commonly referred to nowadays as the “Weak” POE. The so-called “Einsteinian” and “Strong” POEs of modern cosmology are post-Einstein formulations attributed initially to Robert Dicke, though there were doubtless others who perpetrated and embellished this nonsense. Neither extension of the POE has anything to do with the foundations of Einstein’s Relativity Theory. It is those mid-20th century extensions that are misleadingly presented in the video as fundamental features of General Relativity.
The POE, in its current, extended usage, is mostly just a conjecture of mathematical convenience, allowing theorists to use Special Relativity math instead of the more difficult General Relativity formulations. It also results in a theoretical claim that the speed of light in a vacuum is a universal constant. That claim contradicts both GR which predicts that the speed of light varies with position in a gravitational field and observations which confirm that prediction.
This unwarranted belief that the speed of light is a universal constant has also produced a cottage industry of theorists expounding a theory of undetected structures called Black Holes with the physically absurd properties of an event horizon and a singularity. No such structures exist. The relativistic slowing of light in a gravitational field precludes their existence. It does not preclude the existence of massive high-density objects.
Ok, let’s grant that this video presentation is of dubious scientific quality and does not, perhaps, represent the consensus view of the scientific community, particularly with regard to the so-called Principle of Equivalence, although if not the consensus, the Strong POE certainly commands significant support by a majority of theoretical cosmologists . The usual suspects will whine, of course, that pop-science presentations like this video cannot be trusted.
That complaint is also lodged against anything written for a general audience, even when the author is a fully accredited scientist with a relevant FAS (full alphabet soup) after their name. If it’s written so non-experts can understand it, then it is, on some level, wrong.
The reason for this situation is straightforward: much of what theoretical physicists believe cannot be translated into clear, logical, statements of scientific fact. What you get instead is confident handwaving consisting of metaphysical assertions that have no factual basis in empirical reality and a lot of math. According to theorists this is because theoretical physics can only be properly understood by those steeped in years of study of the underlying mathematical esoterica that informs only the truly knowledgeable. To which the only proper retort is: math is not physics and if your math cannot be translated into empirically verifiable physical terms – then your math is inadequate to the task of being a proper scientific model of physical reality.
The modern POE is just a conjecture of mathematical convenience, nothing more. Nonetheless, this modern POE permeates and perverts the scientific literature. Here is an Encyclopedia of Britannica entry for the POE:
In the Newtonian form it asserts, in effect, that, within a windowless laboratory freely falling in a uniform gravitational field, experimenters would be unaware that the laboratory is in a state of nonuniform motion. All dynamical experiments yield the same results as obtained in an inertial state of uniform motion unaffected by gravity. This was confirmed to a high degree of precision by an experiment conducted by the Hungarian physicist Roland Eötvös. In Einstein’s version, the principle asserts that in free-fall the effect of gravity is totally abolished in all possible experiments and general relativity reduces to special relativity, as in the inertial state.
Britannica, The Editors of Encyclopaedia. “Equivalence principle”. Encyclopedia Britannica, 31 Mar. 2019, https://www.britannica.com/science/equivalence-principle. Accessed 6 June 2021.
It should be noted that, according to the encyclopedia’s referenced article on Roland Eötvös, his experiment “… resulted in proof that inertial mass and gravitational mass are equivalent…“, which is to say, that it demonstrated the Weak POE only. It is also clear, that the authors of this entry are confused about the distinctions between the three POEs. But what of that; it’s only an encyclopedia trying to make sense of the nonsensical world of the modern theoretical physicist and modern theoretical physics is an unscientific mess.
One of the great unforced errors of late 20th century theoretical physics was to declare the speed of light in a vacuum, a universal constant. This was done despite the fact that, according to General Relativity, the speed of light varies with position in a gravitational field. This variation in light speed has been observed.
The idea that the speed of light varies with position in a gravitational field is not new. It comes on good authority:
…according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity and to which we have already frequently referred, cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Now we might think that as a consequence of this, the special theory of relativity and with it the whole theory of relativity would be laid in the dust. But in reality this is not the case. We can only conclude that the special theory of relativity cannot claim an unlimited domain of validity: its results hold only so long as we are able to disregard the influences of gravitational fields on the phenomena (e.g. of light).
Albert Einstein, Relativity The Special And The General Theory, 15th edition
The claim of those who wish to maintain the universal constancy of light speed (c) is that it is justified by the Equivalence Principle. The rather lengthy linked discussion goes into some detail but no mention is made of the constancy of c being consequent on the EP. None of the tests of the principle cited in the article involve measuring the value of c directly.
Einstein invoked the EP in the derivation of General Relativity to provide an interpretation of the observed fact that inertial mass and gravitational mass are equivalent. Given the above quote, he obviously did not find justification therein for asserting the universal constancy of c.
The only reasonable conclusion is that the EP does not justify the claim of a universally constant light speed. The claim appears to be only a lazy mathematicist assumption of mathematical convenience. Theoretical physics is a remarkably irrational, unscientific mess because of this sort of nonsense.
