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:

1. By observation, everywhere in the Cosmos that there is no matter, there is electromagnetic radiation.
2. 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.
3. The gravitational effect surrounding a spherical gravitating body falls off as 1/r².
4. The gravitational field then is just the Ambient Local Electromagnetic Radiation field surrounding a gravitating body.
5. In the intergalactic regions, far from any significant gravitating bodies there is only the ubiquitous Ambient Cosmic Electromagnetic Radiation.
6. 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.
7. 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.**

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*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.