A t.e. is an idea. I believe you cannot test an idea with an idea. You can use the idea as the basis of an hypothesis, but eventually you have to test it against reality.
I believe the flaw was thinking the forces (gravity and acceleration) were indistinguishable, thus the same. I believe the purpose was to explain gravity. I believe it failed. I favor a nonviable (meaning uncheckable) hypothesis that gravity, like the electromagnetic force, is an attribute of the elemental particles.
Predictions are proof if there is a cause/effect relationship. Otherwise even partial validity is not demonstrated by the prediction.
The path of light is altered by a gravitational field. Therefore prediction of path deflection, by any hypothesis, would be successful. Both general relativity and materiality of light predict the alteration. I believe space is immaterial, not subject to curvature, so I prefer the materiality of light as the explanation.
Assume space is immaterial and unable to transmit waves.
Assume electromagnetic radiation traverses space.
:.Electromagnetic radiation is substantial.
Observe that electromagnetic radiation exhibits oscillation.
Assume a monad could not oscillate.
:.The unit of electromagnetic radiation is (at least) binary in nature.
Assume the components of this binary system are a positron and an electron mutually orbiting a moving center of gravity, 180 degrees out of phase, the path of motion lying in the orbital plane.
:.The path would be altered by a gravitational field because the system has mass. It would not be altered by an electrical field because the positron and the electron would be pulled in opposite directions, counteracting each other. This opposed attraction would rotate any orbital plane not parallel to the electrical field vector, thus depolarizing some polarized light. Depending on where the particles were in their orbit when passing through a single or double slit, they would experience varying degrees of interference from the fixed particles at the edges of the slits producing the same interference patterns produced by waves. When striking a material surface they would interact with the particles of the surface causing reemission of a pair of particles with the same energy (photoelectric effect). When we see things (other than looking directly at a source of light) we are seeing reemission rather than reflection. The orbiting system would interact with other particles at random positions in their orbit creating 'uncertainty' as to the resultant vectors.
//There are other observed attributes of light but I can't think of any more now.
As stated above I believe gravity is an attribute of matter. I recognize that action at a distance is not generally accepted, but I believe it exists as gravity and electromagnetism. I believe that these are the two basic forces, the others are derivatives. I believe that is why a magnetic monopole has not been found. It does not exist. Every magnetic field is the result of electric charges in motion. As for gravity it is eternal as is its host particle. Wherever the particle goes there goes the force.