Mr Kley,
Thank you for your interest in my essay. It was very late for me when I saw your question. In my reply I used wrong terms in the sentence which should have read: both 'attractive' and 'repulsive' gravity emerge from the same property of the hypersurface of the 4D structure of space that seeks to minimize its hyperarea.
You asked, "Can you offer up any specific experiment or present unexplained phenomena that may be illuminated by your vision of 4D Space/Time?"
Having thought your question over, I decided to address the wave-particle duality, with which physics replaced the paradox of space. This duality is best revealed in the double slit experiments. I would like to use this opportunity to demonstrate that, from the 4D perspective, there is no mystery why both matter and light appear to move in waves. In my essay I only briefly mention this in the Flatland analogy.
Before we begin, it is important to appreciate that a hypersphere has 3-dimensional surface, each point of which is equidistant from its center, in the same way as each point of the 2D surface of a sphere is equidistant from the center of the sphere. This topological fact is what makes the 3D space we perceive invariant in all 3 directions and precludes the possibility of selecting a preferred reference frame. The dynamic nature of the 4D structure also makes it unsuitable for the role of the absolute reference frame (just like sea captains can't use ocean as a reference frame and must rely on the external clues such as stars or GPS).
The other aspect of the 4D geometry worth remembering is that form a 4D perspective, each point of the volume of a cube is visible in one sweep just like we grasp each point of the 2D plane in one glance. In a sense, from a 4D perspective, a 3D volume of a cube appears flat, similar to a 2D plane seen from 3D.
With this in mind, let us see how a double slit experiments works out in 4D, on the simplified analogy of the Flatland Plane (the Flatland analogy is indispensable, because 4D is virtually impossible for most people to visualize).
First, I would like you to please take a look at the following image from google images, since I can't post images here:
http://ej.iop.org/images/0295-5075/94/2/20004/Full/epl13428fig1.jpg
The top image, (a) is a side-view snapshot of a hexagonal lattice aggregate of bouncing droplets on a vibrated liquid bath that interact via the surface waves they emit and form various types of stable crystalline clusters [1]. Suggested by Andrew Norton, it is indeed an excellent model of the Flatland nanoscale with droplets representing nuclei confined to the outer, empty side of the Plane (in the "headroom"). Please take a good look at the image again and imagine 3 such aggregations, at some distance apart from each other. These 3 aggregations of droplets/atoms represent the solid structure of the plate with 2 slits in between.
Now please appreciate the fact that light waves, an electron, an atom or a molecule, all move along the surface of the Plane (or hyperplane in 4D) that contains the EM field. The difference between a light wave and, say, an atom, is that the light wave is the transverse disturbance in the surface itself (just like a transverse wave in the surface of water) and as such is entirely confined to the EM field it contains, while "matter" (stuff with intrinsic mass) glides just above this surface in the 3rd dimension (3rd dimension in the Flatland analogy and in the 4th dimension in our world). Nuclei are integrated into the surface by their electron clouds interacting with the EM field in it. The electron cloud makes the indentation a nucleus makes in the surface locally even with the rest of the surface and at the same time acts as a sort of a roller or better yet, a surf-board on which the nucleus surfs the light waves themselves. (In this context, the increase in the inertial mass at high speeds is mostly due to the electrons interacting with the EM field contained in the surface.)
Thus there is no difference in the path a particle of light or a material object takes. A light particle is a convenient abstraction that stands for the momentum of a light wave in space (or, a hyperplane). A material object, such as an atom, can also be represented by a point that too follows the same path. It is the structure of space itself that dictates all movement by expelling the deformation introduced into it locally into the direction that gives (even though, of course, there is a difference in the transverse disturbance that we perceive as light and a longitudinal disturbance we perceive as mass).
In this model it is essential to realize that everything we perceive directly or with the help of our technology are the projections onto the 3D surface of the hyperplane. Matter moves along the same surface as light waves themselves. Thus the interference pattern seen in the double slit experiments is the reflection of the fluid nature of the structure of space itself.
I also would like to emphasize that the strict separation between matter and space of the model I propose is applicable only at low energies of our own experience. At very high energies, the number of space dimensions grows in proportion to the energy density. At high energies, in higher number of dimensions, the geometries of space and matter intermix and are best described by the multidimensional models of string theories.
Again, I thank you for your interest in my essay and for giving me opportunity to address this important question, which I could not do within the constrains of the requirements.
References
[1] A. Eddi, A. Boudaoud and Y. Couder, (2011, doi:10.1209/0295-5075/94/20004), Oscillating instability in bouncing droplet crystals. http://iopscience.iop.org/0295-5075/94/2/20004