Further discussion on http://eskesthai.blogspot.com/2005/08/fifth-dimension-is-spacetime-fabric.html:
I must agree with Kaku’s view, which you quote above. What attracts me to the 5-D spacetime with the spacetime fabric as the 5th dimension is the suggestion that black holes in 5-D appear as radiation on the 4-D hologram.
I recalled reading that David Bohm seemed to write something like this about the spacetime fabric, but was less definite (I think it was in his book 'Wholeness and the Implicate Order', but I will need to check).
There is a spacetime fabric of any type, Higgs boson or graviton, or photons without longitudinal oscillation.
One way to address this for physical calculations is to consider how much of this fluid space there is in a cubic metre of volume, and what effect ordinary matter has on it.
Assume that 1 m^3 contains a fixed amount of spacetime fabric plus ordinary mass-energy, then what happens when ordinary matter moves out of that cubic metre? Clearly, more spacetime fabric would need to enter to keep the volume filled.
Since there is electromagnetic evidence that ordinary matter may be treated as 4-D black holes, it is neat to think of the spacetime fabric as 5-D black holes which appear as radiation when seen on the 4-D hologram.
The chief difficulty with the LeSage pressure model for gravity is that fluid pressure disperses in all directions, whereas gravity (as a pressure effect) is directional. In a liquid, pressure disperses since molecules strike one another and dissipate kinetic energy in all directions. But because the spacetime fabric permeates through most of the atomic space, it pushes fundamental particles in the shield direction without dispersion. This implies that the source of gravity pressure is similar to light pressure in a vacuum, not to air pressure.