Quantum realism concludes that our 3D space is a surface contained within a 4D quantum space. In 1919, Kaluza derived Maxwell’s equations by expressing Einstein’s relativity equations in four dimensions. The idea was rejected because a real extra dimension would make gravity vary as an inverse cube and the solar system would collapse. Kaluza’s fourth-dimension contradicted physical realism but when mathematicians used complex numbers to explain electromagnetism as a rotation into a fourth dimension, they sensibly called it imaginary to avoid this.
Klein then suggested that Kaluza’s dimension was compactified, curled up in a tiny circle so entering it returned you to the start, but this was also seen as unlikely – until years later string theorists needed to explain the six extra dimensions their mathematics required. So began the idea that space contains extra dimensions within it, but why would nature create extra dimensions that do nothing except make our equations work?
In quantum realism, a virtual reality must present on a screen surface that needs an extra dimension to contain it. If our space is a screen, its three transfer dimensions must be contained by another. Unlike string theory, this dimension contains our reality rather than curls up within it. This then is quantum space. Quantum space is the space that contains our space as a surface within it. It requires an extra dimension that we can no more enter than an avatar on a screen can enter our world. Today, some physicists see our space as a brane in a higher-dimensional bulk because an extra dimension sequestered from our space can explain gravity (Randall & Sundrum, 1999):
“Physicists have now returned to the idea that the three-dimensional world that surrounds us could be a three-dimensional slice of a higher dimensional world.” (L. Randall, 2005) p52
Quantum realism agrees, but sees our space as a polar surface rather than a Cartesian “slice”.