31.2 Physical models
Physicists have already demonstrated that the physical degree (3.), without consciousness,
can be modeled mathematically. Because of the rather uniform metric of physical
space, theories of virtual processes can be mathematically formulated and solved
for the 3.2 sub-degree, either using perturbation theory or some all-order lattice
models on a discretization of space and time that approximates continuous spacetime.
In the 3.3 sub-degree of quantum mechanics, instances of the Schrödinger equation
have been spectacularly successful in describing low-energy phenomena in nuclear,
atomic and chemical physics. In this sub-degree, spacetime is directly taken as
continuous, and differential equations are solved to represent the evolution of
wave-functions describing propensity fields.
The pre-geometric sub-degree 3.1 has proved more difficult to describe, not least
because physicists do not know exactly what processes should be modeled here. As
mentioned in Chapter 5, proposals have suggested ‘spinors’
by Penrose and Rindler (1987); ‘loop quantum gravity’
as described for example in Rovelli (1998),
Rovelli (2010) in terms of spin networks, and ‘causal
sets’ according to Bombelli et al. (1987) and
Brightwell et al. (2003).
Rovelli (2010) interestingly characterizes loop
quantum gravity in terms of superpositions of different-sized lattices, which implies
that the ‘true’ quantum dynamics of the 3.1 pre-geometric sub-degree will involve
(in sub-sub-degree 3.11) some kind of propensities for producing geometric spin
lattices of various sizes. These are largely speculations still being developed.