Go down deep enough into anything and you will find mathematics ~ Dean Schlicter
The unification problem in physics has at its heart the problem of time: quantum physics, via the Heisenberg Uncertainty Principle between time and energy is not compatible with the Einstein notion of time as coupled with space that gives rise to a 'smooth' spacetime continuum. John Wheeler and Bryce DeWitt did successfully resolve this incompatibility via the Wheeler-DeWitt equation: however, at two high prices. One, time ceases to play any dynamical role in the universe since it occurs idly in the equation, and secondly, by metaplectic geometry, there can be no quantum cosmological universal metric definable. In this post, I will try and analyse the metric problem and leave my analysis of the Page-Wootters 'solution' to the WdW problem of time for another post.