Amplitude for existence of spacetime points
  This paper outlines a possibility for spacetime dynamics and structure, without postulating a metric ab initio. In this model, the closer an object is to a mass or energy source, the more paths through spacetime might be available to the object in the direction of the mass/energy, or the higher the amplitude associated with such paths. A simple possibility might be that spacetime points $x$ have an amplitude of existence $E(x)$ consistent with this. The magnitude of $E(x)$ might be greater or less than 1 at any point $x$; or the relative values of $E(x)$ might be what matters. In a classical limit, a function like $E(x)$ might give the effect of a gravitational metric. 
M. Dance