Physics Illusion 7: What You See Is What There Is

                                               To see a duck which is a rabbit (or vice versa).

In the New View of Motion under Gravitation we consider in the basic relation $\Delta\phi =\rho$, the gravitational potential $\phi (x,t)$ to be primordial and the mass density $\rho (x,t)$ to be derived from
$\phi (x,t)$ by instantaneous local action in space of the Laplace differential operator.

In the standard view instead the mass density $\rho (x,t)$ is viewed to be primordial and the potential
$\phi (x,t)$ is viewed to be derived as the solution to the equation $\Delta\phi =\rho$ by instantaneous action at distance in a solution process which can be described as global integration:

• $\phi (x,t) =\frac{1}{4\pi}\int \frac{\rho (y,t)}{\vert x - y\vert}\, dy$. 

Why then is $\rho$ chosen to be primal (input) and $\phi$ secondary (output) in the standard view? The answer appears to be twofold:

1. Matter is visible to the human eye, while gravitational potential and forces are invisible.
2. Matter distribution can easily be imagined by the human mind as input, while corresponding gravitational potential and forces are more difficult to grasp (output).  

A human mind may thus be led to the standard view by reasons which are superficial from physics point of view. In particular, if we consider physics to be some form of computational process, we expect that intantaneous action at distance as instantaneous solution of the differential equations $\Delta\phi =\rho$, cannot be realized as a physical process. The standard view would then seem to be unphysical, and rather reflect how human minds see things than how things in fact are.