This is a question, where I start with some assertions:
Try to consider the universe as a four-coordinate system, x,y,z,t where t is time and where we view a change in t as a change in position, and as a velocity in the same way as any other change in either of the other components of the coordinate. Everything is then moving at the speed of c. The difference between a photon and another particle would be that a photon "spends" its velocity in any of the x, y or z dimensions - but not in the time dimension.
This implies that all photons are on the same coordinate in the t-dimension - only the x,y,z values change while t remains 0. It also implies that time would appear to stop for something travelling in only the other dimensions, while it would pass fastest for something completely stationary.
You can then also consider space-time as a function of acceleration. A physical objects' coordinate could be derived from its velocity, which would have to be derived from its acceleration. Acceleration would be a function of entropy, or "age" I believe.
Is this the basis of general relativity? Is it at least an initial starting point for general relativity, or is it completely wrong?
Would spin have to be part of the coordinate system?