Does a photon see a 0-D universe? For a massless particle the spacetime interval between its point of emission and point of absorption is zero: the two points coincide. From the vantage point of such a particle space-time has reduced to a single point.
In the Standard Model, all particles start with zero mass, so does this suggest that our familiar 4-D spacetime is a consequence of the Higgs field or some similar mechanism by which mass is acquired?
Note: if you believe the large-scale 4D structure of spacetime is a pre-existing given, this question makes little sense. In a relational view, where spacetime emerges out of event relationships, then the question suggests that a universe comprised solely of massless particles would have a fundamentally different event-structure.
 A: Per special relativity, no human measurement device can ever reach the speed of light, and thus we can never test what the universe "looks" like in the eyes of photons. In other words, the question of what light would see is unfalsifiable and thus not a scientific question.
And if you force Lorentz transformation onto the frame of photons, you will get a lot of contradictory conclusions. For example, an object is moving at speed $v$ in some normal frame. Then in the frame of a photon that moves in opposite direction, the object is moving at speed
$$\frac{v+c}{1+\frac{vc}{c^2}}=c.$$
According to the invariance of speed of light, the object must be moving at speed of light in any frame, which contradicts our premise that it is moving at speed $v$ in some normal frame.
Moreover, in general relativity, the spatial and temporal component of a four-vector as measured by an observer is directly related to the four-velocity of the said observer. For instance, energy $E$ is the temporal component of four-momentum, as in 
$$E=-p^\mu U_\mu.$$
Since light-like paths does not have a well-defined four-velocity, you can also see it makes no sense for a photon to "see" or measure anything.

For a massless particle the spacetime interval between its point of emission and point of absorption is zero: the two points coincide.

This is not true. The distance in Lorentzian manifold is not postively definite, so zero distance in no way implies the same point.
A: Interpreting the photon world as in all 4 spacetime dimensions with length=null fully is in a relativistic Einstein tradition. This solves the quantum-mechanical duality problem as 
"photon is a partical" = "a wave in a one point spacetime" 
Thus entanglement of two photons can be said ever is local and hence interpretable in classical ways without spooky quantum-mechanics.
But I must admit I worry if this locality holds for very long distances of billion light years where dark energy comes to my mind :/
A: We see a 3D universe with help of photons.
The "gauge nature" of all particles is an incredible stretch which does not work itself at all. Higgs "mechanism" is a patch of this stretch and mass of Higgs needs another "mechanism" to be explained. 
I think starting from phenomenological masses is the only healthy physical way of giving masses to all particles and bodies. Some masses can be calculated from others then.
