At the moment, I don’t think we’ve got a very good physical intuition for functors — just something which is completely and utterly abstracted away from the physical universe.
* Do functors have focal depth?
* Are there things which are not quite categories in which a functor could be diffracted?
* Think about imaging technologies: MRI, cat scans — anything which we use to construct visual representations of things might have a functorial analogue. Functorial holography? (and no, I don’t mean this: “holographic principle of higher category theory”
* Just how many of these w: optical phenomena have functorial analogues?