[Intralexical]

I think the idea is that the geometry of straight lines in 4D should be similar enough to picture using the same mental abilities.

How we see is frozen by not only physics, but also biology. We can't actually see in 3D, only in the 2D of our retinae (and the embedded 2D of light-exposed surfaces). That's true for both 3D and 4D objects. I suppose fish, with their electroreceptive abilities, might be the only animals that can sorta "see" in true, volumetric 3D.

[search_facility]

biology plays the role, certainly, but nature was trying to capture a model for 3D physical interactions first of all, physics first. And final choice of two 2D sensors is explicitly optimal and minimally effective for 3D - so it can not be similarly descriptive for 4D, just not fair to expect results on same level imho.

For meaningful 4D perception on similar level our body need three volumetric sensors, separated, to define volume with 4D direction