Secret wrote:This works only if there is actually a macroscopic 4th spatial dimension in reality [...]
Not necessarily. You can use a simulated 4D environment. I've actually heard of an experiment with 4D simulators where it was found that people gradually adapted to moving around and manipulating 4D objects. However, I've never been able to actually find the actual details of the experiment -- how they represented 4D, for example, and how the test subjects were supposed to interact with the simulated environment. From what I remember, it was an immersive virtual-reality sort of thing, so I assume you'd wear some equipment over your head with motion sensors on your limbs. But how they translated this to 4D is unknown to me.