Icon wrote:batmanmg wrote:the only reason we can't point to the fourth dimension is that our bodies cannot produce a force in the fourth dimension becuase no part of our body exists in the fourth dimension...

also becuase you cant face in that direction so the photons cant hit your eyes.

Now, this is actually a very interesting area of speculation...

Imagine a 2D being, say in a roughly hexagonal shape, moving around on the plane. Suppose that this plane actually resides on a table of a 3D being, although the hexagon has no way of directly knowing this. Now, light in the 3D room actually

would reach the hexagon: in fact, at every point of its body, both inside and outside. Of course, it doesn't know the real nature of this "background radiation", which appears simply as an inherent property of 2D space.

Now, suppose that one day this 2D being somehow guesses at what is really going on. How would it detect 3D light? It could build a 2D array of cells that are stimulated by this external source, and wire them in such a way that a 3D image could be captured (i.e., 2D projections of objects in 3D space). From the hexagon's point of view, the array of cells cannot possibly capture any image, at least, not any light within the 2D world itself. The only way light can reach cells surrounded by other cells is if it came from outside the 2D plane.

So, in a way,

if a 4D world really exists out there, and

if our 3D space were actually an open surface in 4D space, then theoretically it is possible to build a 3D block of detectors, which, if they can somehow be made sensitive to 4D light, could capture 4D images (i.e., 3D projections of objects in 4D space). Of course, we would have no way to directly manipulate any 4D objects seen in this way, and only a very limited way of orienting the "camera", so this would be a completely passive vision. But still, it is certainly possible, at least in theory.

Of course, all bets are off as to whether our 3D space is really an open space lying on a 4D surface somewhere... it may be that, if 4D space exists at all, we may simply be "sandwiched" between two solid 4D layers (which explains why we only ever perceive 3 macroscopic dimensions), and thus have no way to look very far into 4D space (and there is nothing interesting to look at either, just a blank wall on either side that we can't see through).