Hi, Buzsaw.
Buxsaw writes:
Ok, but it says the 3D world is not perceived via the eye but inferred by the brain.
I wasn't talking about the 3D world, Buzz: I was talking about the 3D retina.
Take a piece of paper with some writing on it. The surface of that paper, and all the letters on it, are only 2-dimensional. Pay particular attention to the lower-case letter "l".
Now, curl your paper into a C-shape in your hand and look at all the little l's again. Do they still look like l's, or have they all been bent into C's because of the curvature of the paper?
Of course they still look like little l's, because you only read l's in two dimensions: the third dimension isn't taken into account for the shapes of letters (did you ever see the movie
Contact?---the aliens in that movie had 3D writing that the scientists couldn't figure out because they were trying to interpret it in 2D).
In the same way, we only define "straight lines" in three dimensions: the fourth dimension isn't considered. It's only confusing because, in my paper example, you can actually
see the third dimension, but, in the "unbent curved bar space" example, you can't see the fourth dimension in which the curvature happens, so you think it's completely bogus.
-Bluejay
Darwin loves you.