What does the world "really" look like?

This question is about the visual cortex, human optics and the "actual" state of our world. I recently graduated with my BFA and I understand optics and light refraction, and lenses and how cameras work. I also understand how our eyes interpret the world similarly to how a camera interprets the frame. What I don't understand is how everything is really "upside down."

"images formed on the retina are up-side-down" according to my understanding of human optics. Certain studies show the brain can be tricked to seeing things up-side-down or right-side-up after some "training" and apparently the "Corpus Collosum" is the thing doing the "flipping."

Here's where I get lost: The physical and literal manifestation of this phenomenon essentially means: err..
we walk on the ceiling, the ocean is above and the sky is below, everything we think we understand is exactly backwards from the way our brains interpret it? can an educated person tell me the true orientation of the tangible world?

now THAT'S a great question! i've always thought of the text books that show the eye and how intitially, the image is seen upside down in the eye. but then the image, from two points in the eye angled towards each other, flips after the intersection of the two points. it could be said that the world is, indeed, upside down and we've trained our brains into thinking the opposite. but could it also be said that this is another complex example of the human body's amazing ability to utilize as much as possible to get the best desired effect? maybe by creating the image in our heads as upsidedown first, we're also creating a whole other level of sight, depth perception, and peripheral vision that otherwise wouldn't be achieved with the image coming right side up?

No. The image is only upside down at one stage in cognition. It's like if you read a book that was once held upside down. That it passed through a stage in which is was upside down doesn't mean anything later on.

We do not walk on the ceiling because we call the surface we walk on the "floor" and we call the surface opposite that the "ceiling".

look, all i know is that the world is round. leave it at that. im not stupid, and i get what your saying, but if you really wanna know the true oreintation of the earth, you'll be waiting a long time, so instead, live off this one, simple sentence and be done with it. THE WORLD IS ROUND!

Wow! This was really informative. You have some really interesting questions. Im still in grade school so i couldnt answer your question, but i sure learned a lot.

"Down" and "up" are learned concepts; "down" means "in the direction of gravity", and "up" the opposite. The brain cannot detect gravity, so it has no way of knowing whether the signals it is getting from the retina are upside-down or not.
In our early years we learn that signals from this part of the retina are from things that are above our eye level and signals from that part of the retina are from things that are below. If you fitted a baby with inverting glasses and he had to wear them all his life, he would learn to perceive the world just the same as a normally sighted person, and would not even be aware that the images he was seeing were inverted (or non-inverted!).