I have always more or less been on a quest to understand the Universe. I decided to start with understanding the more fundamental aspects of the Universe and then build on that understanding to understand more complicated things. But the question came up as to what was the most fundamental thing in the Universe. Elementary Particle Physics seemed to be a good place to start. What could be more fundamental than Electrons, Protons, and Neutrons? Well you quickly find out that Elementary Particles are just made out of Energy. So Energy seemed to be the thing to start with. Eventually I learned that Energy can arise out of Space itself. So what does this mean about our concept of Space? It would seem that Energy might be made out of Space. So then the regression back to find the most fundamental thing ended up with trying to understanding Space, which of course is Nothing. How do you study Nothing?
Eventually I realized that Space was not really Nothing it was Something. Since Space is Something it could exist or not exist. The common notion that Space is an ever existent background Thing that extends out infinitely in three directions could be wrong. There could be different kinds of Spaces besides our 3D Space. There could be a 4D Space. There could be no Space. The possibility of no Space is almost impossible to grasp by the 3D human brain.
I thought that if I could show that 4D Space is a workable reality for a Universe , then I would be able to convince myself that Space is a Thing just as Energy and Matter are Things. The concept of Nothing then becomes a concept of Absolute Nothing where there is no Matter, Energy, or Space.
To understand 4D Space I thought I should try to experience what it would be like to be a 4D Conscious being living in and moving around in a 4D World. See Exploring the 4th Dimension Using Animations. I generated many Animations to help me do this. I think the Animations were helpful but I still feel that I am unable to exactly experience a 4D World in the same way an actual 4D being would. The key thing that we must do is understand how a 4D being can see a 3D Hyperplane as a Flat object. Anything else you think you know is irrelevant until you understand that.
But even though I was not able to experience 4D in the way I had hoped I believe that the Animations have shown me that a 4D World is possible and therefore that our 3D Space is only one type of Space. There can be No Space if there can be 3D Space or 4D Space.
The one thing I learned from the Animations is that the reason I don't understand 4D Space is because I am too embedded in this 3D Universe. I can think about 4D Space in theory and use all the different techniques for visualizing it but my 3D brain will never let me fully understand it. I do not think anyone can. We would need a 4D Brain to do this.
To be able to see in our 3D World we have a Visual Cortex that is roughly a flat (but folded) 2D patch of a little more than 1 billion Neurons. If it were a square patch it would be about 32000 Neurons on each side. A 2D being would only need a line of these Neurons or 32000 of them. The whole 2D Brain Neuron count would be scaled down by a factor of 32000. A 2D Brain would be 32000 times less intelligent than a 3D Brain. A 4D Visual Cortex by analogy would have to be a cube of Neurons with 32000 Neurons on all sides. It would be a 3D Hyper Plane so the 4D being would view it as flat. A 4D being's Visual Cortex would have 32000 times more Neurons than a 3D being's Visual Cortex. The 4D Brain Neuron count would be scaled up by a factor of 32000 and a 4D being will probably be 32000 times more intelligent than we are.
So the conclusion we have to come to is that we, and I mean all of us 3D beings, can never know what it would be like to actually be a 4D being. We are just not smart enough. You might think you understand 4D using one of the techniques but you never really get there. You need to be able to see our 3D Space as being Flat. I think this is an important realization for Philosophy and the study of the limits of our ability to understand things.