Since its inception, human beings have been constantly exploring the world. In the ancient times when the productive forces were backward, the purpose of people's exploration was mainly for better survival, and in the modern era when the productive forces were relatively developed, what promoted human beings to continue to explore was the strong curiosity about the unknown.
According to scientists, the space we live in at this moment is not as simple as it seems, because it may have eleven dimensions.
Usually, we think that the space we are currently in is a three-dimensional space, and if we count the time dimension mentioned in relativity, then we are actually living in four-dimensional space-time. In addition to this, we can completely describe the situation in other dimensional spaces as "knowing nothing".
You may say no, we are also familiar with one-dimensional space and two-dimensional space. But you may not have thought about the question, if one-dimensional and two-dimensional spaces are real, what will they look like inside?
So what you think of as "familiar" is actually just familiarity with their appearance, or our definition of them, not really familiar with their internal details.
Imagine if M Theory is true and the universe really exists in two-dimensional space, what will the two-dimensional creatures living there look like?
The first thing we can be sure of is that if two-dimensional creatures also have organs such as eyes, they should grow on both sides of the body, because if their eyes are as long as humans on the front, then they will never see each other, after all, the two-dimensional world is only up and down, left and right, not front and back.
What can they see in their eyes? According to the concept of the two-dimensional world, we can easily know that the world is just a line segment, curve or arc in their eyes, because their world has no "thickness" (sense of space before and after).
Just imagine, if a two-dimensional creature that originally lived in two-dimensional space suddenly came to our three-dimensional space, would the world seen in the eyes of this two-dimensional creature be the same as the world we saw in our eyes? The answer is: not the same.
Because their body composition dictates that they will only have a two-dimensional perspective, even if they are placed in a three-dimensional world with a concept of "front and back", the world they see is still a line segment, curve or arc.
If they are allowed to move back and forth along something, then the world in their eyes must be constantly changing shape and size, and they may even wonder why the three-dimensional world is so "unstable".
If we can communicate with them, they may not understand even if they are told the definition of the three-dimensional world, just like a child who has never even seen a small water wow, no matter how you describe the vastness of the sea, he will not understand at all.
In order for this two-dimensional creature to understand the basic concepts of a three-dimensional world, we unfolded a cube, so that 6 squares appeared in the world of this two-dimensional creature.
Since there is no concept of space, two-dimensional creatures cannot see 6 cubes at once, and we need to take it to "walk" through the six square rows. After walking it came to the conclusion that the three-dimensional world is made up of six squares. Obviously, its perception of the three-dimensional world is completely wrong.
The two-dimensional creature that had visited the three-dimensional world eventually returned to its own world, combining what it had seen and felt before, and it eventually became the first scientist in the two-dimensional world to explore three-dimensional space.
When two-dimensional space has curved folds in some cases, scientists in two-dimensional space have proposed the concept of gravity and have a preliminary understanding of "fields".
Although they have never personally experienced three-dimensional space, they can always infer the real situation and characteristics of three-dimensional space through some strange phenomena that appear from time to time. They believe that every creature in the three-dimensional world has extraordinary powers and can easily change the structure of the world.
So they are all looking forward to one day being able to experience the strangeness of three-dimensional space. But they certainly can't imagine that even if they do enter the three-dimensional space, due to the structure of the body, they will not be able to see the real three-dimensional world at all.
After looking at the possible thinking patterns of a two-dimensional creature and the world we see in our eyes, we may wish to think about what the four-dimensional space is like, and if there are living things there, what kind of existence they are.
We all know that 6 two-dimensional square patterns can be combined into a three-dimensional space cube, so can the 8 three-dimensional space cubes form a four-dimensional body in four-dimensional space?
Imagine if there were a four-dimensional house with a total of 8 rooms (corresponding to 8 cubes). When you walk into any room, you will find that the other seven rooms are connected to this room, and the indescribable sense of upside-down confusion will definitely make you have a deep fear of the four-dimensional space.
As mentioned earlier, when a two-dimensional creature goes to a three-dimensional space, it may feel that the whole world is chaotic, various lines are intertwined, and the picture in front of it is suddenly large and small, far and near, and it seems to be changing at will without stopping.
And when we enter the four-dimensional world, will we feel the same as two-dimensional creatures? Is it possible that, like two-dimensional beings, they are limited by the dimensions of consciousness and body, so that they cannot truly understand and feel the four-dimensional space? I think the answer should be yes.
Perhaps when we really reach the four-dimensional space, the things that are constantly changing are the four-dimensional creatures that we can never understand and glimpse its full picture.