Hogwarts and the Unspeakable

"The method we use is projection."

Dragonborn said.

What is projection?

As an optical term, "projection" means using a set of light rays to project the shape of an object onto a plane, which is called "projection".

As a database term, "projection" means selecting a number of attribute columns from a specific "relationship" to form a new relationship.

As a mathematical term, "projection" means that the shadow of a figure is cast on a surface or a line.

When we look at the three-dimensional paintings on the blackboard or short videos, we can perceive that the thing in front of us is a cube, cuboid, cylinder, or cone. Especially when doing solid geometry questions, you need to often come into contact with "three-dimensional figures", those cuboids and rectangles that are full of solid and dotted lines that you don't know what they mean, but you can clearly understand. However, are the "three-dimensional graphics" we see on the blackboard and on our mobile phones real visible and tangible objects?

No.

Although we can use our imagination to assume the length, width and height of this "three-dimensional figure", assuming that it really exists.

However, this is actually just a picture.

In fact, "three-dimensional graphics" are just one side of a three-dimensional figure. In addition to the oblique upper views commonly seen in exercises, there are also front views, side views, top views, etc.

"Three-dimensional figures" are nothing but an illusion.

In fact, this is just a flat graphic, presented by hand drawing, printing, or computer vision.

It is just drawn on a piece of paper or presented on a screen to confuse us and make us think that it is a "three-dimensional object".

But, in fact, it is just a piece of paper.

----

Going further,

Can we see the front and back of an object at the same time just with the naked eye?

If you twist the object, say by folding a piece of paper in half, you can see both the front and back sides.

In other words, we tear open a paper bag, twist it in a circle, and then glue it on again. In this way, we make a Möbius strip.

However, even in a Möbius strip or other objects, there are actually corners that cannot be seen.

Because the principle of human vision is to receive reflected light through the retina, convert the light signal into an electrical signal through rod cells and cone cells, and finally transmit it back to the human brain through the nervous system.

When using only the naked eye, light reflection can only be seen from the front.

Therefore, the various objects we see in our daily lives are nothing more than "projections" obtained by our vision.

Through visual sensation, we obtain intuitive understanding, and then through multiple visual sensations and multiple observations of the same object, we obtain visual understanding of the front, back, and sides of a book. Later, it is through the processing of the brain that we gain an overall understanding of a book, which is called "perception" in general psychology.

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It is precisely because of having consciousness,

Only when we see only one side of the wooden table can we judge that it is most likely a wooden table.

We can tell that there is a high probability that this person is a woman just by seeing the braid, twin tails, or the back of the round head.

When you see a made bed, you can see that there are probably many quilts hidden under the ground - it makes it comfortable to lie down.

When I see short sleeves, I immediately think of white arms, immediately think of the human body, and immediately think of the banned content. This is a reflection of the constancy of perception.

In this way, “you can get a glimpse of something and know the whole picture.”

Therefore, just by seeing a bunch of combinations of solid and dotted lines, we can infer that this is a cube.

You can infer the shape of the object just by looking at the top and side views.

----

For this reason, we can not only understand objects through "projection", but also construct "projections" on objects to facilitate understanding.

This is just like how humans figured out integrals after having differential calculus.

"The concept of four-dimensional space-time is often difficult to understand." (This sentence was added by Dragonborn)

Yes.

Our world can only intuitively feel length, width and height.

As humans, we do not have the organs to sense the fourth dimension.

Exhausting all our wisdom, we can only blind men touch the elephant, blow each other's breath, look at the constellations in the sky, and make up one story after another that will later seem absurd.

It is simply impossible to imagine what four-dimensional space-time looks like.

What would a sphere look like in a four-dimensional world?

Allen doesn't know, and neither do we. The Dragonborn may not know either. The Dragonborn may know, but we dare not ask.

If you ask Allen to imagine a mysterious castle, a noble demeanor, and a boring but stylish concert, then Allen is very good at it.

If he were asked to imagine a mysterious world, such as Tang San traveling to Dou Po Cang Qiong, then maybe Allen could imagine it too.

----

Maybe you have seen "paper-cutting", "shadow puppet" and "hand shadow".

Shining light on your fingers, the light passes through the gaps between your fingers, and the rest becomes darkness blocked by your fingers. Black and white are clear, and this is where the story begins.

If there are "two-dimensional" creatures in the world, would they be very surprised when they see the shadows of "rabbits" and "butterflies" we project on the wall?

How do creatures in the two-dimensional world understand us in the three-dimensional world?

The two-dimensional plane Cartesian coordinate system only has length and width, and the same is true for two-dimensional space.

In a three-dimensional coordinate system, length, width, and height exist at the same time. The same is true for the three-dimensional world we live in.

Through the "projection" we mentioned before, items in the three-dimensional world can only leave images of length and width in the two-dimensional world.

----

Based on the inference made by the Dragonborn before.

According to the "Third Law of Cosmology", there is a function or mapping relationship between the times of various worlds.

In most cases, it adopts a functional relationship, that is, there is a one-to-one correspondence.

Every second of the basic world is connected to every second of the other worlds.

Its gears fit perfectly, and once there is an error, it will immediately create a huge amount of entropy, which will lead to the arrival of the Chaos Devourer - and ultimately destruction.

However, at the "bottom level of the world", this is the area where Allen, Dragonborn, and Mora will fight.

The time of the basic world does not have a functional relationship with the time of this world, but a mapping relationship.

The time at the "lowest level of the world" is actually a minimum value and a maximum value at the same time.

He is said to be a "minimum" because he does not correspond to every second of the outside world.

It is said that it is the maximum value because it corresponds to all time in the outside world.

If we say that in four-dimensional space-time, there is a fourth variable other than x, y, z (length, width, height), that is, t (time).

Then, the time function is a higher-level variable similar to a "straight line" or "plane" at t=x (x is any number), that is, an "object".

This "object" corresponds to all x, y, z values ​​of the outside world.

----

It is precisely for this reason that Dragonborn decided to use the "projection" method.

Connect this world to the "base world".

However, the time system is tightly coupled (according to the third law), which creates extremely large amounts of entropy.

Therefore, Dragonborn's method is to project a certain nearby uncertain area.

Let all four dimensions (corresponding to the time of all three dimensions of space) in the area collapse (project) to a specific time.

Let the three-dimensional creature enter this "projection" area, and then "upsize" it.

This is the Dragonborn's plan.

----

What Allen is going through now,

It is the infinite collapse within infinite time,

The entire infinite amount of time will collapse to one second in the space where they are.

In this way, the space-time coordinates can be obtained, calculated, transmitted, and displaced.

Because of this, he experienced extremely terrible dizziness.